text and drawings by Picard578
3D designs by Riley Amos
Modern air forces are getting loaded with highly complex, expensive “mutirole” aircraft. Result is decreasing force size for same or increasing cost, while at the same time combat effectiveness of these air forces decreases. Main reasons are lack of understanding of components of fighter aircraft effectiveness, inability to enforce design discipline upon service and industry, and infatuation with new (and old) technologies without understanding wether, and why, certain technologies work or do not work.
Nature of air to air combat
“Those who cannot remember the past are condemned to repeat it.”
Fighter aircraft exist to destroy other aircraft, and allow other aircraft to carry out their missions without interference from enemy fighter aircraft. That being said, there exists a colloqial – and incorrect – use of term “fighter aircraft” as being applicable to any tactical aircraft, even those that are primarly or exclusively designed for ground attack, such as the A-10 and the F-35. Task of the aircraft is to enable pilot to bring weapons systems in position for a successful kill.
You never make a big truck and tomorrow make it a race car. And you never can make a big bomber and the next day a . . . fighter. The physical law means that you need another airplane. . . . You should do one job and should do this job good.
—Colonel Erich “Bubi” Hartmann, GAP
Most important factor in aerial warfare is pilots’ skill. In every war, 10% of the best pilots skore 60%-80% of the kills. In the 1939 invasion of Poland, few Polish pilots became aces in 225 mph open cockpit fighters while fighting against 375 mph Me-109s. During 1940 Battle of France, French and British did poorly in aerial combat despite having fighters that were technologically comparable to German counterparts – main difference was one of tactics and training. Namely, while Luftwaffe was using finger-four formation (a flight of four fighters organized into two pairs that allowed leader-wingman and mutual formation cover, first adopted by Finland in 1934 and used by German pilots in Spain in 1938), RAF still used a three-ship “vic” formation optimized for bringing greatest firepower to bear on bombers; this formation however was based on gross exaggaration of bombers’ capability for self-defense, and did not take escort fighters into account. Once RAF adjusted tactics, loss rate improved. British fighters were still at disadvantage if they were caught during climb, which did happen despite usage of radar for early warning; this, combined with inferior training and small numbers which caused fatigue of few avaliable pilots caused Luftwaffe to have an advantage in aircraft losses. But 50% of RAF pilots were recovered safely while 100% of Luftwaffe pilots were lost (dead or captured), meaning that pilot attrition worked in RAF’s favor, and due to pilot attrition Luftwaffe eventually lost the Battle for Britain. Another British advantage was their preference for grass fields, which allowed several fighters to take off in a line-abreast formation.
When US fighters started escorting bombers, large twin-engined P-38 was the least successful and had to be withdrawn from role due to being too visible, too inferior in both transient performance (turn onset, roll onset, acceleration) and instantaneous turn rate, and having too low roll rate. Two engines were also a survivability handicap. P-51D had better cruise speed and dive acceleration than German fighters, as well as comparable turn and roll performance. P-47 was larger and slower, but had unparralelled dive and roll performance. It could not however escort bombers to their targets, unlike the P-51 and P-38, and was thus soon relegated to ground attack missions. In fact, effectiveness in air to air combat was inversely proportional to cost: best performer was $51.000 P-51, followed by $85.000 P-47. $97.000 P-38 was by far the worst performer, and had to be withdrawn from air superiority and bomber escort missions in European theatre in spring of 1944, only continuing in photo reconnaissance missions. Its main disadvantages were slow cruise speed (275 mph vs 362 mph for P-51 and 365 mph for Bf-109 G-6), large size and sluggish transient performance as well as slow maximum combat speed (Mach 0,68 compared to Mach 0,75 for Bf-109 and FW-190). Two engines were a survivability handicap – if either was hit, aircraft was likely to be lost. In Pacific theatre it performed well, primarly due to superior training of US pilots by that stage of the war and its faster cruise speed when compared to Japanese Zero – 100 mph advantage over the Zero allowed it to achieve surprise bounces while avoiding a maneuvering engagement.
In the end, large Allied numerical superiority won the air war; Germans were loosing pilots faster than they could replace them (aircraft were being replaced at an adequate rate). Near the end of the war, they introduced the Me-262; a heavily armed aircraft designed around the most advanced technology avaliable, it was called “the most formidable fighter” that the world has seen to date. Its high cruise speed made it hard for enemy pilots to attack it once it was in the air, and allowed it to engage enemy fighters at will. But it changed little; US fighter pilots learned to catch them when taking off or landing, and tactics were developed that allowed propeller aircraft to counter it in the aerial combat. In the end, Me-262s shot down 150 Allied aircraft for a loss of 100 Me-262s in air combat, of which 75 were shot down by fighters.
Against heavy bombers, Germans used a variety of armament. Results show that each 30 mm shell was 6 times as lethal as each 20 mm shell, but lower muzzle velocity meant that fire had to be opened from the closer range. Me-262s, whose primary task was attacking bombers, also operated in an old vic formation instead of a finger-four. Results also show how fundamentally wrong assumptions made by the USAAF bureocracy during peacetime were (a pattern that will repeat itself in every single war US fought after the WWII): USAAF assumed that head-on attacks on the bombers are impossible due to bombers’ speed advantage; tail armament can and must equal fighter’s firepower; manually-aimed turreted guns are more effective than fixed fighter’s armament. Yet by the 1943, bombers were slower, lower-flying and less heavily armed than fighters. Frontal attacks were commonplace, and flexible guns were 10 times less effective than fighter’s fixed armament. To quote RAND briefing: “It is easy for even large groups of smart people to get important assumptions wrong.”. Before escort fighters became avaliable, strategic bomber losses were between 10% and 70% per sortie.
In the night combat, which consisted entirely of stalking enemy bombers, main airframe characteristics required were good endurance and better sustainable speed than the target. There, twin-engined fighters proved useful even before the radar was installed on any of them. Luftwaffe had 350 night fighters by early 1943; despite none of them having a radar, they exacted sustained losses of 3-5% from night raids. First radars were installed on Luftwaffe fighters in early summer 1943, but at the same time twin-engined night fighters were augmented by several wings of radarless single-engined fighters. Combined with introduction of broadcast control, these measures increased RAF night bomber losses to 6,6% during the February 1944 “Big Week”, while USAFs daytime bomber losses were 6% during the same period.
Night combat actually followed same principles as day combat: surprise was primary factor, and IFF could only be established visually. Further, only single-mission specially trained pilots could be used effectively. World War II was also the first and the last time that significant night combat occured.
In Pacific, same principles applied. As Japanese (unlike US) could not replace pilots when they were inevitably lost, United States were eventually able to achieve superiority in both quality and quantity of pilots.
Tracer ammunition was sometimes used to help in targeting, but it often gave pilot away if first firing attempt was not successful, so many pilots had tracers removed from ammunition mix. Further, tracer trajectory alwas varies slightly from actual projectile trajectory, which can be misleading at the long range.
Another lesson from World War II concerns ground attack aircraft, but is relevant for fighters too. P-47 had very low lethality against German tanks, yet Germans considered it the best anti-tank weapon employed on the Western front. Reason was that the P-47 flew so many sorties that any movement by German Panzer forces guaranteed that the same will be attacked, just as any sortie by the Me-262s guaranteed that they will be attacked by superior numbers of Allied turboprops.
In the first two weeks of the Korean War, USAF F-80s have obliterated opposition consisting of slow, poorly piloted propeller Yaks. In November 1950, a flight of four F-80s encountered seven Russian-piloted MiG-15s and fought it to a draw. MiG-15s advantages in cruise speed, climb and acceleration meant that F-80s were outclassed, and first F-86s began appearing in December.
F-86s typically used fuel tanks to extend endurance to 80-100 minutes, allowing them to patrol the MiG valley for 45-50 minutes. Unlike MiGs, they were never under close control and all acquisitions were visual, giving them a substantial advantage, especially since F-86s tended to fly in numerous small formations as opposed to very large formations used by North Korean pilots. In direct comparision, MiG-15 had slightly better rate of climb, acceleration and level flight speed, while F-86 had better speed in a dive and far superior transient performance (roll and pitch rates in particular) thanks to its hydraulic controls. While MiG-15 had an edge in maximum turn rate, tendency to spin at high angles of attack meant that this superiority was rarely to never used.
On average, F-86 achieved 0,34 kills per pass when lead computing gunsight wasn’t used and 0,30 kills per pass when it was used. At 20.000 feet, average of 0,51 kills per pass was achieved, dropping to 0,27 at 39.000 feet.
Exchange ratio favored multiple smaller, independent formations over a single large formation. Further, as total number of aircraft in the air increased, kill/loss ratio went towards the parity. Majority of fighters were also shot down unaware. But it was pilot performance that made the difference: US fighter pilots were far more skilled than their Chinese counterparts, with only few Russian pilots flying in Chinese formations showing similar level of skill and generally being able to match US fighters. While exchange ratio between US Sabres and Chinese MiGs might have been as high as 10 MiG losses for each F-86 loss, exchange ratio between Sabres and Soviet MiGs was around 1,3 MiG losses for each F-86 loss.
With advent of supersonic fighters and missiles, dogfight was declared officially obsolete. In fact, that argument was made even earlier than that – as soon as the F-86 got equipped with Sidewinder, maneuvering combat was declared a thing of the past. Development of the AIM-7 itself started in 1946, and both military and contractors claimed 80% to 90% kill rates for it and other radar-guided BVR missiles. As a result, the F-4 didn’t even have a gun, and neither it nor F-104 or F-105 had adequate maneuvering capability. Cockpit visibility was also very bad, essentially nonexistent to the rear, due to technological promise of BVR combat and tail-warning radar. But missiles turned out to be underperforming – they malfunctioned 50% of the time, and engagements happened exclusively within visual range as there was no reliable way to identify aircraft beyond visual range. IR WVR missiles achieved Pk of 15%, compared to 11% for BVR IR missiles and 8% for BVR RF (radar guided) missiles.
In Vietnam, F-4s large size and the fact that it was the only aircraft in the theatre that smoked allowed NVAF pilots to fire their IR missiles from the edge of the missile’s effective range, thus achieving advantage in the effective engagement range over the F-4 despite latter’s large and complex radar and BVR missiles. F-4 pilots had trouble detecting the enemy due to bad situational awareness resulting from bad cockpit visibility. Only advantages that the F-4 had over the MiG-21 were acceleration, rate of climb and persistence, primarly due to MiG-21s inferior engine. Still, necessity of visual-range combat led to midifications to improve F-4s dogfighting capability – primarly installing a gun and wing slats. Still, MiG-21 scored 2:1 against US fighters in Vietnam, with MiG-17 doing less well but still achieving favorable exchange ratio. Despite the presence of supersonic aircraft, combat happened at Mach 0,5-0,9. One of reasons was that cruise speed for all fighters was no greater than Mach 0,9, but also that pilots tend to fly aircraft to maximize the turn rate, for which lower speeds are required.
In 1966 Fairwind IV exercise, USN Phantom IVs faced old-model French fighters. At the very beginning, French airmen decimated US fighters while carrier was in process of recovering its fighters. As exercise progressed, it became clear that US aircrews were outclassed by French colleagues. This was especially problematic as exercise established requirement for VID to prevent the fratricide – and unlike US, French never stopped training for dogfight. Despite flying far older and “inferior” fighters, they always outperformed the US pilots. F-4 pilot Lieutenant Junior Grade John Monroe “Hawk” Smith quipped “We just had our collective asses handed to us by a second-rate military flying club flying a bunch of cheap, little airplanes by pilots who didn’t even hold down an honest sixteen hour-a-day job. We looked like a bunch of buffoons…”.
Israeli pilots in 1967 and 1973 wars preferred visual-range Mirage III to F-4, referring to the latter as B-4, due to Mirage’s smaller size and better agility. Other than that, few lessons can be drawn from these wars due to the fact that Israelis have fought Arabs – after 1973 Israeli 80-1 victory, General Mordecai Hod remarked that the result would have been the same had both sides exchanged the weapons. For the same reason, both Gulf wars are useless for drawing any but most general of lessons. That being said, there is one useful lesson: when the 1973 war is compared to the Vietnam war, it clearly shows impact of training on missile Pk. While US fighters achieved radar missile Pk of 10,9% (276 shots / 30 kills) against NVAF fighters in a 1971-1973 period, in the 1973 Yom Kippur war, Israeli fighters achieved radar missile Pk of 41,7%, far closer to the 1991 Gulf War. This shows that opponent’s competence was a primary factor in missile performance. As a matter of fact, there was very little if any technological disparity between two sides in the Yom Kippur war, with Israel using F-4 Phantom jets against Arab MiG-21s and MiG-25s. In the Bekaa Valley war, Israeli Air Force outnumbered the Syrians 3:2.
In the 1971 Indo-Pakistani war, Pakistani F-86s achieved 6:1 exchange ratio against supersonic MiG-21s and Sn-7s and subsonic Hunters; only Gnat achieved exchange ratio advantage over the F-86, due to its smaller size and better acceleration. It should be noted that, in reality, majority of “supersonic” fighters are actually subsonic as they do not have useful supersonic endurance. Main reson for F-86s performance was superior training of Pakistani pilots.
In the Vietnam, Yom Kippur and Bekaa Valley wars, 632 radar-guided BVR missiles were fired for a total of 73 kills. Out of all BVR missiles fired, only 4 out of 61 BVR shots were successful. During the Cold War, radar-guided Sparrow missile has achieved Pk of 8% in visual-range shots and 4% in beyond-visual-range shots; this performance can be expected to continue against the competent opponent.
Between the 1975 and 1980, US Navy Fighter Weapons School (Topgun) instructors flying cheap F-5s consistently whipped students flying “more capable” – and definetly far more expensive – F-4s, F-14s and F-15s. In the 1977 AIMVAL/ACEVAL test, F-15 achieved 3,8 to 1 exchange ratio against the F-5 in one-on-one combat, but in 4 vs 4 combat exchange ratio was around 1 to 1. Another lesson was that the incremental hardware advantages tended to wash out as the opponents adapted, and human interactions were at least five times more influental on outcomes than test variables such as force ratio and initial conditions.
In the 1981, AMRAAM OUE (Operational Utility Evaluations) were conducted. Participants from operational squadrons conducted 1.200 engagements with 10.000 simulator sorties. Blue force had the BVR capability while Red force didn’t; yet it was situational awareness that had the most impact on outcome of the engagement as opposed to the hardware. It should be noted that pilot skill is the dominant factor in situational awareness as well as in all other factors, as clearly shown in AIMVAL/ACEVAL test as well as actual air combat through history.
In the 1982 Falklands war, British Harriers equipped with the AIM-9L achieved 19 kills in 26 launches, for a Pk of 73%. However, Argentine aircraft were fighting at the end of their operational range and so typically did not have enough fuel to attempt significant evasive maneuvering. Additionaly, they had bad rearward visibility, low cruise speed due to heavy external stores (majority if not all were heavily laden with bombs) and undertrained pilots. As a result, Harrier pilots were able to regularly execute a rear-quadrant attacks against unaware, and consequently non-maneuvering, targets. While Argentine aircraft were equipped with radar-guided Matra missiles, these did not shoot down any British aircraft; both lack of training inherent unreliability of radar-guided missiles were factors in disappointing performance of these missiles.
In both Gulf Wars (1991 and 2003), single-role aircraft have performed far better than multirole ones. Aircraft performance was independent of cost: expensive F-15 and cheap A-10 were the best performers in their respective roles, and was probably a result of optimization for one type of battle as well as pilot training. There were no gun kills for the first time in the history, but gun did provide a psychological factor of having a fallback option if missiles were expended. Also, despite Iraqi fighters having no ECM and typically failling to take the evasive action when being shot at, radar-guided missiles achieved Pk of 27,3% in the 1991 Gulf War. This was exclusively a result of malfunction in missile or fire control system; as it can be seen, missiles’ technological reliability has not improved at all since days of the Vietnam war. Yet there were only 5 confirmed BVR kills in the First Gulf War, despite radar-guided missiles accounting for 24 kills out of 85. Further, air-to-air-only F-15Cs performed far better than average, achieving radar-guided missile Pk of 34% (67 shots for 23 kills) and IR missile Pk of 67% (12 shots for 8 kills), confirming the overwhelming importance of training in weapons’ performance. For comparision, US Navy’s F-14s and F-18s achieved radar-guided missile Pk of 4,8% (21 shots for 1 kill) and IR missile Pk of 5,3% (38 shots for 2 kills), yet no-one uses that performance as a ballpark for future missiles’ performance, indicating a willful misinterpretation (and misrepresentation) of data.
Survivability-wise, radar stealth proved to be a non-factor: F-117s flew exclusively at night while achieving 0% loss rate. Two A-10 squadrons that also flew exclusively at night suffered no losses, just like the F-117s. There is also an anecdotal evidence that Iraqi ground radars detected the F-117s. In the later Kosovo war, F-117s suffered two losses. If 1991 Gulf War and 1999 Kosovo War are combined, A-10 suffered 4 losses in 12.400 sorties (1 loss per 3.100 sorties) and F-117 suffered 2 losses in 2.600 sorties (1 loss per 1.300 sorties). 1 F-117 and 1 A-10 loss were not shootdowns but unrepairable mission kills. Altitude was also an important factor: as in World War II, kill zone was between 30 and 30.000 feet; F-117s never flew inside it, while A-10s had to make frequent excursions through it in order to use their gun in Close Air Support. In the 2003 Gulf war, only 1 A-10 was lost.
Despite the IFF, NCTR and AWACS, misidentified allied aircraft were lost to US systems as recently as 2003 Operation Iraqi Freedom.
In the end, as has always happened, new technological advances will add new possibilities, but will never negate the need for old-fashioned dogfight, and human factors – both one’s own and opponent’s skill, or lack thereof – still trump technology. Before the Desert Storm, Iraq never flew more than 240 sorties per day, typically far less than 200 sorties. Iraqi training lacked realism in either air-to-air or air-to-ground mode, and it rarely even attempted realistic force-on-force training. Coalition flew 2.100 combat sorties per day compared to Iraq’s 60 combat sorties per day; a 35:1 advantage. Iraq flew only 430 combat sorties in total, compared to Coalition’s 69.100 sorties, a 160:1 advantage for Coalition, as Iraq air force stopped flying alltogether some time into the war. This did not help, however, as Coalition flew 2.990 strikes against Iraqi aircraft shelters.
To quote USAF analysis of Iraq’s performance:
“…the overall performance of the Iraqi air force in Desert Storm in air-to-air combat was abysmal…Although Iraqi pilots sometimes started encounters with decent set ups, the consistent and overriding pattern evident in debriefs of kills by US F-15 pilots indicates a startling lack of situational awareness by their Iraqi adversaries. In general, the Iraqi pilots shot down did not react to radar lock-ons by Coalition fighters. They attempted very little maneuvering, either offensive or defensive, between the time when the intercept radar locked on to them and the time when they were hit by air-to-air missiles (or, …before running into the ground).”
Later on, AIM-120 has achieved 6 BVR kills in 13 launches. However, one kill was a helicopter; as a result, 5 kills in 12 launches gives a Pk of 42%. As before, targets were unaware they were being shot at; they were all flying straight and level, and did not use electronic countermeasures. Serb fighters also had inoperative sensors. All fights also involved numerical parity or US numerical superiority. On one occasion when a target was aware it was being shot at, it successfuly evaded 3 AIM-120Cs despite having no ECM. This clearly shows value of careful examination of combat realities, as humans always have a tendency to overestimate impact of any new technology (for a non-military example, see Ha-Joon Chang: 23 Things They Don’t Tell You About Capitalism, 4th thing, for discussion of relative importance of dishwasher and Internet).
When DACT was held between AdlA Rafales and Greek F-16s, Greek pilots prepared beforehand while Rafale pilots came unprepared. As a result, Greeks dominated the exercise despite Rafale being an overall superior aircraft even in early versions.
