Fighter will have to be stealthy and highly maneverable to surprise and outmaneuver the enemy, as well as to improve survivability against the missile fire. This requires small size, supercruise ability, good aerodynamic design, low wing loading and high thrust-to-weight ratio. Aircraft that uses the radar first will be quickly detected and targeted by passive sensors; as such, only minor RCS reduction measures are necessary, and no active sensors will be carried.
Stealth and sensor fusion are required to achive the advantage in an OODA loop, getting off first shot and possibly achieving a kill with little in way of reprisal. If that fails, breaking the enemy’s OODA loop by being impossible to predict is essential. Supercruise ability helps in both, as it shrinks enemy’s response time after the supercruiser is detected, reduces effectiveness of opponent’s weapons while increasing effectiveness of supercruiser’s weapons, allows the supercruiser to achieve surprise while preventing the enemy from surprising him, and to dictate terms of engagement.
Maneuverability is important in air combat for two reasons: to get the enemy inside one’s own engagement envelope, and to avoid getting hit. It should be understood that the maximum envelope is not the same as the useful envelope – while modern fighters (Rafale, F-35) can use missiles to engage targets at their six o’clock, this is of questionable usefulness as it increases target’s reaction time and causes the missile to loose energy, as well as increasing the likelihood of missile simply not acquiring the target. Missile that has spent its fuel and is flying on inertia alone (most missiles at BVR) also has almost no chance of hitting the maneuvering target. Even in exercises, fighters often get within visual range.
Finally, pilot quality is the most important factor in aircraft’s performance. This means that fighter has to be easy to maintain and cheap to both operate and procure; any technology that gets in a way of a human being is problematic. Result is a comparably simple single-engined fighter. This also allows superiority in another important characteristic, one of numbers.
Fighter also has to have excellent STOL characteristics to operate from road bases as any obvious air strips will get bombed. This requires same characteristics as maneuverability.
In the end, a quote:
Victory smiles upon those who anticipate the changes in the character of war, not upon those who wait to adapt themselves after the changes occur.
While most air planners assume that stealth and UCAVs are the way of the future, it is easy for even (or maybe especially) large groups of smart people to get important assumptions wrong. For example, in 1930s, air planners assumed that a) primary mission of air forces is to use strategic bombers to destroy the enemy means of making war, b) no escort fighter can compete with point-defense interceptors, c) bombers would be faster, more heavily armed and armored than fighters, d) head on attacks are impossible and e) bomber’s guns are more accurate (and thus deadly) than fighter’s armament. All these assumptions were proven wrong; as a result, dayling bombing ceased in late 1943 and did not resume until 1944, when P-51 escort fighter became avaliable. UAVs/UCAVs have a 50% crash rate in peacetime, and are hopelessly outmatched in the most important aspect of air combat – OODA loop.
For historical lessons behind the design, see here.
Aerodynamic design considerations
Maneuverability requires high instantaneous and sustained turn rate as well as high roll rate at angle of attack. But most important requirement is transient performance – that is, roll onset, turn onset and pitch rates as well as acceleration, deceleration and instantaneous turn rate. This needs high lift-to-weight, lift-to-drag, thrust-to-weight and thrust-to-drag ratios even at high g (and consequently high angles of attack); as well as generally low drag at all speeds and high control power with ability to generate large amounts of drag when required. Instantaneous turn rate in particular needs low wing loading, and high lift coefficient. It should be noted that lift coefficient is constant up to Mach 0,7, but at transonic speeds a reduction in C(l)(max) is experienced. Maximum turn rate and minimum turn radius is experienced at a corner speed; for the same g limit, lower wing loading results in lower corner speed, and thus higher turn rate and smaller turn radius.
In order to achieve these characteristics, aircraft will be of a blended wing body configuration with delta wing and a close coupled canards positioned in front of and high above the wing. Blended wing body configuration achieves greater lift and lift-to-drag values than conventional configuration, and increases avaliable volume inside the aircraft. It also reduces the RCS and wave drag. Unstable delta wing has an advantage over the stable delta that, in the level flight at least, trimming required actually helps lift, improving maximum lift by 20% or more, and smaller tail moment arm increases trimmed lift gain; modern close-coupled canard configurations are inherently unstable, and this instability does not revert during the supersonic flight, leading to reduction in trim drag. Delta wing also has inherent advantages in terms of vortex lift and wing loading – vortex lift starts very early on the sharp-edged delta wings, thus increasing lift and reducing drag for any given angle of attack except lowest ones, when compared to other wing planforms; this effect can be helped by close-coupled canards. Angle of attack at which vortices appear can be as low as 2,5°. Canard prevents breakdown of wing vortex at high angles of attack, thus allowing post-stall controllability and maneuverability. Addition of canard also increases Clmax and angle of attack for Clmax, leading to a major improvement in the instantaneous turn rate. It should be noted that total lift of the close-coupled canard configuration is far higher than the additive lift of the wings and the canards; this is a result of their beneficial interference when in close proximity, with canard promoting vortex lift. This enhancement can be effective to such extent that maximum lift is 34% greater for a close-coupled canard configuration than for an otherwise identical configuration with no canard, with canard adding only 15% of the area. In another case, a canard that has added 9% of the area has improved lift by 34% at 22° angle of attack; for this configuration, stall without canard happened at 21°, whereas there was no indication of a stall below 32° for a canard-equipped configuration. Minor lift enhancement can start at angles of attack as low as 10°. Canard mounted above the wing has noticeably better lift-to-drag ratio than coplanar canard, as vortex and wakeflow of the canard do not hit the wing. Maximum lift is achieved when canard’s trailling edge is slightly in front of the wing leading edge; if canard trailling edge and wing leading edge overlap, a loss of lift occurs. Moving the canard forward or down reduces the lift gain. A properly positioned canard creates a low pressure region on front part of the wing upper surface which has a significant contribution to lift, and also causes aircraft to be dynamically unstable, providing advantage in response to control surface inputs when compared to either stable or statically unstable configurations. Lift improvement also depends on canard sweep – increase in sweep typically improves lift gain but at the expense of a lift/drag ratio; thus, a 45 degree (+/-3*) sweep is an optimal solution. Care should be taken that canard and wing vortexes interact constructively. Canard vortex tends to shift main wing vortex towards the wingtip, but also to reinforce it, expanding surface area of the wing that is covered by the wing wortex. This attachment mechanism also results in improved roll performance, including damping of roll oscillations and improved roll onset. Wing aspect ratio should also be low in order to improve roll performance, but low aspect ratio results in a high span loading and thus high drag during the turning fight. Moderate wing sweep angles (around 50°) also help formation of semi-open separation bubbles, helping flow reattachment. Additionally, vortex breakdown starts far later on moderate-sweep wings than on highly swept ones. Delta wing vortices are also very robust under the unsteady pressure gradient.
Larger wing span is preferable for climb and cruise performance, but it means more problematic basing, heavier weight and higher induced drag (drag is a function of both span loading and sweep; lower span loading and higher sweep are better).
Being unstable means that elevons will also be a lifting surface, same as horizontal tail surfaces are for unstable wing-tail aircraft (in level flight only). Canards also improve wing response to aeliron inputs, increasing pitch onset and roll onset rates.
Wing anhedral (downward angle) can also be used in order to improve roll response, and to improve vortex lift. Vertically, mid-wing will be used, as it reduces interference drag.
Canard reduces influence of speed on lift produced by the wing in level flight and maneuver, and its influence on lift is reduced with increasing speed. It also reduces subsonic-supersonic aerodynamic center shift, and provides good battle damage tolerance through overlapping control surfaces.
In addition to the vortices created by canards themselves, wings will also use the sharp (73*) strakes (LEXes) to strengthen its own vortices. At higher angles of attack a vortex formed from LEX flows over the wing, stabilizing wing leading edge vortex and preventing air flow separation. It also interacts with canard’s root vortex; two vortexes strengthen each other and thus delay vortex breakdown, making dela wing’s trailling edge surfaces effective even at high angles of attack. Sawtooth on the wing leading edge may also be used in order to reinforce canard tip vortexes.
Supersonic drag is further reduced by absence of the tailplane. Sweep will not be too large in order to avoid air flow separation. As this fighter will be primarly designed for subsonic and transonic combat (combat speeds in Vietnam and all subsequent wars was always Mach 0,5 – 0,9) with supersonic cruise, wing sweep will be cca 45 degrees, and nose-to-wingtip angle will be 27 degrees. Wing thickness will be 4-7%, with leading-edge flaps to prevent the air flow separation. Due to maneuvering requirements wing aspect ratio (ratio of wing area to span squared) will have to be less than 3,5, even though it will limit cruise performance due to spanwise loss of lift resulting from formation of the trailling vortices (these also cause 75% of drag in maneuvering combat and 50% of drag in cruise flight). Optimum aspect ratio is likely around 2,5 – 2,8. In order to prevent the tip stall, wing will twist towards the tip, reducing the tip AoA. A launcher rail will be located on the wing tip, allowing two missiles to be carried with virtually no drag penalty while improving lift-to-drag ratio. Launch rails that extend forward of the wing leading edge can also act as flutter suppressors.
End configuration will thus use a 47,5 degree delta wing with leading edge extension and a close coupled canard. Canard area will be 9% of the wing area, with vertical distance being 18,5% of the wing mean geometric chord. Canard sweep will be identical to that of the wing. Thrust vectoring will not be used as it does not provide any major advantages for this configuration, while adding another failure point.
Body fineness ratio (length divided by the maximum diameter) should be high, and there should be no sudden discontinuities. Body itself should be slightly wasp-waisted in order to comply with area rule, but it is not a necessity as modern jet engines are powerful enough to push even a flying brick like the F-35 through the transonic region; in any case, aircraft will not spend much in a transonic region as it will either be cruising or maneuvering at supersonic speeds, or maneuvering at subsonic speeds. In fact, of modern fighters only Gripen and F-18 use the area rule – Typhoon, F-22, F-35, F-15 and F-16 all ignore it, though F-35’s combination of a relatively low thrust and high transonic drag results in an abisymal acceleration characteristics. Rafale also uses area rule to an extent, with body getting narrower as wings stretch out, but it is not as obvious as on Gripen; due to need for fuel volume, Rafale’s approach will be used on the FLX.
