SinoDefence Forum

crobato

Like, as if one wonders what happens in PLAAF wargames. What happens if one Jian meets another Jian in mock air combat? Who will win?

Some of my hypothetical imaginings what goes on.

J-6 vs. J-7

Though the MiG-21/J-7 Fishbed was meant to replace the MiG-19/J-6 Farmer, this is one case where the successor isn't better than the former at least in WVR. The J-7 never fully replaced the vast numbers of J-6 during the entire career cycle of both planes.

Although the J-6 is considered a beast to fly, it is an incredible dogfighter. Under Chinese development, the combined output of its twin engines is even better than the single engine of the Fishbed and its thrust to weight ratio is as good as any late model Fishbed.

While the J-7 has better radar, it remains limited. Both planes will have to rely on ground control for situational awareness and engagements will be eyeball to eyeball. Against the J-6, the J-7 isn't necessarily a better fighter. The J-6 is a brute, it's fast, it's got a great turn rate and its got big guns. Its actual combat record has included aircraft considered more advanced among its kills.

The J-7 though, is a much more pleasant aircraft to fly. In the long run it was also more serviceable. The Communist bloc nations replaced their Farmers as as fast as they could when the Fishbed came out. Except in China where the Farmers as the J-6 continued to improve. By the eighties, the J-7 did began to see advantages that would pull it away from the J-6. These are avionics changes, such as the J-7 getting a HUD, a clean cockpit layout. Eventually the J-6 gets into trouble, when the J-7 evolved to get all aspect missiles such as the PL-8. The final end to the J-6 came when the J-7 finally gets a pulse doppler radar that gave the plane an all weather interception capability and a better ability to track a target during combat.

crobato

J-7 vs. J-8

Yet another story where the successor didn't leave up to its promise. The J-8 was designed as a high speed supersonic interceptor that would blow its target with long range missiles. But when the radar didn't fully its specifications and the original missile, the PL-4, failed to achieve its design goal, the J-8I was reverted to short range PL-5 missiles.

Although aerodynamically it looks similar to the J-7, the J-8I, with its size and length, lacks the agility and nimbleness of the smaller plane. Unless it resorts to its speed, the J-8I only has one or two quick passes against the J-7, and if the dogfight drags on, the J-8I would bleed its speed, and the more nimble J-7 will get its kill. Its going to be pretty much the same story when a J-8I engages a late model J-6. The J-8I has to maintain its high speed, and will need to nail the smaller fighter by its shock and surprise, not an easy task with the speed of its opponent.

The J-8I never really got the radar and weapons it was planned with, and development went to the J-8II. The J-8I eventually inherited the same radar systems from the J-7D, along with a HUD and all aspect missiles, but it remains to this day, a BVR fighter forced into the dogfight role.

crobato

J-8II vs. J-7 (all variants)

China's second try on a BVR interceptor was steeped in problems also. Despite being a great leap---China's first workable pulse doppler, the original radar didn't live up to demands of combat. It was fragile, easily jammed and there is a question of proper friend to foe identification. Early J-8II pilots quickly developed a habit of distrusting their radars and resorted to close combat. It is for the same reason why the J-8II never succeeded the J-6/7 either.

Against a J-7, the J-8II's chances is only as good as any J-8I. Speed is essentially, and the J-8II should not be suckered into a turning dogfight, where the more nimble opponent could nail it in.

Like the J-8E, when the J-8II acquired use of all aspect missiles, it can better do its high speed slashing attacks. But then the J-7 did acquire the same capability too starting from the J-7D model to the J-7H and J-7E. The J-7E is even more maneuverable than previous models, and therefore, even more dangerous.

Finally acquiring the PL-11 among late J-8B and J-8D models, it still may not have provided the decisive edge over the J-7. The J-7 could fly low, taking advantage of the terrain and gound clutter, and gaps against the J-8II's radar, then climb and attack the J-8II with PL-8s underneath. If the J-7 got radiated, the J-7 could rely on beam maneuvers that could break the radar lock.

The problem of the PL-11 is that it being a SARH missile, the target must be in continous lock till the missile hits its target. Once the J-7 got locked, the J-7 will go wild and do everything to break that lock. The J-8II pilot could actually exercise an option here, keep the radar beaming on the target without actually shooting the PL-11. Instead, the J-8II will set itself up for a couple of PL-8 shots as soon as the J-7 gets close enough. It will have one or two passes before using its PL-8s and then disengage, using its speed to break and head back home. The enormous thrust to weight ratio---the J-8II is actually superior to almost all 3rd generation planes in that regard---is the plane's main attribute. IF the plane got itself into a low energy situation, its got to burn hot and bring its speed back up, then break off from its attacker.

