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Aviation Analysis: Air Superiority Since Vietnam and the Road to the Raptor

 

The F-22 Raptor, the world’s premier air superiority aircraft, has been around for quite some time now.  Lockheed’s YF-22 design won the competition with Northrop’s radical YF-23 almost 26 years ago, but the end of the Cold War, and resulting lack of urgency with the reduction in the Russian threat, made for an extremely protracted development for the final design (given the complexity of airframe, engines and electronics, perhaps no bad thing).  Though its inordinate cost brought it under Congressional attack and prompted several cutbacks in estimated production run (which cutbacks, in this sort of vicious cycle, spur increases in unit cost), the F-22 entered service in 2005, itself a fairly long time ago in military aviation terms. That year, the first Raptors replaced F-15C Eagles of the First Tactical Fighter Wing at Langley, Virginia, and the capabilities of US fighter pilots leapt forward in a fashion that hadn’t been seen since the transition from piston engines to jets over 50 years earlier.

Now and then, a weapon will appear that changes all the rules, to the point of rendering all other weapons in its class obsolete.  One thinks immediately of the great naval revolutions spurred by H.M.S. Dreadnought, and the USS Nautilus, or, in the aviation world, the shock delivered by the ME-262.  The F-22 represents just such an advance, outclassing all current fighters in the same way that the first nuclear submarine outclassed its diesel-powered contemporaries.  Few in number, Raptors nevertheless dominate the skies more thoroughly than their predecessors – a tall boast for an aircraft that replaced the mighty F-15.  Speaking of which…

The Wondrous F-15 Eagle

To understand what it really means to render an F-15 hopelessly obsolete, one has to understand something of the still phenomenal performance of that classic fighter, now, incredibly, in its 41st year of operational service. Until quite recently, the Eagle was only marginally outclassed by a new and much later generation of foreign fighter aircraft – derivatives of the Soviet “Flanker” family (Sukhoi SU-30, for example), the French Dassault “Rafale”, and the Eurofighter “Typhoon”, produced by a consortium of Britain, Spain, Germany and Italy.  These new fighters, while extremely impressive, really offered only an incremental improvement on what the latest F-15s could do, and it’s arguable that new Eagles, with up-rated engines and advanced electronics, were barely outclassed at all – South Korea appears to have reached just that conclusion in selecting an advanced derivative of the Eagle as its next generation fighter in the early 2000s, favouring it over all foreign competition.  While there are those (myself included) who felt that the last (and sorely missed) F-14 Super Tomcats were the most impressive fighters of the US 4th generation, there was no denying the superlative qualities of the Eagle, both as an aerodynamic achievement and as a weapons system/electronics platform. It remains a formidable adversary to this day.

The F-15 was designed in light of the Air Force experience in Viet Nam.  In the early 1960s, the Air Force had adopted the phenomenal F-4 Phantom II, a naval fighter, as its primary tactical aircraft (it says something of the qualities of the F-4 that the boys in blue suits had to swallow their bile and adopt a Navy machine).  The Phantom had cleaned the clocks of Air Force F-106 interceptors in simulated fighter and interception combat, and was almost the equal of the F-105 Thunderchief in dropping ordnance on ground targets.  With its great maximum speed, blistering climb rate and acceleration, and armament of long-range radar-guided AIM-7 Sparrow missiles, the Phantom was expected to sweep clear the skies over North Viet Nam of any pesky but outdated MiGs.  However, as strike packages of US fighter-bombers encountered resistance from those supposedly obsolescent Soviet fighters, the Air Force received a nasty shock.

It turned out that a maximum speed of over Mach 2 had little relevance in the air combat over Viet Nam (as opposed to the Phantom’s primary design mission of blasting off from a carrier deck and rushing out to meet incoming Soviet bombers).  It did no good to flash by at 1,400 MPH and 40,000 feet when the task was to protect bomb-laden F-100s and F-105s, flying, of necessity, at lower levels and subsonic speeds.  When the strike aircraft were pounced upon at 15,000 feet and lower, the Phantoms had to be there with them to mix it up with the MiGs; in any case, supersonic flight required use of full afterburner, a fuel-gulping mode that would drain an F-4’s tanks dry in just a few minutes.  In Viet Nam, nearly all air combat took place at subsonic speeds.

At subsonic speed and low altitude, The Phantom was out of its element, and this was just where the light and agile aircraft available to North Viet Nam, MiG-17s, 19s and 21s, were at their best.  Struggling to stay with the light, agile MiGs in hard turns at 400 MPH speeds, Phantoms found themselves embroiled in close range visual dogfights, where all their electronics were so much deadweight.

The need to mix it up at visual range was partly due to the AIM-7 Sparrows, which, despite high expectations, did not really work.  Not only were the missiles terribly unreliable, they were likely to be out-maneuvered by the MiGs even if they functioned as advertised – Sparrow was designed with large, decidedly un-maneuverable bomber targets in mind.  Worst of all, it proved impossible to launch Sparrows at beyond visual range.  The Identification Friend or Foe (IFF) systems meant to facilitate long range shots proved as unreliable as the missiles, and faced with a “furball” of US and NVN fighters on the radar screen, an F-4 was every bit as likely to blast a friendly F-105 as a MiG-17.  Long range Sparrow shots were actually prohibited after several US fighters were shot down in “blue on blue” engagements.

 

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A MiG-17, unlikely nemesis to the far more sophisticated F-4 Phantom.

So there were the enormous F-4s, forced to low altitudes and low subsonic speeds, firing off Sparrow missiles at close range with little chance of a hit, just to rid their airframes of the weight, trying to bank into tight turns with nimble little MiGs, and getting themselves shot down with appalling frequency by small silver fighters that were little more than sports planes mounting machine guns.

Quite the embarrassment.

Now, there was nothing inevitable to this.  Even given the failure of Sparrow, and the necessity for subsonic, medium altitude dogfighting, Phantoms could have, and should have, acquitted themselves much better than they did.  The key problem was pilot skill.  Neither Air Force nor Navy pilots, amazingly, had any training in visual dogfights against dissimilar aircraft (so obsessed were military planners with nuclear war scenarios, and so confident had they been in Sparrow).  It was not until the late 1960s, and the creation of the Navy’s Top Gun fighter school, that this was addressed by either service.  Graduates of Top Gun learned to exploit the Phantom’s advantages in speed, climb rate and acceleration, and they learned how to maneuver in ways to defeat a superior turning fighter.

In 1972, Navy Phantom pilots racked up a 13:1 kill ratio against the MiGs, and it was not long before the Air Force created its Red Flag training program to emulate what Top Gun was doing for the Navy.  Combined with new technology – leading edge wing slats for better maneuverability, up-rated engines, improved IFF and Sparrow missiles, new radars, and in the case of Air Force Phantoms, an internal 20 mm Gatling gun – well trained Phantom pilots of the 1970s were actually well able to take on any aircraft they were likely to meet in air combat.

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A pair of F-4Es, the classic variant of the Phantom II. With up-rated engines, improved radars, better missiles, an internal cannon, and leading edge wing slats for improved maneuverability, F-4Es were well able to hold their own against any opposition on the Soviet side. The “fighter mafia”, however, craved utter dominance.

Still, the Air Force “fighter mafia” never got over the shock administered in the mid 1960s: Sweet Jesus, we were head-down in our cockpits, poring over garbled radar pictures and poking at useless buttons, while the little silver bastards were laughing and flaming our asses.

Thus the call rang out for an aircraft that would return to the classic fighter virtues of old, something akin to a high technology P-51 or F-86, something that could “turn and burn”, with superb pilot visibility, and the sort of turn rate that would always put you on the enemy’s tail where a cannon or a heat seeking missile – the staples of visual combat – needed to be to do the most good.  “Not a pound for air to ground” was the new slogan; no more hulking fighter-bombers!  The next fighter was to be a pure fighter, unencumbered by the compromises of multi-role mission requirements.

Just as this was going on, the boys at Mikoyan were administering another dose of anxiety with their remarkable MiG-25 “Foxbat”, a Mach 3 fighter that beat the F-4 at its own game and flew too high and fast for even the latest Phantoms to intercept.  “Foxbat shock” took hold in Western aviation circles, and commentary at the time was obsessed with the inability of Phantoms to stop MiG-25s from going anywhere they wanted.  Anxiety mounted as Foxbats flew out of Egypt and Syria and cruised with impunity over Israel, easily out-pacing the F-4s sent up to intercept them.  The mood soured further when a modified MiG-25 officially broke nearly all of the Phantom’s speed and time to climb records.  I remember an editorial at the front of Jane’s All the World’s Aircraft that struck an almost hysterical tone, as if the MiG-25 would drive all Western fighters from the sky.

Initially, no one grasped that the MiG-25 was, essentially, nothing more than the re-usable first stage of a missile system designed to intercept high-flying supersonic bombers, with very limited maneuverability and poor radar performance in “look down” mode.  Far from the super-fighter it was supposed to be, the MiG-25 actually had no use in almost any scenario save high altitude bomber interception, and posed little threat to US tactical air operations.  In the late 1960s and early 1970s, though, producing an aircraft that could defeat the MiG-25, while at the same time out-maneuvering any other aircraft, was the design goal.  This was terribly ambitious.  It meant achieving the apparently incompatible goals of a fighter with even more radar, missile capability, speed and climb rate than the 24 ton Phantom, yet one even handier in close combat than a seven ton MiG-17.

