Why is Russian super-maneuverable thrust vectoring more prevalent than American?

Question

Based on the sheer number of super-manouverable thrust vectoring Russian fighter jets, it seems that Russia has put more effort into developing thrust vectoring for enhanced maneuverability than the US has. Why is this?

Examples of American thrust vectoring aircraft:

1. F-22 Raptor

Russian thrust vectoring aircraft:

1. Su-30 MKI
2. Su-35
3. PAK FA
4. Su-37
5. Mig-35

Of course you could include the MV-22 Osprey, Harrier, and F-35B as thrust vectoring, but I'm talking about thrust vectoring for enhanced maneuverability, not for STOVL.

Answer 1

This is a case of divergent design, and you can't know the answer without asking why current aircraft are designed they way they are.

Following the work of Col. John Boyd in the 1960's in developing the 'Energy-Maneuverability Theory', the U.S. and allies primarily designed combat aircraft and tactics around the idea that an aircraft's specific energy state defines its performance during basic fighter maneuvering (dogfighting).

Under the E-M theory, in order for a fighter to be survivable (and consequently victorious) during aerial combat, it must maintain a high specific energy advantage throughout its maneuvering - this means it either has higher potential energy (altitude), or higher kinetic energy (speed), and should aim to maintain the capacity to trade one for the other efficiently. In a fight occurring only in the vertical plane, this is easy to quantify, but in a turning fight, induced drag from turning bleeds energy from the aircraft, and E-M theory allows this performance efficiency to be quantified for a particular design or tactic.

Consequently, U.S. 4th Gen fighters like the F-15, F-16, and F-18 are designed specifically around energy maintenance in all flight regimes - high thrust for climb performance (gaining potential energy via altitude) and to maintain speed (overcome induced drag by turning), low wing loading (lower energy bleed in turning due to induced drag), and improved aerodynamics in the expected combat envelope (reducing overall drag in the subsonic regime), and their tactics emphasize maneuvering energy-efficiently, over expending all your energy in tight turns to simply 'get a bead' on your bogey first.

The practical effect of this is that if your first attack pass fails, you still have sufficient energy to either outmaneuver your opponent and get into position for another attack, or run. The disadvantage is, when your kinetic energy is higher than your opponents (speed) you can't turn as tightly as he can - but the hope is your greater ability to maneuver in 3 dimensions with that energy will give you the upper hand for a second attack - classically, this would be considered 'boom and zoom' tactics.

By contrast, the Russian designers have been focusing on 'Supermaneuverability', the ability of the aircraft to remain within the controllable envelope, outside the envelope of aerodynamic control. This is facilitated by 'funny' aerodynamics on aircraft like the MiG-29, Su-27 and Su-33, and by thrust vectoring on the aircraft you mention in the OP. This allows for high angle-of-attack maneuvering at low speeds (low energy state) - with the goal being to allow the pilot to point their aircraft at their opponent to facilitate a weapon release - it's the 'shoot first' strategy. Even if your shot misses, you force your opponent to go defensive, giving you the upper hand for a second shot, often facilitated by high off-boresight missiles like the R-73.

As speed decreases, so does turning radius - however aerodynamic control authority decreases at a greater rate. Thrust vectoring allows you to overcome the decreased aerodynamic control authority - your ability to change the attitude of the aircraft is now mostly independent of its aerodynamic control surfaces. Thus using supermaneuverability, you no longer need to outturn your opponent, you just point the aircraft in a totally different direction to where you were flying, possibly allowing a 'snap shot' with missiles or guns. The classical equivalent is 'turn and burn' tactics.

The practical effect of this strategy is that you might outturn your target and get a shot off first, but if that shot fails, you now have no energy (because you bled it off due to the massive induced drag of a high-alpha turn), and are effectively a sitting duck to your opponents wingman - you have no speed to run, you're losing altitude, all you have is thrust, and thrust is comparatively slow to regain energy. You can spin in place and keep shooting, but if your opponent uses their energy to run, you don't have the energy to chase.

So, why has the U.S. primarily ignored thrust vectoring? Because it's not tactically relevant to them. The West experimented with supermaneuverability towards the end of the Cold War with aircraft like the X-31 and F-15 ACTIVE, and after getting their hands on MiG-29's and Su-27's at the end of the Cold War, and wargaming them, decided that the 'supermaneuverability' advantage just wasn't worth it, when E-M based tactics could simply be adapted to defeat it. The one exception being the F-22 - an aircraft designed before the Wall fell, specifically designed to counter what Western tacticians had imagined the MiG-29 and Su-27 were capable of - illusions that were shattered just several years later.