When the PL-12 ARH missile comes into service, then the J-8II, in its J-8F guise, finally achieves its intended design potential, despite being nearly two decades late. The missile, along with a modern radar capable of tracking and engaging multiple targets without much warning, finally puts the plane on top of even the latest J-7E and J-7G variants, although all these planes are showing the age of their heritage.

tphuang

Nice analysis, Crobato.

I guess pla never did achieve the gap in capability between two variants until J-10 came along. I guess that's our so called generation gap.

I never realized J-6 was that successful of a program for pla. J-7 still seems to be the most successful program in my mind due to its long service with pla and high export totals and such. The later models using updated avionics + PL-8 + latest turbojet engine would give it a good shot against any non-BVR fighter.

J-8 in my mind is just a disgraceful program. As you said, it didn't really prove its worth until in the recent years with the induction of slotted array radar and medium ranged AAM. Of course, it would now be a little unfair to match up a J-8F equipped with 2 PL-12s and 2 PL-8s against a J-7 with a few PL-8/PL-5s. J-8 has seemed to finally achieved the Mig-31 role in plaaf (although not as fast, but more manuverable).

tank

I'm kinda uncomfortable using this transitivity. If the J-6 has some parts superior to the J-7, and the J-7 has some parts superior to the J-8, does this mean the J-6 has parts superior to the J-8?

You guys seem to know alot more about fighter jets than me. Do you think the J-8 will retain any advantages against the J-10? Or for the J-XX(supposed stealth plane I've been hearing about)?

KYli

Hi Tank

No need to worry. J6 had some parts superior to the J7, but J6 airframe is oo old for any upgrade. The newer modifield J7 will definite better than J6 in almost every aspects. J8 is difficult to say, since this project had major delayed done to Cultural Revolution, so J8 come out ten years later than it supposed to be, that why PLA never put too much effort for extensive modification. The late J8II may be better than J7, but does not have clear advantages. About the J10 vs J8, J10 is at least one generation ahead of the J8, J10 has better radar, BVR and always every aspect. So J10 is way better than J8.

Hi crabato

Good analysis.

darth sidious

the J-6 is particaly superior beacuse of the weak chinese aircraft of the past had they manage to sucessfuly copy the engine tech for mig-21 in the 60s it would most definetaly be the dominate chinese fighter today. During the 60s mach 2 is regarded as essenial for intercepation of nuke armed bombers a role that the j-7 is designed for. the j-7 is MUCH easier to manfacture and maiuntain then the J-6 ( RD-9 have a extremly short time bewten overhuals)
J-7 last much longer the J-6 is better at lower attitude because a a common fault in the design of R-21 turbo jet something the Russians fxed on the Mig-21MF. this puls the fact that J-7 have better weapons and radar makes is a obivous choice.

crobato

If you look at the production rates of the aircraft you see a sharply declining pyramid.

J-6s --- over 3500 built over its lifetime
J-7s --- over a thousand built including J-7E/G.
J-8s --- over 500 built of all versions including J-8I.

Now let's go to what Darth was saying.
The J-7 can only achieve Mach 2 in a clean configuration, but I am guessing it really doesn't because it would ran out of fuel before it gets to that desired speed. FYI, the J-8I was much better as a design for a Mach 2 interceptor.

Essentially it can be said that the J-7 is a much easier to manufacture and maintain dogfighter than the J-6.

With two WP-6A engines, the J-6 is actually a brute of a plane, and along with the MiG-17/J-5, the epitome of the classic dogfighter.

But here lies its failings. These jets are only equipped with a ranging radar. If you want to know what a ranging radar is, that was first introduced on the F-86 Sabrejets and intended to help "range" the target better in front of your gunsights, making gunshots more accurate. It was one of the advantages the F-86 had over the superior performing MiG-15. Essentially it is a radar gunsight.

The early IR AAMs function by merely looking at a wide FOV of the sky and lock on to any heat source. That's essentially how the first F-86s carried the Sidewinders. The first ever instance of heaters being used in combat is actually between the ROCAF and the PLAAF, and the PLAAF naturally lost their encounters, basically J-5 and early J-6s against F-86s---though a lodged Sidewinder on a J-5 became one of the biggest intel bonuses the East acquired from the West.