Somehow, that is exactly what McDonnell Douglas handed the Air Force when the F-15 first flew in 1972.

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The Mig-25 “Foxbat”, erroneously cast in the role of airborne bogeyman by Western defence analysts in the 1960s and 1970s. It looked the business, but was a pure interceptor, designed to attack high level supersonic bombers. Despite its fearsome appearance, it posed no serious threat to Western tactical aircraft.

One crucial factor in the F-15’s performance was the advance in engine design achieved by Pratt and Whitney in the late 1960s.  Phantoms were powered by General Electric J-79 turbojets, producing 17,900 lbs. of thrust for an installed weight of about 4,200 lbs.  The engines therefore had a thrust:weight ratio of about 4.25:1, and this gave the Phantom itself a thrust:weight ratio of about 0.8:1, very high for its day.  By 1972, Pratt and Whitney had developed the revolutionary F-100 turbofan, which offered almost 24,000 lbs. of thrust for an installed weight of just over 3,000 lbs.  This gave the engine a thrust:weight ratio of almost 8:1, and allowed the F-15 to be both lighter and more powerful than the Phantom.  Indeed, at a takeoff weight of 44,500 lbs., with armament, an F-15 had more thrust than weight at wheels-up, with a ratio of about 1.1:1.  At combat weight, with half of the internal fuel burned away, an Eagle enjoyed an astonishing 1.3 lbs. of installed thrust for every pound of weight.

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Taking off with more installed thrust than weight.

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An F-15 blasts off the runway with characteristic brute power.

This unprecedented thrust : weight ratio – to this day, no aircraft in service or projected surpasses it, not even the F-22 – gave the Eagle phenomenal acceleration, speed and climb rate.  An Eagle could stand on its tail and climb vertically, straight up, and break the sound barrier while doing it; in Project Streak Eagle, a modified F-15 soon re-took all the time to climb records usurped by the Soviets, with an airframe that reached 20,000 feet – the typical operational altitude of a Mustang – in only 37 seconds, and 50,000 feet – the maximum operational altitude of most current fighters – in only 77 seconds.  An Eagle could accelerate from a leisurely subsonic cruise to 1,000 MPH in less than a minute, and could attain (albeit for short periods) a dash speed of just over Mach 2.5, more than 1,650 MPH.

To exploit all this thrust, McDonnell Douglas designed an airframe that would be the antithesis of the F-4.  A new concept in air combat, “specific excess power”, was now dominating fighter design thinking.  This held that what mattered most to an aircraft engaged in close combat was how much reserve energy it had at any given moment to change its flight path and begin a new maneuver.  Thus, it was not enough if a plane could turn tightly, if turning tightly cost it all its energy and forced it to slow down.  What was needed was an aircraft that could turn tightly and then, if necessary, pull vertical; an aircraft that could pull rapidly out of a dive and ascend faster than its foe; an aircraft that had the excess power, when needed, to accelerate out of whatever predicament it was in, no matter what it was doing at the time.

Obviously, high thrust : weight ratio was one element of specific excess power, but another had to be aerodynamic.  In the vernacular, the new fighter had to be “lightly loaded”, meaning that however heavy it was, it had to have a  wing loading at least as light as the fighters that opposed it, even if the opposition was a far smaller fighter.  Wing loading is the simple ratio of aircraft weight to total wing area, measured in lbs. per square foot.  A Phantom had a wing loading at combat weight of about 80 lbs. per square foot.  When contemplating a 22 ton fighter that had to have high specific excess power at all times, McDonnell aimed for and achieved a target of only 60 lbs. per square foot with the Eagle (about the same as the eight ton MiG-21), using a huge wing of over 600 square feet.

Other features, such as twin tails, and highly-swept, wedge-shaped intakes, assured that the Eagle had sparkling aerodynamic performance at all speeds and fairly high angles of attack.  Heeding the pleas of the fighter mafia, the Eagle was also given a large, high bubble canopy that hearkened back to the P-51 and F-86.  In an F-4, the pilot was buried in the fuselage beneath a flush canopy, the sills up around his shoulders, with poor downward and almost no rearward visibility.  In an Eagle, the pilot sat on top, with the cockpit sills down around his waist, as if mounted on a horse; an F-15 pilot could turn around and look straight back between the twin vertical tails.

It all made for astounding close combat performance at slow- medium speed.  At air show altitude, an Eagle was able to crank into a high-G turn at 300-400 MPH and go a full 360 degrees in a time of about 18 seconds and a radius of about 1500 feet, without losing speed or altitude, and then, at the end of the turn – and this is what caused dentures to fall out at the Paris and Farnborough air shows – immediately pull into steep rapid climbs.  This betrayed an awesome amount of excess power, unimaginable to the fighter pilots of only a decade earlier.

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An F-15 maneuvers with typical gusto at an air show.

Eagles at air shows in the mid 1970s cavorted through routines that included rolling takeoffs using only 800 feet of runway (less tarmac than used up by a Spitfire), vertical climbs at rates exceeding 50,000 feet per minute, Immelman turns, and a host of other maneuvers that had  never before been achieved by a large and heavy supersonic fighter.

The Eagle could do things going straight up that the best Russian and European fighters could not do going horizontal.

Under the skin, the Eagle possessed an extraordinary electronics suite, comprising, among other things, the new digital APG-63 pulse-doppler radar (then surpassed only by the F-14’s AWG-9 system among all the world’s fighters), comprehensive radar-warning and electronic countermeasures systems, and advanced “heads-up” displays that projected vital information directly onto the windscreen, using lasers, in front of the pilot’s field of view.  In close combat, under the big bubble canopy, Eagle pilots received projected laser symbology telling them where to look for the enemy, reminding them of their own and their target’s altitude, heading and airspeed, informing them of fuel state and armament remaining, and providing firing solutions and aiming points, all without once looking down in the cockpit.  At long ranges, the Eagle’s superb radar allowed the pilot to discern targets flying low in ground clutter, and to detect fighter-sized aircraft at ranges as great as 110 miles.

Even better, highly-secret work was done to overcome the limitations of IFF systems.  In a project called “NCTR”, for “Non-Cooperative Target Recognition”, the radar boffins laboured to provide a way for the APG-63 to distinguish enemies from friendlies at extreme range without relying on IFF.  It is still not known for certain how this was achieved, though it is widely reported that the APG-63, in NCTR mode, shines radar waves off the compressor discs of the jet engines of opposing fighters.  The modulation of jet engine compressors is, apparently, distinctive enough to identify aircraft type.  However it was done, NCTR was proved to work in the 1991 Gulf War, during which F-15s shot down dozens of aircraft at long range without once scoring a goal on their own net.

Meanwhile, dedicated efforts to improve the Sparrow had resulted in a much more accurate, maneuverable and reliable radar-guided missile, and the Eagle, able to accelerate rapidly to supersonic speed in order to impart energy to the missile at the moment of launch, was able to “snap-shoot” AIM-7s to ranges up to 70 miles, and altitudes of 90,000 feet.  In practice intercepts, even high-flying Mach 3 SR-71s were not safe from F-15s.  Sparrow remained a semi-active homing missile, meaning, as we’ve discussed, that an Eagle, unlike the Tomcat with its Phoenix missiles, could engage only one target at a time (a limitation that would not be addressed until the 1990s).  For the moment, though, the important thing was that Sparrow now bid fair to work just as planned back in the 1960s.

There was no doubt, in short, that the F-15 could maneuver the tar out of any of the MiGs that had so vexed Phantom pilots in South East Asia, and blast any MiG-25 right off of its high altitude perch.

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Another shot of an F-15 cranking through an air show routine, moisture condensing in the low pressure over the enormous wing.

This must have seemed quite terrifying to Soviet planners, who well understood the limitations of the Foxbat, and knew that in fact no Soviet super-fighter existed.  Indeed, while the MiG-25 was giving US planners conniption fits, the Soviets, taking a sober view of what Phantoms had really accomplished over Viet Nam and the Middle East, were striving to mass produce an aircraft that could compete with the F-4!  In the mid 1970s, they were deploying huge numbers of their swing-wing MiG-23, which we now know to have been a good match for the F-4E.  As the Israelis soon proved over Lebanon, MiG-23s, and indeed MiG-25s, provided little more than target practice for Eagles.  The US Air Force had let an overreaction to the Viet Nam experience, and an overestimate of the Foxbat’s performance, spur them into the development of an expensive super-fighter that was pure overkill when the Eagle was first deployed.

Thus began a crash program in the Soviet Union to match the Eagle.  It took them over 10 years; the amazing post-script to the story of the Air Force’s frantic effort to replace the Phantom is that it was not until 1986 that the Soviets had any aircraft in squadron service that was convincingly superior to the F-4E of 1967.