Any new technology can be countered by appropriate tactics (which can then be countered by countertactics). In 1298, English used the longbow to break Scots at Falkirk, and to similar effects against French in 1346 at Crecy, 1356 at Poltiers and in 1415 at Agincourt. But unlike French, Scots learned their lesson and in 1314 at Bannockburn used cavalry to rout English archers before they deployed. Similarly, RAF in Iraq used obsolete biplanes to deny usage of air bases to modern German fighters deployed to help Arab rebels; Luftwaffe soon had to withdraw. Fact is that, while technology can add new dimensions to warfare, it cannot change nature of the war. Human competence – training, cohesion, adaptability – is always a decisive factor in weapons performance and typically outweights other considerations, such as numbers and technology. As such, no technology should be evaluated without adressing its impact on users. It is also wrong to use new technology to solve old problems (e.g. radar stealth, LPI radar) and ignore new tactical possibilities opened by usage of new technology (e.g. IRST).
Even when fighting inadequatly-trained low-tech opponent and consequently achieving high missile Pk, having a gun provides a pilot with comfort of having a fall-back option if missiles do not work, or if range is too low for missiles to be used effectively (typically
You can have computer sights or anything you like, but I think you have to go to the enemy on the shortest distance and knock him down from pointblank range. You’ll get him from in close. At long distance, it’s questionable.
—Colonel Erich “Bubi” Hartmann, GAF
Denying a gun firing solution can be achieved by accelerating out of the gun’s range. If that can’t be done, then the enemy has to be kept out of the tracking area, typically done by a hard turn and roll (jinking). If the enemy is using radar-based gun tracking, or even just range finding, its performance can be seriously degraded through usage of chaff or ECM, and radar guidance is useless in cluttered low-altitude anvironment. Releasing flares may also break attacker’s concentraton. If the attacker is at 6 o’clock with little closure and inferior roll and acceleration performance, a barrel roll can be an effective defense.
Avoiding a missile requires excellent instantaneous turn rate and transient (particularly roll) performance. Aerodynamically controlled missiles typically offer ther best turn performance at their highest speed since they typically operate well below their corner speed. TVC is typically used for short-range missiles, and is particularly effective at high altitude. A rule of thumb holds that missile needs at least five times the g capability of that of a target, but it can be far more than that depending on various factors – g load in turn is function of a square of speed, so to match the turn rate of a 9 g aircraft flying at Mach 0,79 (450 kts at 40.000 feet), a missile has to pull 130 g at Mach 3, or 230 g at Mach 4. Typical WVR missile can pull 40-60 g at Mach 3, while typical BVR missile can pull 30-40 g at Mach 4. If missile manages to follow despite that (usually due to relative position of a missile meaning that it does not have to correct much for target aircraft’s maneuver), a rapid 180* roll followed by a turn will usually produce a wide overshoot as not only will aircraft now be in a position to beat missile’s turn capability, but missile guidance correction will naturally lag behind target maneuvers. Evading a BVR missile is easier than WVR one not only due to turn performance, but also because higher launch altitude of BVR missiles means that a vapor trail is typically produced, making a visual acquisition easier. Best possibility of missile evasion is at corner speed.
Typical evasion maneuver consists of placing a missile at 3 or 9 o’clock and flying at high speed in order to cause a missile to pull a lead, and pulling a maximum amount of g once missile gets close in order to achieve better turn radius and force an overshoot.
Long range air to air missiles are typically guided through either command guidance, which is doable by either a radar, IRST or RWR since missile is ordinarily guided along the line of sight between the target and the launcher, meaning that no range information is required; beam guidance, where missile follows the center of the guidance beam; and preset guidance, where missile automatically flies to a calculated intercept point. Preset guidance is the least useful one since it is only useful if target does not change direction of flight during missile’s flight time. Command guidance as mentioned typically uses command-to-LOS technique, but having two or more platforms using either radar, IRST or RWR to accurately calculate position of the target in 3D can enable usage of lead-intercept missile trajectory. This however requires sufficiently fast datalink and computing process as well as accurate information on relative positions of both target and aircraft doing the targeting. Guidance instructions to the missile are typically transmitted through a radio data link, which is susceptible to jamming. Trailling wires are resistant to jamming, but are not used since they severely limit missile’s useful range. Beam guidance can be provided by radar or optical system but it requires missile to be maneuverable.
Most effective type of guidance is the homing guidance, which can be passive, semi-active or active. Passive homing relies on emissions from the radar itself (typically visual, IR or EM ones). Semi-active relies on the energy reflected off the target – typically radar or laser – provided by the external source. In active guidance, missile illuminates and tracks the target. Active and semi-active guidance warn the enemy of the impending attack, and even without that problem, these types of guidance tend to be less effective than passive guidance. Indeed, the first AAM to score a kill in combat was heat-seeking Sidewinder missile in 1958. Passive and active homing missiles that require launch platform to maintain track for a significant period of time also put launch platform in jeopardy by limiting its maneuver options and making it a target for anti-radiation missiles if radar is used for the task. For all guidance types, clear sky is the ideal employment background, and clutter may cause a loss of target.
Radar guidance has many problems beyond clutter. Jamming can deny or break the radar lock, as well as deny the accurate range information, or even fake such information to induce wide miss distances. Rapid maneuvers can vary the radar return, making it harder for lock to be achieved and possibly breaking it once it is achieved. Several carefully-spaced targets can cause the missile to home in on centroid, leading to large miss distance on any individual target; early IR missiles had the same problem, but it should be eliminated with imaging IR guidance of new missiles. For this reason, radar guidance is only useful against targets flying straight and level – which usually means strategic bombers, though in some cases (incompetent pilots and/or inadequate warning equipment, as was the case in Gulf Wars) fighter aircraft can also fly straight and level even when being shot at.
Missile range in rear-quarter shots is about 1/5 of range in forward-quarter shots. This severely limits missile’s effective range since target can be expected to turn away from the missile if any but very short flight times are expected. However, rear-quarter shots are the predominant type of engagement type since they allow fighter more time to identify the bogey while having better chance of maintaining surprise. Also, since launching the missile automatically means that at least approximate position of the aircraft is given avay, attack has to be carried from as small distance as possible to maximize probability of first shot being the lethal one. This in turn necessitates maintainig surprise for as long as possible, which then requires a rear-quadrant approach.
Missiles also tend to fare poorly in beam-quarter intercepts due to large possibility of detonation happening at far side of the target and doing no damage. At low altitude, ground clutter can cause a premature detonation of the missile. Altitude also has a major impact on missile range, with the same approximately doubling every 20.000 feet. From that it can be calculated that AIM-120D for example may have a maximum aerodynamic range of up to 180 km at 60.000 feet, but at typical combat altitude – 40.000 feet – it drops to 90 km, and at sea level it is no more than 22,5 km. Usable range is ~40 km at 60.000 feet, and ~20 km at 40.000 feet as target can be expected to turn away from the missile, and actual effective range is far shorter still. At 50.000 feet aerodynamic range is around 140 km, and effective range around 30 km. A 100-knot target speed advantage decreases the rear-quarter maximum range by 5-25 percent, again confirming importance of cruise speed – if a fighter 1 cruises at 40.000 feet and Mach 0,9 (515 kts) and fighter 2 at same altitude and Mach 1,2 (688 kts), then usable missile range drops to 11-18 km. It can also cause acquisition difficulties for radar-guided missiles, and in any case makes it harder for an unseen attacker to actually carry out an effective attack. Even when IFF issues were not a problem, there was no jamming and target did not tarke evasive action, no kill with a BVR missile has been achieved at ranges beyond 30 km. That being said, if firing parameters have been satisfied, and the missile does not malfunction, then an undetected launch is invariably fatal. In practice, at least two BVR missiles have to be launched even against the low-capability, unaware target, with some separation between the missiles.
If attacker does not have a gun, then defender can easily deny a missile shot opportunity by remaining inside the missile’s minimum range, and can turn a defensive position into an offensive one during a lag maneuver by turn reversal. If attacker does have a gun, however, then turn reversal results in a snapshot opportunity for the attacker. This also means that having one type of missile is not enough, since missiles with longer maximum range typically have longer minimum range as well, increasing envelope in which gun has to be used. If that envelope is too large, it may provide the enemy fighter with an effective immunity zone, in which both gun and missile shots are ineffective. This is made worse by the fact that missile’s minimum range increases as defender turns, and missiles’ minimum ranges provided by the manufacturers are for non-maneuvering targets.
Same calculations mentioned in missile evasion section are relevant for gun-only dogfight; speed has larger impact on turn radius than g. However, higher speed means more energy avaliable to trade for positional advantage, and best turn rate is invariably achieved at fighter’s corner velocity. F-16s corner velocity is at just over 0,6 Mach – 24* per second at 9 g with turn radius of 1.500 feet. For comparision, at 0,4 Mach it has turn radius of 1.500 feet but turn rate is 16* per second. To put this in context, 2* per second turn rate advantage allows the fighter to dominate the adversary if pilots are of similar proficiency, and a fighter with superior turn rate will dominate an opponent with inferior turn rate but superior turn radius. Most of the time, 1 g equals 3*-4* per second, which also makes vertical maneuvers important – downhill turn is tighter than the uphill turn with same g.
Better turn radius than the enemy may not be necessary to get a shot – lead pursuit is only necessary for gun shot, while pure pursuit is best for the missile shot and lag pursuit is best for approach. In a gun-only dogfight, lag pursuit should be used until fighter is within gun range (850 – 900 m). At that range, fighter should switch to the lead pursuit, and if necessary slow down through use of throttle, air brakes and out-of-plane maneuvers. However, radar-controlled gunsight always has some lag, and if target is jinking faster than sight could react, result is a highly accurate miss. Using pure pursuit for a gun attack always results in an overshoot.
While optical estimation of range and lead required a lot of practice even with assists, radar estimate was also far from ideal. At low altitude, ground return can render radar targeting unusable. Radars are also vulnerable to a wide variety of countermeasures, and defensive maneuvering can cause problems to radar. While problems are far lesser for gun firing solution than for radar guided missile one, and radar does cope well with steady-state maneuvers, lead correction is typically inaccurate. Thus a shooter has to maneuver within target’s plane of maneuver, causing the target’s apparent movement to be in a straight line. For this, turn rate has to be matched to LOS rate. But tracking shots typically are not advisable as they require pilot to remain in a steady state maneuver for some time. Further, enemy has to be kept within pilot’s field of view to avoid surprises, necessitating good over-the-nose visibility to allow a maximum amount of lead.
If bandit is outside the turn circle, even a tight defensive turn can allow bandit a gun snapshot. In that case, best action is to break suddenly out of the plane. On the other hand, if a pilot manages to get the bandit in such situation, he must be able to exploit a snapshot opportunity – this means that revolver cannon is a best weapon in such position as it can get lethal shot off very quickly. If bandit is outside the turn circle, there is a possibility for fighters to end up in scissors, which are typically won by the fighter which can slow down his forward velocity the quickest; delta wing fighters are in good position here because of delta’s high induced drag at high angles of attack. Lead turn favors fighter with better turn capability, which requires low wing loading and a good over-the-nose visibility so as not to loose track of the bandit. Pure and lag pursuit only requires similar turning capability. In a defensive turn, lift vector should be kept straight on the bandit.
Turn reversals are also effective guns defense maneuver, and if a fighter has better transient performance, several turn reversals can allow it to get into an offensive position. This was a popular maneuver in the F-86 community in Korea, and later in the F-16 community (called “The Snake”). Fighter also has to be able to bleed off speed rapidly to achieve lower turn radius during a flat scissors maneuver. Advantage in roll performance can negate opponent’s advantage in turn radius, but flat scissors are typically preferable maneuver for aircraft with lower wing loading. Variation are rolling scissors, where turn performance, roll performance and slow-speed control are crucial.
Head-on passes are problematic; best option is to turn level, or go either high or low. Mistakes that can lead to losing the dogfight are losing the sight of the bandit, insufficient g, poor airspeed control, bad lift vector control, failure to lead and trying to fight in the F-14 (or now the F-35). Level turn allows fighter to turn the nose towards the bandit, while vertical turn is useful for coming out of the sun at the bandit. If head-on pass is necessary, quick-snapshot capability is crucial, again pointing to revolver cannon as a best option if missiles are unavaliable. Missile shot should be used to force the opponent to break to the side. It should not be too early, else the opponent will have time to go back to the original heading, but too late missile shot gives the opponent a possibility of taking a shot of his own. If there are no missiles avaliable, one can either turn nose low, turn level or go straight into the vertical. Slice (nose-low lead turn) can be used to get nose on the bandit. Level turn is slower but allows the pilot to keep bandit in sight. Pull up to vertical can be used if it will get you between bandit and the sun, but it also gives the bandit a very hot target against the clear background plus the opportunity to gain an angular advantage.
When two fighter aircraft pass each other side-by-side, best option is to initiate a lead turn just as bandit passes 3/9 line. If bandit does the same, however, lead turn can degenerate into a Lufberry circle. In such situation, a fighter with better sustained turn performance will have an advantage. If there is not enough separation, fight will turn two-circle, though a pilot might force a one-circle fight in order to prevent the opponent from getting a missile shot if he himself is out of the missiles.
In multi-fighter fights, most important things are situational awareness and fuel. Fuel however does not mean total amount of fuel or even fuel fraction, but rather a number and type of maneuvers that can be executed with avaliable fuel. This shows value of having high thrust to weight and thrust to drag ratios, as fighter with a lot of thrust and little drag can stay in dry power and run the opponent out of fuel even if said opponent has higher fuel fraction and greater total fuel capacity. Additional factor in multi-fighter fights is that steady-state maneuvers are suicidal; transient performance is paramount, and most if not all firing opportunities are very short in duration. Even in one on one situations snapshot capability is invaluable as the reasonably competent pilot can always deny a guns-tracking solution to an adversary in a similar aircraft as long as he has energy. As energy is always lost during a maximum turn, and fighter must not slow down too much, it is standard approach to trade altitude for positional advantage while maintaining energy. This means that having higher altitude than opponent at beginning of engagement is advantageous.
As fights are always multi-fighter (at least two pairs of two fighters, four in total), with possible presence of more fighters nearby, all fighters will have to keep energy up while maneuvering unpredictably in order to avoid attacks from an unseen opponent. This means that fighters will typically use maximum turn and maximum acceleration, with little to no time spent between these two extremes (except when rolling, and even that will likely be done during a turn).
In the defensive spiral, one wants to achieve minimum acceleration, leading to usage of speed brakes, idle power, extended flaps and slats, and very high angle of attack. Ability to generate high induced drag is desireable. Ground however offers a hard limit, and when defender pulls out of the spiral he offers a very good snapshot opportunity to the attacker, if latter is equipped with WVR missiles or gun.
Energy advantage over the enemy is required if pilot wants to disengage, but as mentioned before, presence of missiles might cause disengagement to be unviable. Escape window is also highly sensitive to fighters’ relative positions and energies. Further, angular advantage is hard to impossible to maintain without having energy advantage, or at least same energy level as the opponent, since everything comes down to exchanging energy advantage for a positional advantage. This means that fighter has to have good ability to gain, keep, trade and recover the energy – basically, good climb rate and acceleration. That being said, higher thrust-to-weight ratio does not necessarily translate in energy advantage during a turning fight – lower wing loading or better thrust-to-drag ratio (which may be result of the low wing loading) may result in the lower TWR fighter having better energy performance. Energy fighter can also perform gun-and-zoom attacks if both fighters are out of missiles; these can be defeated if target can see the attack. If attack misses, however, roles can be easily reversed. Fighter with low wing loading will fight in horizontal plane and fighter with high thrust-to-weight ratio will fight in a vertical plane, but neither plane of fighting has inherent advantage over another, and low wing-loading plane can use tactics to counter zoom-and-shoot attacks by the high energy fighter even in a gun-only combat, in particular by making small angle gains while forcing the energy fighter to bleed out its speed through defensive maneuvering. There are problems, however: with energy tactics pilot may have trouble maintaining sight of the opponent, while slow-speed angle tactics leave fighter more vulnerable to an unseen attacker. Energy fighter is advised to make an effort to hide itself from the opponent by placing itself between the enemy and the sun, cruising at dry thrust and low g level to prevent formation of contrails and smoke, and keeping any active sensors turned off. If TWR is similar but one fighter has higher wing loading, lower wing loading fighter will almost certainly win if there is no significant disadvantage in roll performance or disparity in pilot quality. If wing loading is similar but one fighter has higher TWR, same result can be expected, and even moreso if one fighter has advantage in both wing loading and TWR. In all three cases, angles tactics are preferable to the fighter with performance advantage, while most useful piece of equipment for a disadvantaged fighter is a radio with which to call for help.
Acceleration is highest at 0 g, since there is very little induced drag. Parasitic drag is also reduced, and in the high subsonic regime, critical Mach number is increased by unloading. However, engine design may limit the time that fighter can spend at such condition. A dive can increase acceleration even more through use of gravity, and best overall acceleration is achieved by a steep dive followed by an unloaded acceelration.
If fighter has both gun and missiles, then these weapons complement each other: missile prevents the enemy from simply using extension escape, while gun prevents the enemy from simply staying inside the missile’s minimum range. Even if missile does miss, evasion maneuver required may place the enemy in defensive long enough for attacker to be able to satisfy gun engagement requirements relatively quickly; similarly, threat of a gun shot can be used to force the enemy to bleed off the energy and attempt a straight-line escape, with fatal results. If fighter with only a gun is fighting against a missile-equipped fighter, pilot will want to stay within enemy fighter’s minimum missile range. Missile fighter will want to increase separation and use energy tactics. If the gun fighter has rear-quarter missiles however, increasing separation may not be viable, and presence of missiles in general limits usefulness of energy tactics, making angular (turn) tactics more important. This also means that fuel fraction and efficiency can often decide the fight, with one of fighters getting shot down while disengaging due to the lack of fuel.
STOVL fighters tend to have small wings and consequently high wing loading, with bad acceleration capability and persistence due to high frontal area causing high drag. They may use VIFFing in order to increase instantaneous turn load by about 1 g, but at extreme cost in terms of energy as forward flight will be carried out exclusively on inertia, requiring high TWR to accelerate afterwards – which they tend not to have. VIFFing also uses up a lot of fuel. Conventional fighter can use angles tactics to deplete STOVL fighter’s energy, and switch to energy tactics once STOVL fighter starts to use VIFFing. Pressing the attack is often unnecessary, as high fuel consumption in both classical maneuvering and VIFFing regime combined with typically low fuel fraction will cause the STOVL fighter to rapidly consume its fuel reserves and disengage, giving conventional fighter ample opportunity to shoot it down when it tries to retreat from combat.
Against helicopters, unguided rockets and gun with visual gunsight are the best options as they minimize impact of clutter. Attacks should be made from above. Bombs may be the best anti-helo weapon due to large lethal radius, but they require good ground-attack proficiency and may be suicidal if helo is equiped with IR AAMs. While radar-guided missiles are outright useless in such a scenario due to clutter and jamming effect of helo’s rotor blades, missiles with IIR seeker have good ability to distinguish target from the clutter
In the BVR combat, AWACS or ground based radar can point the fighter in the right direction, but ultimately pilot must be ready to get missile(s) off the rails as soon as bogey has been identified (IFF issues have been adressed earlier). If bogeys are staying passive, only possibility of identification is a visual ID via IRST, camera or eyesight. Best option for this is the stern conversion since it allows most time to ID the bogeys while minimizing the risk of getting detected and attacked if bogeys are hostile.
But even against a good pilot in a superior fighter, one can win if he forces the opponent to make a mistake. For this, one must be better pilot than his opponent – and good pilots are made exclusively by in-flight combat training (as opposed to simulator training). This means that ease of maintenance, reliability and low operating costs are the most important characteristics of a fighter aircraft. Today’s USAF F-22, F-35 and F-16 pilots get 8-10 hours of flight training per month, and USN pilots get 11 hours per month. AdlA Rafale pilots get 15 hours per month, while RAF Typhoon pilots get slightly more at around 17,5 hours per month. This can be compared to a minimum of 20-30 hours per month required for fighter pilot to be truly proficient, while 40-60 hours per month is ideal.
