J-20 goes operational again

Military aircraft - Post cold war aircraft, including for example B-2, Gripen, F-18E/F Super Hornet, Rafale, and Typhoon.
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hornetfinn

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Unread post26 Jan 2022, 10:40

Corsair1963 wrote:
milosh wrote:Compare and you will see no problem there. WS10 is upgraded AL31 something like Saturn 117. 117 have +140kN thrust and at least 4000h service life I saw they mentioned upgraded variant which would have 6000h of service life. That is 4 to 6 times more then old AL31.

For F100 I don't have data but I doubt it is different.

This is what you guys miss, Russians in past didn't make long lasting engines not because they didn't know how but becuase of ww3 prep. Whole idea was to make not long lasting fighter or tank because in case of world war it would have very short life.

I mean USSR if wanted could make most of engine from titanium and they could use crazy steel alloys for high temps.

Chinese are somewhat behind but not that much. For example they did copied soviet close cycle rocket engine which use those steel alloys so they are quite good in metallurgy.

Biggest problem for chinese jet engines were monocrystal blade which look like they finally are able to mass producted. After that hurdle solved things will be lot easier.



Russia could have made longer-lasting fighter engines. Yet, they would have made much less power. That in turn would have made them less competitive with their Western Counterparts.

In short "technology-wise" they were behind the US (and Europe) back then and even more so today.


Exactly. They were basically about a generation behind in engine technology and had to compensate. For example RD-33 and AL-31 were their first afterburning turbofan engines by the time when USA and Europe (well, UK) had second generation engines like PW F100 and RR RB199 already in service.
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milosh

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Unread post26 Jan 2022, 12:10

Corsair, you clearly didn't get what I wrote. I reply on jessmo statement about ws10 being lot worse then f100.

Not true at all if we look 117s engine and i doubt ws10a is noticeable worse then 117s.

117s is +140kN engine with service life of at least 4000h. So it is more like latest f110( ge-132) then 1980s f100.
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tphuang

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Unread post26 Jan 2022, 15:32

In terms of wet thrust, WS-10C is about the same level as 117S and at 90% of the original F-119 (could be more or less than that, the real numbers are classified on both sides). It's underpowered compared to F-22s. Depending on what WS-10C's dry thrust is, it may or may not be able to super cruise. However, it's still going to have better T/W ratio than F-35. And that is good enough for PLAAF for now. That's also why you won't see single engined Chinese fighter jet. If you are 25 years behind US in engine technology, then you have to make up for that with lower service life, fuel burn and building your air frame around larger (or more) engines.

It's a bad idea to dismiss what China has now with turbofan engine. CAC took 17 years from getting picked for the J-10 project to achieving IOC. It only took 8 years to do that with J-20. It took them 10 years to go from putting WS-10 on a J-11 testbed to using it in production J-11Bs. It probably will only take them 5 years to do the same with WS-15 on J-20. The first project is to build your domestic industry and is generally underfunded. With experienced engineers and more funding, the following projects will take a lot less time. That's why you see the Russians having so much difficulty developing Su-57/IZD-30. Chronic under funding and losing engineers take a real toll on your industrial base that's hard to recover from.

I think China originally wanted to develop a stealthy version of J-10 (like silent Eagle type). But once they actually put J-20 into DACT, they realized that a VLO aircraft (even if just from front) is just so much better than one that's not. Even 4th generation aircraft with reduced signature are probably sitting ducks against F-35s. WS-10C is not perfect, but adequate for now. With their recent moves, I see them moving on from J-10 production pretty quickly. Maybe 2 or 3 more years of production for PLAAF. They might produce J-15/16s for a couple of more years due to need for more multi-role and naval aircraft, but that will finish up well before 2030.

China will not allow SAC fall by the away side with just naval aircraft orders. If they are already doing all the work to bring a naval J-35 into production, it won't take much additional work to have a land based version. When FC-31 originally came out, it was just a conceptual aircraft. PLAAF didn't have enough resources to fully fund 2 5th generation project as well as all the other projects they have going on. Things have changed a lot since. Both PLAAF and PLAN budgets are a lot higher. The supply chain and final assembly for J-35 would already be set up. Not a lot of incremental cost to develop a land based version. The overall unit costs of J-35 will also come down with orders from Air Force and navy. That will come down even more with export orders. Even aside from industrial reasons, It would be not surprise me if J-35 turn out to have better all around stealth than J-20.
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allesmorobranna

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Unread post26 Jan 2022, 16:12

milosh wrote:
jessmo112 wrote:How are you going to make an adaptive engine, when they haven't even made a good 4th gen engine yet?
Compare F-100 thrust and service life to Chinese.
At this rate 2050 is more likely


Compare and you will see no problem there. WS10 is upgraded AL31 something like Saturn 117. 117 have +140kN thrust and at least 4000h service life I saw they mentioned upgraded variant which would have 6000h of service life. That is 4 to 6 times more then old AL31.