Answer 2

Part 1 - TVC

Perception

The US also ran several programs with TVC:

1. F-15 STOL/MTD and ACTIVE.
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2. F-16 VISTA / MATV. AVEN:
3. F-18 HARV (High Alpha Research Vehicle). Overview pdf.
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4. F-22 (almost 200 produced)
5. X-31.
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6. X-36. (Yaw only.)
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7. X-44 MANTA (proposed F-22 variant)
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^{(All photos from their respective wiki pages except where otherwise watermarked.)}

The F-22 is far from the sole example of US TVC, though the only design to enter serial production.

From the Russian side, you mention the "sheer number of super-maneuverable thrust vectoring Russian fighter jets":

1. Su-30 MKI
2. Su-35
3. PAK FA
4. Su-37
5. MiG-35

But the PAK FA is still deep in development, the MiG-35 probably won't enter production was delayed, and the Su-37 never entered production. To date, only a handful of those three were ever built.

The Su-30MKI was built for India, not Russian forces (see Su-30 for Russian variant). It doesn't use true 3D TVC, but rather fixed 3D TVC: . Explained here:

The Su-35 is the only one [on that list] in widespread Russian service, and only a few dozen of those were produced.

Also notice that the Su-30/35/37 are all part of the same Su-27 family. In fact, the Su-37s were just converted Su-35s. And the MiG-35 is derived from the MiG-29. So there isn't a preponderance of clean sheet designs built with TVC.

In comparison, the US list above includes four different manufacturers and six clean-sheet designs (plus only one derivative), half of which included original TVC solutions (rather than merely retrofitted).

Conclusion

The US had a number of TVC programs itself.

So why does Russia seem like it "put[s] more effort" into TVC?

Beyond flying more TVC fighters, it's also more popular in the news. The Russians have always liked to talk big about their "secret wonder weapons," and US media doesn't discourage them. People devour headlines like "Russian fighters out-turn F-22, US stealth is a hoax, newest US fighter is a turkey." It sells pretty well.

Real design is complex, hard to understand, and easy to deliberately misinterpret.

In contrast, the newest US fighter, the F-35, doesn't have TVC. Since it's A) the only new US fighter since the Super Hornet (other than the aforementioned F-22) and B) replacing so many a/c (F-16, F-18, AV-8B, and probably some A-10s), it means that much of the US fighter inventory won't have TVC. On the other hand, had the JSF program produced 3 completely separate a/c, at least one of those may have included TVC (though unlikely in my view).

Also, Russian TVC employment is ongoing and fresher in people's minds, whereas the US projects above are a bit older and have apparently fallen out of the public consciousness.

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So why does Russia use it more than the US?

Russia developed its Su-27 and MiG-29 families in response to the F-15, F-16, and F-18, which were a quantum leap in capability over their predecessors, like the F-4, F-5, Mirage, and Century Series. The F-16 had great sustained turn rate, and the F-15 had powerful engines on a big wing.

But their first engagements with F-15s left the Mirage pilots shaking their heads. One Mirage ace with fourteen kills described his first fight with an F-15 whose pilot was just out of F-15 training school to the author. "The rules were that he could not use his AIM-7s, so the fight began with a head-on pass. I started to turn and he pulled up and came around on me. I saw him make three or four mistakes on the way that I could have easily taken advantage of if he had been in a regular fighter, but there was nothing I could do to counter the F-15. He shot me down within forty seconds. I flew home in my Mirage, both of us feeling very old and out of date." -- Revolt of the Majors: How the Air Force Changed After Vietnam, by Marshall L. Michel III

The Su-27 was designed to be a bit better. TVC helped to achieve that [or at least tried to].

TVC is useful at very low speeds and high alpha, where conventional control surfaces are less effective. So it's useful for dogfighting---close range, low speeds, lots of turning.

However, using TVC comes at a cost in forward thrust (and drag and weight), which the video above explains. Outside that envelope (where the control surfaces work fine), TVC doesn't see much use.