As far as leader-wingman support goes, best option is a “double-attack”, where leader and wingman support each other without actually flying in the formation. This reduces chances of detection by the enemy, and allows for coordinated multi-vector attacks. Separation between fighters in this situation should be on order of one or two turn radii at the typical cruising speed. When cruising, optimum separation should be maintained so that one fighter covers another’s rear blind spot up to maximum visual detection range; this obviously favors fighters with good rearward visibility, as fighters should also take care to maintain visual contact with one another. In case that one of fighters engages a bogey, his wingman (even if “wingman” is technically element lead) can move high above the fight to provide effective visual coverage and engage any possible hostile fighters trying to take advantage of lead’s preoccupation with an enemy fighter; this also allows wingman to increase his energy level if his intervention becomes necessary at some point during the fight. If leader looses too much energy, he calls for wingman’s intervention and goes to replenish the energy while wingman engages the bogey, denying it the opportunity to replenish the energy. If a two-pronged attack is pursued, best option is to engage bogey from different vectors so that an offensive or defensive action against one fighter in the pair places bogey into an unfavorable situation relative to a second fighter in the pair. Two-pronged attack can result in a Loose Deuce, a two-on-one dogfight in which engaged fighter typically sets up the bogey for an attack by the free fighter. In either case, bogey is fighting at severe disadvantage. Loose Deuce however means that second fighter cannot maintain proper lookout for possible enemy fighters, making surprise attacks by the same dangerous.
It is possible for one fighter to attack a two-fighter formation if he stumbles across it. In this situation, surprise should be used so as to eliminate one of bogeys immediately, rendering the resulting engagement a one-versus-one, and possibly allowing him to escape. Higher bogey might be attacked first since it has higher energy level, and such attack may allow quick snapshot against the lower bogey, which is typically leader. On the other hand, leader is typically more experienced pilot, making him more dangerous opponent in a follow-up dogfight. If surprise attack is not successful, engaged fighter should switch between targets quickly to prevent them from coordinating attacks, and can use either energy tactics or angular tactics. Both have their drawbacks: energy tactics make him too predictable, while angular tactics quickly deplete the energy, leaving him vulnerable.
In a two-versus-two scenario, it is already possible for a pilot to get overloaded with work, as he has to keep an eye on wingman and two enemies. For this reason, increased number of aircraft in a fight always means that exchange ratio goes towards the equality. Constant practice is vital – as pilot becomes more proficient at each task of his mission, it takes less effort to accomplish them and some eventually pass into an automatism. This means that there is more brainpower, and time, to devote to tasks that cannot be done automatically, and may reduce the time required for even those tasks. Thus, practice gives pilot an advantage in an OODA loop, and makes him more likely to survive in a standard multi-bogey scenario. But these skills are lost quickly, and must be practiced constantly. Easy operation of the aircraft, unrestricted cockpit visibility, clear, dependable communications and reliable, resillient aircraft construction all serve to reduce the workload, and may be as important as aircraft’s flight characteristics in combat. Increasing enemy’s workload by flying the very small and very maneuverable aircraft is also a plus.
Bracket can also allow for a surprise and increasing the enemy’s workload, since in a two-vs-two scenario, neither of the enemy pilots will be able to keep more than one enemy fighter in sight, while both attacking fighters will have all other fighters in the air in sight. If dogfight develops, one fighter can engage in a dogfight with the enemy, while wingman covers him and keeps track of – but does not attack unless necessary – the second bogey. Better turn performance can enable a free fighter to defeat attacks by a free bogey without engaging in a protracted dogfight. If necessary, free fighter can attack the bogey, while a previously engaged fighter becomes a free fighter. This however necessitates a good energy recovery ability, as previously engaged fighter is likely to be low on the energy. If there are two bogeys, both fighters can engage one bogey each, and keep switching between the bogeys while keeping high energy (a Loose Deuce variation). This allows fighter to engage even a superior-performance opponents, but Loose Deuce requires pilots to be highly trained to be effective.
Tactical turn is a best option for disengagement, but it requires a lengthy straight-line extension between the turns, which in turn requires good acceleration capability, and may not be an option when facing a missile-equipped bogey. High cruise speed is also a necessity in order to prevent a reengagement by the opponents.
Large formations, aside from being larger to detect, are also harder to maintain without accidents. This means that pilots will have to spend considerable time and effort in order to maintain the formation. As a result, small formations are optimum, and in some situations single-ship operations may be preferable, particularly if fighter is equipped with RWRs and IR sensors that can provide warning of attack from any direction. Ability to identify and attack the enemy at long range is also valuable in facilitating single-ship operations; detection alone is not enough. Another requirement is a substantial cruise speed advantage, which facilitates rear-quarter attack and makes the same attacks by the enemy more difficult, as well as making withdrawal more difficult. Small aircraft size, maneuverability and lethal weapon systems contribute to single flighter’s survivability. Jamming also increases effectiveness of singles as coordination between fighters becomes impossible.
Single fighter should fly at highest possible sustained speed, and use hit-and-run attacks while avoiding maneuvering engagements if at all possible. Attacks should be made from the rear in order to maximize surprise, which necessitates higher cruise speed than the target. Missiles should be of a fire-and-forget variety, as any guidance type that restricts shooter’s maneuvers after the launch is an undesireable, and oftentimes fatal, burden.
During First World War, Germans usually engaged in large formations for sole purpose of maintaining local superiority, but between the wars focus shifted towards bomber interception, a pattern that will almost invariably repeat itself in the Western air forces up until the present day (examples: P-38/P-47; F-104/F-105/F-4; F-15; F-22; EF-2000). For fighter-to-fighter combat, however, a finger-four formation is optimal as it allows mutual leader-wingman support as well as support between sections. With a finger-four formation, tactics described previously can be used, with each pair acting as a single fighter. Advantage of a fluid-four formation is increased firepower, as well as the fact that each fighter of a pair can act independently if a situation calls for it. Using this doctrine, a four-plane division of F6F Hellcat fighters destroyed 50 Japanese fighter without receiving a single hit. Elements of section traded roles as engaged element and free element, earning it a nickname of “Valencia’s Mowing Machines”.
In modern enviroment, however, a fluid-four doctrine has to be used with greater spacing between fighters and less restrictions on a free element, as well as greater use of double attack and loose deuce. Against a superior number of fighters, it is hard to impossible to maintain coordination between pairs. Free element is also vulnerable to missiles. Three enemy fighters operating independently are also likely to wreak havoc against four enemy fighters in two formations, and greater number of fighters means better support through presence. This is a basis of the “Gaggle” doctrine in which each fighter operates independently, and turning is kept to minimum. In general, a turn should not be continued past 90* in any single direction without a quick reversal. If a bogey cannot be shot within 90* of a turn, pilot should go look for another target.
When engaging, fighters should always maintain at least a parity in elements, if not necessarily single aircraft, but coordination between elements has to be maintained if gaggle doctrine is to be effective; otherwise, fluid-four might be more effective. Gaggle is also generally more effective if enemy has an equal or greater number of fighters. If enemy has less fighters, then a fluid-four formation should be used as it will allow increased defensive ability while still maintaining parity in offensive ability.
It is possible to combine small WVR-only dogfighters with large BVR radar-based fighters, in which case a modified vie can be used. Line-abreast arrangement might be used to employ broadside-style attack. Once dogfight is joined, large fighter should stay out of hassle as it will attract enemy fighters and force dogfighters to defend it. However, using dissimilar fighters often means that one type will suffer from reduced range and/or endurance. High-performance fighters will also typically have to withdraw first for fuel considerations, and may be limited in withdrawal speed if they are to remain with lower-performance wingmen.
In a defensive one-versus-many environment, single fighter must not engage in a protracted dogfight, and instead has to engage in hit-and-run attacks. Higher cruise speed than the enemy might be the best defense as it prevents or at least limits surprise attacks from the rear. Weaving might also be employed to increase probability of detecting such an attack, even at cost of combat radius and increased possibility of attack. Turns however should be limited to simply chacking the blind areas, primarly 6 o’clock low, and should not be so hard so as to bleed speed. Maximum sustained turn should be used, though combination of hard turn with rolling belly check and subsequent straight-line acceleration might be useful. This techniaue provides effective defense even against unseen missiles. Clouds can be used for defense against guns and IR missiles, but are not very useful against radar-guided missiles.
Drawing the enemy into SAM coverage is a useful defense technique, even if SAMs are on his side – radar-guided SAMs typically cannot separate friend from the foe, and bogey is not likely to continue attack through heavy SAM coverage. To defender however, facing SAMs is typically preferable to facing enemy fighter(s).
Optimum formation, as mentioned, is a division of two fighters as it is a best baalnce between offensive and defensive power, especially if there is no reliable speed or altitude sanctuary. If larger numbers are required, they should take form of independant or semi-independant two-fighter divisions. If a two-fighter section(s) come(s) across a superior number of enemy fighters, techniques described in one-versus-many section should be used. With multiple fighters, weaving is actually counterproductive to covering the rear area, meaning that fighters should fly at straight line at their maximum cruise speed.
When attacking a larger formation, surprise should be always sought. If surprise cannot be achieved, attack should not be pursued. In many-versus-many environment, fighters should operate in pairs or individually, using loose deuce or gaggle tactics.
Once air superiority has been established, fighter should turn their attention towards other enemy airborne systems – primarly ground attack aircraft, but also AWACS, tankers etc. Another task is escort of one’s own ground attack aircraft as same carry out attacks against enemy ground troops, air bases and other surface targets. As fighters will be cruising in the contested zone, possibly over the hostile area, fighter sweeps should be staggered so that an entering (fresh) element can provide support for a retiring element, as latter will not have enough fuel for a protracted engagement. This however creates IFF problems, especially at BVR, and calls for fighters to be equipped with sensors capable of quality visual IFF (such as imaging IRST).
AWACS, if present, can provide control for fighter formations. Close control may be preferable during fighter sweep missions if not too many fighters are present, but since it is easily saturated, broadcast control is typically a better option. Data links may be preferable to radios due to greater resistance to jamming, but tactics should not rely on presence of any electronic means of communication.
Strikes are carried out either low-level by small groups of bombers that follow separate paths to the target, relying on surprise for success; or at high altitude by a single large group of aircraft relying on ECM, escorts and bombers’ own defensive armament. Defense against strikes is carried out by either Combat Air Patrol, Ground Alert Interceptor, or combination of the two. CAP has the advantage of intercepting the enemy at greater distance from target, and is typically a must when facing strike aircraft carrying long-range standoff weapons. It is usually stationed at “choke points” through which low-flying attackers must pass, such as valleys, mountain passes, rivers etc. Effective range of far CAP is determined by number of fighters, sensor coverage and fighters’ time on station. Altitude is also a consideration: detection favors low altitude so as to achieve a look-up against the enemy, while endurance of jet fighters is best at high altitude. If multiple fighters are avaliable at any given CAP station, a Lufberry circle can be used to provide continuous sensory coverage. For a single fighter or a pair (there should always be at least two fighters per station), a figure-8 pattern perpendicular to threat axis is optimum. If enemy attack is likely, then fighters should cruise at maximum non-afterburning setting.
CAP should be backed up with ground-alert interceptors, which should provide primary defense against larger raids. With interceptors colocated with protected target, larger number can be kept on the ground, fuelled, armed and ready for action. They can also more easily amass to counter large attacks, and do not need good endurance or sophisticated sensors.
Attack against low-level attack aircraft is quite simple. Since such aircraft tend not to have good rearward visibility, turning off any active sensors to prevent detection by target’s warning systems in conjuction with a rear-sector approach should be effective in achieving surprise. Low-level penetrator, if he detects the attack, might drop a bomb to try and catch a pursuing fighter in weapon’s fragmentation pattern; hard turn to left or right should work in countering that tactic.
High-level attack aircraft typically fly in massed formations with fighter escort. In such situation escort should be neutralized first. Destroying escort fighters may not be necessary; simply forcing them to drop external fuel tanks and engage in heavy defensive maneuvering (usually involving afterburners) might relieve them of so much fuel that they will have to return home and leave bombers vulnerable to further attacks. If defending fighters consist of two types, smaller dogfighters should engage the fighters while large radar fighters engage bombers (which actually is their design mission). However, greater precision of modern weapons and smaller fleet sizes have led to reduced number of massed attacks.
Fighter sweep just before the attack can be an effective way of neutralizing enemy defensive fighters. Still, strike aircraft will require some form of escort. Types of escort are reception, remote, detached and close. Reception escort provides reinforcements when they are needed, and is used in combination with other types of escort. Remote escort fiels ahead of the strike package and clears the route of enemy fighters, but it should be close enough so as to remain engaged until the strike is complete. Detached escort is positioned around the escorted aircraft so it can attack enemy fighters before same manage to attack escorted aircraft, and additional elements can be positioned to the rear and above the rear elements of the detached escort, acting as a reserve and a guard for lower-flying rear elements. Flanking escorts can be positioned between forward and rear escort, depending on distance between these elements. If speed of the air group is less than fighter’s preferred cruise speed, weaving might be employed. Close escort attacks the enemy in the final stages of his attack, once the enemy fighters are within visual range of their targets. It can also serve as a backup for detached escort, filling holes in perimeter, providing reinforcements and attacking enemy fighters that have broken through. Remote escort and fighter sweeps are most important elements of the escort.
Box formation is good defensively as well as offensively, as any fighters attacking the lead pair will be attacked by a trailling pair, while fighters in the trailling pair can lend each other support. If an enemy formation is encountered, box can use a pincer attack, with each pair attacking from one side. Pincer is also a good tactic for a fighter pair, but requires considerable training, as it is easier to mistime the attacks at beyond visual range than it is within visual range.
Cross-lock is useful in countering enemy pincer attack. As bogeys turn inward in a pincer, each fighter attacks the bogey that is further away from him, crossing paths. If executed properly, each fighter should have a firing opportunity against both the bogey he is attacking head on, as well as a second bogey.
In 4 vs 2 head-on attack, a double pincer can be used, when enemy formation as a whole is caught in a pincer, and each of the bogeys is caught in a pincer as well as they separate.
Hook maneuver can be used to allow one fighter to VID the bogeys while another prepares for a BVR attack, or both fighters can merge with bogeys. The leader continues on a collision course, while wingman achieves large vertical and lateral separation from the leader, and accelerates to approach bogeys from the side.
Break-away can be used to confuse the enemy and get one fighter to the merge unobserved. In this scenario, wingman initially trails the leader very close until the enemy takes radar lock, then rolls over and pulls into a split S. If the enemy is using Doppler radar, this should make the wingman invisible, and will result in clutter problems regardless of which type of radar are bogeys using. Once aircraft is purely vertical, wingman pulls out to the original collision heading.
When intercepting an aircraft at BVR, forward quarter intercept is preferable to direct head-on intercept due to longer identification range and better weapons performance compared to a direct head-on intercept. It is however easy to counter, and mans that attacker is likely to be detected, especially if enemy fighter has forward-facing sensors such as radar or IRST. Stern conversion is preferable to maintaining surprise and allowing more time for target identification, but it reduces weapons’ range and is easier to counter by jinking. Both these conversions can be combined, with fighter firing initial salvo from the front, followed by a stern conversion and rear-qarter attack.
Large, visible air bases will get bombed or attacked by sappers. While speed, maneuverability and stealth enable aircraft to survive in the air, aircraft parked on the ramp of a typical air base has none of these characteristics. Between 1940 and 1992 there were 645 attacks on air fields, of which 384 were aimed at destroying the aircraft parked. 75% of the attacks used standoff weapons, while remaining attacks were penetrating (22%) or combined. Between 1940 and 1943, British Special Forces destroyed 367 Axis aircraft in North Africa. USAF in Vietnam quickly developed countermeasures against penetrating attacks, but no effective countermeasures against standoff attacks have been implemented up until the end of the war. During the Afghan War, guerillas used man-portable SAMs to shoot down Soviet aircraft when taking off and landing.
During invasion of Crete, RAF used revetments to protect fighters from indirect hits, but aircraft were eventually evacuated. Yet no attempt was made to render air fields unusable, and they were eventually captured and used by German invasion force transports. Revetments are also useful in limiting damage done if aircraft is destroyed by satchel charge. Same measures were used by USAF in Vietnam, as well as armored concrete shelters.
Air attacks are also a major threat. In fact, Allied air bases in World War II were subjected to attacks through the entire war – Germans bombed RAF air fields in the 1940 Battle for Britain, and in the 1945 they launched Operation Bodenplatte, destroying or damaging 500 Allied aircraft. Most of the Soviet Air Force was destroyed on the ground during Operation Barbarossa, and such attacks were commonplace through the entire war.
Again, Gulf Wars were an anomalous point – Iraqis were poorly motivated, uncreative and incompetent adversary, and made no effort at all to attack Coalition air bases, despite the fact that these air bases were closer to Iraq and Yemen than German air bases were to British lines in North Africa.
Reliance on fixed air bases not only increases vulnerability to attacks and possibility of enemy capturing the bases and using them for his own purposes, but also decreases flexibility and ability to generate sorties. STOL and rough basing capabilities are thus a must.
Yet US Air Force, and most European air forces (except Flygvapnet) operate under assumption that close and secure air bases will be avaliable in order to generate sufficient sorties. However, there is a number of threats that make typical air bases, as well as aircraft carriers, unviable. Ballistic missiles, bombers and cruise missiles can take out both air bases and ships; carriers are also under a very real danger of attack by submarines and fast attack craft. Ballistic missiles have range of 800-2500 km, while Flankers carrying ASCMs can attack ships 1.350 km from their bases. Missiles with submunition warheads could destroy 75% of the aircraft stationed at the typical USAF air base.
Fighter will have to be capable of flying from a two-lane highway. Lane width typically varies from 2,5 to 3,25 meters minimum width in Europe, with US Interstate Highway System standard width being 3,75 meters; same width is standard in most of European countries. Shoulder width in US is 3 meters on outside and 1,2 m on the inside, and in Europe it is 2,5 meters.
As a result, allowable wing span is between 7,5 and 10 meters, both values being less than in a previous proposal. To give a safety limit as well as allow as many European roads to be utilized as possible, starting wingspan goal will be =<8,75 meters, with 7,4 meters being optimum (assuming that it can be achieved without compromising other characteristics such as wing loading).
In most European countries required tunnel height is 4,5 meters, while Geneva convention requires 4,8 meters.
This requirement also leads to other design requirements: high thrust-to-weight ratio, good lift coefficient, low stall speed.
Since maintenance will also have to be carried at road bases with no access to complex hangar facilities, fighter will have to be as simple as possible. This does not mean sacrificing effectiveness; indeed, most effective weapons have always tended to be comparably simple in design – see “design requirements” for details.
Dirt strip basing is required in areas where there are no roads, or if roads get bombed (dedicated air strips certainly will). Further, ability to take off from dirt and grass strips gives major advantage in scramble time, allowing many fighters to take off abreast and quickly deploy in formation.
This means that front landing gear will have to be positioned behind air intakes, and ground clearance will have to be 100-170 cm. Wheels will also have to be placed relatively widely separated, necessitating placement in a base of the wing. Wheels will have to be proportionally big.
Modern IR sensors are rivaling radar in capability. PIRATE IRST of Eurofighter Typhoon can track subsonic fighter-sized targets from 90 km from front or 145 km from rear. It can identify the target at 40 km, and track 200 different targets. Range figures will be 10% greater against fighters supercruising at Mach 1,7, and a Mach 4 AMRAAM can be detected at 80 km. Angular resolution is less than 0,05*, possibly as good as 0,0143*. Fighter supercruising at Mach 1,7 generates shock cone with stagnation temperature of 87* C, and Mach 4 AMRAAM generates 650* C shock cone, while temperature of the surrounding air is -50* C at 10.000 meters, -54* C at 12.000 meters and -70* C at 15.000 meters. This shows that significant IR signature reduction is nothing but a dream, with even commercial IR detectors being able to detect 0,1* C differences in temperature. IRST can also use Doppler-shift measurements to estimate closure speed of the target. Atmospheric conditions also aren’t as much of a problem as typically believed: during testing, Rafale’s OSF managed to detect a turboprop C-160 through the cloud at range beyond MICAs engagement envelope. Even if cloud cover is thick enough to affect the IRST, most clouds do not extend above cca 10 km. Skyward-G, based on the PIRATE, has been stated to be capable of picking up all aircraft flying at speeds above 300 kts, regardless of IR signature reduction measures, simply through aerodynamic heating of the skin. It is also thought to offer better performance than PIRATE. Further, most of adverse conditions that may affect the IRST occur below the 10.000 feet, and radar has problems when detecting, and especially targeting, low-flying aircraft.