A real breakthrough in IR AAMs came with the AIM-9L, the so called all aspect missile. In this case, the fighter radar is used to lock on to the target after IFF interrogation. The radar then cues the seeker head to the direction of the target, enabling the seeker head to focus on more weaker or more distant heat sources without being distracted by other heat sources. This allows such missiles to engage targets head on or near front aspects, or simply at all directions. This fundamental advantage gave the Israelis such a major advantage over their encounters later at Bekaa Valley.

This is how the J-6 became even more obsolete. It would have no room for a cueing radar. This on the other hand was possible on the J-7, but all aspect missile technology didn't become possible with the PLAAF until Israeli knowhow intervention, the development of the JL-7A radar on the J-7D, and the PL-8 missile based on the Python 3.

If it is just a classic gun battle or battle with rear aspect missiles, it is hard to see how a J-7, no matter how easier to fly or maintain, can be better than a J-6 in a furball. The J-6 might probably be faster and sustain its turn rate better, and MiG-19s/J-6s have been known to actually shoot down MiG-21s, -23s, Starfighters and even Phantoms in combat---causing NATO to reevaluate the threat of this so called obsolete type. Let's add that the J-6 versions can have as many as three nasty cannons.

But once all aspect missiles came to the J-7, and it came to it quite late---around 1989-91 perhaps---there was no way for the J-6 to match such.

It is interesting to note why the Q series is based on the J-6, but not a J-7 or even a J-8? For one thing, the J-6 airframe is quite rugged, yet cheap and expendable. While the engines have a short life, like all J-6s, they are also cheap---it is cheaper to replace the engines with brand new ones than to overhaul the old engines---creating history's first 'disposal' jet engine.

crobato

Su-27 vs. the old fighters.

The introduction of the Su-27 is probably much as a shock not just to the pilots who have to fly them but the fighters who have to engage them in wargames.

One of the critical problems of the PLAAF is that, for the lack of a decent fire control radar, it remains to be essentially, a one trick pony dogfight airforce. Pretentions of bombers and attack jets aside, the best it could do was send large gaggles of close range dogfighters into the sky.

Every attempt to replace the J-6 didn't succeed because every successor essentially became nothing more than another dogfighter because of the lack of a decent long range radar.

The Su-27 changed all that. It was essential to the history of the PLAAF because it marked a massive paradigm change.

It would not be hard to imagine how the Su-27 would lock on to targets at BVR ranges, targets like the J-6, J-7 or J-8s that could only engage at close range, or how the Su-27 could dispatch these targets at close range even without its nose pointing at them, thanks to the wide off boresight capabilities of the R-73.

But the essential point of it all---is that it would force all these units with 'inferior' planes to adapt to an enemy with superior technological capability. You cannot train properly without a proper adversary. For the PLAAF, the Su-27s will result in a profound change in tactics, not just in learning how to use a modern jetfighter, but to learn how to fight against one.

I can only imagine that after the 'culture shock" of having been blown out of the sky by an opponent with superior radar and BVR missiles, those with J-7s and J-8s would learn tactics intended to defeat an opponent with better radar. Things like flying low to mask your approach and hide under ground clutter. Or to use "beam" maneuvers to throw off the dopplers.

Those with J-8s are probably with a greater disadvantage against the Su-27s. They are not fast enough to break off, nor agile enough to hang on, yet big enough to be detected early and get locked at, while their radars are not capable of matching an Su-27 in detection range. The J-7s on the other hand, are small jets and Fishbeds have a reputation for a rather low radar signature. Add ground clutter and ECM, you could probably tie down an Su-27.

Once in close range, your best sensor is now your eyeballs. Small fighters like the J-7 are more difficult to fight this way, compared to large fighters like the J-8 and Su-27. Is it possible for a J-7 to nail an Su-27 at close range? Yes. A-4 and F-5 Aggressor squads have nailed big fighters like F-15s and F-14s before. Though it does require an experienced and bold pilot who knows what he is doing.

darth sidious

J-6 surived only because the chinese failed to produce effective radar/missile

if you want to talk about short endurance I can assure you the J-6 has to consider where to land literaly withen minutes after take off with after burner