Replacing the F-15

The Americans had created a monster.  With an air force full of fighters that were mincemeat in the teeth of the F-15s, the Soviets had no choice but to come up with their own super-fighter.  The new Soviet plane had to do everything the Eagle could do, and better, if possible, and it also had to contend with the even more agile light fighters that followed the Eagle into service, the F-16 and the F-18.  Prototypes were flying as early as 1977, but beating the Eagle wasn’t easy.  Protracted development was needed to overcome the many design challenges.  Mikoyan produced a relatively small fighter in the F-18 class, the MiG-29, given the NATO reporting name “Fulcrum”.  Sukhoi produced a more imposing design for an air superiority fighter that was as big as an F-14, with the thrust:weight ratio of the Eagle, and aerodynamics borrowed liberally from all the US “teen series” fighters.  This became the SU-27, given the NATO reporting name “Flanker”.  These began deploying around 1986, 12 years after the Eagle.  The F-15 had given the Americans 12 years of unrivalled supremacy, a breathing space that no air power, not even the Americans, had ever before enjoyed.  It was a feeling the Americans had gotten used to.  Now, there were new kids on the block.

Both of the new Soviet fighters were just a little more agile than the Eagle, but only the Sukhoi was true competition for the US fighter across the whole spectrum of air combat.  It had a radar of nearly equivalent capabilities to the APG-63, and it also had a useful infra-red search and track system (something that the Eagle, though not the Tomcat, lacked).  It had long range, and was able to carry an equally large load of missiles that were at least as good as the Sparrows and Sidewinders that were the Eagle’s primary armament.  As has since been proved at air shows around the world, the Flanker could turn even tighter than an Eagle (though not much, about 1 to 2 seconds faster for a 360 degree turn at low level), and could sustain much higher angles of attack.  As if to rub it in, the Russians stripped down a Flanker, gave it up-rated engines, and broke all of the Streak Eagle’s time to climb records (though by a fairly small margin; the Americans certainly could have up-engined an Eagle and taken them right back).  The Eagle retained an advantage in maximum speed, and it had a narrow edge in the quality and reliability of its electronics.  Overall, the Flanker was obviously able to take on F-15s on equal terms.

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New kids on the block: the MiG-29 “Fulcrum”, broadly equivalent to the F-18 Hornet.

Looking at the Flanker, American planners had to acknowledge that they had goaded the Soviets into producing a fighter that could go toe to toe with the F-15.  With the Cold War still freezing, and facing the prospect of a confrontation with superior numbers of equally potent super-fighters, the quest for something to surpass even the F-15 became an unquestioned defence priority.  Americans cannot stand to be outclassed in air combat.

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New kids on the block: the SU-27 “Flanker”.  Bigger, more powerful, more sophisticated, and entirely more elegant than the MiG-29, the rather un-Russian SU-27 was the F-15’s equal in almost every measure, and surpassed the Eagle in some respects.  It became the new benchmark for US defence planners.

At the same time, surveying the air defence environment over the central European front, American planners became increasingly dismayed at the proliferation of layered Soviet surface to air missile systems.  The SAM belt became so thick over the likely combat zone, and the quality of Soviet late generation SAMs so daunting, that it began to seem as if battling with Flankers was going to be the least of our worries.  Among the new SAMs were such frightening weapons as the S-300 and S-400, huge, long-ranged and fantastically fast – some sources quote speeds as high as Mach 7 for these missiles.  The F-15 has many virtues, but low radar cross section is not one of them; the angular US fighter is very easy to spot on radar (“looks like a frigging barn coming over the horizon” is one quip I’ve  read).  This made the US fighters vulnerable to interception by SAMs at all operational altitudes.  The same could be said about any Soviet fighter, but Soviet fighters didn’t have to face the sort of SAM belt that F-15 pilots would be up against.  It actually became plausible that SAMs alone could cripple the US air superiority campaign, making it impossible for NATO strike aircraft to penetrate Soviet defences, and for F-15s to protect them.

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An S-300 mobile SAM launcher, raised to the vertical firing position.

Against this backdrop, something strange was being proved over the skies of Lebanon and Iraq.  The fighter mafia had got it all wrong; the lessons derived from Viet Nam were not valid.  Having insisted on fighters that were able to engage other fighters in close combat, to turn hard until they were on the enemy’s tail for a cannon or heat-seeking missile shot, the US Air Force was realizing that Eagles in combat were doing no such thing.

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The S-400. These SAMs are credited with a speed of over 2 kilometers per second, or about 5,000 MPH. An even more potent S-500 system is now entering service.

A good fighter pilot is a not a knight of the air.  He’s a sniper, an assassin, and only a reluctant pugilist (aviation writer Bill Sweetman – I think it was Bill! – has noted that the ideal of the Medieval knight has never meshed with the behaviour of real pilots, or for that matter any other combatants, “the peasant-whacking lance jockeys of the Middle Ages included”). Dogfights at close range are often likened to a knife fight in a phone booth.  They are unpredictable, for the most part fair, and therefore only for hotshots, and other such mental cases.

Taking advantage of their far-seeing radars, NCTR and the snap-shot technique for firing Sparrow missiles, F-15 pilots much preferred to pick off the enemy at long range, before the poor bastards even knew they were under attack.  Vectored by AWACS aircraft into firing position, F-15s of the Israeli and US Air Forces slaughtered Syrian and Iraqi fighters at beyond visual range; the majority of Eagle kills (104 so far, without loss) have been Sparrow kills, and nearly all of the US victories in the 1991 Gulf War were achieved with Sparrow.  The maneuverability of the F-15, so important to its designers, was almost irrelevant, as indeed was the unquestionably superb agility of the half dozen or so MiG-29s that F-15s dispatched over Iraq (not to mention the several Yugoslavian Fulcrums that were later downed over Kosovo).  It was almost certain that the Syrians and Iraqis would have been just as easily destroyed by F-4s, if the Phantoms had been given the Eagle’s radar, and the new engines needed for that rapid rush to supersonic speed that was crucial to the snap-shot.

You could turn and cavort all over the sky, but what mattered was who got the first look, and who took the first shot.

Gradually, the assumptions spawned by the Viet Nam experience gave way in the face of combat results.  The Americans were not about to abandon fighter agility, and would certainly not deploy a new fighter unless it was able to outmaneuver the SU-27 Flanker in close combat.  Anything less would have gone too much against the grain.  Yet, it now seemed obvious, close combat was not the point at all, was not even likely, especially as missiles improved.  The new AIM-120 AMRAAM (Advanced Medium Range Air to Air Missile) would soon give the Eagle, or any plane that carried it, the ability to fire multiple shots at long range against multiple targets (like Phoenix, AMRAAM carries its own active radar, albeit in a much smaller package with shorter range).

At the same time, new heat-seeking missiles were being deployed that could, at shorter ranges, acquire a target from all aspects – there was no need to “saddle up” in the enemy’s rear quarter for a shot straight into the afterburner can.  The Soviets were first out of the blocks with a highly potent heat-seeker, the AA-11 “Archer”, that could attack from a very broad envelope.  Using an AA-11, a Soviet pilot could not only shoot you head on, he could shoot you line abreast, aiming the seeker head of the missile with a turn of his head, employing a link to a sight mounted in his helmet.  As work began on a version of the Sidewinder that could match the AA-11 – the AIM-9X, now in widespread service – it became clear that turning fights to get behind the enemy were almost certainly a thing of the past.  This had been predicted in the Phantom’s heyday, but the failure of the missiles made it a false prophecy in South East Asia.  Now, the missiles were working.

All that mattered was who got the first look, and who took the first shot.

The F-22 Emerges

“First look, first shot, first kill” became the slogan for the Advanced Tactical Fighter, the program that led to the Lockheed F-22 Raptor.  The new fighter would maneuver better than anything that had come before it, but that was just the beginning.  Though the Air Force knew that it was useless to try to design a fighter that would out-perform the Eagle in the classic “brochure statistics” of maximum speed and climb rate (it is hard to imagine how present technology could achieve this, especially when the Eagle can always be given new engines), the requirements for the ATF were more subtle, and much more ambitious.  The new fighter was to synthesize a number of technologies in order to ensure that its pilot had a better grasp of the situation than his opponents, and saw his opponents before they saw him.  It was to be less vulnerable to their missiles than they were to its.  While no faster in maximum speed, it was to have a much higher average cruising speed, enabling it to cover more air space, faster, than enemy fighters.  It was also going to be able to operate with near impunity in spite of the worst that the Soviet SAM belt could throw at it. Making all this possible would be a breathtaking set of revolutionary developments:  stealth, thrust vectoring, supercruise flight, “sensor fusion”, information systems superiority, datalinks for “networked” warfare, and extremely high operational altitude.

Stealth

“Stealth” is the popular word for what aerospace technicians call “low observable” or “LO” technologies.  Stealth is not one, but several systems and technologies that make an aircraft more difficult to detect, not just by radar, but also by infra-red tracking systems.  The idea was born in the 1970s as a result of the heavy losses incurred by the Israeli Air Force in the early days of the Yom Kippur war of 1973.