IRST will remain useful for several reasons. It is a passive system, therefore it does not warn the enemy. IR stealth is also a physical impossibility – act of moving an object through the air at high speeds causes air to compress and thus heat. Friction is likewise insurmountable problem, with leading edges of a supersonic aircraft heating up to very high temperatures, and jet engines themselves help to heat the airframe. None of these problems can be physically adressed; even if an IR-absorbent coating was to be invented and used, it would still not adress issues of friction, compression, glint, reflected IR radiation and engine exhaust. Further, it would cause anything inside it (crew, systems) to cook. Even if all these issues were somehow adressed, aircraft would have to be at the perfect temperature of the background, else it would still appear on the IRST regardless of wether it is hotter or cooler than the surroundings.
Aircraft also tend to have electronics that requires cooling, but also some that requires heating. F-22 in particular has two pitot tubes under the nose which are electrically heated to 270* C to prevent them from icing at high altitude.
For comparision, CAPTOR has range of 185 km vs 3 m2 target, angular resolution of 0,05* at 165 km, and can track 20 different targets.
If rangefinding precision greater than what PIRATE can offer is necessary, a laser rangefinder can be used. Downside is a range of only 20 kilometers as well as its negative effect on achieving surprise, so it should be most useful for generating gun firing solution in close-combat maneuvering scenarios. For this reason, LIDAR research should be pursued.
IRST also presents a stealthy opponent with a head-I-win tails-you-loose problem: a stealth aircraft can attempt to reduce IR signature by flying at a slower speed, but that will also reduce its own missile range. If it attempts to increase its missile range by flying at a higher speed, it increases its own IR signature.
“Keep it simple, stupid.”
— WWII saying
First and foremost, fighter should be easy to maintain and cheap to buy and operate. This means that a small single-engined fighter is optimum: small size leads to reduced weight and unit acquisition cost, while single engined design makes maintenance easier. It also means that fighter should only use essential electronics, and be a single-role aircraft as unit price of a multirole aircraft is typically a sum of unit prices of aircraft it combines.
Easy maintenance and low operating cost is required to facilitate training, since fighter pilots have to fly to gain and maintain proficiency level required. Larger complexity of modern fighters is showing – most Western air forces’ pilots train for 120-180 hours per year, while it was around 240-300 hours per year a mere decade ago. Between 1975 and 1980, US Navy Topgun instructors got 480-720 hours of flight training per year, and consistently whipped students coming from squadrons that got only 170-240 hours per year, despite latter flying F-4s, F-14s and F-15s against instructors in the F-5s. All studies support inverse relationship between reliability and complexity; complexity itself can be defined in a number of components that can go wrong (IRST + radar vs only IRST) and complexity of components themselves (EJ200 is a simple design compared to earlier turbofans). Not only do more complex systems have more parts that can go wrong, but it is also more likely that any given part will go wrong due to interaction between parts. More complex aircraft also more frequently require cannibalization to remain operational, and support structure of a more complex aircraft is more vulnerable to disruption in wartime. Increased hardware complexity also increases costs and decreases predictability of future costs. While some modern complex aircraft have better base level maintenance numbers than less complex aircraft (examples: Rafale, Typhoon), this is invariably achieved by transferring base level maintenance back to the depot, thus increasing vulnerable logistical tail. That transfer is achieved through Line Replaceable Units – M88 engine of Rafale for example consists of 21 replaceable modules. While this concept allows very easy flight line maintenance, it increases complexity of the support structure, since technicians have to maintain both modules (each of which includes a computer) as well as computers used to maintain the engine. It also means that each aircraft has to have greater number of spares for each component, since any faulty component will spend more time being maintained or transferred to/from maintenance, and there is less margin for absorbing the unexpected. For this reason, more complex aircraft have higher operating costs than their unit flyaway costs would suggest. 45 million USD Gripen costs 4.700 USD per hour to operate (ratio 9.574); 70 million USD F-16 costs 7.000 USD per hour to operate (ratio 10.000), 90 million USD Rafale costs 16.500 USD (ratio 5.454), 130 million USD Typhoon costs 18.000 USD (ratio 7.222), 128 million USD F-15C costs 30.000 USD (ratio 4.267) while 273 million USD F-22 costs 51.300 USD (ratio 5.322) (higher ratio is better). More complex aircraft also require more maintenance personnel: Gripen needs 10 assigned flightline maintenance personnel, compared to 30 for the F-15 (again, a difference roughly proportional to difference in unit flyaway cost). These maintenance personnel also have to be better trained (and by extension, receive higher pay), increasing personnel-related costs of maintenance far more than would be expected from simple increase in number of personnel.
Larger number of aircraft than the enemy allows more flexibility in force deployment and greater ability to absorb inevitable losses, as well as to saturate the enemy’s ability to process data and respond. In fact, history suggests that there is a limit of around 3:1 where quality can not compensate for superioir enemy numbers. This means that fighter should be as simple as possible while not sacrificing combat performance – which in turn means that design should be based around basic historical lessons which rarely to never change (details often change but underlying lessons do not). It is important to note that this refers to both total number of aircraft and number of sorties per day that number of aircraft procured can generate. Again, avaliability is related to complexity, avaliability for Gripen is typically 90%, for Typhoon 70% and for the F-22 it is 55,5%.
It should be noted that many times more complex aircraft were promised to have better MTBF and be easier to maintain than their less complex predecessors (A-7D vs F-111D; F-15C vs F-22A). It always turned out to be false – while F-111D Mark II avionics were predicted to have 1,42 MMH/S and MTBF of 60+ hours, as opposed to A-7Ds 2,79 MMH/S, it turned out that Mark IIs MTBF was well under 3 hours with 33,6 MMH/S. F-15 was similarly guaranteed to require no more than 11,3 MMH/FH with MTBF of 5,6 h (as opposed to F-4Es 24 MMH/FH and MTBF of 1,3 h); after entering the service it required 26,7 MMH/FH, a number that got reduced to 22,1 MMH/FH by 1990s.
Greater complexity also means that battle damage is harder to repair. During the Vietnam War, the depot backlog of damaged aircraft reached a point where it took two-years to get an F-4 repaired, and the ratio of damaged aircraft to lost aircraft fluctuated between 3 to 1 and 6 to 1. For this reason, advenced aluminum-lithium alloys might warrant investigation; these give the same weight for strength ratio as advanced composites, but are far easier to repair. (On a related note, “force multipliers” cannot be expected to work very well, or at all, in a war due to their typically high complexity level).
“The biggest target in the sky is always the first one to die.”
— Topgun saying
Visual and IR signatures should be small. Aircraft should be light in color so that either portions of aircraft in the light or in the shadow will blend in a background. Pastel gray might be the best choice, but actual color is not as important as long as it is dull – very bright colors however can be recognizable at distances greater than 10 miles, while small, well camouflaged fighter might not get detected until 2-5 miles. Light pastel background (sunset) combined with shadows on back-lit fighter can increase detection to 30 miles. Small fighters are best colored in two shades, and camouflage pattern should appear random. Camouflage can also be used to disguise aircraft’s attitude and maneuver. “Dazzler” camouflage is best for this purpose, but it increases initial detection distance.
Small IR signature requires small aircraft, minimizing usage of afterburner and low drag.
Due to importance of surprise, emphasis should also be placed on the situational awareness. Surprise is achieved by detecting and identifying targets more quickly and accurately than the enemy. This means that only passive sensors will be used, as these do not warn the opponent of fighter’s presence, and in any case only optical sensors (cameras, IRST) are capable of reliably identifying enemy aircraft outside the range of human vision – while PIRATE can identify fighter at up to 40 km, visual identification requires fighter to close to 400-800 meters regardless of wether it is equipped with radar. Radar is straight out useless as aside from not being capable of identifying the target*, it provides the target with a way of identifying and targeting the radar-using fighter at extreme ranges. Radar range varies with an inverse fourth power, while RWRs range varies with an inverse square power; in other words, an RWR of equal sensitivity to the radar can detect radar’s signals at 4 times longer range than radar can detect its own signals; this is without accounting for the fact that only a minor portion of signal (less than 2%) actually gets deflected back towards the emitter. This can also be used to target the emitting fighter via anti-radiation missiles. Even LPI techniques do not help – two standard techniques are frequency hopping, as well as spreading signal over a range of frequencies. But frequency hopping can be countered by RWRs capable of memorizing signals received and analyzing memorized data; as for spread spectrum technique, it is useless for a simple reason: radar signal as a whole is between 1 and 10 million times as strong as the background noise. AN/APG-77 can use 4 independent beams at any given time, which means that a signal from any of the beams is at very least 250.000 times as strong as the background noise of the same frequency. Even if it were able to project a single beam from each of its 1.956 T/R modules (a physical impossibility since it is interference between modules that allow the radar beam to be steered without moving the radar plate), each beam would be at least 500 times as strong as the background noise of the same frequency. As a result, any usage of radar alerts the enemy far beyond the effective radar range, solves his IFF problem and gives him a perfect beacon to guide his missiles. This means that the ultra-expensive F-22 is effectively a visual-range-only fighter, but in that mode it is disadvantaged due to its large size and high weight.
*[Except in ideal conditions through use of ISAR image, but even in ideal conditions range is less than IRST’s; usage of jamming, unknown external loads or maneuvering can severely degrade range or even prevent identification alltogether. Since radar has to dwell a long time on the target, and target must move in a predictable manner for relatively long time, ISAR is only usable against ground targets. Another similar technique, jet engine modulation, which uses jet turbine signature to identify the aircraft, is no more than 30% reliable and is useless if there is jamming or if the engine face is hidden – as it is in almost all modern fighters. For this reason, radar requires IFF transmitters to discern friend from foe, but pilots tend to shut these down in order to avoid being tracked – unless they are fighting incompetent opponent].
Another factor is that any bogeys attacking are likely to approach from the rear. But except for the relatively short-range missile warners, only sensors on a standard fighter aircraft capable of covering the rear hemisphere are pilot’s own eyes. Missile warners also do not guard against the gun attacks, which remain the best option for a quick surprise kill.
Due to consequentually overwhelming importance of visual and IR sensors, signature reduction measures will be focused on visual and IR domains (small size, ability to fly supersonically without afterburner). Initial detection range for PIRATE against a subsonic fighter is 145 km from the rear and 90 km from the front; supercruising at Mach 1,7 adds 10% to the range, and using afterburner increases fighter’s IR signature even more.
Avoiding getting surprised is achieved with good all-around situational awareness via good visibility from the cockpit and good RWR and IR sensor coverage. Many characteristics required for achieving surprise (such as small visual and IR signatures, passive-only sensors and high cruise speed) also help figher to avoid getting surprised. Unlike IRST, radar has no ability to detect an incoming air-to-air missile, and radar-based missile warners have limited range compared to IR MAWS. Radio and datalinks can also help, though they are likely to get jammed.
“As technology advances, we will rely more and more on passive sensors and visual search. This will be the case in a full-stealth environment. The radar cross section of an aircraft will be a fraction of what it is in today’s fighters. Detection using conventional radar will be difficult and likely to occur at a greatly reduced range. The aircraft that illuminates first will be quickly detected and targeted by accurate, state-of-the-art passive sensors. The importance of visual detection has not diminished with technological advances.”
– S.Schallhorn, K.Daill, W.B.Cushman, R.Unterreiner, A.Morris – “Visual search in the air combat”
Canopy should provide a 360* horizontal visibility, 15* over-the-nose visibility and 40* over-the-side visibility. Helmet should be lightweight and should not restrain the vision – no part of the helmet should be visible to the pilot wearing it. It should be fitted with a dark visor that can be quickly flipped into position, but visor should not be used unless absolutely necessary as even a clear visor degrades vision to some extent, and reduces visual depth of field. HMD in particular should not be used, as it can cause data overload in addition to reducing visual acuity; high off-bore aiming should be provided with a simple wire aid. Anything inside the cockpit should be dark and nonreflective. Rear-view mirrors should be placed outside the canopy, else their effectiveness will be nullified by canopy reflections. Airspeed and altitude measurements should be displayed on HUD.
Higher cruise speed is required in order to make rear-quadrant approaches as enemy is comparably blind in that sector; maximum cruise speed should be maintainable for 20+ minutes that fighter spends in the enemy air space, plus 200+ miles (322+ km) subsonic transit to and from the operations area, and additional 2 minutes of maximum afterburner. It also gives a fighter excess kinetic energy, increasing range of its missiles and allowing it to dictate terms of the engagement. It can also offset a possible situational awareness disadvantage – knowing where the enemy is is of little use if you can’t engage him. Supercruise requirement dictates a wing with 45* or greater sweep.
Maneuvering performance requires good ability to transit from one maneuver to another (roll onset, turn onset, pitch onset; roll performance could be identified as time to roll 90 degrees and then 180 degrees in another direction) as well as outturn, outclimb, outaccelerate and outdecelerate the opponent. Transient performance requires good wing response to control surface inputs in order to achieve maximum abruptness of maneuver while still retaining control, and also low weight to reduce inertia. Roll performance, which factors in a transient performance, requires low wing span. As mentioned before, rolls of more than 180* are rarely required in air combat, and maximum roll rate may not be reached during such short periods of roll; therefore, greater emphasis should be placed on the roll onset rate than on the maximum steady-state roll rate. Roll acceleration is a function of control power, but also of moment of inertia. Greater total weight and farther distribution from the fuselage axis both produce greater roll inertia. For this reason small single-engined fighters tend to have best roll performance. Transient roll performance is particularly important for guns defense, and also for missile defense, as this video shows.
Pitch rate is a combination of turn rate and angle of attack increase. Faster pitch onset typically results in a faster turn onset, and can also help in gun tracking. Pitch performance results from effectiveness of the pitch control and fighter’s resistance to pitch. AoA increase is useless beyond the stall onset angle, and maximum lift AoA cannot be achieved above corner speed due to g limits. Best pitch performance typically corresponds to best instantaneous turn performance.
Turn performance requires good lift-to-weight ratio, best approximated with wing loading, and aircraft with lower wing loading tend to have advantage in both instantaneous and sustained turn rate. Lift is particularly important for instantaneous turn performance, and is limiting factor below the corner velocity. Minimum sustained turn radius is typically achieved at 1,4-1,5 times the power-on stall speed, which is far less than speed for sustained turn rate. Sustained g capability is proportional to thrust-to-drag ratio; therefore a fighter with low thrust-to-weight but high lift-to-drag ratio can posses a better sustained turn capability than a high TWR fighter. If both fighters have same sustained g, one with lower wing loading will have better turn rate and radius. Climb performance requires good lift-to-weight ratio and thrust-to-weight ratio.
Acceleration requires high thrust-to-drag ratio, approximated through thrust-to-weight ratio, while deceleration requires ability to achieve high induced drag on demand. Acceleration can be approximated through climb rate. It should be noted that air combat alternates between maximum turn and maximum acceleration, with little time spent in sustained turn conditions, in order to remain as unpredictable as possible to an unseen attacker. Instantaneous turn performance coupled with transient performance is especially important for defeating gun or missile firing solution. Advent of missiles has placed increased emphasis on maneuvering performance by eliminating the non-maneuvering accelerating escape used to defeat gun attacks (except at relatively long ranges, but missiles are rarely used at ranges approaching their maximum ballistic range), which has historically prevailed; in case of either gun or missile attack, however, transient and instantaneous turn performance is the most critical for either attack or defense from the attack succeeding.
Drag can be reduced by minimizing aircraft surface area and minimizing its frontal area. Induced drag (produced during maneuvering) is minimized by reducing the wing sweep. It is also reduced by reducing the weight, since less weight requires less lift for a given turn performance. However, high energy loss rate might be desireable in some circumstances. Wave drag is reduced by sweeping the wings and reducing the aircraft cross-sectional area. Drag is especially high in the transonic region, where parts of the air flow over the airframe are supersonic while other parts remain subsonic; lower end of this area is at Mach 0,8-0,9, while higher end is at Mach 1,1-1,2.
Maneuvering endurance should also be good so as to minimize a possibility of running out of the fuel during a dogfight. High fuel fraction is achieved by a maximum simplicity of design as well as high fuel volume; latter can be achieved through wing-body blending (this approach has several other benefits, such as improved lift when turning and reduced drag). Low fuel consumption ironically is best achieved by very high thrust-to-weight ratio, thus minimizing number of tasks which require usage of afterburner. It is also helped by a single-engine design. Another requirement is combat radius, which is also helped by the high fuel fraction. Combat radius might be extended by external fuel tanks, but that is not a perfect solution as fuel tanks take up avaliable hardpoints, reduce cruise speed, and are inefficient (half of the fuel in external tanks is used to counter increased drag).
Dry thrust drops to 50% at 6.500 m / 21.000 ft and to 25% at 12.000 m / 39.400 ft. Afterburning thrust drops to 50% at 12.000 m / 39.400 ft, to 16% at 15.000 m / 50.000 ft and to 10% at 18.000 m / 60.000 ft. SFC is affected by speed and altitude – an engine with SFC of 1,8 at Mach 0 and sea level will have SFC of 2,0 at Mach 1,6 and 50.000 ft, and 1,95 at Mach 1,2 and same altitude.
In terms of weapons, emphasis should be placed on surprise and achieving kills quickly. Weapons should be easy to use, reliable, non-counterable and effective. Achieiving reliable kills requires creating and exploiting firing opportunities. In terms of weapons range, firing opportunities are limited by range at which positive identification can be achieved, typically visually (by eye or by visual sensors) – beyond visual range missiles tend to have maximum range well in excess of identification range of visual sensors. This does change if possible target uses active sensors which can then be used to identify it; in this case, identification tends to happen well outside weapons range. IFF is not useful as it is typically shut down to prevent enemy from tracking one’s aircraft, and random intermingling of aircraft makes it almost impossible to use it to sort friend from foe (both aspects were absent from Gulf Wars due to Iraqi’s incompetence). Other limitation in this regard is weapons’ acquisition and engagement envelope: gun can fire only forward, while missiles have limitations in terms of minimum range, ability to engage off-bore targets and target acquisition time. Background clutter can hamper both identification and engagement, and enemy can always use maneuvers to hamper engagement.
Fighter should also have adequate ammunition aboard to facilitate several kills. This is easy calculated by multiplying number of missiles and gun bursts with probability of kill of any given type of missile or gun. In the Korean war, linear-action guns achieved 0,31 kills per firing pass. Rotary guns used in the Vietnam war achieved 0,26 kills per firing pass due to slow fire rate acceleration, low lethality per round and slow flight speed beyond 1.000 feet. As for missiles, AIM-9 achieved 0,15-0,19 kills per firing attempt depending on model, while AIM-7 achieved between 0,08 and 0,1 kills per firing attempt. Both of these values are likely to be towards the lower end in combat between modern fighters.
Most reliable, easiest to use, hardest to counter and overall most effective weapon is gun/cannon (difference being in that cannon uses explosive projectiles and are typically 20+ mm in caliber) and visual-range IR missile, followed by BVR IR missile and only then by radar-guided missile (air-to-air anti-radiation missiles are in between the BVR IR missiles and radar-guided missiles, but these are not in a typical employ of the Western air forces). Rules of gun combat have remained mostly the same. Attack has to be made from as close distance as possible in order to reduce dispersion; obviously, high-calibre revolver cannons have advantage in effective range over rotary counterparts due to less projectile dispersal. They also tend to have higher effective firepower: in close combat, it is imperative to get shot off nearly instantly in case that tracking shots are impossible or enemy tries to defeat it by changing plane of turn by rolling, and while rotary guns take some time to achieve maximum rate of fire, revolver and linear action cannons achieve it almost instantaneously. Motion imparted by rotating barrels and vibrations produced by rotation can lead to major reduction in gun accuracy. Gun does have to be placed in a way that will avoid ingestion of gasses produced by the aircraft engine. IR missiles are also effective as they help maintain surprise, while radar missiles are only effective against non-maneuvering or lightly maneuvering targets.
In order to facilitate road basing, wing span should be less than 8,75 meters, with 7,4 meters being optimum. In order to facilitate dirt strip basing, air intakes should be 100-170 cm above the ground to minimize possibility of FOD ingestion, and should have FOD screens. Wheels should also be proportionally large.
Number of engines
Single engined fighters tend to be smaller, lighter, cheaper to buy and operate, easier to maintain and better optimized aerodynamically (better lift-to-weight, lift-to-drag and thrust-to-drag ratios); they are also regularly more fuel-efficient and have higher fuel fraction. Yet there is a belief that single-engined fighters are inherently less survivable than twin-engined fighters.
