J-20... The New Generation Fighter II

delft said:

But your acrobatic maneuvers are still limited by two factors:
* the ability of the pilot to remain functioning. He or she is well supported, but there are still limits

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In aerial combat, its all about maneuvers to get to the kill zone / tail of your enemy.
There are limits ofcourse, the extents that a pilot can withstand the G-force when doing acrobatic maneuvers, and like I mentioned in the last post, in the future, if there is no long range fighter size anti-stealth radar deployable, close air-to-air combat is the logical conclusion and should be expected.

So, the pilots would be expected to be trained even harder to withstand the G-force for these types of combat. Either that or a new type of G-suit that would allow the pilot to withstand more Gs than the current one.

* the speed loss of the aircraft during the maneuver. If your aircraft loses too much speed your still lost.

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That's assuming the enemy is already on your tail and you are already being targeted from a long range (not able to maneuver out of enemy radar's cone of detection). At close range air combat the radar cone would have much narrower field of view thus it would be much harder to target when a highly acrobatic foe would be easier to maneuver out of that cone.

Also, with thrust vectoring, the engines are still providing the thrust, while the thrust are directed - the speed loss will be much lower than using the canards because canards rely on air resistance / air bleed to achieve the effect of turning.

Using thrust vectoring aggressively means turning your aircraft over a large angle to the airflow, thus incurring a massive increase in drag. Unless used moderately, and in combination with conventional flight controls, your thrust vectoring will loose you a lot of airspeed, which means a loss of maneuverability.

Really want to ask everyone's opinion, do you guys really think that China would have more than one 4th generation fighter designs, similarly to the ATF program that resulted in the F-22？

I personally think that China currently doesn't have the resources or the capability to do this. Chengdu is the only bureau so far that has completely designed a brand new plane from a blank paper, whereas Shenyang, despite of its experience in manufacturing heavy fighters, is still inexperienced in designing a plane from scratch. On top of that, China's supplying networks of sub-system is not as developed as the American counterpart. If China proceeds with the multiple design plan, then all the different designs would end up using all the same things, with the only difference being body design, which becomes pointless. On the other hand, China's Aero industry doesn't have the capability as the Americans. The J-20 project probably already drains the whole system's attention, whereas the American industry can do the ATF competition and design several other completely different and brand new planes at the same time. So I guess China doesn't doesn't have the ability to develop more than one design at once.

pugachev_diver said:

Really want to ask everyone's opinion, do you guys really think that China would have more than one 4th generation fighter designs, similarly to the ATF program that resulted in the F-22？

I personally think that China currently doesn't have the resources or the capability to do this. Chengdu is the only bureau so far that has completely designed a brand new plane from a blank paper, whereas Shenyang, despite of its experience in manufacturing heavy fighters, is still inexperienced in designing a plane from scratch. On top of that, China's supplying networks of sub-system is not as developed as the American counterpart. If China proceeds with the multiple design plan, then all the different designs would end up using all the same things, with the only difference being body design, which becomes pointless. On the other hand, China's Aero industry doesn't have the capability as the Americans. The J-20 project probably already drains the whole system's attention, whereas the American industry can do the ATF competition and design several other completely different and brand new planes at the same time. So I guess China doesn't doesn't have the ability to develop more than one design at once.

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Although I am no fan of SAC work ethics I don't think we can overestimate them. First of all they have designed the J-8 (a mediocre plane, but still an original design) in the past and more importantly they've accumulated significant amount of experience with the J-11s.

pugachev_diver said:

Really want to ask everyone's opinion, do you guys really think that China would have more than one 4th generation fighter designs, similarly to the ATF program that resulted in the F-22？

I personally think that China currently doesn't have the resources or the capability to do this. Chengdu is the only bureau so far that has completely designed a brand new plane from a blank paper, whereas Shenyang, despite of its experience in manufacturing heavy fighters, is still inexperienced in designing a plane from scratch. On top of that, China's supplying networks of sub-system is not as developed as the American counterpart. If China proceeds with the multiple design plan, then all the different designs would end up using all the same things, with the only difference being body design, which becomes pointless. On the other hand, China's Aero industry doesn't have the capability as the Americans. The J-20 project probably already drains the whole system's attention, whereas the American industry can do the ATF competition and design several other completely different and brand new planes at the same time. So I guess China doesn't doesn't have the ability to develop more than one design at once.