Low wing loading is required for high altitude cruise, airfield performance (takeoff/landing), sustained turn rate and instantaneous turn rate, while subsonic cruise requires high lift-to-drag ratio and thus medium wing loading. Aircraft with higher wing loading needs higher angle of attack to achieve the same turn rate, which results in higher drag, thus requiring higher thrust-to-weight ratio; even so, wing loading limits the maximum achievable turn rate no matter the TWR. Delta wing also gives a more gradual lift loss beyond the maximum lift AoA, and wing depth gives good fuel volume and allows undercarriage stowage in the wing. Takeoff and landing distances will be further reduced by usage of leading edge slats (of a slotted type). These will also serve to reduce drag in maneuvering flight.
Angle of attack limit will be 32 degrees, with 40 degrees avaliable as an override option.
Good roll performance must also be achievable at high angles of attack. As blended wing-body configuration best works with the mid wing, wings will be anhedral, combined with dihedral canards so as to provide the optimum vortex placement while still keeping good roll performance; wing anhedral will offset the dihedral effect of the wing sweep.
Vertical fin will be relatively small in order to achieve low drag, but it will be positioned far back to provide good directional stability, and will be combined with the dorsal fin fairing to delay the stall. It should also be kept in the clean air even at comparably high angles of attack, which may be achievable through the vortex system. Too large vertical stabilizer can act destabilizing and potentially cause aircraft to spiral out of the control, while too small area can cause a Dutch roll which, while not inherently dangerous, causes a major increase in drag.
Air intakes need to provide good air flow at high sideslip angles and angles of attack. This means avoiding vortices and boundary layer, while being placed in the areas shielded by the wings and/or the fuselage; shielding will also improve supersonic performance. Boundary layer is thickest on the top of the aircraft, and thinnest on the bottom. These considerations mean that the Rafale-style placement is the most optimal. 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. Another consideration is an all-important rough field capability, which means that FOD screens may be necessary. This will be expanded on later.
No or few compression surfaces will be added since acceleration and cruise speed are far more important than a top speed, which is relatively useless as it can be maintained for only a very short time.
Aircraft will be of a single-engined design as – unlike ground attack fighters – twin engined air superiority fighters do not have better survivability than single engined fighters; if one engine is lost, then enemy fighters are very likely to shoot down the straggler. On the other hand, single-engined fighters are more maneuverable, especially in roll and transient performance, and so are better able to avoid getting hit in the first place; they also tend to be better optimized aerodynamically (especially in terms of drag) and have smaller visual and IR signatures. While peacetime loss rate did use to be far greater for the single-engined fighters compared to the twin-engined ones, experience with the Saab Gripen suggests that a single engine is not a serius survivability problem any more even during the peacetime.
Forebody finesse ratio (forebody length divided by the maximum diameter; forebody includes cockpit and anything in front of it) will be low in order to avoid formation of the asymmetric vortex system. Nose itself will be near-elliptical as such shape tends to improve directional stability. Lack of radar will also help here with directional stability, as a large nose can lead to loss of directional stability.
Situational awareness is one of the most important characteristics. Basic measure is visibity from the cockpit, but it can be imporved with a variety of sensors.
Cockpit visibility is divided into two basic sectors: forward visibility, required for an early target detection (absent visual sensors such as IRST, but even then it is advantageous to see the enemy early if a merge is pursued), and an aft visibility, which is crucial for avoiding a rear hemisphere attack (again, sensors can help here but in a dogfight it is still crucial). Pilot also has to be able to visually check for threats in the rear quadrant, and also to see wether aircraft is producing any contrails. In terms of forward visibility, most crucial is over-the-nose visibility (at least 15 degrees).
At beyond visual range, by definition, eyes cannot be used. Here, having onboard sensors capable of detecting and identifying other aircraft is crucial. Radar cannot reliably identify the detected aircraft (allied aircraft were lost to US systems as recently as 2003 Operation Iraqi Freedom), and it warns them of scanning aircraft’s presence far before it actually can detect them, thus allowing them to take measures appropriate for the situation, and allowing them early advantage in the OODA loop. Unique radar characteristics can, if known, enable enemy aircraft to identify the fighter using the radar, and radar itself is vulnerable to electronic countermeasures. Modern ESM and/or anti-radiation missiles can also enable fighters to passively target the emitters. IFF will be kept off as it allows the enemy to track the fighter. Thus most important sensor for an air superiority is the IRST, as it can both detect and identify faraway targets completely passively. ESM sensors (RWR) are also important, but they depend on enemies using their own radars, which is not likely to happen in a war.
It should be understood why LPI cannot be achieved. As shown here, main defenses against ESM are frequency hopping and reduction in emitted power. But radar emissions have to be powerful enough for any return signals to be detected over the noise. Only a small portion – less than 1% – of the signal that does hit the target gets reflected back towards, and detected by, the radar (while a jeep has an RCS of 200 square meters, fighter aircraft of a similar frontal surface has an RCS of 0,1-2 m2). Most LPI techniques are only applicable for very weak radars and sidelobe suppression, but are nearly-useless for hiding powerful fighter-based search radars; even if ESM is 20 dB less sensitive than radar, with RCS of 1 meter square, ESM will be able to detect radar sidelobes at 30 times the range at which radar can detect the fighter, and main beam will be detected at over 1.000 times the radar range. Frequency hopping also is not very effective – fighter radars have to stay within X band (8-12 GHz) to be fully effective, which is well within frequency coverage of modern radar warners (1-18 GHz or more). Same problem is experienced with a spread spectrum technique, and both techniques actually increase the probability of a modern RWR detecting radar signals. Spread spectrum technique is also very limited – unlike an often-repeated misconception, all T/R modules of the AESA radar that are involved in generating a beam have to operate at the same frequency. While AESA radar can generate several beams of different frequencies at the expense of resolution, number of these is very limited (four for the APG-79) and the process itself results in major worsening of a signal-to-noise ratio, countering LPI benefits. As a result, AESA radars typically generate a single beam that “jumps” frequencies. Another limit is size of the modules – due to the diffraction limits, modules can be no closer than half the wavelength; any change in frequency from the optimum one results in reduced radar performance. Lowest frequency fighter radar in use is the L-band radar on the Sukhoi figters, whose frequency (1-1,5 GHz) is well within the RWR frequency range noted above.
Even if a true spread-spectrum radar is developed, less than 1% of the signal returns to the emitter; this means that any component of the signal has to be hundreds of times stronger than the background noise of the same frequency. In fact, a fighter radar’s emission is between 1 million and 10 million times stronger than the background noise; as APG-77 has 1.500 T/R modules, each beam would be at least 650 times stronger than the noise of the same frequency. This in turn means that the frequency hopping is the main defensive mechanism of such radar. This approach does indeed work against older radar warners as it does not allow them time to analyze the signal; newer radar warners however can store and analyze the signals, making them more than capable of detecting any radar in existence at over four times the radar’s own detection distance. Only advantage that LPI radar has against modern RWRs when compared to older-type radars are far weaker sidelobes. They also do not allow for a reliable IFF; thus, if aircraft has no optical sensors (such as IRST), it has to get within 1 mile of the opponent for a reliable identification; in some conditions, ID distance may be as low as 400 meters. More on visual search can be read here. Initial visual detection distance depends on target size and aspect: from front, it is ~2,3 miles for the MiG-21 and ~4,5 miles for the F-14; from side, it is ~6 miles for the MiG-21 and ~7 miles for the F-14; from top, it is ~7,5 miles for the MiG-21 and ~13 miles for the F-14 (table avaliable in the document). It should be noted that curve drops off rapidly towards smaller sizes, so an aircraft slightly smaller than the MiG-21 might have significant visual detection range advantage. Smoke can increase detection range by 2 nautical miles. While aircraft that do smoke in military power tend not to smoke when using afterburner, afterburner usage massively increases the IR signature and the fuel consumption. Visual search is still important despite all technological advances, and will remain so, as all sensors have limitations – radar is unlikely to be used as it opens up aircraft using it for the attack and warns the opponent(s), IRST has a limited scan speed and field of view, while 360* coverage IR sensors such as EO DAS and DDM are primarly missile warning devices.
Radar importance has alvays paled in comparision to that of the visual detection. In the 1971 Indo-Pakistani war, Pakistani visual-range-only F-86s achieved better than 6:1 exchange ratio against Indian supersonic MiG-21s, Su-7s and Hawker Hunters, in good part due to its small visual signature and good cockpit visibility. Only Indian fighter that managed to match the F-86 was also subsonic Folland Gnat, which had advantage of being the smallest fighter in the war. In earlier 1965 war, Gnat also had advantage over F-86: even Pakistani sources credit it with 3 F-86 kills for 2 losses to the F-86, while Indian sources credit it with 7 F-86 kills.
CATBird test aircraft for the F-35s sensors actually managed to detect, track and jam F-22s radar.