While this definetly does hold true for the ground attack aircraft, it is far less clear-cut for fighters. If a twin-engined aircraft loses a single engine, it immediately looses 50% of the thrust and 81% of the performance, making it a sitting duck and easily killed by the opponent. Single engined fighters meanwhile tend to be smaller and lighter, which automatically improves survivability in a dogfight. Further, small size tends to make them easier camouflaged on the ground, and larger number of aircraft in the air can help survivability as well.
Twin engined designs do not necessarily have better peacetime survivability either. F-106, despite being single-engined, had 15 losses in first 90.000 hours, compared to 17 for the F-4. In the first 213.000 hours, it had 26 losses, compared to 44 for the F-4. It can be seen that the more complex F-4 had worse loss rate than the F-106 despite having two engines, and while F-106s loss rate improved, F-4s grew worse. Single-engined F-105 also had low peacetime loss rate, and most losses of both the F-16 and the F-18 were due to human screw-ups. Another reason is the fact that the F-16s are multirole fighters and often fly very fast close to the ground, plus being a first relaxed stability design operational. Swedish JAS-39 has a better safety record than the F-18 despite having one engine less – 13% of Canada’s CF-18s have been lost in crashes compared to 2% of Gripens; a loss rate of 0,36% per year versus 0,08% per year for Gripens. Comparing JAS-39 (Gripen) with EF-2000 (Eurofighter Typhoon), Gripen suffered 5 crashes total in 203.000 flight hours. None were related to either engine or aerodynamic configuration of the aircraft: 2 were due to underdeveloped FCS, 2 were due to the pilot error and 1 was due to ejection seat issue. Typhoon suffered 3 crashes total in 240.000 flight hours. One was due to double engine flameout and two due to unexplained reasons. Rafale suffered 4 crashes in 64.000 hours. F-15 had a crash rate of 2,36 per 100.000 hours. F-18 crash rate is 3,6 per 100.000 hours.
MiG-21 is much maligned in India due to its high crash rate. However, many crashes are not a result of the single-engined design but rather of bad cockpit visibility and high landing speed. Further, MiG-21s have high total crash numbers because they constitute 75% of the IAF fighter fleet. Other problems include lack of simulators and inadequate maintenance. Many MiG-21s, and majority of spare parts, were produced locally in India and were not up to Russian (let alone Western) standards. Lastly, twin-engined MiG-23 actually had higher crash rate than MiG-21.
In the end, theoretical superior peacetime survivability of a twin-engined aircraft is neither large or certain enough to offset lower combat survivability, typically smaller fleet size, higher maintenance downtime and higher operating cost. (A more extensive article regarding single vs twin engined fighter issue will follow sometime after this article).
Engine used will be EJ200 variant, as EJ200 is the modern engine that is closest to turbofan (except for the excessively large PW F119). EJ200 is also designed to have high amount of resistance to FOD, and has a comparably simple design. Like the F414, it uses a blisk (bladed disk) for its fans and compressors, improving maintenability and FOD resistence.
EJ230 variant has been tested in 2010, and EJ270 variant should be avaliable after 2015.
Data is as follows (EJ230):
Dry: 7.348 kgf
Afterburning: 10.478 kgf
Dry: 0,74 kg / kgf*h
Afterburning: 1,7 kg / kgf*h
Dry: 5.438 kg/h
Afterburning: 17.812 kg/h
Pilot’s seat will be reclined back 29 degress to help tolerate the g forces. Standard AoA limit will be 28*.
Basic configuration will be a close-coupled canard-delta. This will allow excellent maneuverability by delaying stall and thus allowing higher maximum lift, and also by reducing drag due to larger amount of vortex lift. Instantaneous turn rate will be significantly improved through dynamic stall, as a stall of pitching up wing gets delayed to angle of attack well above that of a static stall angle. Safety will also be improved, as free-floating close coupled canards make aircraft stable, allowing pilot to use analogue system to fly it without need for a computer help. Close-coupled canard configurations are naturally dynamically unstable as canard moves center of lift forward, and canard is located in wing’s upwash; dynamic instability also allows for better response to control surface inputs than standard static instability does (better pitch rate through the mean angle of attack range and pitch/turn onset rate). A properly positioned canard creates a low pressure region on front part of the wing upper surface which has a significant contribution to lift. However, canard has to be relatively high above wing’s plane else it will reduce lifting ability of the wing at low angles of attack due to canard’s downwash; on the other hand, downwash can serve to reduce wing’s effective angle of attack and delay separation at high angles of attack (cca 18-20* and above). Since aircraft spend combat time at either maximum turn or maximum acceleration, that loss will not adversely affect combat performance, though it will harm STOL performance. Lower-swept wing (44-45*) is less affected by negative effects of downwash on wing lift than higher-swept wings (60*), and presence of the canard may cause it to produce significant amounts of the side-edge vortex lift on the low swept wing. While canard strake can delay the canard stall, there is little effect on the wing lift. Another advantage of a close-coupled canard is greater trim control.
High canard configuration produces significantly more lift at high angles of attack than coplanar or low canard configuration, as well as the most linear pitching moment curve (low canard configuration can in fact decrease lift by causing a formation of the low pressure area at the wing underside). Maximum lift gain with the close-coupled canard can be 20-50% when compared to a sum of lift produced by the canard and the wing on their own, meaning that higher wing loading may be acceptable; larger canards also tend to produce greater lift coefficients, and adding a strake to the canard can improve lift generation capability. In fact, lift gain from a close-coupled canard is typically twice of what could be expected by simply adding canard area to area of the wing itself, though it can be far more (a canard with 9% of the wing area in one case increased maximum lift by 34%). F-4 equipped with a foreplane was able to pull a full g more at 470 kph and 9.000 meters, reducing time needed for a 180* turn by 30 seconds, and had 14 kph lower approach speed. Saab Viggen similarly used canards to increase lift at low speeds and reduce landing and takeoff speeds for STOL capability. Modern unstable close-coupled canards have lift-drag ratios in the level flight and at low AoA comparable to those of the conventional aircraft as canard is trimmed for minimum drag in level flight, while at high AoA there is a large improvement in a lift-to-drag ratio compared to the conventional aircraft in addition to the favorable trimmed lift interference. Both lift and lift/drag ratios are enhanced at all angles of attack above cca 10*, while optimizing canard for maximum lift at 10* angle causes a large drag penalty; for this reason canard will be set to minimize drag at low AoA. Lift enhancement will start above cca 12-15* AoA. Maximum lift coefficient (and thus turn rate) can be expected at 32* AoA. Lift/drag ratio decreases at very high angles of attack, indicating that significant thrust levels will be required, though not as significant as for conventional configuration with thrust vectoring. Increasing the size of canard does increase maximum lift up to canard/wing size ratio of 0,25; any further increases result in a loss of the lift. Presence of canard eliminates wing vortex breakdown, allowing vertical tail to remain effective at comparably high angles of attack, as well as allowing far higher maximum angles of attack to be achieved (110* for close-coupled canard configuration vs 70* for long arm canard configuration). Canard area should be 16-21% of the wing area, and canard trailling area should be slightly in front of the wing leading area and not overlap, else a loss of lift occurs.
In the supersonic flight, close-coupled canards suffer from smaller center of lift shift, maintaining maneuvering advantages of unstable aircraft for longer – studies show that effectiveness of canard in increasing lift and decreasing drag is independent of Mach number. Another advantage is that canard produces upload in supersonic maneuvre while tail produces download as tailed aircraft is now stable, giving a superior lift/drag ratio in maneuvre when compared to tailed aircraft, as well as superior lift-to-weight ratio. Absence of tailplane and the canard’s position above the wing also results in a lower supersonic drag, as there is no interference drag which is present in a tailed configuration. Close coupled canard’s benefits do reduce with increasing Mach number, however, and above Mach 2 may be negative. Canards are best used on aircraft intended for supersonic cruise and transonic maneuver.
When comparing various canard sweep angles (25*, 45*, 60*), 60* swept canard produced maximum lift while maximum L/D ratio was developed with a 25* swept canard; thus a 45* sweep can be considered optimal compromise.
Delta wing allows good lift-to-weight ratio due to the large surface area and relatively low weight of the wing itself. One of reasons for its good lift production is that large part of the wing area is near the wing root, and is thus less affected by the spanwise loss of lift which occurs towards the wing tips. Nonslender delta wings (<55* wing sweep) allow for air flow reattachment even after breakdown reaches the apex of the wing, however vortex generating surfaces (LERX and close-coupled canards) are required for flow reattachment at high angles of attack in the post-stall region. Flexible wing can increase lift and delay stall compared to the nonflexible wing of the same geometry. This effect is helped by vibrations which promote reattachment of the shear layer and thus lift enhancement. Moderate wing sweep angles (around 50°) help formation of semi-open separation bubbles, helping flow reattachment.
Region between the trailling vortices is also subject to downwash, which affects the classical tail control surfaces. Trailling-vortex drag also represents approximately 75% of the drag in maneuvering combat and 50% in subsonic cruise. For this reason aspect ratio (span squared divided by wing area) has a major influence on drag. Low span loading reduces drag in both cruise and maneuvering flight; as a result, low wing sweep wings are more efficient. However, aspect ratio for combat aircraft should not be higher than 3,5, as wave drag is dominant at supersonic speeds. Relaxed static stability combined with delta wing means that elevon trimming loads in level flight are positive, with elevons adding to lift. Another effect is a reduction of supersonic trim drag. Delta wing also has a benefit of more gradual transonic drag rise and lower supersonic peak drag. 45* wing sweep is the minimum required for efficient supercruise.
Additional benefit of the delta wing is reduction of aerodynamic centre shift. Combined with similar effects of the close-coupled canards, this results in a major increase in a supersonic maneuverability, as well as greater possible variation in external loads. With unstable delta wing trimming actually improves lift in level flight by 20% or more.
Using sharp LERX (maneuver strake) combined with close-coupled canard can promote vortex interaction, strengthening wing and inner canard vortices and delaying air flow separation further than either device could do by itself. Canard leading edge vortex will also move downwards and inwards (improving body lift) and LERX vortex will move outwards (improving wing lift); outer canard vortex will remain unaffected and energize outer portion of the wing. Maneuver strake is best combined with relatively low-sweep wing. LERX also improves typical benefits of a standard delta wing, which are a consequence of a large amount of the vortex lift. Aside from delaying air flow separation and thus improving maximum lift, these vortices also serve to improve directional stability and spin recovery characteristics, although none of these benefits are as pronounced with LERX as they are with close-coupled canards; best effects are achieved by using both canards and strakes. This allows wing to be smaller for the same amount of maximum lift, thus reducing wing span and roll inertia.
Overall, delta wing with close-coupled canards produces significant improvements in maneuvering ability and controllability in all axes, including those typically thought to be exclusive to thrust vectoring – such as extensive supersonic and post-stall maneuvering capability. To quote John M Kersh: “a properly located closecoupled canard can greatly enhance lift at high angles of attack with no drag penalty when compared to a wing/body configuration. If it is desired to perhaps more elegantly enhance lift at higher angles of attack and avoid some of the pitfalls associated with thrust vectoring — such as the expense, weight penalty, and excessive fuel consumption — the use of a close-coupled canard may be an excellent choice.” Close coupled canards provide a natural resistance to departure from a controlled flight, and unlike long-coupled canards, they have proven spin recovery capability for complete cg and AOR range as well as superstall recovery capability.
In order to reduce drag, all pylons should have sharply swept leading edge. Straight tip with launcher rail can improve lift/drag ratio of wing, and cropping required to mount the launcher rail avoids tip drag at high angles of attack. When aircraft reaches a transonic region, wave drag appears, causing a major rise in a total drag. At supersonic speeds, wing sweep is required to reduce wave drag and avoid usage of sharp leading edges, which would cause unacceptable maneuvering performance. Another cause of supersonic drag is trim drag; since aerodynamic centre moves aft with increasing speed, greater control surface deflection is required to negate any pitch-down moment. Since close-coupled canard-delta aircraft suffer from a smaller aerodynamic centre shift at supersonic speeds compared to the tailed configuration, thus reducing trim drag, they would appear to be ideal for supersonic cruise. There is also no adverse tailplane / afterbody pressure drag interference. Wing does have to be stiffer as trailling edge surfaces are ones providing roll control. Wingtip launcher rail can improve lift/drag ratio. Frontal crossectional area should be reduced as much as possible in order to keep drag down, and airframe should conform to the area ruling – while not necessary for the supersonic flight, it results in a major transonic drag reduction. Area ruling means that body crossectional area should be reduced as wing crossection increases. Tail cone can be long and without control surfaces in order to reduce aft body drag; this will also allow usage of air brakes.
Vertically, wing should be positioned mid-body with large degree of wing-body blending. Beneficial effects of such configuration include reducing drag in level flight (due to elimination of interference drag from wing-body juncture as well as reduction in wave drag), increasing lift at high angles of attack and increasing avaliable fuel volume. Disadvantage is a heavier structure due to need to reinforce the wing structure at base of the wing. Negative dihedral can be incorporated in order to increase roll sensitivity.
Wing thickness should be 3-4% near the tip and 6-8% near the root to reduce supersonic drag and eliminate shock stall. Any lower thickness would lead to too heavy wing and too much drag due to the lift. Separation due to the low thickness can be supressed with leading-edge flap, leading to improved airfield performance and reduced drag. Aerofoil should be supercritical.
Trailling edge control surfaces (ailerons/flaperons) should be sharp. Outboard aileron placement provides large moment arm when rolling, but this limits allowable wing twist due to aileron reversal effect, requiring stiffer wing. Inboard placement allows for a more flexible wing. However, canards can help prevent wing tip stall, and high lift devices are better placed inboard in order to reduce fatigue on the wing. Ailerons should also be relatively large so as to allow acceptable roll response during times when wing is generating large amount of lift.
Leading edge flaps can be used in a sawtooth configuration to help prevent the separation on the outboard part of the wing by producing vortex. This vortex also helps improve the longitudinal stability and reduce the buffet levels, as well as prevent the outboard spread of the stall. Flaps can also reduce drag by 10-20% for a given lift coefficient. High lift devices should take up cca 70% of the wing span and =<20% of the wing chord.
Rafale-style air intakes provide good air flow at high sideslip angles and angles of attack. Boundary layer means that the intakes will be offset from the fuselage by 1% of their distance from the nose, by using a boundary layer bleed. Inlet placement will energize the airflow over the wing and around the vertical tail fin; combined with LERX and canards, it will allow much higher controlled angle of attack, and reduce drag. However, intakes also have to be placed in front of canards in order to stop the wake from canard from entering the intakes, and they should also be in front of the front wheel to prevent FOD damage.
Landing gear bay doors should open forward, acting as air brakes when landing. Canards and elevons should also be used as air brakes. Landing gear itself should be of a tricycle configuration, with nose landing gear being just aft or just forward of the air intakes in order to minimize possibility of FOD and aft landing gear being to the sides of the engine. This configuration also makes aircraft directionally stable while taxiing, improving safety during cross-wing landing. It also allows a better view for the pilot while landing. Nose gear will use two wheels to allow ctapult assisted takeoff. Overturn angle (angle between vertical axis going from center of gravity and the line between center of gravity and main gear wheel) should be at least 25*. Angle between the wheel base and lower end of the engine nozzle should be at least 15-20 degrees. Nose wheel will be steerable.
IR signature should be reduced as much as possible. Largest source of the IR signature on the aircraft is the engine, due to both exhaust plume and rear airframe heating. Since usage of afterburner leads to a major increase in IR signature, it should be minimized. This video quite clearly shows the effects of airframe heating due to the engine operation as well as the effects of afterburner usage. Non-afterburning plume actually has less significant IR signature level (IRSL) than tailpape and rear fuselage skin, since only IR radiation from broadening wings of the plume reaches the IR detector. Notched nozzle can reduce the length of the hottest part of the plume and facilitate radial spreading of the jet exhaust and its mixing with the ambient air.
Other sources are aerodynamic heating of the airframe, sunshine and earthshine reflections and electronics. Parts of the airframe that are most subject to the aerodynamic heating are those in most direct contact with the air stream – aircraft nose, wing and vertical tail leading edges, inlet lips, drop tank and missile noses. Swept pylons might reduce IR signature somewhat, but greatest reduction is avoiding usage of drop tanks. Minimizing amount of electronics also reduces the need for cooling, reducing IR signature. IR absorbent paint is another possibility, but some such paints increase aerodynamic drag, thus increasing IR signature.
RCS, while not as important as visual, IR and EM (electromagnetic emissions) signatures, should not be ignored, as smaller RCS provides more time for RWRs to sort out incoming radar signals, and increases effectiveness of ECM. Many aerodynamic and IR signature reduction characteristics will also reduce the RCS, such as swept wings and pylons. Engine front face should be shielded, and landing gear bay doors should have swept or sawtooth design on leading and trailling edges.
Nose will be as short as possible and pointed downwards to allow for a good over-the-nose visibility, while still providing enough room for required equipment (sensors). Strakes can be used to help stabilize the vortices and prevent adverse yaw. Elliptical nose is stabilizing along the longer but destabilizing along the shorter axis – horizontally aligned elliptic nose produces a significant pitch-up moment. While horizontally stabilizing nose may be beneficial in preventing a spin, it can aso prevent, or make more difficult, a spin recovery if spin actually develops.
Cockpit should have a bubble canopy with relatively high-positioned pilot seat in order to provide as good visibility as possible, not only over the nose but also rearward and over the side. Visibility should be 360* horizontal, 15* over-the-nose and 40* over-the-side, though having a fixed windshield might be useful in the event of the canopy failure.
Vertical tail fin will be located at top of the aft fuselage. Height from the ground to the top of the vertical fin should be less than 4,8 meters, though larger fin might be required for sufficient directional stability. Destabilising effect of the forward fuselage depends on the fuselage height squared and the length ahead of the centre of gravity. It will have dorsal fairing to increase effectiveness at high sideslip angle. Ventral fins might be used to reduce the need for large dorsal tail fin, as they are mounted in the clean air at high angles of attack.
Wing loading at combat configuration should be between 190 and 280 kg/m2, with target goal being around 250 kg/m2. Wing span should be less than 8,5 meters, preferably around 7,4 meters. Aside from improving basing ability, low wing span will improve roll performance. Low wing loading improves airfield performance, instantaneous and sustained turn rates at both subsonic and supersonic speeds, and ceillings.
RWR antenna spacing of 25 wavelengths is required for 0,1* accuracy. As X-band radar has a wave length of up to 3,75 cm, 94 cm distance between receivers will be required. On the other hand, antennas should be placed as close possible to the body of the aircraft so that there is a minimum of aeroelastic warping, and spacing of 9,4 cm is enough for 1* accuracy.
Design outline – summary
* single engine
* wingspan between 7,4 and 8,74 meters
* front landing gear behind air intakes
* large wheels and wide landing gear base
* ground clearance 100-170 cm
* IRST a primary sensor
* good visibility from cockpit (360* horizontal, 15* over the nose, 40* over the side)
** 16,35* over the nose achieved
* 45*-55* wing sweep
* high fuel fraction
* canard area 16-21% of the wing area; canard sweep 45*
* LERX sweep 73*
* wing aspect ratio <3,5 * wing thickness 3-4% at tip, 6-8% at the root * flaps 70% of the wing span * air intakes akin to Rafale * Overturn angle (angle between vertical axis going from center of gravity and the line between center of gravity and main gear wheel) >=25*.
* Angle between the wheel base and lower end of the engine nozzle >=15-20 degrees.
* notched engine nozzle
* 4,8 m from ground to top of the vertical tail fin
* RWR antenna spacing >94 cm
As PIRATE has 40 km identification range (target of unknown size), 80 km range MICA IR should be more than adequate as a basic BVR missile, with Meteor being used in beyond radar range engagements with RWR providing the IFF. MICA can also be used as a secondary IRST, allowing better coverage of a frontal area than PIRATE by itself would allow.
Basic WVR missile will be IRIS-T, with other options being A-Darter and Python 5. IRIS-T is capable of 60 g peak at Mach 3 with weight of 87,4 kg and range of 25 km, while A-Darter should be capable of 100 g peak at Mach 3 with weight of 93 kg and range of 10 km.