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Well, what do you mean by having more than one 4th generation design? Do you mean the YF-22 vs YF-23 idea? The reason China probably didn't have CAC and SAC put forward real proposals was the money and time required.
Or... do you mean J-20/J-XX/current twin engined heavy F-22 class stealth fighter, and additional F-35 type situation?
The J-20 is flying now, and I'd bet CAC and SAC are probably already putting advanced studies into an F-35 class fighter, if not looking at early 5th/6th generation.
I think the chinese aerospace industry has the capability to, but not the requirements, to have more than one 4th gen fighter program running at the same time. With the J-20 I think we can all say that Chengdu has a relatively good grasp of VLO principles -- but is this knowledge only relegated to CAC? What about SAC and XAC? I imagine all the big players in AVIC would've done their own research and have some proficiency in the technologies of a 4th generation fighter, so just because J-20 is using part of CAC and a tiny bit of SAC doesn't mean the other companies can't field their own designs if the PLAAF wanted it.

I think you're also overrating how experience in designing "new" planes can give... So long as you've had experience in manufacturing aircraft for a long time and you've invested into R and D I see no reason why designing a new plane from the ground up should be an issue. There's also no need to build a new fighter if... there isn't a need.

The main issues facing the aerospace industry imo isn't the technical side, but rather the management/political and economic side. And the engine issue, which we can put into a class of its own.

I'm not sure if we'll be seeing a real 4th generation fighter from China anytime soon -- they could be going for a J-20 high + J-10/J-11 low for their medium to long term force composition, or a J-20 high + F-35 class medium + J-10/J-11 low. If it's the latter then we might start hearing about such a plane in a few years, before a first flight around, and probably slightly before 2020. It would probably come from CAC, considerign how incompetent SAC seems to be right now.

pugachev_diver said:

Really want to ask everyone's opinion, do you guys really think that China would have more than one 4th generation fighter designs, similarly to the ATF program that resulted in the F-22？

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I'd be shocked if they didn't have other planes under works. Keep in mind that work on the J-20 must have proceeded in parallel with work on the J-10 and J-11. They certainly have budget limitations and priorities that prevent them from going into production with more than one design. There are thousands of people who are designing military aircraft full-time. They're working on something.

I personally think that China currently doesn't have the resources or the capability to do this.

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They certainly have the basic technical expertise. What they may be lacking are people who have gone through the process a few times and can manage a huge undertaking like designing a new fighter. But they only way to create that experience is to do it. If there are delays and failures along the way, that's part of the cost of building R&D capability.

pugachev_diver said:

Really want to ask everyone's opinion, do you guys really think that China would have more than one 4th generation fighter designs, similarly to the ATF program that resulted in the F-22？

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If you talk about capability, the problem is on the material science and engines, not so much on coming out with a design. China isn't lacking in design capability, and the stealth solution is a known math equation drawn up by the Russian decades ago, all you need is to throw in the operation requirements and with good CAD you can make one; neither does the Chinese have problem with fly-by-wire and software section.

But it always the problem with composite and engine, both of which the outside knows very little of its recent progress if there's any. Since you need all these work together so I have it splitted up as such. And most importantly, to make a complete design you need to integrate all those things into one package, what's the lacking will have to be compensate by other design details.

Now let's see about manpower...within the AVIC you've the SAC and CAC make fighters for most of their existence, and with SAC busy with the R&D of J-15, that leaves CAC have the capability to put the best efforts into Project 718. For what it's worth, the initial selection must have been through years ago and SAC lost its bid for some reason, whether theirs look like reworked Su-27 (logical assumption, they've a whole generation of design team drenched in Su-27 designs) or not as suitable as the CAC candidate, that'd be something only to be known at least a decade later, when Project 718 finally enter service as J-20...or if they ahead of schedule, we might see them reveal at 2019 National Day Parade fly-by.

pugachev_diver said:

Really want to ask everyone's opinion, do you guys really think that China would have more than one 4th generation fighter designs, similarly to the ATF program that resulted in the F-22？

I personally think that China currently doesn't have the resources or the capability to do this. Chengdu is the only bureau so far that has completely designed a brand new plane from a blank paper, whereas Shenyang, despite of its experience in manufacturing heavy fighters, is still inexperienced in designing a plane from scratch. On top of that, China's supplying networks of sub-system is not as developed as the American counterpart. If China proceeds with the multiple design plan, then all the different designs would end up using all the same things, with the only difference being body design, which becomes pointless. On the other hand, China's Aero industry doesn't have the capability as the Americans. The J-20 project probably already drains the whole system's attention, whereas the American industry can do the ATF competition and design several other completely different and brand new planes at the same time. So I guess China doesn't doesn't have the ability to develop more than one design at once.