IRST is especially useful against stealth fighters, which tend to have higher IR signature than equivalent non-stealth fighters. Stealth fighters’ unwieldy aerodynamic shape, when combined with IR compromised radar-absorbent materials (it is impossible to make a material that will reduce both radar and IR signature), increases fighter’s basic IR signature, as well as increasing the shock cone produced during the supersonic flight as well as temperature of the stagnation point in front of aircraft. Temperature of the stagnation point is around 260*C at Mach 2, and that of the shock cone is 87*C at Mach 1,7. Ambient temperature at 30.000 feet is -44*C (131* difference), and at 50.000 feet it is -57*C (144* difference). Only problem may be if target fighter is flying at low subsonic speeds (less than 300 kts) and low altitude, and has IR signature reduction measures, as at such speeds IRST will likely have to rely exclusively on detecting the engine and exhaust plume heat. This speed (< Mach 0,5) is unlikely to be used as it is far below the standard cruise speed (no less than Mach 0,7 for any fighter, typically around Mach 0,9). At high altitude it will not even help while sacrificing combat radius and weapons range, as well as causing the aircraft to rely on the enemy accidentally passing through its engagement envelope, while at low altitude missiles have so limited range that fighter will have to come within visual range anyway. Low-flying fighter might use the clutter to hide from a high-altitude fighter using the IRST, but radar has the same problem. Further, it is less likely that an IRST will loose track of a low-flying target once acquired. Additional sources of IR signature are fighter’s radar and cockpit sun glint. Powerful radars typically used on radar-centric fighters – stealth or not – will cause major heat generation, while radar absorbent materials used for canopies on stealth fighters will increase sun glint. Even if stealth fighter employs cooling of wing leading edges, temperature band that the IRST scans is far wider than what cooling system can cool. Uncooled IRST can detect 0,1K of temperature difference, while cooled ones can detect 0,01K. This means that detection range is primarly dependant on aircraft size and sensor resolution – which in modern IRST systems is large enough to allow IRST to perform an unassisted initial detection. IRST can also identify aircraft at longer range than possible visually – 40 kilometers for PIRATE. Rangefinding can be performed either actively, through laser rangefinder, or passively, through triangulation or atmospheric propagation model.
Problem with speed vs IR signature mentioned above means that pilot of a stealth fighter will be faced with a very tough decision – if he attempts to fly faster and thus increase the range of his weapons, he will be detected; if he tries to avoid detection, he will have to severely limit maximum range of his weapons. Even in the latter case, missile launch plume will give him away even if he manages to attack the enemy without being detected (such as by using the IRST or offboard sensors).
Stealth aircraft can also be detected by an IRST or AWACS searching not for the fighter itself but for the background behind it; same method can be used with radio-telescopes, as from the radioastronomical perspective, every part of the sky is covered with stars. Over-the-horizon radars and the VHF radars can also be used to detect such aircraft (USAF has actually conceded that the B-2 is detectable by such radars), as VHF radars cause resonance of fins or even wings of aircraft, while over-the-horizon radars cause resonance from the entire aircraft, making both shape and RAM irrelevant, meaning that RCS of stealthy aircraft approaches that of non-stealthy targets of comparable size. Further, over-the-horizon radars come from direction for which the stealth aircraft are very much not optimized for, and also detect the turbulent wake. Their resolution is typically 15-25 kilometers, more than enough to guide in the IRST-equipped fighters. Various multistatic passive radars are also a possibility, and even X band radars might detect stealth aircraft at comparably long range with right programming (burds and insects don’t fly at Mach 0,9-1,5 at 30.000-60.000 feet).
Impact of frequency on RCS can be best shown with an example given by a Russian engineer. A Chinese DF-15 missile has RCS of 0,002 m2 in X band, but it rises to 0,6 m2 in VHF band.
Historically, MiG-25 and MiG-31 were more than capable of detecting the Blackbird with their IRST systems at ranges well in excess of 100 kilometers. Not a problem, since at Mach 3+ speeds at which the Blackbird regularly flew, heating would be enormous. MiG-31s skin and canopy could reach temperatures of 760*C during the intercepts.
While modern stealth aircraft are often compared to submarines, it is immediately possible to see that such an argument by stealth proponents is not well thought out. Submarines are silent hunters in all meanings of the word, moving slowly or even lying still when in threat area and relying primarly or even solely on passive sensors and weapons in order to detect their targets. They also use terrain features to hide their sound signatures when moving and to hide from searching sonars. If detected by active sonar, submarines deploy noisemakers and decoys to confuse the searching and/or targeting. But when these things are applied to fighter aircraft, it becomes obvious that RCS reduction is comprably immaterial, since any usage of active sensors is risky, even suicidal. Passive sensors and passive missiles have dominated, and will dominate, aerial warfare. Fighters will have to continue flying from cloud to cloud while remaining completely passive in order to hide from enemy sensors, or cruise at very high altitude to limit effectiveness of enemy weapons. But the IRST cannot be completely countered, since flying at very low speeds means that intercepting the enemy will be a matter of luck, and that missiles will have a very short range against faster-flying enemies. If a fighter uses the radar, it will be targeted, while its radar may be jammed. In one way they are similar to submarines, however. Allied aircraft detected German submarines’ snorkels by using centimeter-wavelnegth radars as snorkels resonated with radar waves; this is the same princible by which VHF and HF radars can detect the stealth aircraft.
Impact that passive detection will have on mission planning for both “legacy” and “stealth” aircraft cannot be overstated. Penetrating aircraft, especially VLO ones, typically keep strictly silent, tracking hostile emitters in vicinity and keeping clear of them. But if the enemy is completely passive, pilot cannot know wether he has been detected. Even if AWACS is present, there is always a possibility of the enemy letting the stealth aircraft go deep inside the hostile territory before springing a trap. These considerations may make it militarily and politically unfeasible to commit very expensive and politically violatile (due to both the cost and the hype) stealth aircraft to the mission. Similarly, IR SAMs are the greatest danger for manned aircraft, exactly because they are passive and are thus detected later than active-radar SAMs.
Signature reduction considerations
Aircraft’s signature has to be reduced in six disciplines: infrared, visual, smoke, contrail, radar and acoustic. Enemy detecting aircraft from 18 km with radar is of no use if he can detect it from 50 km with IRST (not to mention that radar is the least relevant sensor).
Visual signature requires aircraft to be small, but also elimination of the smoke trail. It is also helped with camouflage painting, which for air superiority fighters is typically light gray.
EM signature means that no radar will be carried. Still, it is advantageous to reduce the radar cross section and allow oneself more time to action after the radar-using enemy has been detected and identified. This means that surfaces at right angles to each another have to be avoided in order to limit the number of the corner reflectors, and surfaces will be parallel to each other whenever possible. Engine face will also be hidden, and all surfaces will be angled when looked at from front, while wing and fuselage will be blended.
IR signature reduction is the most important and the most complex one. While small size, single engine and lack of radar will help with it, aircraft’s nose, wing and tailfin leading edges and fuselage will remain major contributors, as will the engine exhaust plume. Most important factor in reducing the engine IR signature is avoiding usage of the afterburner, as afterburner increases IR energy emitted by the plume as much as 50 times. Shielding the engine exhaust or using the high bypass ratio engine (thus mixing in a cooler air) can be used to additionally reduce the exhaust plume IR signature.
Acoustic signature will be naturally limited by aircraft’s small size and single engine.
Basing and rough field capability
Fighter will have to have a rough-field landing capability as any concrete/asphalt air strips will get bombed early in any serious war (fighters I know of that possess such capability are Gripen, F-5, MiG-21, MiG-29/35, Su-27/30/35). This means that front landing gear will have to be positioned behind air intakes to avoid ingesting debris kicked up, and the landing gear itself will have to be strengthened. FOD screens or MiG-29 style auxilliary intakes may have to be implemented. It should be noted that MiG-21 did not need such screens as its air intake was positioned well in front of the forward landing gear. It will also have a double-tire arrangement in order to lower the ground pressure. Undercarriage doors will only be open when the gear is cycling, remaining closed when it is either up or down. Both main undercarriage and the main fuel tanks have to be around the center of gravity, and dorsal spine will be provided for the control cables. Aft gear will carry most of the weight and be close to the center of gravity, while taking takeoff rotation into account. Gear will be made of titanium in order to be light. Ground clearance will have to be at least 70 cm, preferably 100 – 170 cm. Looked from the side, angle between a vertical going from the center of gravity and the line connecting center of gravity with a side wheel will have to be greater than 25 degrees. On the other hand, wheels will still have to be placed within the fuselage body or base of the wings; any wider placement risks unacceptable elastic deformation of the airframe while aircraft is on the ground. Tires themselves will have to be wide in order to achieve low ground pressure. Another possibility is a tracked landing gear such as tested on the P-40.
This means that aircraft cannot be radar-stealthy, since any stealth aircraft must have major maintenance facilities and clean concrete air strips. If these are destroyed, stealth fighters have to fall back to further away air bases, further reducing their already low sortie rates. Additional complicating factor in that case is that “stealth” aircraft tend to have lower fuel fraction and higher fuel consumption than “normal” aircraft of similar size, leading to a lower fuel fraction and thus lower persistence and range for a given size and weight. Stealth aircraft could use tankers to refuel in the air, but these are large, very visible on all sensors and very vulnerable. These concerns also apply to complex “non-stealth” aircraft such as the F-15 or the Eurofighter Typhoon. All these fighters, just like the modern IADS, rely on a very limited number of nodes to be effective; if these are eliminated, their effectiveness drops sharply, possibly to the point of complete irrelevancy.
Mission turnaround will be 10 minutes, and each fighter will be able to fly 3 sorties every day. Repairs and maintenance – including changing of the engine, avionics etc. – will be carried out in the field.
How important this capability is can be seen on example of World War II. Despite Allies having undisputed air superiority, air bases were regularly bombed. On January 1st, 1945, Germans launched Operation Bodenplatte, destroying or damaging 500 Allied fighters. In the Korean War, US forces were forced to bring back prop P-51, F-4U and A-1 aircraft which could operate from grassy fields. But some P-51s were shot down by Yaks when taking off. In fact, bi-planes could be equipped with Sidewinders and used to shoot down modern jet fighters when they try to take off. This reason is also why “multirole” fighter-bomber monstroities requiring concrete runways are a very bad idea.
Supersonic cruise requirement necessitates a fuel fraction of at least 40%. This means that all unnecessary equipment will have to be disposed of, and that fighter will only perform air superiority and related (point defense, interception, combat air patrol) missions, with ground attack being left to the dedicated aircraft. It also requires high dry thrust-to-weight ratio, made even more important by the fact that pilot will need to minimize fuel consumption in combat while maximising maneuverability. These characteristics will also help in outlasting the enemy in the air. Cruise speed and persistance (one is useless without another) can be a deciding factor in fighter’s performance. P-38 has performed so badly in the European theatre yet it proved successful in the Pacific. Sole reason for this is that it had lower cruise speed than German fighters, but higher cruise speed than Japanese fighters, and so in the Pacific it could compensate for its maneuvering shortcomings, most damning of which was lacking transient performance.