To compare, Mach 1 at 30.000 feet is 589 knots, and at 40.000 feet and above it is 573 knots. As pointed out here, in order to pull as tight turn as a fighter aircraft, missile has to pull amount of g that is amount of g’s aircraft can pull multiplied by difference in speed squared. This means that A-Darter will have 2,1 times as wide turn radius as a Rafale pulling sustained 9 g turn at 360 kts at 40.000 feet. When avoiding the missile, however, roll and instantaneous turn performance are more important. Rafale pulling 10 g at 440 kts will result in Darter having 2,7 times as large turn radius as Rafale. This makes it clear that missiles are not end-all of aerial combat, and gun is still necessary.
Gun will be French GIAT 30 due to high firing acceleration, rate of fire and round weight combining to give it highest firepower of all current cannons in first half a second; round weight combined with high muzzle velocity gives it large effective range. This can be seen when comparing the GIAT 30 with M61 and BK.27.
Data is as follows:
Gun: GIAT 30
Round weight: 530 g
Projectile weight: 275 g
HE/I content: 17,5%
Muzzle velocity: 1.025 m/s
Maximum rate of fire: 2.500 rpm
Time to max RoF: 0,05 s
Rounds in first 0,25 s: 9
Rounds in first 0,5 s: 19
Weight in first 0,25 s: 2,48 kg (0,43 kg HEI)
Weight in first 0,5 s: 5,23 kg (0,92 kg HEI)
High acceleration and rate of fire, heavy round weight, high HE/I content and high muzzle velcoity combine to make GIAT 30 the best air-to-air cannon in existence. Rate of fire can be reduced to 1.500 rpm, giving 12 rounds and 3,3 kg in first 0,5 s.
Round weight: 263 g
Projectile weight: 100 g
HE/I content: 11%
Muzzle velocity: 1.030 m/s
Maximum rate of fire: 6.600 rpm
Time to max RoF: 0,5 s
Rounds in first 0,25 s: 13
Rounds in first 0,5 s: 27
Weight in first 0,25 s: 1,3 kg (0,14 kg HEI)
Weight in first 0,5 s: 2,7 kg (0,3 kg HEI)
As it can be seen, GIAT 30 can throw 190% as much weight and 300% as much HEI in first 0,25 s, or 194% as much weight and 307% as much HEI in first 0,5 seconds.
Round weight: 516 g
Projectile weight: 260 g
HE/I content: 15%
Muzzle velocity: 1.100 m/s
Maximum rate of fire: 1.700 rpm
Time to max RoF: 0,05 s
Rounds in first 0,25 s: 7
Rounds in first 0,5 s: 14
Weight in first 0,25 s: 1,82 kg (0,27 kg HEI)
Weight in first 0,5 s: 3,64 kg (0,55 kg HEI)
BK-27 has advantage in firepower over the M61A2 but it can only throw 73% as much weight and 63% as much HEI as GIAT 30 can in first 0,25 seconds, or 70% as much weight and 60% as much HEI in first 0,5 seconds. It only surpasses GIAT 30 in destructiveness if latter’s rate of fire is reduced to 1.500 rpm.
Sensors, communications and defense suite
Primary sensor will be Skyward IRST coupled with Type 158 laser rangefinder. Rangefinder will be turreted.
Defense suite will be SAABs IDAS-3. Radar warning system will cover UHF-Ku bands, and use interferometric technology for 1* accuracy and geolocation capability. Internal jammer will be DRFM MDS. Missile warning will be provided by IR version of MAW-300. Brite Cloud decoy jammers will be used in dispensers. Each dispenser will have 39 flares or 19 decoys. While typical flares are ineffective against imaging IR missiles, liquid fuel pyrophoric decoys might provide some level of effectiveness against them, depending on wether missiles in question are designed to home in on the exhaust plume or the airframe itself. BriteCloud decoy will be the primary jamming device as internal jammer can cause missiles to home in on the jammer’s emissions. This is not very likely with a DRFM or deceptive jamming, but it does mean that using more classical types of jamming (barrage, base and possibly pulse) is not advisable, and that offboard jamming devices are a preferred option. Internal jammer can still be useful for jamming missile’s radar or fuse.
Data link will be MIDS FDL, and radio will be IDM. IDM also has ability to act as a secondary data link.
If necessary, an X-band air-to-air radar will be used in an external pod – this should be primarly useful for intercepting bombers and transports, though a dedicated bomber interceptor aircraft (such as the F-15 variant) is a preferred option, with FLX left free to focus on the air superiority.
HUD will be same as in Gripen.
Helmet will not have HMD or it will be optional; it will however provide HOBS capability. As a result, current Tornado helmet might be the best option; another possibility is to mount Scorpion HMCS on a relatively lightweight helmet, or simply use a wire aid.
HMD might however be helpful for night and bad-weather flying, in which case Thales Topsight E will be used.
Before using the HMD, a basic night vision gear should be tested for the purpose.
It should be interesting to note that a first powered fixed-wing manned aircraft, 1903 Wright Flyer, was an unstable canard-wing configuration. In Flyer’s case, canard provided only control power and not lift. First jet fighter to use wing sweep for its aerodynamic advantage, as well as first fighter to use LERX to increase wing lift at high AoA was Saab J29 Tunnan. J-35 Draken was the first double delta and remained in service for 45 years. Saab Gripen was second modern canard-delta design, entering production only one year after Dassault Rafale.
Forebody: 5.280 cm2 = 5,7 ft2
Air ducts: 114*2*39*pi + 2*350*19*pi = 27.935 cm2 + 41.783 cm2 = 69.718 cm2 = 75 ft2
Canards: 10.122 cm2 = 10,9 ft2
Wings: 203.644 cm2 = 219,2 ft2
Vertical stabilizer: 33.496 cm2 = 36 ft2
Fuselage: 524 cm*764 cm + 415*230 cm = 495.786 cm2 = 533,7 ft2
Splitter plates: 5.300 cm2 = 5,7 ft2
Forebody: 9,7 kg * 2
Air ducts: 128,1 kg * 2
Canards: 18 kg * 2
Wings: 336 kg * 2
Vertical stabilizer: 58,9 kg
Fuselage: 911,1 kg * 2
Splitter plates: 10 kg
Total: 2.874,7 kg
Wing + body: 177.160 + 168.270 + 34.000 = 379.430 cm2 = 37,9 m2
Wings themselves: 121.626 px2 * 2 = 243.252 cm2 = 24,3 m2
Canards: 5.061 px2 * 2 = 10.122 px2 = 1,01 m2
If standard wing area calculation approach is included (that is, includes surface of body between the wings, as seen here), then FLXs wing area is 32,4 m2.
EJ230: 1.235 kg installed weight, 4 m length, 0,737 m diameter
GIAT 30: 120 kg, 2,4 m length
Skyward IRST: 30 kg * 3
Type 158 laser transciever: 3,4 kg * 1, 251x105x104 mm
RWS-300 Dual Front End Receiver: 2,5 kg * 2; 170x40x220 mm
RWS-300 0,7-40 GHz Spiral Antenna: 0,5 kg * 6; 110x110x67,5 mm
LWS-310 sensor: 1 kg * 4; 115x90x76 mm
MAW-300 sensor: 2,2 kg * 4; 134x130x130 mm
BOP dispenser: 2 kg * 8; 236x128x270 mm
Flare: 0,215 kg * 156
BriteCloud decoy/jammer: 0,7 kg * 76, 200 mm l
MDS DRFM jammer: 5,9 kg * 1, 121x149x305 mm
Skyward IRST processor unit: 25 kg * 1
Laser electronics unit: 1,3 kg * 1; 150x103x75 mm
EWC-300 Controller: 10 kg * 1; 193x359x124 mm
Safety switch unit: 0,7 kg * 2, 82 mm length, 65 mm width, 11 mm height
FCS: 16 kg * 2, 85 mm length, 85 mm width, 55 mm height
System, navigation: 15,6 kg * 2, 386 mm length, 191 mm width, 191 mm height
TDCU: 2 kg * 1; 128x127x120 mm
HUD: 15 kg * 1
Screens: 5 kg * 2
IDM: 3,8 kg * 1; 188x91x224 mm
Terminal: 16,8 kg * 1; 340x190x190 mm
RPS: 6,5 kg * 1; 340x60x190 mm
Antennas: 2,2 kg * 3
Ejection seat: 59 kg
Titanium landing gear: 315 kg
Electrical: 90 kg
Environmental control, pressurization, oxygen: 100 kg
Hydraulics, actuators: 90 kg
Missile rails: 12 kg per rail
Refueling probe: 50 kg
EPU: 79 kg
Canopy: 130 kg
Pilot w/ G suit, helmet, Mae vest, personal weapon: 100 kg
Total: 2.800,44 kg
3.751.600 cm3 – side fuel tanks
1.551.000 cm3 – wing tanks
5.302.600 cm3 total
3 x 450 gal (5.109 l total) or
1 x 450 gal + 2 x 300 gal (3.975 l total) or
3 x 300 gal (3.408 l total)
Standard fuel will be JP-8, a military version of JET-A with corrosion inhibitors and anti-icing additives and density of 0,804 kg/l. JET-A itself can also be used, and it has the same density.
Maximum internal fuel: 4.263 kg
Maximum external fuel (subsonic): 4.108 kg
Maximum fuel (subsonic): 8.371 kg
Maximum external fuel (supersonic): 2.740 kg
Maximum fuel (supersonic): 7.003 kg
Gun ammunition weight
Ammo box: 750*240*180 mm
Total ammo: 8*25 = 200; 106 kg
External stores weight
IRIS-T: 87,4 kg
MICA IR: 112 kg
Meteor: 185 kg
300 gal tank: 167,4 kg (empty), 1.087,56 kg (full)
Design empty: 5.275 kg
Basic empty (design empty + unusable fuel, undrainable oil, survival equipment): DE + 85,26 + 9,89 + 72,7 = 5.442,85 kg
Operational empty (basic empty + crew, weapons racks, ejectors, gun, etc.): BE + 100 + 12*4 = 5.590,85 kg
Armed empty (operational empty + gun ammo, missiles): OE + 106 + 2*87,4 + 6*112 = 6.543,65 kg
Combat (armed empty + 50% fuel): AE + 2.088,87 = 8.632,52 kg
Combat takeoff (armed empty + 100% fuel): AE + 4.177,74 = 10.721,39 kg
Maximum takeoff (practical): Operational Empty + Internal Fuel + Gun Ammo + 2 MICA IR + 6 MBDA Meteor + 3×450 gal fuel tanks: 5.580,85 + 4.177,74 + 106 + 2*112 + 6*185 + 3*1.485 = 15.663,59 kg
Maximum takeoff (theoretical): 16.200 kg
NOTES: 2% of the fuel is not usable; oil is 1% of the engine weight; pilot weights 100 kg with equipment; theoretical maximum takeoff weight is calculated with [weight in kg = dry thrust in lb]; practical maximum takeoff weight includes 100% internal fuel and heaviest designed loadout; standard armed emptyassumes gun ammo, 2 IRIS-T and 6 MICA IR; empty weight of EFT is 10% of its fuel capacity.
Point-defense takeoff (armed empty + 30% f.f.): 6.533,65 + 2.800,14 = 9.333,79 kg
Point-defense combat: 6.533,65 + 1.400,07 = 7.933,72 kg
Minimum takeoff distance
Takeoff distance is 650 meters for Gripen C and 600 meters for Gripen E. Wet TWR is 0,82 for C and 0,89 for E. This means that 9% increase in TWR means 8% decrease in the takeoff distance – even more actually, since the Gripen NG has higher wing loading.
As a rule of thumb, 10% increase in takeoff weight increases the takeoff run by 21%.
10% increase in landing weight increases the landing run by 10%.
10% increase in wing area (9% decrease in wing loading) decreases the takeoff speed by 5%. Roll is proportional to the square of the takeoff or landing speed.
Compared to concrete, dry grass increases the takeoff run by 15%. It also increases the landing roll.
Rafale Cs takeoff distance at a concrete runway is 820 m dry, 590 m AB, with 490 m landing roll. Its combat takeoff weight is 14.942 kg, with a wing loading of 327,61 kg/m2 and thrust-to-weight ratio of 1,007 wet or 0,665 dry. Landing weight is cca 10.500 kg (est.), with wing loading of 230 kg/m2 and thrust-to-weight ratio of 1,436 wet or 0,948 dry.
FLX combat takeoff weight is 10.721,39 kg kg, with a wing loading of 330,9 kg/m2 and thrust-to-weight ratio of 0,977 wet or 0,685 dry. Landing weight is 6.728,61 kg, with wing loading of 207,7 kg/m2.
Wing loading increases takeoff roll by 0,5%. Weight difference means reduction of takeoff roll to 56,43%. TWR difference decreases takeoff roll by 3% at dry thrust and increases it by 1% at wet thrust. This means that FLXs takeoff distance is 451 m dry, 338 m AB at concrete air strip and 519 m dry, 389 m AB at grass strip.
Lower wing loading reduces landing roll to 99%. Weight difference reduces landing roll to 64%. This means that FLX has 310 m landing roll at concrete air strip and 357 m landing roll at grass strip.
FLX point defense takeoff weight is 9.333,79 kg, with a wing loading of 288,08 kg/m2 and thrust-to-weight ratio of 1,12 wet or 0,79 dry. Wing loading decreases takeoff roll by 1,5%. Weight difference means reduction of takeoff roll to 32%. TWR difference decreases takeoff roll to 87% at dry thrust and 90% at wet thrust. This means that FLX has takeoff distance of 225 m at dry thrust and 167 m at afterburner.
Time for takeoff
Dassault Rafale needs 8 seconds to take off in full afterburner. FLX would thus need 6,3 seconds for takeoff with afterburner at normal weight and 5,1 seconds at point defense takeoff weight.
Rafale C has a dry TWR of 0,790 at combat weight and cruise speed of Mach 1,4. 90 kN M88, which would give a dry TWR of 0,972, would increase it to Mach 1,65 (both speeds are with 6 missiles). 4 missiles add speed penalty of 0,1 M, it means that 23% increase in dry TWR increases cruise speed by 17,2%. As FLX has a dry TWR of 0,851 at combat weight, its cruise speed should be 5,79% above Rafale Cs when clean, or Mach 1,59; with 8 missiles, it should be Mach 1,49. Maximum speed will be limited to Mach 2,0 by air intake design.
7* increase in wing sweep increases the cruise speed by Mach 0,1. Since wing sweep is 50* as opposed to Rafale’s 48*, calculated cruise speed will be increased by Mach 0,03, to Mach 1,62 with 4 missiles and 1,52 with 8 missiles.
Rafale C accelerates from M 0,8 to M 1,2 in 26 seconds with 4 MICA and 50% fuel. In same configuration, FLX would need 24 seconds for acceleration of M 0,8 to 1,2.
Climb rate and service ceilling
Time to 10.000 meters is 100 seconds for Gripen C, while Gripen NG should better this by 10-15%, again shoving a roughly proportional increase in performance compared to dry TWR. Initial climb rate for Gripen C is 15.240 meters per minute, or 254 meters per second. Initial climb rate for Dassault Rafale is 18.300 meters per minute, or 305 meters per second, with 18.000 m / 59.055 ft service ceilling. From that it would follow that Rafale can climb to 10.000 meters in ~83 seconds.
FLX has dry TWR of 0,685 at combat takeoff weight, compared to 0,665 for Rafale. Thus FLX should be able to climb to 10.000 meters in 81 second, with initial climb rate of 313 meters per second, and service ceilling of 18.457 m / 60.513 ft.
At point defense takeoff weight, it has dry TWR of 0,79. Thus it should be able to climb to 10.000 meters in 70 seconds with initial climb rate of 362 m/s.
9% decrease in wing loading decreases speed by 5%. Rafale has wing loading of 275,6 kg/m2 at combat weight, compared to 266,13 kg/m2 for the FLX. Assuming that the effect is similar, this means that turn speed for instantaneous turn will be reduced by 2%. This will improve instantaneous turn rate by 2,9%. Since FLX has slightly higher wing sweep but also higher TWR and similar overall aerodynamics, same will be assumed for sustained turn rate; that is, turn speed for sustained turn will be reduced by 2%, and turn rate increased by 2,9%.
Roll rate will be assumed to be similar to Rafale’s. It should be notes that this is FCS limit, and aerodynamics would allow significantly higher maximum roll rate. More importantly, FLX will have more rapid roll onset than any fighter in existence due to combination of aerodynamics and small wing span.
Instantaneous turn rate: 31 deg/s
Sustained turn rate: 25 deg/s
Roll rate: 300 deg/s
Gripen C uses 48,5% of the fuel for subsonic cruise from and to the combat area, giving 1.164 kg of fuel for 800 km trip (400+400), or 1,455 kg/km in air-to-air configuration. Novi Avion had range of <940 km (est.) at 2.565 kg of internal fuel, for 1,323 kg/km, presumably clean. A value of 1,3 kg/km (1.276,47 kg/h) will be used for FLX due to its smaller size and superior aerodynamics compared to those of Novi Avion. Fuel consumption at maximum dry thrust is 5.438 kg/h and at maximum reheat it is 17.812 kg/h.
Time and fuel usage:
startup and taxi: 77 kg
takeoff: 31,17 kg
climb to 10.000 meters: 122,36 kg
supersonic cruise: 1.812,67 kg
combat: 594 kg
descent and landing: 75 kg
landing reserve: 24,7 kg
unusable fuel: 85,26 kg
cruise to and from combat area: 1.355,58 kg
Supersonic combat radius without combat area cruise: (3.168,25 kg of fuel)
Internal fuel: 470 km @ M 1,52
1×300-gal EFT: 501 km @ M 1,42
3×300-gal EFT: 538 km @ M 1,22
Subsonic combat radius with supersonic cruise: (1.355,58 kg of fuel)
Internal fuel: 521 km
1×300-gal EFT: 813 km
3×300-gal EFT: 1.398 km
Subsonic combat radius without combat area cruise: (3.168,25 kg of fuel)
Internal fuel: 1.218 km
1×300-gal EFT: 1.391 km
3×300-gal EFT: 1.737 km
1×450-gal EFT: 1.477 km
3×450-gal EFT: 1.996 km
Ferry range: (3.762,25 kg of fuel)
Internal fuel: 2.894 km
1×300-gal EFT: 3.240 km
3×300-gal EFT: 3.932 km
1×450-gal EFT: 3.413 km
3×450-gal EFT: 4.451 km
Range in point defense interception (no combat area cruise, no external fuel tanks)
Time and fuel usage:
startup and taxi: 77 kg
takeoff: 25,23 kg
climb to 10.000 meters: 105,74 kg
supersonic cruise: N/A
combat: 594 kg
descent and landing: 70 kg
landing reserve: 24,7 kg
unusable fuel: 85,26 kg
cruise to and from combat area: 1.818,21 kg
Subsonic combat radius without combat area cruise: 699 km
Supersonic combat radius without combat area cruise: 269 km
Speed of the sound at 30.000 ft is 1.091 kph or 303,1 mps. FLXs supercruise speed in combat configuration is likely achieved at ~40.000 ft, where speed of sound is 1.062 kph or 294,9 mps.
Climb is at full military power.
50% of the fuel in the external fuel tank is used to counter increased drag.
300 gal tank has 920 kg of fuel; this gives 900 kg of usable fuel.
450 gal fuel tank has 1.350 kg of usable fuel.
Weight of a drop tank is 10% of its capacity in kg, without a pylon.
Combat wing loading should be 250-325 kg/m2.
Cruise speed, climb rate, sustained turn rate and roll rate will actually be better than indicated here due to the FLX being a single-engined design while Rafale is a twin-engined design.
Gripen C has a unit flyaway cost of 44 million 2014 USD at 6.800 kg, or 6.471 USD/kg. Gripen Es unit flyaway cost is 43 million USD; at 7.100 kg this gives 6.056 USD/kg.
Rafale C has a unit flyaway cost of 92,7 million USD at weight of 9.550 kg. Removing one engine would reduce weight by 897 kg and cost by maybe 4,3 million USD (assumption based on the F414), leading to a cost of 88,4 million USD and weight of 8.650 kg, for 10.220 USD/kg.