The lightning victory achieved by the Israelis in the Six Day War of 1967 had encouraged a certain arrogance among those in the Israeli military.  That war, won largely on the back of a perfectly executed pre-emptive strike by the Israeli Air Force, had left Israel in charge of the Golan Heights and the Sinai desert; Syria and Egypt therefore had a score to settle (Jordan, despite losing the West Bank, wisely abandoned the game).  By 1973, the Arab nations were faced with an Israeli air force that had vastly upgraded its capabilities, with the purchase of both F-4E Phantoms and A-4M Skyhawks to supplement the Mirage IIICs that had been the key players in 1967.  The Mirage III was a neat little fighter, roughly equivalent to the MiG-21.  The Phantom, of course, was a whole other order of warplane, and the Skyhawk had already proved itself a tough and reliable tactical bomber in countless missions over Viet Nam.  The Israelis could be forgiven some arrogance.

Yet in 1973, they were thrown back on their heels.  In a coordinated, Soviet-style shock attack, the Syrians stormed into the Golan while the Egyptians – this was truly horrifying – threw modular plastic bridges (courtesy of their Soviet pals) across the Suez Canal, to rapidly create a bridgehead in the Sinai.  Skyhawks and Phantoms attacked relentlessly on both fronts, and took very, very heavy losses, particularly in their attempts to drop the bridge spans over the Suez.  Without the laser and GPS guided bombs that would one day be standard issue in all Western equipped air forces, the Israelis were forced into dive bombing attacks, the only reliable way to hit something long and narrow like a bridge with an unguided iron bomb.  As any Stuka pilot could tell you, a dive-bombing run is all well and good until you run into a determined air defence, at which point it becomes the surest way to get your ass shot to pieces.  A sophisticated and determined air defence was just what the Israelis now found themselves up against.

The problem was a then-new surface to air missile, the mobile Soviet SA-6, roughly equivalent to the US Hawk (and thus very good indeed).  The Americans had not encountered it in Viet Nam, and it was a bitter surprise, decimating the Phantoms and Skyhawks with losses that were just barely made good by rapid transfers of US aircraft (direct from squadron service in some cases) to Israel.  Trained pilots, however, were not so easily replaced.  Such were the losses that early on, it looked as if the vaunted Heyl Ha’Avir might be destroyed as an effective fighting force.  New tactics, and a hasty transfer of the latest Westinghouse electronic countermeasures equipment from the US, soon turned things around, yet it was not until Ariel Sharon made his famous, Inchon-like dash across the canal, chewing up the Egyptian SAM belt on the ground, that the Air Force could operate freely over the canal zone.

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The mobile SA-6 SAM system, scourge of the Israeli Air Force in the early days of the Yom Kippur war, and a key stimulus to the development of stealth technology.

All of this was viewed with despair by Western planners, who contemplated confrontations with the Soviets in Europe.  A secret program to swing the pendulum back was initiated under the aegis of Lockheed’s famous Skunk Works, birthplace of the U-2 and SR-71.  In an odd twist, the designers at Lockheed had become aware of a paper by a Soviet scientist on radar wave propagation that offered a possible solution.  Though it would be an aerodynamic mess, it might be possible to design a tactical aircraft that did not return radar signals to hostile emitters.

By about 1977, Lockheed was flying a prototype stealth aircraft out of Area 51 in Nevada, under the code name “Have Blue”.  The design was influenced more by the laws governing radar wave reflections than aerodynamics; the key was to ensure that even very powerful radar waves shone at the aircraft would either be absorbed, or bounce off somewhere where the emitting radar’s receiver could not receive them.  This was achieved through the use of various radar absorbent materials (RAM), and by creating a skin for the aircraft that was faceted, like a cut gem.  A radar wave hitting the aircraft would encounter a myriad of facets pointing in different directions; only a few of those small facets, and perhaps none of them, would be aligned such that a radar wave could hit them and return to the radar receiver.  Those few aligned facets would, like all the others, be covered in RAM, and thus return a very weak signal.

It was a sound idea, but extremely difficult to get right in practice.  Radar waves are a form of light.  An object is not less visible to a powerful radar simply because it presents a relatively smaller reflective surface, any more than a mirror is any less visible to a flashlight in a darkened room simply because it is, say, only half as large as another mirror. To thwart a radar return, the aircraft had to present almost no reflective surfaces to be “seen” by the radar – the Have Blue prototype, it was discovered, returned a radar signal detectable at 50 miles if even a half dozen screw heads were not quite flush with the fuselage skin.

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A rare shot of Lockheed’s Have Blue stealth demonstrator.

Practical, effective stealth was nevertheless achieved, but in an aircraft, the F-117, that was an aerodynamic basket case, subsonic, and not a fighter at all.  Its faceted shape made it so unstable that it was, in its early years, prior to the perfection of its subtle computer controlled “fly-by-wire” software, blessed with the nickname “Wobbly Goblin” (without fly-by-wire technology, that is, automatic computer-controlled actuation of control surfaces, the F-117 would not be able to fly at all).  It has been said that “they did everything but flip on their backs while taxiing down the runway”.  Owing to their poor performance, they had to be restricted to night operations; invisible to radar and obscure to infra-red sensors they may have been, but a chance daylight encounter with any cannon-armed fighter would spell doom.

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The “Wobbly Goblin” in broad daylight, when anything with a machine gun would be lethal to it. Its gem-like facets were highly stealthy, but aerodynamically ludicrous. Only sophisticated fly-by-wire systems allowed the F-117 to keep out of its own way and fly. Yet the  advantages of stealth were proved beyond doubt in Desert Storm.

Contemplating the SAM belt over central Europe, not to mention the powerful air search radars of SU-27 Flankers, the Air Force knew it needed stealth to be central to the design of the new fighter.  Yet, adapting stealth technology to an aircraft that was aerodynamically superior to an F-15 posed what should have been insurmountable technical challenges.  It was rather like stating in 1962 that America would send men to the moon before 1970.  The technology didn’t exist; the means to invent the technology didn’t even exist.  Yet, with typical American elan, the problem was cracked.

Improved computer power was one thing that came to the rescue.  With more powerful computers, it became possible to devise computer models for stealthy radar wave propagation that would accommodate smooth, curved surfaces rather than flat, faceted ones.  At the same time, advances in RAM technology meant that practical, robust radar-absorbent materials could be developed for use on fighters that would not be prohibitive to maintain (F-117s, and B-2 bombers as well, have very delicate RAM surfaces that need careful maintenance in air-conditioned shelters, not the sort of thing you need on forward-deployed fighters).

A quick glance at a drawing of the F-22 reveals one aspect of the stealth philosophy at work.  All of the leading and trailing edges line up with each other (in the vernacular, the design is “edge-aligned”).  The leading edges of the wings match the leading edges of the intakes, and the tailplanes, and so on; same story with all the trailing edges.  This ensures that radar waves can only encounter sharp, flat surfaces at right angles if they are oriented at one specific direction from the aircraft.  In a fighter maneuvering in combat, such precise exposure to radar is certain to be brief.  The rest of the time, the radar waves will bounce off into space, away from the emitter, if not absorbed by RAM.

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An F-22 seen in plan view. Note how all of the trailing and leading edges of wings, intakes and tailplanes line up with each other – “edge alignment”.

The stealth measures incorporated in the new fighter also include, among other things, changes to the fighter’s own radar and the way it emits signals, and reduction of the infra-red signature of its engines, both discussed separately below.  Just as important, true stealth demands that the aircraft be in “clean” condition at all times, with no angular missiles, bombs or external fuel tanks hanging off of equally angular pylons under the fuselage and wings.  This posed another significant challenge.  Fighters had been using external fuel tanks to extend their range since the days of the P-51, and huge external tanks and pylons were a feature of all US tactical aircraft when the F-22 was designed.

Carrying weapons and fuel externally allows an airframe to be much smaller and lighter.  Why build the drag and weight penalty into the structure of the aircraft, when external carriage allows the drag and weight to be dumped as soon as it’s expedient?  An Eagle, for example, almost never takes off without a large and heavy 600 gallon fuel tank slung under the center fuselage.  This centerline tank gives it the fuel to go all the way to the combat zone.  Once there, the tank is dumped, leaving behind an aircraft much smaller and lighter, and therefore with higher specific excess power, than a hypothetical rival that had to take off with an extra 600 gallon fuel tank inside.

If stealth was a priority, though, there was no way to get around the need to put that extra 600 gallon tank inside.  The missiles, too, would have to be mounted in weapons bays inside the fuselage, with doors that opened only briefly at launch.  Here, at least, the Air Force had some experience.  Remarkably, the challenge of forcing open and then slamming shut weapons bay doors into the teeth of a howling supersonic air flow, while thrusting missiles safely out of the bay and away from the aircraft before their motors fired, had been solved as far back as the 1950s.  The F-102 and F-106 had internal bays for their Falcon and Genie missiles, and the Avro Arrow was to have had an internal weapons bay as well.  It was therefore feasible to put weapons and fuel inside.  It did, however, force the design to be large.  The Air Force aimed for a 25 ton fighter and concluded, reluctantly, that the end result would almost certainly be a 30 ton fighter – before long, a 35 ton fighter. Somehow, a 35 ton aircraft was going to have to out-fly the 22 ton F-15.