J-6 is not invincible in dog fight either the view from the cokpit is horrible with the ejection seat placed low

the poor Rd-9 engine wastes more fuel and lacks the power of the 13 the chinese should have given up on such a design long ago

the J-6 scored aginst the americans in vietnam because the bomber formation they were attacking is foreced to fly at mediun altiude at around 300 knots. where the J-6 its at its best as for vistory aginst phantom same story exceft the J-6 can accelerate faster then phantom giving them the ability to escape.

mig-21 will not be flying in such a formation as longer as it retine the speed/altiude advantage( not hard for the mig-21 to do) the J-6 will always be on the losing end

the Q series weere design ed in the late 50s when no J-7/98 knoldge where avilible

crobato

J-7C/D vs. J-7E

For me, one of the most interesting events in the history of the PLAAF is the way they trashed the J-7C/D development after spending more than a decade developing it.

As you know, the project started when China acquired a few MiG-21MF from the Egyptians as part of a barter that also included MiG-23s. The Egyptians got some J-6s in return. The bonanza was the more powerful R-11-300 Tumansky engines.

The J-7C was developed from the third generation airframe the MiG-21MF exemplified. Basically, the history of the Fishbed can be summed into four generations:

1st --- MiG-21F and variants, the original
2nd --- MiG-21PF and variants (-PFM)
3rd --- MiG-21MF and variants
4th --- MiG-21bis

In theory, the J-7C, with the more advanced airframe from the 3rd generation is supposedly better than the J-7A and -B, which is based on the 1st generation. Right? Yet the J-7E which came quickly afterwards, reverted to the first generation airframe, and quickly enough, the J-7C and its "fixed" variant, the J-7D, only had two regiments and faded into obscurity.

In theory, supposedly, the later generation designs are better right? In practice, successful fighter designs tend to evolve with adding requirements. The result from that evolution is a heavier and beefier design, which can do better bombing a target. But the weight gains also made a fighter less agile, faced with increasing wing loads. The ME-109 faced this factor as it evolved from the Friedrichs to the Gustavs and Kurst versions.

As the Fishbed evolved and got beefed up, it also started packing more pork and weight while wing area remained the same. A more powerful engine helps lift the aircraft from the ground and maintain its speed on turns, but it does not make the plane more agile, or helped its low speed handling. A more powerful engine is no substitute for wing loading. The plane would have higher take off and landing speeds. In turns, it would reach a stall point from a higher speed. Overall, not only is the plane less agile, it is a bit more dangerous to fly.

While the rest of the world seemed okay with the 3rd and 4th Fishbed generation, it wasn't okay with the PLAAF pilots. Did the PLAAF make a better choice?

The reason for the 3rd and 4th generation Fishbeds is that one of the rationales for their entire design is based on accomodating a bigger radar. You could probably live with the handling penalties of the type if the advantages of having a better radar would offset this. But my guess is that the problems and capabilities of the J-7C/D radar didn't offset this well enough, combined with the PLAAF pilots have become accustomed to a culture where radar use is ignored and not trusted. Back to the dogfight only culture, they return.

I would probably regard as the first and second generation Fishbeds as the ones best to fly, with the least 'pork' on them. The first generation, after all, is the original vision of the plane. Sometimes, losing that vision may not be good, and it is often good to go return to one's roots.

Thus I think that is why the next variant of the J-7 went back to its roots.

But there was more to that too---a brand new wing design---which marks the first fundamental new addition to the Fishbed design since the -bis.

What makes this new double delta wing design a leap compared to the classic delta wing?

The break in the wing from a sharp inclination to a lesser sweep, would cause the air from leaking spanwise at the front edge of the wing, and force the flow to go over and under the wing, improving lift. Vortices from the break aid in control at higher angles of attack. In addition, the new wing has about 25% more wing area from the classic wing while retaining the light weight of the -F class, though slightly heavier now to endure 8G turns (the Fishbed is generally a 7 to 7.5G fighter). Add to that is an extra wing span and higher wing aspect ratio, all combining to give a better lift at lower speeds. To top everything off, the wing now has a Fishbed first---adjustable variable wing camber at the front edge of the wings, improving the efficiency of lift. The new wings also allow for more fuel to be stored in the wings.

The J-7E then adds the more powerful engine from the J-7D to the lighter J-7B type airframe, a classic hot rod formula akin to using the engine of the MiG-21MF to their original -21F airframe. Toping all that is the radar developed from the J-7D which enables use of the all aspect PL-8.