FLXs unit flyaway cost will be assumed to be 7.582 USD/kg. At operational empty weight of 5.590,85 kg, this gives a unit flyaway cost of 42.392.000 USD.
RWR antenna spacing of 25 wavelengths is required for 0,1* accuracy. As X-band radar has a wave length of up to 3,75 cm, 94 cm distance between receivers will be required. On the other hand, antennas should be placed as close possible to the body of the aircraft so that there is a minimum of aeroelastic warping, and spacing of 9,4 cm is enough for 1* accuracy.
A finished design has minimal RWR spacing of 152 cm or 40,5 wavelengths. This means that FLXs RWRs will have accuracy of 0,062*. AIM-120 has seeker range of 12 nm, AIM-54 of 11 nm and MICA of 10 nm (10 nm = 18,52 km).
This can then be used to determine maximum range at which missile can be used in theory. By using arbitrary 9 km effective seeker range (1/2 of MICA’s maximum seeker range) and +-45* search angle, we get 0,062 = 2 arcsin (0,5*9/d); 0,062 = 2 arcsin (4,5/d); 0,032 = arcsin (4,5/d), 4,5/d = sin (0,032); 4,5/d = 0,032; 0,032 d = 4,5; d = 141 km. Even with a safety factor, it is clear that the FLX will be capable of engaging radiating fighters at well over 100 km. With 18 km seeker range and +-45* search angle, engagement range of 281 km is possible, and if search angles greater than +-45* are allowed, engagement ranges of well over 300 km (up to 578 km with +-90* search angle) are possible.
Using AIM-120s seeker range of 22 km and 45* search angle, we get 0,062 = 2 arcsin (0,5*22/d); 0,062 = 2 arcsin (11/d); 0,032 = arcsin (11/d); 11/d = sin (0,032); 11/d = 0,032; d = 344 km maximum engagement range. As before, allowing greater search angle allows a significantly greater engagement range.
FLX has similar overall design when compared to Rafale but is much smaller. Rafale has RCS of 0,15-0,3 m2 from front, so FLXs RCS could be 0,1-0,2 m2. With 8 missiles, and considering that 4 of these have no pylons, RCS will be 0,65-1,00 m2. To take Su-35, it will detect FLX with radar at 255-284 km, and will start locking on at 204-227 km.
However, with jamming, reduction in range can be as much as 78%:
In that case Su-35 will start locking on at 45-50 km. Electronic acquisition will take at least 10 seconds, against cooperative target, and in this situation several times longer. With Mach 2,69 mutual approach speed (1,49 + 1,2 supercruise), 10 seconds means that distance between fighters will decrease by 8,15 km; 30+ seconds which is more likely means that distance between fighters will decrease by 24,5 km. Consequently, Su-35 can launch a missile at 20-42 km, and even then it may not know target’s identity due to lack of good IRST and FLX remaining passive. In all cases (20 – 220 km launch distance), Su-35 will be vulnerable to passive attack by the FLX using radar warners for targeting.
Length: 13,1 m
Wingspan: 8,5 m
Height: 3,44 m
Wing area: 32,4 m2
Canard area: 1,01 m2
Empty weight: 5.442,85 kg
Loaded weight: 10.721,39 kg
Combat weight: 8.632,52 kg
Maximum takeoff weight: 15.663,59 kg
Maximum internal fuel: 4.263 kg
Fuel fraction: 0,44
Powerplant: 1xE230 afterburning turbofan
dry thrust: 72 kN (16.200 lbf / 7.348 kgf)
wet thrust: 103 kN (23.100 lbf / 10.478 kgf)
Maximum speed: Mach 2,0
Cruise speed: Mach 1,52 with 8 missiles, Mach 1,62 with 4 missiles
Combat radius on internal fuel:
521 km standard mission profile
1.218 km maximum
2.894 km on internal fuel
4.451 km with max. fuel
Service ceilling: 60.513 ft
Climb rate: 313 m/s
331 kg/m2 combat takeoff
266 kg/m2 combat
0,98 combat takeoff
Instantaneous turn rate: 31 deg/s
Sustained turn rate: 25 deg/s
Roll rate: 300 deg/s
Guns: 1xGIAT-30 with 200 rounds
3 * Skyward IRST (150 km range, 170* field of regard)
1 * Type 158 laser transciever
6 * RWS-300 RWR (100-300 km engagement range)
4 * LWS-310 LWR
4 * MAW-300 IR MAWS
internal DRFM jammer
disposable jammers / decoys
Unit flyaway cost: 42.297.000 USD
Operating cost per FH: 4.600 USD
3D designs by Riley Amos and Alex Postevca (added 15.11.2017.)
Fighter pilots with modern anti-g suit and appropriate (inclined) seat can handle 9 g sustained maneuvers and short g peaks far in excess of that.
Limit load is the maximum load expected in service, and there must be no permanent deformation of structure at the limit load. Ultimate load is defined as a safety factor times the limit load, and aircraft must be capable of withstanding the ultimate load for 3 seconds without the structural failure. For fighter aircraft, safety factor is 1,5, and 1,85 for naval variant. Naval variant of FLX will thus have limit load of 9 g.
With baseline EJ200 (20.250 lbf / 9.185 kgf), thrust-to-weight ratio would be 1,07 at combat weight and 0,86 at combat takeoff weight. Dry TWR at combat weight would be 0,71, leading to cruise speed of Mach 1,32 clean and 1,22 with air-to-air loadout.Canard area is 5% of the wing area in the final design, about same as it was for Rafale A. This means that lift gain should be 10-20%, possibly 20-30% when combined with LERX.
Engine should have multi-fuel capability.
200 cannon rounds gives 18 0,5-second or 8 1-second bursts at 1.500 rpm, or 10 0,5-second or 5 1-second bursts at 2.500 rpm.
If necessary, GIAT 30 could be replaced with BK-27. This would give 205 27 mm rounds for the same weight, and a total of 14 0,5-s bursts or 7 1-s bursts, but at significantly lower per-burst destructiveness (0,55/1,09 kg of HEI vs GIAT 30s 0,92/1,88 kg of HEI).
3D design by Riley Amos (added 16.8.2016.)
Existing missiles to be used
Weight: 87,4 kg
Length: 2,94 m
Diameter: 0,127 m
Wingspan: 0,447 m
Operational range: 25 km
Flight altitude: SL to 20 km
Speed: Mach 3
G load: 60 g
Seeker: passive IR
Weight: 112 kg
Length: 3,1 m
Diameter: 0,16 m
Wingspan: 0,32 m
Operational range: 50 km
Flight altitude: SL to 11 km
Speed: Mach 3
G load: 50 g
Seeker: passive IR
Weight: 185 kg
Length: 3,65 m
Diameter: 0,178 m
Operational range: >315 km (ballistic flight path); 100 km (straight line)
Speed: Mach 4
G load: 40 g
Seeker: passive anti-radiation with secondary active RF mode
BVR missiles proposals
Weight: 180 kg
Operational range: >250 km
Seeker: passive IR
Dual-stage IR missile (IRIS-T + MBDA Meteor)
Weight: 250 kg
Operational range: 300-350 km
Seeker: passive IR
Dual-stage IR missile (MICA IR + MBDA Meteor)
Weight: 275 kg
Operational range: 350-400 km
Seeker: passive IR
Dual-stage anti-radiation missile (MBDA Meteor + AIM-120)
Weight: 315 kg
Operational range: 450-500 km
Seeker: passive anti-radiation with secondary active RF mode
Combat configurations overview
Standard: wingtip stations IRIS-T, underwing and body stations MICA IR
Dogfight: wingtip and body stations IRIS-T, underwing stations MICA IR
Interception: wingtip stations IRIS-T, underwing stations MICA IR, body stations Meteor
Heavy interception: wingtip stations IRIS-T, underwing stations dual rails with MICA IR, body stations Meteor, central station dual rail with Meteor
Long range combat: wingtip stations IRIS-T, body stations MICA IR, underwing stations Meteor
Combat air patrol: wingtip stations IRIS-T, outer underwing and body stations MICA IR, inner underwing and centerline stations 300 gal fuel tanks
Long range patrol: wingtip stations IRIS-T, outer underwing and body stations MICA IR, inner underwing and centerline stations 450 gal fuel tanks
Point defense: wingtip stations IRIS-T, underwing and body stations MICA IR, 30% fuel fraction at takeoff
Performance: dry thrust: 72 kN (16.200 lbf / 7.348 kgf), wet thrust: 103 kN (23.100 lbf / 10.478 kgf), wing area: 32,4 m2
Standard: 8.632,52 kg weight, 266 kg/m2 wing loading, 1,21 TWR
Dogfight: 8.583,32 kg weight, 265 kg/m2 wing loading, 1,22 TWR
Interception: 8.778,52 kg weight, 271 kg/m2 wing loading, 1,19 TWR
Heavy interception: 9.530,52 kg weight, 294 kg/m2 wing loading, 1,1 TWR
Long range combat: 8.924,52 kg weight, 275 kg/m2 wing loading, 1,17 TWR
Patrol: 10.497,39 kg weight, 324 kg/m2 wing loading, 0,998 TWR
Point defense: 7.933,72 kg weight, 245 kg/m2 wing loading, 1,32 TWR
NOTE: “Performance” numbers are for aircraft with armaments + 50% internal fuel if there were no external fuel tanks carried, and armaments + 100% internal fuel if configuration included external fuel tanks
Subsonic radar pod (design by Riley Amos)
Supersonic radar pod (design by Riley Amos 14.9.2018.)
These drawings show the maximum possible display options. However, any display symbols should be disabled if the pilot wishes so, to prevent information overload during combat. For example, if central AoA scale is distracting or blocks the view, it should be possible to disable it with one press of a button. For this, FLX would include a set of buttons just below the HUD so that pilot can quickly choose which parameters will be displayed on HUD and/or HMD before entering the combat zone. In fact, the only symbols for which such on/of switches would not be included would be gun piper (which only appears if gun is a selected option anyway) and missile track/lock icons. Low fuel warning would also appear automatically.
More powerful engine
EJ270 will be used as a possible upgrade option; data is as follows:
Dry: 7.938 kgf
Afterburning: 12.247 kgf
Dry: 0,74 kg / kgf*h
Afterburning: 1,7 kg / kgf*h
Dry: 5.874 kg/h
Afterburning: 20.820 kg/h
Subsonic cruise consumption will stay the same, but higher dry thrust will increase supercruise speed as well as fuel consumption during supercruise. It will also raise thrust-to-weight ratio at combat weight to 1,42 at combat weight and 1,16 at combat takeoff weight.
Thrust-to-weight ratio at dry thrust and combat weight will be 0,92. Cruise speed will be Mach 1,69 with 4 missiles and Mach 1,59 with 8 missiles.
If necessary, an advanced LIDAR might be used to complement the IRST, replacing the laser rangefinder. A 9.115 micron LIDAR would be sufficient to detect jet engine exhaust soot particles at distances up to 80 km, while enhancement by condensed ice particles in wake contrails will allow for detection well beyond 100 kilometers. When contrails are present, detection at ranges well beyond 200 km may be possible. LIDAR is superior to radar not only in detection range against “stealth” aircraft but also in that it only warns the aircraft it hits directly. It is still inferior to the IRST on both counts however, so it is best used as a secondary sensor in the case that a range estimate more precise than what the IRST can provide by itself is required. Long wavelength LIDAR is also safer for eyes than shorter-wavelength ones.
LIDAR is most effective at altitudes at which stealth fighters typically operate (55.000 – 65.000 feet), as atmosphere is quite thin there, while there is a very large chance of aircraft producing the contrails (aerodynamic, convention and engine exhaust contrails). Engine exhaust contrails actually form very rarely at less than 30.000 feet. Wake trail vortices however are a necessary byproduct of lift creation by aircraft’s wings and cannot be eliminated.
Taiwan invasion scenario
Scenario is adapted from RAND Pacific Vision presentation. Gun Pk for 1-second burst will be assumed to be 31% for revolver and linear action cannons, 26% for rotary guns, 15% for IR WVR missiles, 11% for IR BVR missiles and 8% for radar-guided BVR missiles. Thus salvo Pk will be:
3-missile RF/AR BVR salvo: 0,08 + 0,074 + 0,068 = 22,2%
4-missile RF/AR BVR salvo: 0,08 + 0,074 + 0,068 + 0,062 = 28,4%
3-missile IR BVR salvo: 0,110 + 0,098 + 0,087 = 29,5%
4-missile IR BVR salvo: 0,110 + 0,098 + 0,087 + 0,078 = 37,3%
Su-30MKK: 6 RF BVR AAM, 4 WVR AAM, 6 gun bursts
F-15C: 6 RF BVR AAM, 2 WVR AAM, 8,6 gun bursts
F-16A: 6 RF BVR AAM, 2 WVR AAM, 4,7 gun bursts
F-16C: 6 RF BVR AAM, 2 WVR AAM, 4,7 gun bursts
F-18E: 12 RF BVR AAM, 2 WVR AAM, 5,2 gun bursts
F-22 (S): 8 RF BVR AAM, 4,8 gun bursts
F-22 (H): 12 RF BVR AAM, 4,8 gun bursts
F-35A (S): 4 RF BVR AAM, 2,6 gun bursts
F-35A (H): 10 RF BVR AAM, 2,6 gun bursts
Rafale C: 8 IR BVR AAM, 2 WVR AAM, 3 gun bursts
Typhoon: 6 RF BVR AAM, 2 WVR AAM, 5,4 gun bursts
Gripen C: 4 RF BVR AAM, 2 WVR AAM, 4,2 gun bursts
Gripen E: 6 RF BVR AAM, 2 WVR AAM, 4,2 gun bursts
F-5E: 2 WVR AAM, 11,2 gun bursts
FLX (S): 6 IR BVR AAM, 2 WVR AAM, 5 gun bursts
FLX (H): 4 RF/AR BVRAAM, 8 IR BVRAAM, 2 WVRAAM, 5 gun bursts
Su-30MKK: 55 million USD
F-15C: 128,1 million USD
F-16A: 30,5 million USD
F-16C: 71,1 million USD
F-18E: 71,6 million USD
F-22: 273 million USD
F-35A: 145 million USD
F-35C: 264,8 million USD (B is halfway between A and C)
Rafale C: 92,7 million USD
Typhoon: 129,2 million USD
Gripen C: 44 million USD
Gripen E: 43 million USD
F-5E: 26,5 million USD
FLX: 39,4 million USD
Number of fighters:
Su-30MKK: 97 (5,34 billion USD)
Rafale C: 57
Gripen C: 121
Gripen E: 124
Sortie rate (sorties/fighter/day):
Su-30MKK: 1,0 (assumption)
Rafale C: 2,7
Gripen C: 2,18
Gripen E: 2,0 (assumption)
Number of fighters in the air: (number of fighters * sortie rate / 3,6)
Rafale C: 43
Gripen C: 73
Gripen E: 69
First shot to Red Force:
27 Su-30MKK fire 54 3-missile RF BVR salvos. 12 F-15s killed. Total losses: 0 Su-30, 12 F-15C
27 Su-30MKK fire 54 3-missile RF BVR salvos. 12 F-16s killed. 46 F-16s fire 92 3-missile RF BVR salvos. 20 Su-30s killed. 7 Su-30s fire 28 WVR missiles. 4 F-16s killed. 42 F-16s fire 84 WVR missiles. 7 Su-30s killed. Total losses: 27 Su-30MKK, 16 F-16A
27 Su-30MKK fire 54 3-missile RF BVR salvos. 12 F-16s killed. 13 F-16s fire 26 3-missile RF BVR salvos. 6 Su-30s killed. 21 Su-30s fire 84 WVR missiles. 13 F-16s killed. Total losses: 6 Su-30MKK, 25 F-16C
27 Su-30MKK fire 54 3-missile RF BVR salvos. 12 F-18s killed. 19 F-18s fire 57 4-missile RF BVR salvos. 16 Su-30s killed. 11 Su-30s fire 44 WVR missiles. 7 F-18s killed. 12 F-18Es fire 24 WVR missiles. 4 Su-30s killed. 7 Su-30s fire guns. 2 F-18s killed. 10 F-18s fire guns. 3 Su-30s killed. 4 Su-30s fire guns. 1 F-18 killed. 9 F-18s fire guns. 2 Su-30s killed. 2 Su-30s fire guns. 1 F-18 killed. 8 F-18s fire guns. 2 Su-30s killed. Total losses: 27 Su-30MKK, 23 F-18E
27 Su-30MKK fire 54 3-missile RF BVR salvos. 3 F-22s killed. Total losses: 3 F-22A
27 Su-30MKK fire 54 3-missile RF BVR salvos. 4 F-35s killed. Total losses: 4 F-35A
27 Su-30MKK fire 54 3-missile RF BVR salvos. 3 F-35s killed. Total losses: 3 F-35C
27 Su-30MKK fire 54 3-missile RF BVR salvos. 12 Rafales killed. 31 Rafale fires 62 4-missile IR BVR salvos. 23 Su-30s killed. 4 Su-30s fire 16 WVR missiles. 2 Rafales killed. 29 Rafales fire 58 WVR missiles. 4 Su-30s killed. Total losses: 27 Su-30MKK, 14 Rafale C
27 Su-30MKK fire 54 3-missile RF BVR salvos. 12 Typhoons killed. 15 Typhoons fire 30 3-misile RF BVR salvos. 7 Su-30s killed. 20 Su-30s fire 80 WVR missiles. 12 Typhoons killed. 3 Typhoons fire 6 WVR missiles. 1 Su-30 killed. 19 Su-30s fire guns. 3 Typhoons killed. Total losses: 8 Su-30MKK, 27 Typhoon
27 Su-30MKK fire 54 3-missile RF BVR salvos. 12 Gripens killed. 61 Gripen fires 61 4-missile RF BVR salvos. 17 Su-30s killed. 10 Su-30s fire 40 WVR missiles. 6 Gripens killed. 55 Gripens fire 110 WVR missiles. 10 Su-30s killed. Total losses: 27 Su-30MKK, 18 Gripen C
27 Su-30MKK fire 54 3-missile RF BVR salvos. 12 Gripens killed. 57 Gripens fire 114 3-missile RF BVR salvos. 25 Su-30s killed. 3 Su-30s fire 12 WVR missiles. 2 Gripens killed. 55 Gripens fire 110 WVR missiles. 3 Su-30s killed. Total losses: 27 Su-30MKK, 14 Gripen E
27 Su-30MKK fire 54 3-missile RF BVR salvos. 12 F-5s killed. 27 Su-30s fire 108 WVR missiles. 16 F-5s killed. 173 F-5s fire 346 WVR missiles. 27 Su-30s killed. Total losses: 27 Su-30MKK, 28 F-5E
27 Su-30MKK fire 54 3-missile RF BVR salvos. 12 FLXs killed. 89 FLXs fire 178 3-missile IR BVR salvos. 27 Su-30s killed. Total losses: 27 Su-30 MKK, 12 FLX
27 Su-30MKK fire 54 3-missile RF BVR salvos. 12 FLXs killed. 89 FLXs fire 89 4-missile RF BVR salvos. 25 Su-30s killed. 89 FLXs fire 178 4-missile IR BVR salvos. 2 Su-30MKK killed. Total losses: 27 Su-30MKK, 12 FLX
101 FLXs fire 101 4-missile AR BVR salvos. 27 Su-30s killed. Total losses: 27 Su-30MKK, 0 FLX
First shot to Blue Force:
12 F-15Cs fire 24 3-missile RF BVR salvos. 5 Su-30s killed. 22 Su-30s fire 44 3-missile RF BVR salvos. 10 F-15s killed. 2 F-15s fire 4 WVR AAMs. 1 Su-30 killed. 21 Su-30 fires 84 WVR AAMs. 2 F-15s killed. Total losses: 12 F-15C, 6 Su-30MKK
58 F-16As fire 116 3-missile RF BVR salvos. 26 Su-30s killed. 1 Su-30 fires 2 3-missile RF BVR salvos. 0 F-16s killed. 58 F-16s fire 116 WVR missiles. 1 Su-30 killed. Total losses: 0 F-16A, 27 Su-30
25 F-16Cs fire 50 3-missile RF BVR salvos. 11 Su-30s killed. 16 Su-30s fire 32 3-missile RF BVR salvos. 7 F-16s killed. 18 F-16s fire 36 WVR missiles. 5 Su-30s killed. 11 Su-30s fire 44 WVR missiles. 7 F-16s killed. 11 F-16s fire guns. 3 Su-30s killed. 8 Su-30s fire guns. 2 F-16s killed. 9 F-16s fire guns. 2 Su-30s killed. 6 Su-30s fire guns. 2 F-16s killed. 7 F-16s fire guns. 2 Su-30s killed. 4 Su-30s fire guns. 1 F-16 killed. 6 F-16s fire guns. 2 Su-30s killed. 2 Su-30s fire guns. 1 F-16 killed. 5 F-16s fire guns. 1 Su-30 killed. 1 Su-30 fires gun 2 times. 1 F-16 killed. Total losses: 21 F-16C, 26 Su-30
31 F-18Es fire 93 4-missile RF BVR salvos. 21 Su-30s killed. 6 Su-30s fire 12 3-missile RF BVR salvos. 3 F-18s killed. 28 F-18s fire 56 WVR missiles. 6 Su-30s killed. Total losses: 3 F-18E, 27 Su-30
3 F-22s fire 6 4-missile RF BVR salvos. 2 Su-30s killed. 25 Su-30s fire 50 3-missile RF BVR salvos. 3 F-22s killed. Total losses: 3 F-22, 2 Su-30
3 F-22s fire 9 4-missile RF BVR salvos. 3 Su-30s killed. 24 Su-30s fire 48 3-missile RF BVR salvos. 3 F-22s killed. Total losses: 3 F-22, 3 Su-30
4 F-35As fire 4 4-missile RF BVR salvos. 1 Su-30 killed. 26 Su-30s fire 52 3-missile RF BVR salvos. 4 F-35s killed. Total losses: 4 F-35A, 1 Su-30
4 F-35As fire 4 4-missile and 8 3-missile RF BVR salvos. 3 Su-30s killed. 24 Su-30s fire 48 3-missile RF BVR salvos. 4 F-35s killed. Total losses: 4 F-35, 3 Su-30
43 Rafale Cs fire 86 4-missile IR BVR salvos. 27 Su-30s killed. Total losses: 0 Rafale C, 27 Su-30
27 Typhoons fire 54 3-missile RF BVR salvos. 12 Su-30s killed. 15 Su-30s fire 30 3-missile RF BVR salvos. 7 Typhoons killed. 20 Typhoons fire 40 WVR missiles. 6 Su-30s killed. 9 Su-30s fire 36 WVR missiles. 5 Typhoons killed. 15 Typhoons fire guns. 5 Su-30s killed. 4 Su-30s fire guns. 1 Typhoon killed. 14 Typhoons fire guns. 4 Su-30s killed. Total losses: 13 Typhoon, 27 Su-30
73 Gripen Cs fire 73 4-missile RF BVR salvos. 16 Su-30s killed. 11 Su-30s fire 22 3-missile RF BVR salvos. 5 Gripens killed. 68 Gripens fire 136 WVR missiles. 11 Su-30s killed. Total losses: 5 Gripen C, 27 Su-30
69 Gripen Es fire 138 3-missile RF BVR salvos. 27 Su-30s killed. Total losses: 0 Gripen E, 27 Su-30
27 Su-30MKK fire 54 3-missile RF BVR salvos. 12 F-5s killed. 189 F-5Es fire 378 WVR missiles. 27 Su-30s killed. Total losses: 12 F-5E, 27 Su-30
101 FLX fire 202 3-missile IR BVR salvos. 27 Su-30s killed. Total losses: 0 FLX, 27 Su-30
101 FLXs fire 101 4-missile AR BVR salvos. 27 Su-30s killed. Total losses: 0 FLX, 27 Su-30
Most likely to gain first shot (factors: sensors, EW suite, kinematics, missile range):
Su-30MKK vs F-15C: Su-30
Su-30MKK vs F-16A: Su-30
Su-30MKK vs F-16C: Su-30
Su-30MKK vs F-18E: Su-30
Su-30MKK vs F-22: F-22
Su-30MKK vs F-35A: either (F-35 will have detection range advantage and first overall shot advantage, but Su-30MKK will have longer *effective* missile range)
Su-30MKK vs Rafale C: Rafale
Su-30MKK vs Typhoon: Typhoon
Su-30MKK vs Gripen C: either (Gripen will have advantage in EW suite and cruise speed, but Su-30 will have advantage in sensors, acceleration and top speed)
Su-30MKK vs Gripen E: Gripen
Su-30MKK vs F-5: Su-30
Su-30MKK vs FLX (S): FLX
Su-30MKK vs FLX (H): FLX
As it can be seen, FLX carries same number of missiles as Gripen E, and achieved similar exchange ratio in both scenarios. What this means is that 70 FLXs can be used to deal with PLAAF forces while remaining 31 go after PLAAF support assets or hang back to protect their own support assets.