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An F-106 launches a nuclear-tipped “Genie” missile from its internal weapons bay.  The open bay doors can be seen on the underside of the fuselage.

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An F-22 with its weapons bay doors extended – almost 50 years after the F-106, the old technology proved crucial to stealth.

There is much more that could be said, but in brief, the stealth technology that was developed for tactical bombers in the wake of the Yom Kippur War was successfully adapted for use in fighters that have conventional fighter virtues.  An F-22 actually has a radar return that is much smaller than an F-117, and probably on a par with the B-2, yet it sacrifices little in aerodynamic terms to achieve this.  This is an incredible accomplishment. It ensures that SAMs on the ground, and fighters in the air, will probably know nothing of the Raptor’s presence, or at least they will know of it too late to do anything about it.  This alone, other things being equal, would give the F-22 a decisive advantage over any other fighter that preceded it.

And, other things were not equal.

 Supercruise

Most current operational fighters are capable of high supersonic speeds, but they are “supersonic” in the same way that U-Boats of WW II were “submarines”.  While most of a U-Boat’s features were determined by the requirement to submerge, they were actually submersible torpedo boats, rather than true submarine craft.  They spent nearly all of their time on the surface, even while attacking in many cases, and could submerge only for brief periods, usually in response to attack.  Once underwater, they were slow, vulnerable, and had a limited air supply.  The first priority of every submerged U-Boat, after surviving,  was to get back to the surface.  It was not until nuclear power was installed that submersibles became true submarines that spent all of their time underwater, where they were faster, safer, and completely combat effective.

In the same way, an F-15 or SU-27 can make brief forays to supersonic speed, and the need to do so determines much of their aerodynamic structure, yet they spend nearly all of their time at subsonic speeds.  The state of jet engine technology determines this – though extremely powerful, contemporary fighter powerplants develop the most power at subsonic speeds.  As speed increases, more and more air is rammed into their intakes, and the engines begin to overheat.  This is why supersonic fighters have complex “ramps” in their intakes, which move, counter-intuitively, to decrease the amount of air that flows into the engine as speed increases.  Otherwise the engines would start to melt!  The only way to go supersonic, then, is to add thrust at the back end through the use of afterburners – and afterburners do nothing more clever or difficult than dump raw fuel into the jet exhaust, which then ignites, creating rocket-like thrust.  A very high percentage of the thrust at supersonic speed must be produced by this method, yet dumping buckets of raw fuel into the jet exhaust consumes the fighter’s fuel supply at prodigious rates.  Any fighter that spends more than a couple of minutes at supersonic speed had better start figuring out where the nearest air-refueling tanker is.

A typical “supersonic” fighter is therefore a subsonic aircraft capable of brief excursions into the supersonic realm.

The Air Force had something truly revolutionary in mind for the new fighter.  They wanted it to spend almost all of its time over hostile territory at supersonic speeds in the Mach 1.5 to Mach 1.8 range, about 1,000 – 1,200 MPH.  Any fighter that travels at that speed for extended periods will cover a great deal of ground, making it possible to cover larger areas with fewer aircraft.  It would also be very difficult to intercept, even if it wasn’t stealthy – a plane that is zipping by at high altitude and 1,100 MPH, and can sustain that speed, is very hard to catch with an aircraft that can only accelerate to that speed for a couple of minutes before running low on fuel and breaking off the chase.  Interception problems for ground-based SAMs would also be multiplied by the higher speed.

Even better results would flow if the aircraft could fly for extended periods at higher altitudes than other fighters.  The Air Force wanted the new fighter to cruise supersonically at 65,000 feet, almost three miles higher than other jets are able to operate.  At those altitudes, even F-15s and SU-27s begin to wallow in the thin air, and lose power of maneuver; they also lack the pressurization needed to keep the pilot alive at that altitude.  The new fighter would have to be comfortable, fast, and maneuverable at a height where other fighters could only zoom up and dive away, like fish jumping out of a pond trying to catch a dragonfly.  Designers referred to this operational altitude as the “high-fast sanctuary”, a zone that had been exploited in the past by exotic designs such as the SR-71 and MiG-25, but nothing that possessed conventional fighter attributes.

Aerodynamics have a lot to do with the F-22’s ability to operate comfortably at high altitudes, in particular a huge wing that dwarfs even that of an F-15; Raptor pilots will also be fitted out in a new G-suit/pressure suit ensemble that will keep them breathing and lucid 12 miles up.  However, flying level up there also requires a great deal of thrust, and flying level up there at 1,100 MPH requires more thrust than most engines could produce even under full afterburner, let alone in “military power”, without afterburner.  Yet extended supercruise necessarily implied high engine thrust without recourse to afterburning.

65,000 foot supercruise thus became a problem for the engine designers, and Pratt and Whitney narrowly beat out General Electric with a powerplant that marks a watershed in fighter engine development: the F-119 turbofan.  This engine still has afterburners, and in full afterburner produces something on the order of 38,000 to 40,000 lbs. of thrust, more than both J-79s produced on the Phantom, and about five tons more thrust than is produced by even the most powerful engine now available for current fighters.  With an installed weight of about 4,000 lbs., this gives the engines themselves a thrust:weight ratio of 10:1, a significant improvement over the 8:1 ratio of the prior generation.  The real story, though, is how much thrust these engines produce without resorting to afterburner: over 25,000 lbs., more than the engines on an F-15C at full, fuel-guzzling afterburner, and almost twice what an Eagle’s engines can produce at full military power.  Without using afterburner, then, an F-22 has more thrust than an F-15, and a thrust:weight ratio that still approaches 1:1 at combat weight.

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An F-119 engine on the test rig.  Here, the massive thrust is seen deflecting both upward and downward in a multiple exposure. The rear nozzle does not merely expand and contract, as on conventional engines, but also swivels up and down.  This is known as “thrust vectoring”, and greatly increases aircraft agility at both subsonic and supersonic speeds.

Moreover, the F-119 engine can sustain this high thrust, without afterburner, even as it tears through the sky at supersonic speeds with air being rammed into it at volumes and velocities that would liquefy the turbine blades on an Eagle’s powerplant.  It does this by running hot, far hotter than was possible in prior engines, the result of extremely subtle materials technology and cooling methods too complex to be discussed in detail here.  Suffice to say that with the F-119 engine, the Raptor has proved fully able to cruise along for extended periods at Mach 1.7 and 65,000 feet.

There was more.  A conventional fighter, straining to maintain supersonic speed at full thrust, is out of specific excess power with which to do anything else.  It is basically a straight-line missile at that point, if it wants to sustain the pace.  Any maneuver has to involve a loss of speed and a return to subsonic velocity.  With the F-119, a Raptor still has 13 tons of thrust in reserve while cruising at Mach 1.7, and can access this power with brief use of afterburners.  An F-22 can therefore maneuver at supersonic speed, yet remain supersonic – a first.

The new engines embody yet another advance: thrust vectoring.  The nozzles of the engine swivel up and down within a range of about 40 degrees, meaning that the Raptor can vector its engine thrust away from the centerline to point the nose in any direction more quickly than it could by relying on control surfaces alone.  The F-22 is thus able to “get around within its envelope” – to transition from one flight state to the next – much more quickly than non-vectoring fighters.  This has important implications for subsonic agility, as will be discussed.  When travelling at high altitude in supercruise, thrust vectoring, combined with the high available thrust, allows the Raptor to pull quite extreme maneuvers at supersonic speed, when other fighters could only go straight and level and wait to run out of fuel.

As an added bonus, Pratt and Whitney designed the vectoring nozzles to be rectangular, rather than circular.  While not ideal for a pressure vessel, the rectangular nozzles confer real benefits to the stealthiness of the aircraft; the hot air coming out is shaped into a flattened plume that disperses more rapidly than the efflux of a conventional engine, making the Raptor harder to detect with infra-red sensors.  In league with this, the limited use of afterburner itself confers infra-red stealthiness, as it is the red-hot afterburner efflux that really makes an aircraft vulnerable to long range detection by infra-red systems.

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The F-119 in cross section.

Supercruise opens up whole new fields of tactical opportunity, and fighter pilots are only beginning to figure out how to exploit the radical new capability.  For example, an F-22, at ordinary cruise, is always in position to take a “snap-shot”.  Against a fighter cruising at subsonic speed, the Raptor is able to fire off a missile at high velocity immediately, whereas the subsonic fighter must either take a minute to accelerate itself to supersonic speed, or try to fire back at subsonic speed.  Yet, even if it detects the Raptor at the same time as it is detected – impossible, given the Raptor’s stealthiness – the opposing fighter will not be in a position to fire back.  Flying higher and faster, the missiles on the F-22 will have about 50% more range than the missiles on the opposing fighter, even if they are both armed with missiles that have the same “brochure” statistics for range and speed.  The Raptor will thus be launching at the enemy while the enemy is not yet in range to return fire.  By the time the enemy could accelerate to supersonic speed and get within range of the Raptor – again, assuming for the moment that it could detect the Raptor at all – it would be too late.