Though late, in my opinion, the PLAAF finally got the J-7 it wanted with the J-7E. The plane in my opinion, is probably the best dogfighting Fishbed to date, and its surprising performance, even against Su-27s, probably led to the continued production of the type. The type went on to become popular with the PLAAF, though a tight budget squeezed by Su-27 and J-8II purchases, and production capacity diverted to export the airframe as the F-7PG prevented all the PLAAF regiments that wanted it from getting the plane. At best there are probably just over 300 maybe 400 optimistically, of the J-7E and the improved -G type, not much considering all the Flankers and J-8II out there.

The J-7G is basically the PLAAF version of the F-7MG export variant of the J-7E. The main changes is the one piece windshield, MFDs in the cockpit, and a new slotted array KL-6E radar replacing the old Type 226. How many Chengdu will build, one wonders, as the type came in a bit too late given the J-10 and J-11 company it has to live with.

But in my opinion, the J-7E/G makes a great ACM training fighter. It's not something one should like to go to war with, without proper BVR, it is facing an immense disadvantage. But in peacetime, it can be used to train pilots for WVR air combat without the expense of a J-11 or J-10, especially for units without the most advanced plane types, for adversary units, and for pilots who need to increase their flight hours while their main aircraft is at maintenance.

As for the fate of the J-7C/D, it never got past over two regiments, though both are assigned to the "elite" 29th Division guarding the Nanjing area, where they serve as all weather interceptors. I wonder if they are still there, as one of the 29th Division regiments have upgraded to the Su-30MKK.

It seemed though, while they are newer than the quite similar J-8I, their fate in obscurity seemed even worst than the J-8I which at least populated two divisions.

Ironically, CAC has been looking to "BVR" the J-7 with designs like the J-7FS, why didn't it just take a look at the J-7D once again, given that India did quite well using the same airframe design on the Bison. Give it a decent radar and PL-12 capability. But I guess the proper time for such ideas have long passed.

crobato

Same thing happens on the J-7 too.

Not much different from the J-7 or MiG-21MF either, and those planes have a spine that affects their back view. Actually the J-10 even has a low ejection seat relative to the Lavi or F-16.

But there were two of them for combined thrust. They were also easier to manufacture and replace than the WP-7. WP-31FII might have 66Kn; each WP-6A has a thrust of 39Kn.

I can't really see the speed and altitude advantage of the MiG-21.

It's actually designed in the sixties, not withstanding conceptual designs which I don't consider real serious work. By the seventies to the eighties, China has all the time to consider other Q platform alternatives, such as using the J-7 or J-8 platforms.

darth sidious

work on the Q-5 begin in 1958 by 1962 the work is mostly finished the production is only delayed becaused of political struggle / stortage of supply
chinese programe to copy the Mig-21 did not work until the mid 60s due to difficulty with the ejection system and r-13 engine.

Plan also dident mass produce the PL-2 until the late 70s

the J-7 has a higher operational ceiling/speed rate Plus good agility this ensure they are atlest equal in dog fight saved for lower altitudes ( problem with r-13 engine)

crobato

Most combat takes place well under transonic speed. Thus having Mach 2 is of no advantage for the J-7, which does not have the fuel to reach it either. Unless you are in bomber interception, low altitudes is where many commonly engage in visual air combat because long range radar does not work well at low altitudes, making detection more difficult.

As for the missiles, the MiG-21F type always had a cannon, unlike the -PF type. So it could always fight at gun range. Besides missiles suck in the sixties in general so it does not matter much if you have a missile or not.

KYli

I agreed that J7/J8 may not have clearly advantages over J6, but I still think J7 is better than J6 in many aspects.

The mass production of J6 are more to do with the situations in 60. China needed quantity to fight with quality, and the gad between China and the western were not as much as when J7 were introducted. When J7 were ready to produce, the gad had widen. So it did not made sense for J7 to produce in mass quantity, since J7 did not had much improvement than J6.
But that did not mean J7 were not better than J6.

1. J7 may not acheive full March 2 in the interceptor, but J7 still have speed advantage over J6. When J7 is in the defensive role, J7 will do much better than J6.
2. J7 had better design platform, since they already acknowlege the need of radar and missles. The only problem is they never develop a good radar and missles until eighty, but it really had to do with political situation.
3. J6 had only little modification left, you really could not install any modern radar or missles. So sooner or later J6 will dead out, the only reason J6 continued to produce is early J7 suck.

If China did not had Cultural Revolution, I would whether think J7 modification will move 7/8 years ahead. So J7 will replace all the production of J6.