Robert L Shaw – Fighter Combat
Pete Bonnani – The Art of the Kill
Ray Whitford – Design for Air Combat
Patrick Highby – Promise and Reality: Beyond Visual Range Air-To-Air Combat
Roger Thompson – Reforming America’s Overhyped Airpower
Overreliance on Technology in Warfare: The Yom Kippur War as a Case Study
Our radar-laden weapons attract their own doom
Air-to-air weapons effectiveness
190 thoughts on “Air superiority fighter proposal 6”
I just read through Pierre Sprey’s excellent PDF on fighters, albeit dating back to the late 70’s, and I agree with almost everything he says. I especially appreciate how honest he is with regards to the possibility that the F-86 is actually better than the F-16, all things considered. Having said that, at one point he starts talking about a modern engine for a fighter plane, and I’m not entirely sure what he’s talking about. I do understand what he means when he says that bypass engines are false economy, at the speeds the planes fly the increase in drag matters much more, but I thought that the bypass air was basically just coolant for these engines. Also, he talks about using lower inlet temperatures, and going down to 3 or 4 compression stages. Could you explain why he thinks that? Sprey has a habit of being right all the time, but I don’t know enough about engines to understand what he’s going on about here. Is he saying to design the intake in such a way as to greatly aid in compression or something? Any help would be appreciated.
Secondly, his fighter that he calls for is absurdly small. I don’t mean that in a bad way, but it was really refreshing seeing a design for a fighter that weighs less than 5000kg’s empty. As I’ve said before, there are two air superiority missions, Interception (requiring long range, high speed, less maneuverability, ability to carry large missiles), and Point Fighting (requiring small size, extreme maneuverability, lots of gun, high T/W). Of course, since the implication of Point Fighting is that it’s in support of the army, Air Forces around the world absolutely hate it, but a plane designed heavily for that really ought to be around the size that Sprey wants. The A-4 Skyraider has an empty weight of 4700kg’s, and a loaded weight of 8000kg’s. The CF-86 has an empty weight of 4800kg’s, and a loaded weight somewhere around 7000kg’s. The F5 has an empty weight of 4300kg’s, and a loaded weight of 7100kg’s, all per wikipedia. Supercruise presents us with some challenge, although raw top speed is ultimately less important in the “king of the hill” that is Point Fighting, but I really don’t see why it’s so damn hard to make a plane that’s the size of the F5. Take the F5, add canards, and redesign the thing around a small single engine, and I think you’ve got yourself a winner. On top of that, for some reason, I’ve always loved the twin 20mm’s in the nose. The F5 never had a great range, nor great cruise speed, but the canard redesign would free up space for fuel. Secondly, Point Fighters don’t have to carry a ton of enourmous missiles, since close range combat requires a gun and small missiles. Still, I couldn’t help but think that there really might be something to two special planes instead of one, and the tiny fighter Sprey was designing would be a beautiful thing indeed.
No, bypass air does indeed result in lower temperature, but it is not “basically a coolant”. There is a specialized cooling channel for that. As for lowering inlet temperatures and going down to compression stages, that has to do with reliability. Higher inlet temperatures mean either more exotic materials or shorter service time.
It is not hard to make a fighter smaller than F-5, it is just not profitable. Military industry is about turning profit, not about combat effectiveness.
As for point defense fighter, I had one crazy idea:
Add landing gear, and you can use the same fighter for point defense.
I’ve read the engine comparison article, but I still don’t totally understand what Sprey is getting on about. My understanding is that the higher the inlet temp, the more efficient the engine. This is somewhat countered by increased wear on the engine. If we use less compression stages, and lower temperatures, is he saying that the weight savings actually make this better overall? Or is he just saying that reliability in and of itself is worth the reductions?
I think he is saying both, though I haven’t read his article for a long time so I don’t exactly remember. But I do remember that he placed a lot of emphasis on reliability.
Picard, I’m personally curious as to why you like the side pitot design similar to the Rafale for the air intake. I read in an interview that the man who designed that believed it to be the best design for a dual engine fighter, but he was very specific in that dual engines were his goal. Personally, the design of the F-16 seems to my eyes to be the best in terms of minimizing cross section and drag. I am not an aeronautical engineer, but it would make sense to me that it would be more efficient to have one intake as opposed to two in terms of induced drag. Secondly, to my untrained eyes, the F-16 has much less “bulk” viewed from the front, despite being a larger plane overall, which is mainly from the single larger intake, as opposed to the dual smaller intakes, which gives the Rafale a sort of “fat” look.
Rafale’s design is done for several reasons, which are pretty much the reasons I chose the same configuration. First reason is carrier ops. The way intakes are mounted and designed – as part of main structure rather than as a separate structure, plus being flush with the body with no hard breaks – means that loads and impacts of carrier operations get transferred from the intakes to the body. This is quite important issue for aircraft meant for road operations. Gripen’s intakes do not quite achieve that as efficiently, and F-16s intake doesn’t achieve it at all.
Second reason is road ops. F16s intake is vulnerable to FOD damage. Gripen’s design would be ideal, especially with FOD screens – if I ever find time, I will redesign a fighter with that design – but Rafale’s intakes still are better than F-16s type.
Third reason is performance. F-16s intake is positioned the way it is in order to achieve high air intake at high angles of attack. However, it has major issues with sideslip, and single intake means that any problems with air flow at the mouth of the intake can cut off the engine. Gripen’s intakes solve the security issue of having just one intake, and are very good at sideslip, but interaction with aircraft body can cause issues with performance at high angles of attack. Rafale’s intakes, being shielded from both top and the side, offer the best of both worlds.
All of that makes a lot of sense, but my understanding was that the cockpit placement mostly determines the intake. I mean, looking at the F-16 from the side and we can basically see the engine work its way out to the intake. If we don’t have an intake that’s beneath the plane, then there’s basically no way to have an engine that low in relation to the cockpit. That means that we just have inherently bad rearward cockpit visibility. Looking at something like the Gripen from the side we can see that there’s just no way to make that plane have as great rearward visibility as the F-16 because the engine is “higher” in relation to the pilot than on the F-16. All of this despite the smaller engine on the Gripen. Having a bottom intake would allow the Gripen to have a thicker fuselage, allowing for more fuel and a larger engine, while still having better rearward visibility.
But I suppose it all comes down to the hazard of FOD. Looking at the F-16 on a runway, we can see that they put the front leg of the landing gear on the bottom of the air intake. As a result, the F-16’s intake is basically at the same height of the Gripen anyway, which has a much larger leg just to get the air intake to the same height. Unfortunately I question the practicality of FOD screens for takeoff on the F-16 for a few different reasons. The first of which, any screen must be sufficiently thick to outright repel any FOD. Secondly, the F-16’s intake is not square, so designing a FOD screen is a bit challenging. Thirdly, extending and retracting that FOD screen needs to be done seemlessly, and the screen must be stored with minimal aerodynamical losses. Finally, any screen will interfere with air intake, lowering our effective power for takeoffs and landings, which will extend our takeoff distance, and may well actually make takeoffs and landings more dangerous overall, even with perfect FOD protection.
I know that the Canadian F5’s were given a special front leg, which would extend further than the stock F5 in order to give the plane better AoA on the runway, which facilitated shorter takeoffs. I wonder if such a thing could be given to an F-16 to allow it to takeoff FOD screen free.
Cockpit placement does have an impact, but it is not the only factor. As for FOD-free takeoff, it may be a possibility.
NASA took the Canadian F-5 extended front gear leg to its logical conclusion and produced a “jump strut”.
Click to access 19950005812.pdf
Basically an aerospace implementation of the pneumatic jumping cars to induce rotation earlier and gain a better angle of attack for the wing. 10% of reduction in take-off roll was observed and at no point were the safety margins in the aircraft structural loads or the nosewheel gear exceeded. The complexity over a simple oleo strut is not significantly greater, and the strut itself can simply be started pressurised and act as an extra long travel oleo strut with pneumatic damping for its AoA effects only.
Now this is not necessarily a solution for FOD because FOD can be picked up and hurled into the intakes by strong winds and by other aircraft taking off. This is the reason why airbase personnel go on FOD walks to police bits of debris, or scare away birds, even on still days.
Even with the risk of FOD the danger is not necessarily as large as one might think.
Click to access ej200%20specs.pdf
This MTU paper details the design process in getting the EJ-200 fully designed. Choices were made to simplify the engine and as part of that variable inlet guide vanes were deleted and choices made to make the fan have a greater speed range and still have effective compression. The result is a cheaper, simpler engine that without VIGVs is more resistant to bird strike. Other factors like the fact that the use of blisks makes for a stronger, lighter fan structure also helps with ingestion.
Ultimately the fact that Sweden operates its Gripens with an eye to road basing without FOD screens is a vindication of modern military jet engine design in mitigating against the risk of FOD or bird strike. 4 decades ago it might have been quite necessary for jets like the MiG-29 to operate with FOD screens. Proper placement of intakes and nose gear as well as engine selection can make it a non-issue. FOD walks are still done if only to stop a lengthy inspection and/or repair job. The practice is a peacetime luxury and not necessarily a wartime necessity. In any case, FOD screens that still yield adequate airflow to the engine on a high-hot takeoff are not going to catch the most insidious of FOD anyway – fine, sharp sandy grit typical of the MENA region. That kind of sand will erode engine blades quickly and there is nothing you really can do about it except not to take off in a sandstorm.
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Thing is, if any debris results in even peacetime inspection and repair of an engine, there is no way aircraft will be able to operate for extended periods of time from dirt or even road strips in wartime.
As for sand, the only solution I can think of is having topside air intakes and doors that completely close off main intakes, to if nothing else reduce the amount of sand ingested.
Interesting find there Malthias. Yeah, kind of solves the last issue there for road basing, if the Swedes have already been doing this with little to no downsides. Really just goes to show the difference in seriousness between the underfunded Swedish AF and the insanely bloated USAF.
“On one occasion when a target was aware it was being shot at, it successfully evaded 3 AIM-120Cs despite having no ECM. ” — I’ve read a comment that the pilot was able to get a warning and notch the incoming missiles.
All Doppler radars are vulnerable to notching — flying at relative speed below the threshold of the radar (which is needed to filter out road traffic, effects of wind on trees, etc — usually threshold is set at > 120 km/h).
To achieve notching, you fly close to perpendicular to the aircraft or missile heading. After notching is achieved and you’ve become invisible to the Doppler radar, release chaff so that the missile would lock on to it instead of you once you change direction and become visible again (if the missile is in auto locking mode).
Counter tactic is having at least 2 aircraft spread out abreast far enough so that it won’t be possible to notch them both at the same time.
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Become invisible may be an overstatement. If you are the only thing in the air you are still going to stand out against the background. However, by beaming the missile you will be bleeding it of its energy. Any additional changes in direction will trigger further over-corrections in the missile as it plots to intercept.
However, I’m sure notching does make it very difficult for the missile radar to accurately track the fighter, especially if used in conjunction with chaff. I think missile manufacturers really overestimate, or simply oversell, the tracking capabilities of their missiles.
Having multiple fighters in the air firing multiple missiles is definitely a good idea. Not simply to overcome Notching/Beaming the missile as a defence, but in order to capitalize on a plane with lowered energy after pulling the hard G turns required in order to dodge a missile. They wouldn’t like you to say that though, as it implies that numbers matter as well as the flight performance of the aircraft.
Picard, I definitely love this fighter proposal, and wish you would create a new updated one. I remember the lead designer for the F-16 remarking in an interview that the major weakness of fighter design remaining, this was back in the 90’s, was that he felt design should be based around the plane with the actual missile load it will take into a battle. Missile rails are, as you have noted, a very large drag on an aircraft. Additionally, the further out the missile is on the wing, the worse the roll performance of the plane is, as well as the lower its structural g force limit, although both depend on the weight of the missile. It’s been proven to be fairly innocuous to have small wingtip missiles, such as the F-16 with it’s 188lbs AIM-9 sidewinder. We need that missile rail, or something like it, for wingtip vortices anyway, so while this decreases flight performance in terms of weight, it increases lift at the same time.
I have an idea that may or may not work out for a sort of conformal missile. It looks like you may have the same idea looking at the front of the FLX 6. My idea is to build an ejection rack into the fuselage in the center there. Additionally, shape the fuselage with the air intakes as you have done here, perhaps even an exaggerated version. Since we’re using an ejection rack, there is no issue with one missile being behind the other. Additionally, we can put these wherever we would like on the fuselage, so we should be able to avoid conflict with the landing gear, and still fit in two of these things, even with a smaller fighter. It may well be that we just can’t find the room inside the fuselage for the ejecter system, although I believe that they are fairly small. Still, space is at a premium, and it might not be worth it.
If we do go with this idea, then we are going to have to have the missile in mind for the space carved out, since the fins will require a certain amount of seperation from the fuselage anyway. Alternatively, we could go all in with this idea and just have cutouts for the fins. That might cause us some problems though when the missile is no longer attached to the aircraft, so we should probably still have a bit of a hang and clearance in all directions.
If all goes correct, then it’s basically a missile carriage without the massive drawbacks in terms of weight, complexity, drag, and delay between targeting and firing. We will probably have to use smaller missiles, but BVR missiles are overrated anyway. Of course, we don’t get to claim fake stealth, but really who cares?
I should have mentioned, we will still have the option of putting on at least 4 missile rails on the wings should we decide that we need that extra utility.
I was planning on doing a new version, but I have some RL stuff to do + I’m working on a military sci-fi.
My idea with FLX 6 was to have a four-missile clean configuration – two wingtip missiles + two conformal missiles in “sunk” body stations (similar to how Eurofighter Typhoon carries its AMRAAMs). Possibly six missiles – and yes, I had an idea similar to what you outlined with the ejection rack.
Well it’s nice to see great minds thinking alike. More seriously I think we would need to first design the missile that we’re going to be putting into these conformal stations. I’m very skeptical of most modern missiles. Personally, what I would like to see my country, Canada, do, is replace all of our current CF-18’s with the winners of a flyoff. Then, turn our CF-18’s into remote controlled drones, where we fire a bunch of missiles at them in various configurations, testing various evasions and tactics, as well as testing the performance of IR and UV MAWS at various distances/aspects. Actually, there’s a lot of other things to test, but that brings me to my next point.
Find out which missiles actually work. We are going to need some estimation for the efficacy based upon harder to quantify values, radar being less surprising than IR for example, but we should be able to pick a few winners. Personally I suspect we’ll find that BVR missiles are basically all useless, but finding the true Pk of all missiles WVR, in realistic situations is going to be an exciting and profitable endeavor. I would also do this for as many SAMs as possible. Anyway, once we have either picked a winner, or designed our own, then we can finish designing our conformal “sunk” body stations perfectly with that missile in mind.
Ultimately, we might have to redesign the air intake. I’ve always loved the elegance of the F-16 intake, and the whole overall feel like the plane extends from the engine out. Similarly, the Rafale intake looks extremely elegant and downright sexy. However, for conformal missiles it appears to be easier to build them into fairly square surfaces. I can see them on the Eurofighter, the F-4, the F-15, and the F-18, all of which have square intakes. This might simply be coincidence, but it intuitively makes sense to me, and is something that we would have to design the plane around right from the very start.
Good ideas. And yes, conformal stations are easier to design with a square intake.
There was a Sukhoi prototype for a cancelled light front fighter from the early 90s called “S-37” with a delta-canard wing configuration and single engine. It looks similar to your project.
Thanks. Didn’t know about that one, but yeah, quite similar.
Managed to find more info: https://www.secretprojects.co.uk/threads/sukhoi-s-37-su-37-multirole-canard-delta.94/
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