Combined with stealth, supercruise provides an unbeatable advantage over previous generations of jets.  Test pilots are now working out whole new ways of attacking.  Working in simulators, they game out scenarios in which the F-22 detects the enemy, or perhaps a whole formation of enemies, while still unseen by the enemies’ radar.  It is then a simple matter to loose off a few AIM-120 AMRAAMS towards them while they are still too far away to return fire, even if they know they are under attack (which they will not) and could pick up the Raptor on radar  (which they cannot).  Then, engaging the afterburners to provide the excess power needed for supersonic maneuvering, the Raptors could make tight, 6G thrust-vectoring turns at 1,200 MPH, circling behind the unwitting enemy.  As the missiles strike the first few targets,  and the remainder go to afterburner to escape, the Raptors are positioning themselves, still undetected, for an easy stern shot against the accelerating but still subsonic enemy, who is now looking forward, in the wrong direction, for signs of the foe.

If attacked from behind, assuming the attacker can see the F-22 at all, a Raptor can engage afterburner, accelerate to Mach 2, and pull into a turn that may be too tight for the high velocity missile to follow, while bringing the attacker to bear.

High altitude supercruise may even make the Raptor a better bomber than other aircraft, able to loft specially-designed weapons towards targets tens of miles away, while avoiding radar detection, or out-running the SAMs if detected at all.  A stealthy, supercruising aircraft with excess power of maneuver, exploiting the “high-fast sanctuary”… for anyone thinking of going up against F-22s, these capabilities are the stuff of nightmares.

Yet, that is not all that the Raptor has in its bag of tricks.

Sensor Fusion, Information Superiority, and Networked Warfare

 

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The cockpit displays of an F-22, topped with a wide-angle head-up display.

In Viet Nam, the varied electronics of the F-4 imposed too much workload upon stressed pilots.  Electronic countermeasures boxes would squeal in their ears and display symbology on dedicated screens.  The radar had its own screen to be kept under close scrutiny.  Heat-seeking missiles would announce their ability to “see” the target by producing a loud “growl” (the “annunciator tone”) in the pilot’s earphones.  Fuel gauges, altimeters, throttle settings, artificial horizons, all manner of separate dials and gauges had to be checked repeatedly.  Pilots, overloaded by all this, were often shot down while trying to get a grip on all the screens and dials and gauges and squeals and growls, never even realizing they were being shot at. I recall seeing an interview in which ace pilot Robin Olds, commander of the 8th Tactical Fighter Wing in Viet Nam, sat in the front seat of an F-4 and pointed to all the systems he would simply turn off before entering combat, the better to prevent information saturation.  He would even turn off the microphone of the radar intercept officer in the back seat.  “He could hear me, that’s all I cared about”.  Colonel Olds was a seasoned fighter jock, having become an ace flying over Europe in WW II.  He knew how crucial it was to focus when entering battle.  Far too many of his peers were shot down before they learned this lesson, killed, in effect, by the very systems meant to protect them.

This is hardly surprising; an ordinary person could scarcely park a car while monitoring such a diverse set of inputs, much less dodge MiGs, evade SAMs, and swerve through puffs of anti-aircraft artillery in a fast jet while experiencing Gs equal to six times the force of ordinary gravity.

In the 1970s, a new discipline emerged in fighter design, aiming to improve the pilot’s “situational awareness”.  The heads-up display, described above, was a great stride down this road, allowing pilots to keep their eyes where they belonged while receiving the most vital information and ignoring the rest.  By the 1980s, improvements in digital cockpit design made for very much improved cockpit arrangements, using multi-function computer screens with clear symbology to augment the heads-up display.  Dials and gauges were all but banished.  A groundbreaker in this category was the F-18, with a cockpit that set the standard for future fighters.

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The F-18 cockpit. Superficially similar to that of the F-22, it operates under different functional principles, and does not provide “sensor fusion” via its multi-function displays.

Yet, clear displays or not, even an F-18 forced the pilot to look in several places to build up a coherent picture of what was going on.  All fighter displays worked on the same old principles.  If there was a radar, you had a separate radar display.  Countermeasures had their own display.  Infra-red or TV sensors had still another display.  A single pilot, with lots on his mind and plenty to do, could still be overwhelmed.

The Raptor will cure this problem with a revolutionary concept known as “sensor fusion”.  Taking advantage of the huge strides being made in computer power, the Raptor will replace all the separate screens with a central display that tells him everything he needs to know at any given time.  Separate displays may show different information, but they are entirely secondary.  On the central display, the computers will assemble the information from all the various sensors and instruments – called “apertures” in the jargon – and amalgamate them into one processed input.  The radar image will be combined with electronic warfare information, and so on, so that what the pilot looks at is “synthetic data”, made clear and comprehensible, that tells him several things at once.  Colour and shape will be a key element of this new display strategy.  The human brain responds instinctively to these characteristics. For example, an enemy aircraft will appear as a red triangle.  A line drawn from the center of the triangle will indicate direction of flight.  The length of that line will indicate relative speed.  An advancing red triangle sporting a long line pointed straight at you like a lance is an intuitively alarming thing.

At the same time, to avoid overload, the F-22 will operate on the “dark cockpit” principle.  The on-board computers, monitoring all systems and serving as intermediary between the aircraft and the pilot, will take care of routine functions.  If there is nothing to report, most of the cockpit displays will actually go dark, showing nothing.  Only if something happens requiring the pilot’s attention – detection of a target or threat, internal damage, arrival at crucial way-points, fuel status reminders, and so on – will the computers ask the pilot for instructions.  The very powerful computers at the heart of the Raptor’s information systems will function eerily like a separate mind; an F-22 is practically a simple organism on which the pilot rides, taking orders and making routine decisions behind the scenes, rather than a mere machine.

Other neat techniques are also being investigated to improve the ability of pilots to process information.  The heads-up display may be replaced by see-through displays mounted on the inside of the pilot’s visor, technology being perfected at present for the newer F-35.  The helmet’s earphones may present sound in a way that indicates the source of the information – for example, if a wingman is low on the right, his voice on the radio may be made to sound like it is coming from that direction.  The idea is to always tap in to the brain’s natural, intuitive ways of keeping track of things.

Sensor fusion in a single aircraft provides any given pilot a great advantage in situational awareness.  With the Raptor, however, the opportunity is being seized to fuse the sensors of several F-22s at once, as well as the sensors of other aircraft, and perhaps, one day, even ground-based units and surface ships.  High speed computers that can encrypt data on secure radio links now allow a single F-22 to communicate with the computers of all other F-22s in the area, transferring to them everything it knows – and vice-versa.  A pilot may therefore see on his own screen data that was gathered by a different aircraft, or data provided by links to radars or other sensors on the ground.  The computers will process and synthesize this behind the scenes before throwing it on screen.  The pilot will not always know, nor need to know, where, exactly the information is coming from.  All that matters is that he knows.  Linking various aircraft and other platforms together is what’s known as “networked warfare”- the fighters and other platforms are joined together in a network –  and the amalgamation of all this information gives F-22 pilots a tremendous informational advantage over their adversaries. What one Raptor knows, they all know.  What they all know, each Raptor knows.

The benefits are, potentially, limitless, and only beginning to be explored.  For example, one F-22 will be able to guide missiles fired by another.  If several F-22s approach a large number of enemy fighters, their computers will talk to each other and divvy up responsibility for the attack, ensuring that no two fighters waste missiles by engaging the same target.  This will all happen without the pilot having to think about it.

Networking also has obvious benefits in the pursuit of stealth.  A Raptor will be able, if the situation demands, to turn off all of its own emitting sensors, “go dark”, and cruise along without spewing out any energy that might give it away to the electronic countermeasures gear of other fighters, all the while receiving a clear tactical picture from other platforms over the data link.

At the same time, the quality of the sensors in each individual F-22 will be vastly improved over those in even the latest F-15s, no small feat.  Of particular note is the use of Active Electronically Scanned Array radars, or AESA.  An AESA is very like the phased arrays of the Aegis system we discussed in a prior essay, but even more advanced.  Rather than a single radar dish, an AESA comprises hundreds of smaller emitter/receivers that can operate in phase.  The tiny, pencil-thin beams of the AESA are pointed electronically with far greater speed and precision than a mechanical radar dish can accomplish by swivelling, and the hundreds of tiny emitter/receivers can operate together at one frequency, or break off into separate groups that operate at different frequencies and in different modes.  An AESA can, in effect, configure itself into more than one radar antenna at the same time, or operate in two different modes in a sequence so rapid that for all practical purposes it is doing two things at once.

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Once again, this electronic advance feeds back into stealth.  When the F-117 was designed, the goals of stealth seemed incompatible with an active radar, since radar gives off emissions that betray the presence of the aircraft.  As a result, F-117s have no radar, only passive receivers and infra-red sensors, an acceptable compromise for a bomber.  Yet, the next generation of fighter to replace the F-15 could not possibly function without an extremely powerful radar – to get the first look, and take the first shot, you have to be able to detect the enemy.

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The APG-77 AESA radar of an F-22.