Unfortunately for TVC, engagement ranges were growing, and within visual range combat was becoming less common, so those kinds of performance parameters were losing utility. New technologies and tactics made it very difficult to get close in the first place: AWACS, improved fighter radars (greater range, look down/shoot down), BVR ID (non-cooperative target recognition), data-fusion, networks, and new long range missiles (higher reliability, improved countermeasure resistance, fire and forget, datalink). BVR combat finally came of age.

Even if you made it to close range, new dogfighting missiles made combat very lethal (see: HOBS, all-aspect engagement envelope, LOAL, HMCS, IIR seekers).

Long-range wasn't the only thing that sidelined TVC. Other designs could also provide control at low speed and high AOA without TVC. The euro-canards are basically supermaneuverable. The F-35 is controllable to ~50 deg AOA and was successfully tested to 110 degrees:

You'll remember that the YF-23 (competitor to the YF-22) doesn't feature TVC. It counted more on higher speeds and better stealth to help keep adversaries at arms' length, rather than tangoing at low speed with TVC. (But note that the YF-23 was also very maneuverable, with a higher sustained turn rate than the F-16, as required.)

So while the US did not neglect TVC, it did opt for different designs and doctrines that had much less use for TVC. It didn't need TVC to attain performance goals, and it doesn't plan on needing that kind of performance very often in the first place.

Now, once the Cold War ended, Russian defense budgets were slashed, and funding for new a/c development dried up, so Russian forces haven't fielded a brand new fighter for over two decades. At least not in meaningful numbers. They're still using the Su-27 and MiG-29 families from pre-1991, just newer variants thereof. So they're not so much 're-emphasizing' super-maneuverability as they are still 'stuck' on it.^{[That word isn't quite right, but I can't think of a better one.]}

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Part 2 - Responding to other answers

Please pardon my pet peeves.

1. The F-18 "[emphasizes] maneuvering energy-efficiently, over expending all your energy in tight turns to simply 'get a bead' on your bogey first."

That depends. Compared to an F-16, the Hornet has a lower sustained rate of turn but a much higher AOA (Hornet = 50, F-16 = 15-26.5 degrees, depending on g and loading). The Hornet should never win a fight against an F-16. But it does. Sometimes.

The Hornet can yank its nose, spending that energy, to get the first shot. But if it misses, the F-16 can gradually work its way into a firing position. Rate v. radius.

2. E-M theory as a revolution

Boyd is credited with a lot of things. Humility is not one of those things. Embellishment and self-promotion are. The cult of the man has grown to such proportions in the popular conception that it's difficult to critique him and his ideas without becoming a lightning rod.

While E-M was useful for summarizing some principles of aerial maneuver, it did not invent those principles. Arguably, its real utility was being able to quantify paper designs, not just metal ones.

3. E-M theory in a/c design. "F-15, F-16, and F-18 are designed specifically around energy maintenance in all flight regimes"

I wouldn't say they were "designed around" E-M. It was used to evaluate the designs (after they were already designed), sure, but so were many other metrics.

For example, Boyd wanted the F-15 limited to 5.5 g's because that's what his E-M charts said was most efficient. Needless to say, that didn't happen.

Kinematics are only one aspect of fighter design. Avionics are often more important.

In Korea, F-86s went 10:1 against MiG-15s. Both had the same thrust, but the F-86 weighed significantly more than the MiG, lowering its acceleration/climb rate and altitude.

[Korean fighters aces and Doolittle] felt that the high-technology avionics, while heavy and hard to maintain, allowed the Air Force F-86s to have the high kill ratio despite the Soviet fighters lighter weight. Indeed, Soviet MiG-15 pilots who later examined downed F-86s were extremely envious of the very F-86 systems Boyd and others criticized. --- Revolt of the Majors, 80

It's arguably more accurate to say the F-15 was built around its complex, expensive radar, which Boyd opposed, having never flown an a/c with either radar or missiles.

Boyd was unhappy with both the F-15 and F-16, especially with what they became: high-tech.

4. "US aircraft development has pretty much stopped cold in the mid-late 1980s..."

The F-35 is a HUGE leap over its predecessors (F-16, F-18, AV-8B, F-117): stealthy AESA radar; advanced EW suite; advanced, spherical missile approach and warning; new helmet mounted cueing system and display; integrated FLIR, laser designator/range-finder, and IRST; stealthy, high data rate comms; longer range; DSI; ALIS; lower maintenance electrohydrostatic actuators; lower maintenance, more durable, "baked in" stealth coatings; tightly integrated and fused sensors.