Seat will be reclined at 30 degrees with raised rudder pedals, while control stick will be side-mounted. Canopy will be opened and closed manually, saving cca 10 kg on actuators.
First candidate is an F-414EPE for a simple reason that it has incorporated all of RM12s upgrades in terms of reliability, simplicity, ease of maintenance and resistance to FOD while having fewer parts.
Length: 3.912 m
Diameter: 0,889 m
Dry weight: 1.110 kg
Dry thrust: 7.620 kgf
Wet thrust: 11.975 kgf
Specific fuel consumption:
Dry: 0,84 kg/kgf
Wet: 1,85 kg/kgf
Dry: 6.401 kg/h
Wet: 22.154 kg/h
Another possibility is an upgrade of an actual Volvo RM-12. Upgrade will be done in two phases, depending on technological feasibility.
Phase 1 / Phase 2
Length: 3,912 m
Diameter: 0,889 m
Dry weight: 1.110 kg
Dry thrust: 7.699 kgf / 8.911 kgf
Wet thrust: 11.762 kgf / 13.748 kgf
Specific fuel consumption:
Dry: 0,74 kg/kgf h
Wet: 1,7 kg/kgf h
Dry: 5.697 kg/h / 6.594 kg/h
Wet: 19.995 kg/h / 23.372 kg/h
Third possibility is an EJ230/270, with EJ230 being a basic variant and EJ270 used as a possible upgrade:
Length: 4 m
Diameter: 0,737 m
Dry weight: 989 kg
Installed weight: 1.037 kg
Dry thrust: 7.348 kgf / 7.938 kgf
Wet thrust: 10.478 kgf / 12.247 kgf
Specific fuel consumption:
Dry: 0,74 kg / kgf h
Wet: 1,66 kg / kgf h
Dry thrust: 5.438 kg/h (5.874 kg/h)
Reheat: 17.393 kg/h (20.330 kg/h)
F-414EPE is the worst candidate due to the high specific fuel consumption, while both it and the RM-12 upgrade are “paper engines” (only F-414EDE had been tested). Thus, an EJ200 variant may be the best choice (EJ230 is already avaliable for production), though it may have to be modified for improved FOD resistance. All variants of the Snecma M88 are too weak for the fighter, and M88-2 has higher specific fuel consumption in dry thrust than the EJ-200 variants. EJ200 also has relatively few stages, facilitating easier maintenance. Most importantly for a fighter with supercruise requirements, EJ200s low bypass ratio of 0,4:1 gives it a near-turbojet cycle, resulting in a higher percentage of dry thrust relative to reheat thrust, and better supersonic performance. Thrust vectoring nozzle will not be used in order to improve reliability and reduce maintenance requirements.
As a result, EJ230 will be used, with EJ270 being a possible future upgrade.
During dogfight, firing opportunities come and pass quickly. This means that gun has to have high destructive power per projectile, high muzzle velocity, short projectile flight time to the target, high rate of fire and high firing acceleration. This requires a high-calibre revolver cannon with heavy projectiles, high muzzle velocity and high rate of fire – while Gattling guns may have higher rate of fire, they also need a long time to achieve it. As such, GIAT-30 is an ideal choice.
Data is as follows:
Length: 2,4 m
Weight: 120 kg
Muzzle velocity: 1025 m/s
Rate of fire: 2500 rpm
Spin-up time: 0,05 s
Rounds in first 0,5 seconds: 19
Rounds in first second: 41
Shell: 30×150 mm
Projectile weight: 275 g
Cartridge weight: 530 g
Weight in first 0,5 seconds: 5,23 kg
Weight in first second: 11,28 kg
Compare this to the M61A1/A2:
Length: 2,4 m
Weight: 120 kg
Muzzle velocity: 1050 m/s
Rate of fire: 6000 rpm / 6600 rpm
Spin-up time: 0,5 s / 0,25 s
Rounds in first 0,5 seconds: 25 / 41
Rounds in first second: 75 / 96
Shell: 20×102 mm
Projectile weight: 102 g
Cartridge weight: 262 g
Weight in first 0,5 seconds: 2,55 / 4,18 kg
Weight in first second: 7,65 / 9,79 kg
Other information states that M61A2 still needs 0,5 second spool-up time with 6.000 rpm maximum rate of fire, in which case its statistics stay same as the M61A1. Yet other info states that it takes 0,25 seconds to get to 3200 rpm to start firing; assuming a linear acceleration, it takes 0,47 seconds to maximum rate of fire. Thus statistics would go like this:
Length: 2,4 m
Weight: 120 kg
Muzzle velocity: 1050 m/s
Rate of fire: 6000 rpm
Spin-up time: 0,47 s
Rounds in first 0,5 seconds: 19
Rounds in first second: 69
Shell: 20×102 mm
Projectile weight: 102 g
Cartridge weight: 262 g
Weight in first 0,5 seconds: 1,94 kg
Weight in first second: 7,04 kg
As it can be seen, GIAT 30 throws more weight in both first half a second and first second of firing than either variant of the M61; if info noted above on the M61A2 is correct, then GIAT 30 also matches them in number of rounds fired in first half a second.
Missiles need to be easy to use, reliable, non-counterable and effective. This means that only IR missiles will be considered, as EM missiles are unreliable, easy to counter, and consequently ineffective – radar guided missiles need 15 seconds to lock on, allowing ample time for the RWR to detect and analyze attacker’s radar emissions. Secondary BVR missile can be of the anti-radiation variety in order to provide diversity in seeker types. To show a relative effectiveness of the missiles, Vietnam data is optimal (as it was the last war where USAF engaged a competent and reasonably equipped opponent, as opposed to the Gulf Wars and Bosnian War). Probability of kill was 26% for the gun (due to rotary design; compare to 31% achieved in Korea by linear action guns), 15% for the Sidewinder (IR WVR), 11% for the Falcon (IR BVR) and 8% for the Sparrow (EM BVR). So gun was 73% more efficient than IR WVR missile. IR WVR missile was 36% more efficient than IR BVR missile, while IR BVR missile was 38% more efficient than EM BVR missile. Effectiveness however is a function of both efficiency and usage opportunity. During the Vietnam war, 51 kill was made with guns, 83 with heat-seeking missiles and 56 with radar guided missiles (of which 2 at BVR); it should be noted here that USAF had a major bias towards the radar-guided missiles, and for some time US fighters were forbidden from carrying IR missiles alltogether. In the Yom Kippur and Bekaa Valley wars, Israeli made 93 kills with guns, 225 with IR missiles and 17 with radar-guided missiles (2 at BVR). It can be seen that IR WVR missile is fighter aircraft’s primary weapon, and opportunity for engagement depends on identifying the enemy – usually via visual identification.
Due to need for achieving the surprise, missiles used will be IRIS-T for dogfight, with MICA IR and MBDA Meteor serving in the air-to-air role. Meteor will be used as an anti-radiation missile, homing in on opponent’s EM emissions; if the enemy shuts down the radar and other sources of emissions, missile will switch to an active mode (other possibility is a fighter providing updates via uplink and IRST, but even in such scenario missile will likely have to turn on its seeker head for a final approach). Another advantage is that the IR missile needs 5-7 seconds to lock on, obtain parameters and launch, compared to 10-15 seconds for radar-guided missile; this issue has been somewhat negated by the lock-on after launch capability. Gun kill requires 3-6 seconds. 7 seconds is a maximum “safe” time for achieving a kill during dogfight.
All weapons listed are complimentary. While visual-range IR missile is a primary weapon, presence of the gun prevents the enemy from simply keeping within the missiles’ minimum effective range. Likewise, presence of a BVR missile forces the enemy to adjust tactics accordingly.
It should be noted that the last air-to-air combat happened in 2001, and it was a visual-range dogfight between 2 IAF F-15s and 2 Syrian MiG-29s.
Primary sensor will be PIRATE IRST. Detection range against subsonic fighters is 90 km head-on and 145 km tail-on, with 40 km identification range. It can track up to 200 targets, with angular resolution better than 0,05*. It should be noted here that PIRATE has completely passive rangefinding; while it is not stated how it is achieved, it presumably involves kinetic ranging (fighter performs a weaving maneuver, and the range is determined by the change in azimuth). For increased accuracy, two or more aircraft can share data via the datalink. As such, any active sensor – such as radar or laser rangefinder – is unnecessary.
Radar warning receiver will be SAAB’s BOW-21, using interferometric technology so as to allow for 1* accuracy. Link1 Link2 This will allow for a completely passive engagement of targets, without need to use the IRST or any other sensor.
Data link will be MIDS.
Existing missiles to be used
IRIS-T will be primary dogfighting missile, due to its better maneuverability than rivals’ (MICA IR, ASRAAM, AIM-9X). Since it is an imaging infrared missile, flares will likely have little to no effect on it unless they manage to block enough of the aircraft’s signature to impair missile’s ability to recognize the target. Its seeker can be cued by helmet mounted sight, IRST, missile approach warner and datalink. It also has an anti-missile capability. Alternative missiles will be AIM-9 (primarly AIM-9X) and Python 5. Data: weight 87,4 kg, length 2,94 m, range 25 km, speed Mach 3, 60 g.
MICA IR will be primary BVR missile due to the passive engagement facilitating surprise, better performance of IR seeker compared to EM one, as well as the fact that its comparably small size will result in a better maneuverability than most BVR missiles. It can be ejected from the airframe points up to 4 g while wing pylons allow release up to 9 g. Data: weight 112 kg, length 3,10 m, range 60 km, speed Mach 4. Alternative option is AIM-132 which has identical maneuvering capability (50 g at Mach 4) but a shorter range of 50 km.
MBDA Meteor will primarly be used as an anti-radiation missile, homing on enemy radar emissions in order to hit the aircraft; if enemy fighter switches off the radar, missile will switch to the active homing. This should be doable simply with software modifications. Another possibility is replacing its EM seeker with an IR one. Alternative missiles will be AIM-120 and MICA EM, and will be used in the same way (AIM-120 should also get an IR variant). Data: weight 185 km, length 3,65 m, range 225 km, speed Mach 4, 40 g.