AESA resolves the problem with its ability to send pencil-thin beams to discreet parts of the sky, while jumping frequencies and changing modes.  Though capable of detecting targets at much longer ranges than the F-15’s APG-63, the AESA on the Raptor actually throws much less energy around the sky, making it far less likely to set off any enemy radar warning receivers.  At the same time, by jumping frequencies and changing modes, the fainter signals of the AESA will form no coherent pattern for enemy systems to identify.  It will just seem like background chatter, interference, radio noise, anything but the telltale sign that somebody out there is now painting you with a powerful radar and fixing to blow your tail off.  In the jargon, this is known as “low probability of intercept”, and it’s a crucial factor in the “first look, first shot, first kill” equation.

With all these systems working to supply clear and useful data, Raptor pilots will have a better picture of their surroundings and tactical situation than any pilots have ever before dreamed they might enjoy.  There is plenty of room for growth, too.  More platforms may be able to join the data-link network in the future (conceptually, there is no reason why even individual soldiers, using laptops, should be excluded from the network – think of the flood of information that would then become available on ground targets and air defences).  Each Raptor’s own systems may be augmented with infra-red or television sensors, though this is not budgeted at present.  The modules for the AESA need not remain clustered in the nose; more could be placed along the fuselage sides, expanding the radar’s field of view (the current design reserves space, weight and cooling for this, though again, it has not yet been funded).

All in all, the Raptor’s myriad systems come close to penetrating, once and for all, the fog of war.  Other things being equal, this alone would give F-22s a decisive advantage over all anticipated foes. Yet even this does not finish the story.

The Advanced Tactical Fighter competition settled on two finalists, Lockheed and Northrop, the only two companies with a proven track record in producing stealth aircraft (Lockheed built the F-117, Northrop the B-2 bomber).  In many ways, the Northrop YF-23 was much the more exciting design, with its trapezoidal wing, long sinuous profile, and canted tail surfaces.  It looked like a sort of airborne manta ray.  It proved faster in supercruise than the Lockheed design, and it was almost certainly more stealthy.  Northrop had taken very seriously the Air Force requirements, which had emphasized these qualities, while downplaying close combat agility.  It had an engine outlet arrangement that completely hid the engines from the ground, making it far more stealthy in the infra-red spectrum than the Lockheed prototype.  This arrangement, however, did not allow for thrust vectoring nozzles.  The Air Force had not made thrust vectoring a priority, and Northrop opted for stealth instead.  In the result, there was no question that the YF-23 was a design masterpiece.

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The amazing Northrop YF-23, one of the great “what ifs” of post-war aviation.

Lockheed’s YF-22, by contrast, looked almost conventional, like an F-15 that needed to go on a diet.  It was less stealthy and slower than its rival, and by the Air Force’s own criteria it should have lost the competition, but Lockheed had cannily created a machine that would appeal to the viscera as well as the intellect.  Its engines could incorporate thrust vectoring, and it was the most agile of the two.  Agility was not supposed to be the priority, yet Lockheed’s designers seem to have understood that the spectacle of SU-27s and their derivatives running around to air shows and performing spectacular maneuvers was bound to rub professional US airmen the wrong way.  Reason indicated that the Flankers could pull all the snazzy maneuvers they liked – it would avail them nought when they exploded under the impact of long-range missile fire they never saw coming.  Still, there was bound to be an urge to take on the Flanker, one on one, close up in a visual range knife fight, and beat it hands down.  Lockheed catered to this urge, and won the contract.

The F-22 is a 34 ton brute, but its enormous power gives a thrust : weight ratio more or less equal to the F-15, 1.2:1 at takeoff and 1.4 at combat weight.  The F-22 also has a huge wing of over 840 square feet (vs. 608 square feet for the F-15), giving a wing loading of only 63 lbs. per square foot at combat weight, again equal to the F-15.  The Raptor, in spite of its bulk, therefore has the raw material to be just as agile as the Eagle, even if it was no more sophisticated in its aerodynamics.  Of course, its aerodynamics are much, much more sophisticated.

The Raptor is designed with a sharp edge that circles almost the entire perimeter of the aircraft.  This edge generates energized vortices of air at high angles of attack, which vortices increase lift, and allow the F-22 to hold angles that were unheard of in the Eagle’s day, and well beyond even the Flanker.  A Raptor can happily plough through the air with its wings at an angle more than 60 degrees off the line of flight direction, yet remain under full control.  This ability to sustain such angles gives the Raptor an extreme measure of what’s known as “nose authority”, the ability to point the nose in any direction desired.

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An F-22 as it ploughs through the air at an absurd angle of attack.

The huge wings of the Raptor are also less swept than those of the Eagle. By settling for Mach 2, instead of Mach 2.5, as the maximum speed, the Air Force permitted Lockheed to come up with a design that had wings a little better suited to rapid, hard banking turns.

The Raptor is also almost impossible to stall, and impervious to spins.  It can be flown, according to pilots, with “carefree abandon”.  There is no fear of pushing the airframe beyond its aerodynamic limits and inducing irrecoverable flat spins or deep stalls.

Finally, there was thrust vectoring.  The Raptor can almost certainly out-do both Eagles and Flankers at close quarters without thrust vectoring, but with vectored thrust, the Raptor is almost in a league of its own (the only exception being the SU-30s that are being purchased by the Indian Air Force, and the latest Flanker derivative, the SU-35, which will also incorporate thrust vectoring).  Using vectored thrust, a Raptor can actually perform somersaults.  It can point the nose at radical angles, sustain absurd angles of attack all day, and turn far more rapidly than all previous fighters. Published reports indicate that at altitude, the Raptor can sustain 28 degrees per second in a turn, which is far more than any 4th generation fighter. The MiG-29, for example, can muster up 28 degrees per second of instantaneous turn rate, but as energy bleeds off, its sustained turn rate is far lower.

In my own experience, I have seen Raptors at air shows pull “J-turns” that appeared to demonstrate a low altitude instantaneous turn rate of almost 60 degrees per second – unbelievable, but I have the videos to prove it. It pulls a 180 degree turn in three seconds, or perhaps a little longer.

Take away everything else then, strap it up with radar reflectors and strip it of its AESA, deprive it of AMRAAM and send it out with a cannon (yes the F-22 retains the trusty Gatling gun behind a radar-reflecting door in the starboard wing root) and a Raptor is still able to take on anything in close combat and come out on top (with those nasty Indian SU-30s, and still newer Flanker derivatives such as the SU-35) being its only potential equals in the close combat regime).

Of course, if the Raptor works as advertised, none of that will matter in the slightest, but it sure looks cool at the Harland County Agricultural Fair and Air Display.

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The Revolution Dawns: 2005

As Lockheed perfected its design, the Cold War ended. Funds were cut, technical hurdles encountered, and development extended.  Some questioned the need for the F-22 at all. In the result, while the Raptor was first deployed as planned, in 2005, its production run was savagely curtailed, from an initial order of over 700 airframes, to just over 300, and finally to only about 190, as the need for a gold-plated air superiority fighter was reassessed, prematurely, in light of operational experience in Afghanistan and Iraq, where US forces enjoyed air dominance on the strength of 4th generation fighters like the F-15. Given the sorts of wars America was now fighting, was something like the F-22 really necessary?

Defence Secretary Robert Gates, working within the Obama administration, thought not. In this, it now seems clear, he was utterly, foolishly wrong. Total command of the skies against limited opposition was not the new normal, to be taken for granted. New threats, and old geopolitical realities, were making their presence felt even as the Raptor production line ground to a halt.

Gates and those who agreed with him also failed to appreciate that air supremacy wasn’t the only mission for which F-22s were suitable. The Air Force almost immediately began looking beyond its capabilities in air to air combat, and envisioned a fighter that could penetrate enemy airspace to drop precision guided munitions – a supersonic stealth aircraft which, unlike the older F-117 and B-2, can be maintained in the field, operate in broad daylight, and crucify any fighters so foolish as to cross its path. In Syria, use of the Raptor as a stealthy strike aircraft has been an outstanding success. Conceived to best the Soviets, with their Flankers and advanced SAMs, F-22s may be the most hard-hitting tactical bombers ever made, dropping their weapons from as high as 65,000 feet, unseen by radar.

We all heaved a sigh of relief at the end of the Cold War, happy in the delusion that we might actually have reached “the end of history”. Even if that had been true, we would have done well to remember how many countries to which France and Russia were then selling their best fighters, making it irrelevant that major war with peer and near-peer states was a thing of the past. Raptors might never clash with the Russian Air Force, yet they were still quite likely, at some point, to encounter both Flankers and Dassault Rafales in combat.

And of course, history didn’t end. Great power competition was on hold, but by no means extinct. Over Syria, for example, NATO warplanes share air space uneasily with Russian fighters as we all support our preferred factions in that country’s miserable civil war. Should push come to shove, we count on our Raptors to overpower the most advanced Russian fighters in theatre, the SU-35 variant of the Flanker, a design that certainly matches or betters any other aircraft we could throw against it.

Yet the SU-35 is not the ultimate threat. The potential now exists to encounter still more advanced fighter aircraft manufactured by China and Russia, which are supposed to join the F-22 in the fifth generation. It’s not at all clear that they really do, not yet, but their existence is enough to make many of us wish we could give Robert Gates a number of swift kicks to his short-sighted hindquarters.