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I agree with you.

I am still skeptical of the whole J-20. I still think the CAC (or AVIC as whole) is still fairly immature in the whole aviation development game. The latest Comac ARJ21 and Comac C919 for example, still largely use western avionics, engine, flight control system, etc etc. The only thing that's made and designed in China of these supposedly "indigenous designed" aircrafts are the airframes.

I think from developmental point of view, its hard to believe how China can suddenly leap forward from just 3rd/4th generation fighter aircraft design to 5th generation. It takes time to digest the lessons learned from each generation, with many variations before the designers are comfortable enough to experiment and start from scratch for the next generation. China just introduced J-10 not so long ago, and Shenyang is still digesting the lessons in making J-11B (from the look of it, engines is still the main problem - and we don't know the avionics and all the electronic sub-systems).

J-20 could very well be just an experiment in airframe design. Since airframe is the easiest part of the aircraft development - sort of like car's bodywork - low entry requirement - look at street racers modifying cars at home - it usually starts with the bodywork, then it gets more technical - modifying the engine, and the very technical and experienced will eventually construct their own engine.

Like I said before, it seems in current time frame China starting to be able to do very advanced airframe designs - which parallels its civilian aircraft developments. It still needs substantial help in sub-systems and engines in both civilian and military sectors. An example is the recent news just few days ago that AVIC is still seeking partners from western business jet manufacturers for co-development of its industry.

Chinese Fighter Group Seeks Bizjet Partners


If China is capable of doing everything itself, why would AVIC be asking for partnership? China is certainly not short of cash right now (in fact it is flush with it - look at the recent aggressive buying spree of western aviation companies - eg. Future Advanced Composite Components (FACC) and Cirrus Industries....etc), so we can rule out finance is certainly not the reason for the desire of a partnership.

delft said:

Using thrust vectoring aggressively means turning your aircraft over a large angle to the airflow, thus incurring a massive increase in drag. Unless used moderately, and in combination with conventional flight controls, your thrust vectoring will loose you a lot of airspeed, which means a loss of maneuverability.

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No, you don't use TVC like that. If you turn so aggressively to incur such massive increase in drag, it is almost certain you will snap the pilot's neck or pilot will lost conciousness. TVC is almost always use in conjuction with conventional flight control surfaces. The flight control surfaces makes up 50% of the maneuverability, and the TVC enhance it and takes up the other 50%. It is sort of like 2WD (two-wheel drive) vs 4WD (Four-wheel drive).

Asymptote said:

Ofcourse it is useful. Thrust vectoring improves turn rate on ALL directions - something very desirable in the super agility criteria in the 5th generation fighter.

Pitch

Roll

Remember, that J-20's canards only improve the pitch and roll part (see the picture above) - they don't offer any improvement with yaw. J-20 completely relies on its all-moving tailfins (vertical stablizers) to do the yaw. With thrust vectoring, it will hugely improve combat turn rate along the yaw axis (see below).

Yaw

The "super maneuverability/agility" criteria stems from the hypothesis that, if no fighter size long range "anti-stealth" radar is operational in near future, and as stealth technologies improve - it means stealth fighters of opposing sides would fly into each other "blind" until visual range - and thus the need for close range dog fighting capabilities for 5th generation aircrafts.

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Try watching some video of those acrobatic maneuvers and you'll understand what I meant. It's nothing like a sustained turn or an instantaneous turn which you normally see fighters perform. Right after the acrobatic maneuvers, the pilot will have to immediately recover his aircraft from stalling or possible stalling, and regain flying speed before the aircraft gets to the point of no return and falls to the ground. In the meantime of doing so, the aircraft is virtual sitting duck.