It should be noted here that air-to-air anti-radiation missile is not a new idea. USAF tested the BRAZO missile in 1970s, which proved quite capable of shooting down target drones, but it was cancelled despite – or more likely because – of its successful performance and implications it had for USAFs radar-centric approach. In Iranian-Iraqi war, Iranian F-14s used AIM-54 to devastate rather incompetent Iraqi air force, but in 1988 France supplied some Super 530D missiles with anti-radiation mode which Iraqis used to down several F-14s. US also abandoned the IR BVR missile despite the fact that it actually performed better in Vietnam (11% vs 8% Pk for radar-guided missiles).
Longer detection range is irrelevant if it cannot be exploited for engagement; likewise, a longer engagement range is irrelevant if missiles are unlikely to hit. Therefore a missile is a crucial part of a kill chain, and one of two main points of failure in the BVR combat (other point being IFF). Within the missile itself, main points of failure were the seeker head (radar-guided missiles are more vulnerable to countermeasures and easier to detect than IR ones) and the maneuvering limitations of the missile itself.
This missile will use propulsion section of the MBDA Meteor as a first stage, and IRIS-T as a second stage. As a result, it will be capable of hitting a maneuvering target during entire flight time, unlike modern “BVR” missiles which can only hit an evading target within visual range. Maximum ballistic range will likely be around 200 kilometers, with maximum effective range of 100 kilometers. Weight will be around 225 kg, with cost of 1,5 million USD. Length will be 5,16 m. Guidance will be carried out through two-way datalink until the IR seeker acquires the target. Missile will be only used against fighters.
This missile will be an MBDA Meteor equipped with AIM-120s propulsion section. Thus weight of Meteor (185 kg) will be added to weight of AIM-120s propulsion section (75 kg), for a total weight being somewhat above the sum at 275 kg in order to account for the modifications needed. Maximum range will likely be around 400 km. Cost will be around 3 million USD. Length will be 5,38 m. Missile will have a primary anti-radiation mode with active seeking possible if the target switches off the radar; it will also have a two-way datalink. Missile will be primarly used as an AWACS-killer, though usage against fighters remains a possibility.
Due to their large size and high weight, both missiles will likely only be carried on body hardpoints.
Meteor’s range is not stated directly, rather it is only said to have a range that is 3 times the range of AIM-120B in a head-on engagement.
Aircraft will use a single EJ2X0 engine for propulsion. Gun will be French GIAT 30, with PIRATE IRST being the primary sensor. Saab’s BOW-21 will be a radar warner.
Airframe will make an extensive use of wing-body blending. Wing will be of a tailless delta configuration, with 47,5* degree sweep and 73* degree LERX. It will have a slight anhedral, and will be of a mid-position vertically, in order to reduce the interference drag. Nose to wingtip angle will be 27*. Wing thickness will be 4-7%.
Canard will be positioned in front of and above the wing, with canard trailling edge being positioned in front of the wing leading edge, slightly overlapping the LERX. Canard area will be 9% of the wing area, with canard sweep being around 45*, preferably identical to wing 47,5* sweep. Vertical distance will be 18,5% of the wing mean geometric chord, and canard itself may be slightly dihedral.
Body will get narrower from canards to the aft end as wings spread out in order to reduce transonic drag. Vertical fin will be positioned far aft, with a dorsal fin fairing.
Air intakes will be positioned on the lower side of the body, shielded (and separated) by the fuselage. Intakes will be offset from the fuselage by 1% of their distance from the nose. Air bleed area will go from the bottom of the body to the wing-body junction above the wing itself to energize the vortices and thus air flow over the wing and around the tail fin.
Forebody finesse ratio (forebody length divided by the maximum diameter; forebody includes cockpit and anything in front of it) will be low. Nose itself will be near-elliptical as such shape tends to improve directional stability. Lack of radar will also help here with directional stability, as a large nose can lead to loss of directional stability.
Cockpit will provide a good visibility. For aft visibility, pilot has to be capable of seeing the aft fuselage. As for forward visibility, most crucial is over-the-nose visibility (at least 15 degrees).
Surfaces at right angles to each another will be avoided, and will be paralel whenever possible. Engine face will be hidden to reduce both RCS and IR signature, and all surfaces will be angled relative to the front-looking radar (even the missile hardpoints).
Front landing gear will be positioned behind the air intakes, and will use a double-tire arrangement. Undercarriage doors will be designed so they can remain closed when the gear is down. Main (aft) undercarriage will be positioned near the center of the gravity. Gear will provide between 70 and 170 cm of ground clearance. Looked from the side, angle between a vertical going from the center of gravity and the line connecting center of gravity with a side wheel will have to be greater than 25 degrees. On the other hand, wheels will still have to be placed within the fuselage body or base of the wings.
Seat will be reclined at 30 degrees with raised rudder pedals, while control stick will be side-mounted.
Note: two innermost wing hardpoints can be used for fuel tanks, so following options are also possible:
2 WVRAAM, 4 BVRAAM, 2 EFT
There should be at least 1 meter of free space between two AAM stations. Gripen E, with 8,4 meter wing span, has 8 side-to-side missile stations.
Canard area in Dassault Rafale C is 8% of the wing area, compared to 17% for Gripen and 5% for Rafale A. Proposed Novi Avion had canard percentage area similar to Rafale C.
Gripen’s canard tips are half a metre above the wing plane, and so are Novi Avion’s canards . In all three cases, canard trailling edge is just in fron of the wing leading edge.
Aircraft airframe will be based on the aluminum-lithium alloys. As can be seen here and here, these alloys allow as much as 10% weight reduction for same strength when compared to modern composites (Al-Li alloys have density of around 2,55-2,59 g/cm3, compared to 1,3 for carbon, 1,6-2 for epoxy, and 2,5 for glass fibre; however, composites are typically far thicker than aluminum parts of equivalent strength). Further, metal airframe is easier to produce, maintain and repair, and has better damage tolerance than traditional composites. It is not toxic, and does not burn; on the contrary, plastic adhesives that keep the composite layers together can be ignited at temperatures well below the temperature of burning fuel, and produce exceedingly toxic fumes.
Cables go through the spine at top of the aircraft.
Wing area: 73.048 cm2 * 2 + 155.324 cm2 = 30,14 m2 = 301,4 kg
Canard area: 1.880 cm2 + 7.380 cm2 + 7.210 cm2 = 1,65 m2 = 16,5 kg
Canard area is 5,5% of the wing area
Vertical stabilizor area: 11.000 cm2 + 14.300 cm2 + 25.000 cm2 + 1.500 cm2 = 5,2 m2 = 92 kg
Lower fuselage area: (29 + 24 + 30 + 26 + 16) * 703 * 2 cm2 = 175.750 cm2 = 17,6 m2
Upper fuselage area: (30 + 12 + 44 + 25 + 18) * 703 * 2 cm2 = 181.374 cm2 = 18,1 m2
= fuselage: 656 kg
Nose: 2 * 39 * pi * 400 cm2 = 35.200 cm2 = 3,52 m2 = 65 kg
Total airframe weight: 1130,9 kg
Weights and dimensions (L:W:H) are as follows:
PIRATE IRST: 48 kg; 680 mm length, 591 mm width, 300 mm height
missile warners: 2,2 kg * 4; 134 mm length, 130 mm diameter
laser warners: 1 kg * 4; 115 mm length, 90 mm width, 76 mm height
front RWR: 2,5 kg * 2; 170 mm length, 40 mm width, 220 mm height
Spiral RWR antennas: 0,5 kg * 4; 67,5 mm L, 110 mm diameter
Total: 67,8 kg
Dispensers: 2 kg * 8; 236 mm length, 151 mm width, 269 mm height
Jammer: 18,6 kg; 161 mm length, 184 mm width, 420 mm height
Disposable decoy: 0,7 kg * 12
Total: 43 kg
EW suite controller: 10 kg; 193 mm length, 359 mm width,124 mm height
Safety switch unit: 0,7 kg, 82 mm length, 65 mm width, 11 mm height * 2
FCS: 16 kg, 85 mm length, 55 mm height, 85 mm width * 2
System, navigation: 15,6 kg, 386 mm length, 191 mm height, 191 mm width * 2
Total: 82,9 kg
Data link (MIDS):
Term: 22,2 kg; 340 mm length, 190 mm width, 190 mm height
RPS: 6,5 kg; 340 mm length, 60 mm width, 190 mm height
Total: 28,7 kg
GIAT 30: 120 kg, 2,4 m length
EJ230: 1.037 kg; 4 m length, 0,737 m diameter
HUD: 14 kg
Screens: 5 kg * 3
Total: 29 kg
Ejection seat: 59 kg
Titanium landing gear: 300 kg
Electrical: 90 kg
Environmental control, pressurization, oxygen: 100 kg
Hydraulics, actuators: 90 kg
Total equipment weight: 2047,4 kg
Fuel will be a high-density jet fuel with 0,84 kg/l, but a standard density fuel (0,81 kg/l) and isobutanol (0,802 kg/l) will also be used.
Side fuel tanks: (11.892 – 4.932) * 700 = 4.872.000 cm3 – 1.570.464 cm3 = 3.301.536 cm3
Wing fuel tanks: 11 * 107.702 + 11 * 12.915 * 2 + 11 * 12.833 * 2 = 1.184.722 + 284.130 + 282.326 = 2.141.480 cm3
Total fuel capacity is 5.443.016 cm3 = 5.443 l = 4.572 kg
Each external fuel tank will hold 840 kg of fuel and has empty weight of 85 kg for a total of 925 kg; pylon (connected to the tank) weights 50 kg.
Gun holds 320 rounds weighting 169,6 kg.
IRIS-T weights 87,4 kg, while MICA IR weights 112 kg. This means that a standard loadout of 4 IRIS-T + 6 MICA IR weights 1.021,6 kg.