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The F-22 at altitude, going through Mach 1 – the deadliest fighter aircraft yet conceived, the Raptor was meant to give the US 40 years of total air superiority. When it was first deployed, it seemed certain that no other nation had both the money and the technical prowess to deploy such an aircraft at squadron strength. Times change, but perhaps this rosy prediction remains substantially accurate.

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High speed pass. Note the gold-tinted canopy – that’s not actual gold, but it is metal, something called indium-tin-oxide, applied in a thin film, to deflect radar waves away from the edges and angles of the cockpit interior.

The World Catches Up – Or Does It? Russia.

Once again, the Americans had enjoyed about a dozen years of complete air superiority, and once again, there then arrived some new kids on the block. The first challenger was a new fighter from Sukhoi, in many ways an evolutionary development of the Flanker, that attempted to emulate the most advanced features of the F-22. This was model T-50 in the Sukhoi Design Bureau sequence, referred to by the Russian as the “PAK-FA”, the Russian language initials for “future aircraft system – frontal aviation”. Recent reports suggest “SU-57” will be its official designation.

The T-50 was a very impressive looking design, and it gave rise to the usual hysterical response in the Western aviation press. Though upon its first appearance it was obviously a developmental prototype with perhaps a decade of work ahead of it before it would be a deployable fighter, the PAK-FA scared the crap out everybody at first sight. As they had with the F-15, the Russians had enjoyed a protracted period of study in designing a counter to the F-22; remember, the YF-22 won the fighter competition in 1991, and has been deployed since 2005. So, as was the case with the development of the SU-27 Flanker, the Russians had many years in which to absorb what the Americans had done and come up with something that looked even scarier. The PAK-FA has been widely touted as at least equal to the F-22 already, and God only knew how much better it would be when development was finished.

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Various views of the Sukhoi T-50, or “PAK-FA”, an admittedly formidable-looking beast, with several features obviously optimized for stealth.

This was a bit alarmist. Sober observers took a close, critical look at the PAK-FA and concluded that it might emerge one day as a monster, but the model on current display is not yet a true 5th generation fighter. It’s obviously fast, designed for supercruise, and it will obviously be highly agile – whether there is actually any point to super-agility is open to question, but it’s plainly designed for it, and might even be more agile than the tail-sliding, J-turning, back-flipping Raptor, if that’s possible. But it seemed badly compromised in stealth. In fact, experts reckon that the arrangement of it’s canopy framing and infra-red sensor ball alone would return a bigger signal than the whole F-22; it’s engine nozzles are wholly unsuitable from a radar-return perspective; and in the prototypes, you could still see right down the engine intakes, apparently to the faces of the compressor fans, a huge no-no in stealth aircraft, which simply must have “S-ducts” to prevent this.

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Looking down the T-50’s intake. Blades or blocker?

As far back as 1991, F-15s were identifying Iraqi aircraft types at over 80 miles by beaming APG-63 emissions on to their compressor disks. God knows what our latest Active Electronically Steered Arrays can do. The Russians must have some sort of grille, inlet blocker or some such up their sleeves, because by settling on podded engines with weapons stored in between, like the F-14, they’ve rendered F-22 style S-ducts impossible. The photo above perhaps shows this – that might not be the compressor disc at all, but rather a radar-fooling blocker of the type also seen on the Super Hornet. This is the view down the intake of an F-18E/F:

Those aren’t fan blades. They’re radar absorbent apertures that keep radar away from the spinning disk behind. It only makes sense that the Russians have done the same thing.

Well and good, but remember, a true stealth aircraft needs much more than this, and must be assembled to an extraordinary level of precision, with no unwanted seams, bumps, or small protuberances – recall how the Have Blue stealth demonstrator glowed brightly on radar if even a couple of screw heads weren’t quite flush. It’s not at all clear that the Russian aviation industry is quite up to the task. Indeed India, which has joined in the program with the intent to supply a large number of T-50 derivatives to its own air force, has consistently complained over the years of inadequate assembly standards and compromised stealth. Engines have also been an issue, and as for the electronics, we can only speculate, but it’s doubtful they can match the US on that score (though the Russians are far more adept at avionics than snarky comments from some Western sources would lead you to believe).

These figures may not be reliable, but public sources indicate that the T-50 may have a frontal radar cross section of 0.1 square metres, which compares very favourably with a Flanker or an Eagle, but is similar to the Super Hornet, and one thousand times as great as the Raptor’s reported figure of  0.0001 square metres. 

The T-50 is formidable, yes, but as Bill Sweetman says, based on what we’ve seen so far, “Don’t even think the word ‘Raptorski’. It’s not even close.”  

At the time of writing, the T-50 is still years away from squadron service, and seems likely to be purchased in limited numbers, perhaps as few as 12-24 machines initially.

The World Catches Up – Or Does It? China.

The Chinese, with considerably more GDP to play with than Russia, and cyber-theft capabilities that are unmatched (and clearly in evidence in their new aircraft designs), are flying the initial batches of two purported 5th generation fighters, the large and powerful Chengdu J-20, and the smaller Shenyang J-31.

The J-20 is a very large aircraft, quite a bit bigger and heavier than an F-22, and it isn’t clear yet what it’s meant to do. It’s about the size of an F-111, a plane designed for long range strike, and it may be that the J-20 is so big owing to substantial internal fuel supplies meant to give it the range to operate effectively over the vast Pacific Theatre. It may be capable of deep strike with air-to-ground munitions, but thus far its internal weapon bays have been photographed carrying only air-to-air missiles. It’s hard to judge how agile it might be, given its size and weight, and one widely-accepted theory is that it’s meant to sneak up upon and destroy the vulnerable support aircraft that are vital to US air operations – airborne tankers, AWACs, and so on. These large and vulnerable assets tend to operate at what’s meant to be a safe distance from the combat zone, but a long-legged and stealthy fighter might just be able to reach them with long-range missiles.

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Two views of the J-20.

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Size comparison, J-20 vs. F-22.

It’s not clear how stealthy the J-20 is, either. While it has borrowed shaping and edge alignment techniques from the Raptor, it has large canard foreplanes, which tend to compromise stealth – in the early days of the design of the F-22, a Lockheed representative was reported to have stated at a conference that his company had exhaustively studied the issue, and determined that “the best place for a canard is on somebody else’s airplane”. As with the T-50, the engine nozzles are incompatible with rear-aspect stealth, and build quality is probably an issue. The Chinese, too, have problems with propulsion and integrated avionics.

If information is spotty on the J-20, it’s even more incomplete when it comes to the much smaller J-31. In size and overall configuration, the J-31 looks a lot like the Raptor’s smaller and highly controversial cousin, the F-35 Joint Strike Fighter. It’s alleged this is because Chinese hackers penetrated Lockheed Martin’s systems and stole reams of data on the F-35.

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Compare and contrast; the F-35 at top, the J-31 below.

As with the J-20, estimates of its radar cross-section are little more than speculation, at this point, and the relative quality of its engines and avionics is also a mystery. It isn’t even clear that the J-31 is meant for service in the Chinese air force – it may be meant to be an economical alternative to the F-35 on the international market. It would certainly be an attractive item for those air forces whose adversaries field only 4th generation designs – while perhaps less stealthy than its US counterparts, the J-31 might have an  advantage over machines like the F-16 and MiG-29.

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At first blush, it seems a credible little fighter that may one day emerge as a 21st century equivalent to the MiG-21; not the best, but superb bang for the buck.

So, We Can Conclude…?

At this point, none of the foreign 5th generation designs would appear to be a match for the Raptor, or even the JSF, across the whole spectrum of air combat. The T-50 will in any case be purchased in numbers too small to matter, and the J-20 may not be intended for air superiority in quite the same way that we conceive of the mission.

The Chinese fighter, however, has the potential to upset the balance of power in Asia. Its development has prompted both South Korea and Japan to order F-35s (the Raptor was never for sale outside the US, even when it was still in production), and its ability to strike at vulnerable US support assets could be a game changer. The J-20, unlike the T-50, is also likely to be procured in significant numbers.

With so few F-22s – at any time, only about 120 are combat coded – the US may seem in imminent danger of losing its edge over its nearest geopolitical rivals. It should be remembered, though, that the smaller F-35, while less capable in many ways, is still shaping up to be a formidable multi-role fighter that ought to level the table, and perhaps shift the balance in America’s favour. It can’t supercruise; in stealth configuration its air-to-air weapons load is limited; it’s had horrible teething troubles and is a favourite punching bag in the press; its general purpose design means it isn’t optimized for air combat. Despite all that, my view is that its combination of stealth and radically advanced sensors will allow it to hold its own against all comers, and reports that it’s an aerodynamic pig that can’t even handle an F-16 are, I’ve concluded, inconsistent with pilot reports and mock combat results at realistic exercises like Red Flag. It will also be produced in relatively huge numbers, more than 2,000 for the US alone, and many hundreds more for various NATO and Asian allies. It’s not a Raptor; but the Raptor production line isn’t going to re-open, despite everyone’s hope that it might, under the Trump administration.

The F-35 is going to have to hold the line. I think it will.

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A pair of F-35s perform a classic break maneuver.

 

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