In some ways, the F-35 is more advanced than the F-22. For example, the radar, EW suite, and MAWS are more modern versions of those on the F-22. Some of the F-35's technologies, like coatings and software, will be retrofitted onto the F-22.

5. "[Only] the F-22 and F-35 [entered] production since [the mid-late 1980s]"

The F-22 and F-35 aren't the only US a/c that entered production in the last 26 years.

• C-17 entered production in 1991/92.
• V-22 entered full-rate production in 1995.
• The Super Hornet entered production in 1995.
• Growlers entered production in 2007.
• P-8 Poseidon entered production ~2009.
• E-2D saw initial deliveries in 2010.
• KC-46 entered production a few years ago.
• T-X (new trainer) will likely start production soon.
• JSTARS is looking for a replacement.
• On the helo side, there's KMAX and the proposed S-97.
• The B-21 Raider ("mini B-2") is deep in development.
• And let's not forget all the UAVs: ^{(Dronesurvivalguide.org)}

And there's also the less public ones, like the Doritos over Texas.

Also, "just" the F-35 is understating things a bit, since its 3 variants are intended to replace several different fighters (F-16, F-18, AV-8B, F-117, and probably some A-10s) and over 2,500 airframes in US inventory.

6. The F-22 and F-35 are "decades overdue"

They've only been in development for 15-20 years (depending on how you count), so they can't be "decades" overdue. This is average for modern fighters:

The F-35’s development timeline is also relatively moderate. The Rafale started development in 1982 and introduced in 2001(19 years). The Euro-fighter started in 1983 and was introduced in 2003(20 years). The Raptor started in 1986 and entered service in 2005(19 years). The PAK-FA, an evolutionary aircraft, started in 2001 and will be introduced in 2017(16 years). The Gripen started development in 1979 and was introduced in 1998(19 years). The Hornet was a redesign of the YF-17(9 years) from 1975 to 1983(8 Years) from which the Super Hornet evolved from 1992 to 2000(8 years). The F-35 in comparison to all of these started in 1996 with USAF IOC in 2016(20 years). Source.

7. "...TV simply wasn't ready for operational deployment."

The US experimented with TVC a number of times, but [I'd argue] they deliberately didn't employ it in the "current generation" (ie F-35) because the cost, complexity, weight, and increased maintenance weren't worthwhile for the rare times they'd be useful.

CORRECTION: I misunderstood what s/he meant by "current operational generation." S/he meant F-15/16/18, not F-22 onwards. So they're right that TVC definitely wasn't ready for the F-15/16/18. Otherwise it might have been incorporated into those designs.

Answer 3

A very important reason is stagnation.

US aircraft development has pretty much stopped cold in the mid-late 1980s, with just the F-22 and F-35 entering production since, and those decades overdue.

Meanwhile, the Soviets created and fielded all the types you mention. At the time the current operational generation of US aircraft entered service, TV simply wasn't ready for operational deployment. And remember that the USSR/Russia has always fielded a wider variety of combat aircraft than does the US, typically having multiple types in production at the same time for the same job.

All the aircraft you mention are of the same generation, built after the last new US aircraft prior to the F-22 (the F-15) entered production or even prototype stage.

The US experimented with a thrust vectoring variant of the F-15, and another one based on the F-16 as well, but both projects fell foul of budget cuts when Clinton took over from Reagan and no orders were ever placed. In the Soviet system most things that weren't total failures would see at least some models produced and put into operational service. A far more expensive way of doing things, but fitting into their political/economic system.

Answer 4

In short: there is no need.

There are at least two reasons why 'super-maneuverability' isn't really a concern:

1. Missiles are so advanced that dogfights seldom take place.
2. High G-forces increase the risk to develop physical injuries, shortening pilots' careers.

Automation is making the fighter pilots more and more unnecessary. Missiles do their jobs so effectively that the pilot seldom has a chance to see the target anymore. And while the aging fighters are still somewhat useful, their unmanned counterparts are advancing rapidly and taking more responsibilities on the battlefield. In fact, thrust vectoring might find its way to drones, since they can withstand more aerodynamic stress than manned aircraft.

Focusing on the manned fighters leads one to think that not much is happening, but take a look at drone development and you'll see that the future of military aviation is there.