Design empty: 3.178 kg
Basic empty (design empty + unusable fuel, undrainable oil, survival equipment) = 3.296 kg
Operational empty (basic empty + crew, weapons racks, ejectors, gun, etc.) = 3.468 kg
Armed empty (operational empty + gun ammo, missiles) = 4.659,2 kg
Combat (armed empty + 50% fuel) = 6.945,2 kg
Combat takeoff (armed empty + 100% fuel) = 9.231,2 kg
Maximum takeoff (practical) = 11.892 kg
Maximum takeoff (theoretical) = 16.200 kg
2% of the fuel is not usable.
Oil is 1% of the engine weight.
Missile rail launcher weights 12 kg.
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, 2 IRIS-T, 4 MICA IR and 4 external fuel tanks.
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%.
Compared to concrete, dry grass increases the takeoff run by 15%. It also increases the landing roll.
At concrete runway, Rafale C has 590 m takeoff distance and 490 m landing distance. Its combat takeoff weight is 14.942 kg, with a wing loading of 327 kg/m2 and thrust-to-weight ratio of 1,01. Compared to the FLX, its combat takeoff weight is 162%, which means that FLXs takeoff distance should be 228 meters. FLXs TWR of 1,14 additionally decreases takeoff distance to 204 meters. FLX also has wing loading of 306 kg/m2, decreasing the takeoff distance to 198 meters. Landing distance will thus be 164 meters. Takeoff distance from grass will be 228 m.
For comparision, 4th variant of proposed ALR Piranha was to have a normal takeoff weight of 6.200 kg, wing loading of 388 kg/m2, 4.579 kgf of thrust (= thrust-to-weight ratio of 0,74) and takeoff distance of 450 meters.
Gripen E, with a dry TWR of 0,67 at combat weight can supercruise at unknown Mach when clean, while Gripen C has dry TWR of 0,62 at combat weight and cruises at Mach 1,05 (in ideal conditions and no air-to-air load). This means that 8,5% increase in dry TWR translates into 9,1% increase in cruise speed. With 4 missiles, Gripen NG can supercruise at Mach 1,2, and Mach 1,1 with 6 missiles, resulting in a penalty of Mach 0,05 per missile, suggesting a cruise speed when clean of Mach 1,3. Supersonic external tank has a penalty of Mach 0,1.
Rafale C has a dry TWR of 0,79 at combat weight and cruise speed of Mach 1,4. 90 kN M88, which would give a dry TWR of 0,97, would increase it to Mach 1,65 (both speeds are with 6 missiles). This means that a 23% increase in dry TWR translates into 18% increase in cruise speed.
7* increase in wing sweep increases the cruise speed by Mach 0,1.
FLX has dry TWR of 1,06 at combat weight and wing sweep of 47,5*. This results in a cruise speed of Mach 1,82 when clean (this includes 4 missiles), Mach 1,5 in air-to-air configuration (10 missiles) and Mach 1,1 in long-range patrol configuration (6 missiles, 4 supersonic tanks).*
Fixed intakes allow a maximum speed of ~Mach 1,8; Mach 2,0 is achievable with splitter plate producing an additional shock.
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. From that it would follow that Rafale can climb to 10.000 meters in ~83 seconds.
FLX would have a 30% better climb rates than Rafale going by thrust alone, resulting in 58 seconds to 10.000 meters and an initial climb rate of 397 meters per second.
Fuel consumption at the economic (Mach 0,9) cruise and without external tanks will be based on the Saab Gripen E (1.487 kg/h) or Novi Avion (1.411 kg/h). Latter one is more likely due to similarity in aerodynamics and size. Half of the fuel carried in the external fuel tanks is used to overcome the extra drag.
Standard combat radius will be calculated with following parameters: 1) takeoff; 2) time to 10.000 meters at full dry thrust; 3) 20 minutes of dry thrust supersonic cruise; 4) 2 minutes of afterburning thrust in combat; 5) subsonic cruise to and from the enemy territory. Times will be: 5 seconds of maximum dry thrust for takeoff, 63 seconds of maximum dry thrust to 10.000 m, 1.200 secons of maximum dry thrust for cruise, 120 seconds of maximum wet thrust for combat, ? seconds of cruise thrust for landing. Remaining time will be used for flight to and from the combat area, with a caveat that 450 kg of the fuel will be kept in reserve.
As a result fuel usage will be as follows: startup and taxi: 40 kg; takeoff: 8 kg; climb to 10.000 meters: 95 kg; 20 minute supercruise: 1.813 kg; 2 minute combat: 580 kg; descent and landing: 45 + 10 kg. With 450 kg of the fuel in the reserve, and 2% (108 kg) of the fuel not being usable, this leaves 1.429 kg of the fuel for the cruise to and from the combat area. This in turn gives 1,01 hours of flighttime, for a combat radius of 519 km.
Supersonic combat radius will assume that ingress, patrol and egress are all performed at supersonic speed, while subsonic combat radius will assume that all are performed at subsonic speed.
Fuel usage for supersonic combat radius will be: startup and taxi: 40 kg; takeoff: 8 kg; climb to 10.000 meters: 95 kg; 20 minute supercruise: 1.813 kg; 2 minute combat: 580 kg; descent and landing: 45 + 10 kg. With 450 kg of the fuel in the reserve, and 2% of the fuel not being usable, this leaves 1.423 kg of the fuel for the cruise to and from the combat area. This in turn gives 0,26 hours (15,7 minutes) of flighttime, for a combat radius of 210 km.
Fuel usage for subsonic combat radius will be: startup and taxi: 40 kg; takeoff: 8 kg; climb to 10.000 meters: 95 kg; 20 minute subsonic cruise: 470 kg; 2 minute combat: 580 kg; descent and landing: 45 + 10 kg. With 450 kg of the fuel in the reserve, and 2% of the fuel not being usable, this leaves 2.782 kg of the fuel for the cruise to and from the combat area. This in turn gives 1,97 hours of flighttime, for a combat radius of 1.000 km.
Fuel usage for maximum combat radius on the internal fuel will be: startup and taxi: 40 kg; takeoff: 8 kg; climb to 10.000 meters: 95 kg; 2 minute combat: 580 kg; descent and landing: 45 + 10 kg. With 450 kg of the fuel in the reserve, and 2% of the fuel not being usable, this leaves 3.252 kg of the fuel for the cruise to and from the combat area. This in turn gives 2,3 hours of flighttime, for a combat radius of 1.240 km.
At 10.000 meters (32.808 feet), Mach 1 is 299,5 m/s or 1.078,2 kph (link).
Rafale C’s unit flyaway cost is 66,8 million Euros in 2014, or 92,65 million USD. Cost per hour of flight was 10.000 Euros in 2012, or 10.400 Euros in 2014; this would translate into 14.400 USD. At empty weight of the 9.550 kg, cost per kg is 9.701 USD.
Gripen E’s unit flyaway cost is likely to be around 57 million USD, with cost per flight hour of 5.000 USD. At expected empty weight of 7.100 kg, cost per kg is 8.028 USD.
Gripen C’s unit flyaway cost is 43 million USD, with cost per flight hour of 4.850 USD (3.200 USD for Flygvapnet). At empty weight of 6.800 kg, cost per kg is 6.324 USD.
As FLX will have some of Rafale’s and Gripen Es advanced features, but will also lack some cost-increasing but ultimately unnecessary luxuries such as radar, multirole capability or a second engine, cost per kg will be estimated at 7.176 USD. Cost per flight hour will be 0,011279% of the unit flyaway cost. Spares and ground equipment procured alongside fighter will cost 50% of the fighter’s unit flyaway cost.
With an operational empty weight of 3.468 kg, FLX will cost 24.900.000 USD, with operational cost of 2.184 USD per hour of flight.
All values are in FY 2014 USD.
Length: 12,65 m
Wing span: 10,4 m
Height: 3,3 m
Wing area: 30,14 m2
Canard area: 1,65 m2
Angle of attack limit:
30* peacetime operational
32* wartime operational
40* emergency override
9 g / – 3 g peacetime operational
11 g / – 3,2 g wartime operational
13 g / – 3,2 g emergency override
16,5 g ultimate
Engine: EJ230 (EJ270)
Length: 400 cm
Diameter: 73,7 cm
Dry weight: 989 kg
Dry thrust: 7.348 kgf (7.938 kgf)
Wet thrust: 10.478 kgf (12.247 kgf)
Specific fuel consumption:
Dry: 0,74 kg / kgf h
Wet: 1,66 kg / kgf h
Subsonic cruise: 1.411 kg/h
Supersonic cruise: 5.438 kg/h (5.874 kg/h)
Reheat: 17.393 kg/h (20.330 kg/h)
Empty: 3.178 kg
Dogfight: 6.273,2 kg
Combat: 6.945,2 kg
Combat takeoff: 9.231,2 kg
Maximum takeoff: 11.892 kg
Dogfight: 208 kg/m2
Combat: 230 kg/m2
Combat takeoff: 306 kg/m2
Maximum takeoff: 395 kg/m2
Thrust to weight ratio: Dry thrust: 7.348 kgf (7.938 kgf); Wet thrust: 10.478 kgf (12.247 kgf)
Dogfight: 1,67 (1,17 dry)
Combat: 1,51 (1,06 dry)
Combat takeoff: 1,14 (0,80 dry)
Maximum takeoff: 0,88 (0,62 dry)
Subsonic cruise: Mach 0,95
Supersonic cruise: Mach 1,5
Maximum operational: Mach 1,8
Maximum dash: Mach 1,88
4.572 kg internal
3.360 kg external
0,5 at combat takeoff weight
0,67 at maximum takeoff weight
Combat radius on internal fuel:
Standard: 519 km
Subsonic: 1.000 km
Supersonic: 210 km
Subsonic with no patrol: 1.240 km
Internal fuel: 2.782 km
External fuel: 3.392 km
Service ceilling: 16.800 m
Initial climb rate: 378 meters per second
Time to 10.000 meters: 63 seconds
Instantaneous turn rate: 40 deg/s
Sustained turn rate: 30,5 deg/s
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 military aircraft, safety factor is 1,5.
Turn rate calculator:
Mach 1 at 30.000 feet is 1.091 kph.
FLX will use its small size, passive sensors and supersonic endurance to surprise the enemy fighters. Some possibilities are shown below.
If needed, twin-seater Eurofighter Typhoons may act as command aircraft for groups of FLXs, though their lack of supersonic performance will make such usage difficult. Another possibility is designing a completely new command aircraft which will have a similar supercruise performance as the FLX, while sporting a large array of both active and passive sensors. This aircraft will be a twin-seater and will search for the passive targets that the FLXs IRST may have missed.
Taiwan invasion scenario
This scenario is taken from the 2008 RAND Pacific Vision briefing, and is designed to adress the attrition rates, force size and sortie rates. Scenario itself is simple – Chinese Flankers will head high and straight towards Taiwan in a “wall” formation, while deployed NATO fighters will do the same in order to prevent them from reaching the Taiwan and deployed support assets (AWACS, tankers, etc.). Chinese pilots cannot run because they will be shot as traitors, while NATO pilots cannot run because Chinese will take out their support assets and they cannot land on Taiwan.
BVR missiles will be fired in salvos of either 3 or 4 missiles, while WVR missiles will be fired independently. Attack will alternate and one side will be given the advantage of both first BVR salvo, first WVR salvo and first gun shot in order to get both best and worst scenarios.
Probability of kill:
3-missile EM BVR missile salvo: 0,08 + 0,0736 + 0,0677 = 22,1%
4-missile EM BVR missile salvo: 0,08 + 0,0736 + 0,0677 + 0,0623 = 28,4%
3-missile IR BVR missile salvo: 0,11 + 0,0979 + 0,0871 = 29,5%
4-missile IR BVR missile salvo: 0,11 + 0,0979 + 0,0871 + 0,0776 = 37,3%
IR WVR missile: 15%
Rotary cannon: 26%
Revolver cannon: 31%
Linear action cannon: 31%
Su-30MKK: 4 WVRAAM, 6 EM BVRAAM, 5,0 gun bursts
F-22A: 2 WVRAAM, 6 EM BVRAAM, 4,8 gun bursts
F-35A: 4 EM BVRAAM, 2,6 gun bursts
F-15C: 2 WVRAAM, 6 EM BVRAAM, 8,6 gun bursts
F-16C: 2 WVRAAM, 6 EM BVRAAM, 4,7 gun bursts
F-18E: 2 WVRAAM, 6 EM BVRAAM, 5,2 gun bursts
Typhoon: 2 WVRAAM, 8 EM BVRAAM, 5,4 gun bursts
Rafale C: 2 WVRAAM, 8 IR BVRAAM, 3,0 gun bursts
Gripen C: 2 WVRAAM, 4 EM BVRAAM, 4,2 gun bursts
Gripen E: 2 WVRAAM, 6 EM BVRAAM, 4,2 gun bursts
FLX: 4 WVRAAM, 6 IR BVRAAM, 6,1 gun bursts
Unit flyaway cost (FY2014):
Su-30MKK: 55 million USD
F-22A: 277 million USD
F-35A: 182 million USD
F-15C: 128 million USD
F-16C: 71 million USD
F-18E: 69 million USD
Typhoon: 129 million USD
Rafale C: 92,7 million USD
Gripen C: 43 million USD
Gripen E: 55 million USD (est.)
FLX: 24,9 million USD
Number of fighters:
Su-30MKK: 97 (=5,34 billion USD)
Rafale C: 57
Gripen C: 124
Gripen E: 97
Sortie rate (sorties/fighter/day):
Rafale C: 2,7
Gripen C: 2,18
Gripen E: 2,0 (assumption)
FLX: 2,91 (halfway between Gripen C and F-5E)
Number of fighters in the air: (number of fighters * sortie rate / 2,91)
Rafale C: 53
Gripen C: 93
Gripen E: 67
First shot to the Red Force
33 Su-30s fire 66 3-missile EM BVR salvos. 3 F-22s shot down. Total losses: 3 F-22, 0 Su-30
33 Su-30s fire 66 3-missile EM BVR salvos. 4 F-35As shot down. Total losses: 4 F-35A, 0 Su-30
33 Su-30s fire 66 3-missile EM BVR salvos. 15 F-15Cs shot down. Total losses: 15 F-15C, 0 Su-30
33 Su-30s fire 66 3-missile EM BVR salvos. 15 F-16Cs shot down. 16 F-16Cs fire 32 3-missile EM BVR salvos. 7 Su-30s shot down. 26 Su-30s fire 104 WVR missiles. 16 F-16Cs shot down. Total losses: 31 F-16C, 7 Su-30
33 Su-30s fire 66 3-missile EM BVR salvos. 15 F-18Es shot down. 25 F-18Es fire 50 3-missile EM BVR salvos. 11 Su-30s shot down. 22 Su-30s fire 88 WVR missiles. 13 F-18Es shot down. 12 F-18Es fire 24 WVR missiles. 4 Su-30s shot down. 18 Su-30s shoot down 6 F-18Es with guns. 6 F-18Es shoot down 2 Su-30s with guns. 16 Su-30s shoot down 5 F-18Es with guns. 16 Su-30s shoot down 1 F-18E with guns. Total losses: 40 F-18E, 17 Su-30
33 Su-30s fire 66 3-missile EM BVR salvos. 15 Typhoons shot down. 19 Typhoons fire 38 4-missile EM BVR salvos. 11 Su-30s shot down. 22 Su-30s fire 88 WVR missiles. 13 Typhoons shot down. 6 Typhoons fire 12 WVR missiles. 2 Su-30s shot down. 22 Su-30s fire guns. 6 Typhoons shot down. Total losses: 41 Typhoon, 13 Su-30
33 Su-30s fire 66 3-missile EM BVR salvos. 15 Rafale Cs shot down. 38 Rafales fire 76 4-missile IR BVR salvos. 28 Su-30s shot down. 5 Su-30s fire 20 WVR missiles. 3 Rafales shot down. 25 Rafale fires 50 WVR missiles. 5 Su-30s shot down. Total losses: 18 Rafale, 33 Su-30
33 Su-30s fire 66 3-missile EM BVR salvos. 15 Gripen Cs shot down. 78 Gripens fire 78 4-missile EM BVR missile salvos. 22 Su-30s shot down. 11 Su-30s fire 44 WVR missiles. 7 Gripens shot down. 71 Gripens fire 142 WVR missiles. 11 Su-30s shot down. Total losses: 22 Gripen C, 33 Su-30
33 Su-30s fire 66 3-missile EM BVR salvos. 15 Gripen Es shot down. 52 Gripen Es fire 104 3-missile EM BVR missile salvos. 23 Su-30s shot down. 10 Su-30s fire 40 WVR missiles. 6 Gripen Es shot down. 46 Gripen Es fire 92 WVR missiles. 10 Su-30s shot down. Total losses: 21 Gripen E, 33 Su-30
33 Su-30s fire 66 3-missile EM BVR salvos. 15 FLXs shot down. 199 FLXs fire 398 3-missile IR BVR salvos. 33 Su-30s shot down. Total losses: 15 FLX, 33 Su-30
First shot to the Blue Force
3 F-22s fire 6 4-missile EM BVR salvos. 2 Su-30s shot down. 31 Su-30 fire 62 3-missile EM BVR missile salvos. 3 F-22s shot down. Total losses: 2 Su-30, 3 F-22
4 F-35As fire 4 4-missile EM BVR salvos. 1 Su-30 shot down. 32 Su-30s fire 64 3-missile EM BVR missile salvos. 4 F-35As shot down. Total losses: 1 Su-30, 4 F-35A
15 F-15Cs fire 30 3-missile EM BVR salvos. 7 Su-30s shot down. 26 Su-30s fire 52 3-missile EM BVR salvos. 11 F-15Cs shot down. 4 F-15Cs fire 8 WVR missiles. 1 Su-30 shot down. 25 Su-30s fire 100 WVR missiles. 4 F-15Cs shot down. Total losses: 8 Su-30, 15 F-15C
31 F-16Cs fire 62 3-missile EM BVR salvos. 14 Su-30s shot down. 19 Su-30s fire 38 3-missile EM BVR salvos. 8 F-16Cs shot down. 23 F-16Cs fire 46 WVR missiles. 7 Su-30s shot down. 12 Su-30s fire 48 WVR missiles. 7 F-16Cs shot down. 16 F-16Cs fire guns. 4 Su-30s shot down. 8 Su-30s fire guns. 2 F-16Cs shot down. 14 F-16Cs fire guns. 4 Su-30s shot down. 4 Su-30s fire guns. 1 F-16C shot down. 13 F-16Cs fire guns. 3 Su-30s shot down. 1 Su-30s fire guns. 0 F-16Cs shot down. 13 F-16Cs fire guns. 1 Su-30s shot down. Total losses: 33 Su-30, 18 F-16C
40 F-18Es fire 80 3-missile EM BVR salvos. 18 Su-30s shot down. 15 Su-30s fire 30 3-missile EM BVR salvos. 7 F-18Es shot down. 33 F-18Es fire 66 WVR missiles. 10 Su-30s shot down. 5 Su-30s fire 20 WVR missiles. 3 F-18Es shot down. 30 F-18Es fire guns. 5 Su-30s shot down. Total losses: 33 Su-30, 10 F-18E
34 Typhoons fire 68 4-missile EM BVR salvos. 19 Su-30s shot down. 14 Su-30s fire 28 3-missile EM BVR salvos. 6 Typhoons shot down. 28 Typhoons fire 56 WVR missiles. 8 Su-30s shot down. 6 Su-30s fire 24 WVR missiles. 4 Typhoons shot down. 24 Typhoons fire guns. 6 Su-30s shot down. Total losses: 33 Su-30, 10 Typhoon
53 Rafales fire 106 4-missile IR BVR salvos. 33 Su-30s shot down. Total losses: 33 Su-30, 0 Rafale
93 Gripen Cs fire 93 4-missile EM BVR salvos. 26 Su-30s shot down. 7 Su-30s fire 14 3-missile EM BVR salvos. 3 Gripen Cs shot down. 90 Gripen Cs fire 180 WVR missiles. 7 Su-30s shot down. Total losses: 33 Su-30, 3 Gripen C
67 Gripen Es fire 134 3-missile EM BVR salvos. 30 Su-30s shot down. 3 Su-30s fire 6 3-missile EM BVR salvos. 1 Gripen E shot down. 66 Gripen Es fire 132 WVR missiles. 3 Su-30s shot down. Total losses: 33 Su-30, 1 Gripen E
214 FLXs fire 428 3-missile IR BVR salvos. 33 Su-30s shot down. Total losses: 33 Su-30, 0 FLX
Greatest likelihood of one side getting a first shot is:
Su-30 vs F-22: F-22 BVR, Su-30 WVR
Su-30 vs F-35: Su-30
Su-30 vs F-15C: Su-30
Su-30 vs F-16C: Su-30 BVR, F-16 WVR
Su-30 vs F-18E: Su-30
Su-30 vs Typhoon: Typhoon
Su-30 vs Rafale C: Rafale
Su-30 vs Gripen C: Su-30 BVR, Gripen WVR
Su-30 vs Gripen E: Gripen
Su-30 vs FLX: FLX
Gripen C vs FLX: FLX
Gripen E vs FLX: FLX
With 8 and 4 internal hardpoints respectively, neither the F-22 or the F-35 have enough missiles on-board to shoot down Su-30s, even with perfect (100%) kill probability. Even assuming that the entire force is launched in a single go, F-22s will need average missile Pk of 64%, and the F-35s of 90%, in order to shoot down the entire Su-30 force, assuming that Su-30s don’t shoot back. Similarly, if sortie rate is taken into the account, then Su-30s need average missile Pk of 26% in order to shoot down the entire Gripen C force, and 20% to shoot down the entire Gripen E force.
Against the FLX, Su-30 will need an average missile Pk of 22% if both forces are launched at a single go, and 44% if sortie rate is taken into the account. FLX on the other hand will need an average missile Pk of 5% and 2%, respectively.
Avaliability was also not considered, as it is difficult to estimate avaliability in the wartime and I didn’t have any numbers for the Su-30 or most other fighters. That being said, peacetime avaliability is 92% for the Saab Gripen and 50% for the F-22. It is likely to be around 30% for the F-35 and 95% for the FLX. This would make the above comparisions far worse for the stealth fighters. Typhoon, Rafale and Su-30 are most likely to have the avaliability somewhat worse than the Gripen, but far better than the F-22.
If fighters are deployed on an aircraft carrier, an issue of range appears. Chinese anti-ship ballistic missiles have range of 1.500 km, while Flankers carrying anti-ship cruise missiles can attack targets as far as 1.350 km away from Chinese mainland. This means that carriers equiped with any existing Western carrier fighter (F-18, Rafale, F-35) are within the danger zone. Even the FLX would need external tanks to resolve the problem.
Some of Western fighters are penalized by assumption that one hardpoint equals one missile, and that stealth fighters carry no external missiles (though latter is not exactly a penalty since doing so defeats the entire point of stealth). Maximum missile loadout is 14 missiles for the F-18E, 12 missiles for the F-22 and 10 missiles for the F-35. Su-30 also can be upgraded to carry 14 missiles, but there is no indication that the Su-30MKK has that capability. Gun combat is also not quite realistic: gun Pk is certain to be better against sluggish fighters like the F-35 and F-18 or large fighters like the Su-30, F-22 and F-15, than against small, nimble fighters like the Rafale, Gripen or the FLX. F-22 and F-35 are also likely to have gun Pk inferior to even standard rotary cannon Pk, as they require gun doors to open in addition to the spin-up time of the Gattling designs, adding 0,5 second delay.
Importance of numbers is confirmed in both real war and exercises. In all wars, larger number of aircraft in the air pushed the exchange ratio towards parity, as pilot can (even with best sensors) deal with only so many targets at once (twin seaters were actually worse than single seaters in such scenarios as weapons officer overloaded the pilot with inputs). This was also confirmed in AIMVAL/ACEVAL tests. Computer simulations predicted that the F-15 will have 70:1 exchange ratio advantage over the F-5. Pilots flying the preliminary engagements suggested it to be lowered to 18:1. With 2 F-15s against a single F-5, ratio was 5:1 in the F-15s favor. In 1-on-1 scenarios, it fell to 3:1. With 4 F-15s against 4 F-5s, exchange ratio was 2:1 in the F-15s favor, while 2 F-15s against 4 F-5s resulted in the exchange ratio of 1:1. Large numerical advantage can saturate pilots of the outnumbered side, and it also allows the force to “grab the enemy by the nose and kick them in the ass”, metaphorically speaking. As an example, if enemy relies on AWACS and tankers, part of the attacking fighters can keep the protection screen busy, while the other part shoots down the support elements. Numerical advantage also increases the probability of getting the first shot (it should be noted here that this does not only apply to the total number of aircraft: it is always better to have three formations of 4 aircraft each than one formation of 12, or maybe even 16, aircraft). There is also a story how the F-5 pilots, being killed off by the F-15s at BVR, decided to equip their aircraft with radar detectors from automobile stores. The next day, exchange ratio changed into the F-5s favor.
But pilot quality is just as important. Between 1975 and 1980, instructor pilots that logged 40 to 60 hours of ACM per month used F-5s to consistently whip students (which got only 14 to 20 hours per month) flying “more capable” F-4s, F-14s and F-15s. As pilots need to fly in order to train, this means that simpler (and thus cheaper) aircraft typically perform better than more complex ones, even if latter are genuinely more capable from technological performance viewpoint. In 2006, F-22 pilots got 12-14 hours of training per month, a situation that has not significantly improved since. There is also a danger that fighters will simply get grounded due to maintenance issues, as happened to Iranian F-14s during the Iraqi-Iranian war.
J-20 is not adressed. Its likely unit flyaway cost is around 175-210 million USD at least, as China’s cost of labor is lower than US one, though the J-20 itself is more massive than the F-22. This will allow a force in the above scenario of 25 to 30 fighters. With one sortie every three days, this will give 8 to 10 sorties per day. As each fighter will likely carry 6 missiles internally, they can shoot down 3 or 4 enemy fighters if given a first shot, but will get wiped out by a return BVR salvo if facing anything other than the F-22, F-35 or the F-15.
While this scenario is highly specific, numbers always matter. In other scenarios however cruise performance (speed, endurance) and situational awareness also matter, meaning that some fighters (F-22, Typhoon, Rafale, Gripen E, FLX) may fare better than suggested in this scenario; on the other hand, obvious air bases are also likely to get bombed and supplies to be stretched, meaning that most fighters – excepting the Su-30, Gripen and FLX – may not even be capable of taking off in any numbers at all.
Comparision with modern fighters
At 30.000 feet, range for the F-22 is 0,02 nautic miles per lb of fuel at Mach 1,5 (1.636,5 kph; 589 kts), and 0,066 nautic miles per lb at Mach 0,9. 20 minutes of supercruise equals 196 nautic miles covered for expenditure of 9.817 lbs of fuel, and two minutes of afterburning combat uses up 1.377 lbs of fuel, leaving 6.806 lbs of fuel. This allows the F-22 a combat radius of 224 nautic miles or 415 kilometers. Realistically, radius will be less than that as this calculation does not account for takeoff, landing, or climb.
With 2 WVR missiles, 6 EM BVR missiles and 4,8 1-second gun bursts, F-22 has a total of 2,03 kills on board.
Fuel consumption is 2.250 l or 1.800 kg per hour at Mach 0,9 (987 kph at 30.000 feet). At full dry thrust, fuel consumption is 8.000 kg per hour, and 26.250 kg/h at maximum afterburner. Thus, 2 minutes of combat uses up 875 kg of fuel, while 20 minutes of supercruise use up 2.667 kg of fuel, leaving 1.178 kg of fuel. This allows for a flight time of 39 minutes at cruise thrust, allowing a combat radius of 320 km. Again, the calculation does not account for takeoff, landing or climb.
With 2 WVR missiles, 8 IR BVR missiles and 3 1-second gun bursts, Rafale’s total number of on-board kills is 2,11.
With takeoff, landing and climb the FLX has a combat radius of 519 km. If calculation is done the same way as for the F-22 and Rafale, fuel consumption is 580 kg for two minutes of combat and 1.813 kg for 20 minutes of supersonic cruise, leaving 2.179 kg of fuel for subsonic cruise. This allows for a flight time of 1,54 hours at cruise thrust, allowing a combat radius of 800 km.
With 4 WVR missiles, 6 IR BVR missiles and 6,1 1-second bursts, FLX’s total number of on-board kills is 3,15.
If necessary, an advanced LIDAR might be used to complement the IRST. 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. 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.
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.
Assymetric nature of the FLXs response to radar-based (especially “stealth”) fighters will result in its unprecedentet effectiveness. At Crecy, British responded assymetrically to French knights, obliterating them; likewise, in all other wars an assymetric response was typically far more effective than a symmetric one (submarines vs battleships, aircraft carriers vs battleships, dive bombers vs tanks, anti-tank guns vs tanks, dive bombers vs battleships, dive bombers vs aircraft carriers, aircraft carriers vs submarines, anti-tank rockets vs tanks, tank destroyers vs tanks, tanks vs fortifications etc. These cases when studied also very clearly show that there is little, if any, relation between cost and effectiveness).
Furthermore, its small size and comparably simple design result in a large force presence. While some may say that radar stealth is an excellent addition, ultimately it is a very costly one: stealth fighters tend to be 50% heavier with per-kg cost 40% greater than equivalent non-stealth fighters while being capable of generating only 1/3 of sorties. Thus the stealth!FLX would have an empty weight of 4.797 kg, cost per kg of 10.046 USD, unit flyaway cost of 48.191.000 USD and be able to generate 0,7 sorties per day per aircraft, resulting in a total of 111 sorties per day for a force costing 5,34 billion USD. Each would carry 2-4 missiles internally.