For F100 I don't have data but I doubt it is different.

This is what you guys miss, Russians in past didn't make long lasting engines not because they didn't know how but becuase of ww3 prep. Whole idea was to make not long lasting fighter or tank because in case of world war it would have very short life.

I mean USSR if wanted could make most of engine from titanium and they could use crazy steel alloys for high temps.

Chinese are somewhat behind but not that much. For example they did copied soviet close cycle rocket engine which use those steel alloys so they are quite good in metallurgy.

Biggest problem for chinese jet engines were monocrystal blade which look like they finally are able to mass producted. After that hurdle solved things will be lot easier.

The WS-10 family is not an upgraded AL-31. It is nothing to do with the russian AL-31F. The WS-10 core section (the gas generator) is actually came from the General Electric CFM56/F101GE102 engines before the Tienanmen square story. It is more american than any other chinese engine. The other sections, such as the low pressure compressor, the afterburner, the afterburner chamber and even the nozzle is competly different, than anything from the AL-31F. Just check and compare. Even the number of the stages, the diameter, the combustion chamber design, the type of the nozzle (ejector instead of the Laval one) is different.
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jessmo112

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Unread post26 Jan 2022, 16:55

tphuang wrote:In terms of wet thrust, WS-10C is about the same level as 117S and at 90% of the original F-119 (could be more or less than that, the real numbers are classified on both sides). It's underpowered compared to F-22s. Depending on what WS-10C's dry thrust is, it may or may not be able to super cruise. However, it's still going to have better T/W ratio than F-35. And that is good enough for PLAAF for now. That's also why you won't see single engined Chinese fighter jet. If you are 25 years behind US in engine technology, then you have to make up for that with lower service life, fuel burn and building your air frame around larger (or more) engines.

It's a bad idea to dismiss what China has now with turbofan engine. CAC took 17 years from getting picked for the J-10 project to achieving IOC. It only took 8 years to do that with J-20. It took them 10 years to go from putting WS-10 on a J-11 testbed to using it in production J-11Bs. It probably will only take them 5 years to do the same with WS-15 on J-20. The first project is to build your domestic industry and is generally underfunded. With experienced engineers and more funding, the following projects will take a lot less time. That's why you see the Russians having so much difficulty developing Su-57/IZD-30. Chronic under funding and losing engineers take a real toll on your industrial base that's hard to recover from.

I think China originally wanted to develop a stealthy version of J-10 (like silent Eagle type). But once they actually put J-20 into DACT, they realized that a VLO aircraft (even if just from front) is just so much better than one that's not. Even 4th generation aircraft with reduced signature are probably sitting ducks against F-35s. WS-10C is not perfect, but adequate for now. With their recent moves, I see them moving on from J-10 production pretty quickly. Maybe 2 or 3 more years of production for PLAAF. They might produce J-15/16s for a couple of more years due to need for more multi-role and naval aircraft, but that will finish up well before 2030.

China will not allow SAC fall by the away side with just naval aircraft orders. If they are already doing all the work to bring a naval J-35 into production, it won't take much additional work to have a land based version. When FC-31 originally came out, it was just a conceptual aircraft. PLAAF didn't have enough resources to fully fund 2 5th generation project as well as all the other projects they have going on. Things have changed a lot since. Both PLAAF and PLAN budgets are a lot higher. The supply chain and final assembly for J-35 would already be set up. Not a lot of incremental cost to develop a land based version. The overall unit costs of J-35 will also come down with orders from Air Force and navy. That will come down even more with export orders. Even aside from industrial reasons, It would be not surprise me if J-35 turn out to have better all around stealth than J-20.


We must agree to disagree. You see incremental engine improvements. I see the same generation of engine development for the last 20 years. I doubt your claims about the F-119, but even if the engine got within 90% of the F-119, the engine is 20+ years old. I think you underestimate the F-135, it's a beast of an engine.
There is a reason why Non of the current Chinese aircraft can supercruise. There is a reason why we haven't seen a F-35B/Harrier clone. There is an obvious lack of confidence in the designs they are using. Raw dry thrust is only part of the problem you need reliability.

The Americans have supercruise.
The Euro-canards can supercruise
Even the Su-35 has a modest supercruise

The Chinese are not even close.
I don't hate China, it's just time to face facts.
The engine program is stalled.
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tphuang

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Unread post26 Jan 2022, 19:30

jessmo112 wrote:[

We must agree to disagree. You see incremental engine improvements. I see the same generation of engine development for the last 20 years. I doubt your claims about the F-119, but even if the engine got within 90% of the F-119, the engine is 20+ years old. I think you underestimate the F-135, it's a beast of an engine.
There is a reason why Non of the current Chinese aircraft can supercruise. There is a reason why we haven't seen a F-35B/Harrier clone. There is an obvious lack of confidence in the designs they are using. Raw dry thrust is only part of the problem you need reliability.

The Americans have supercruise.
The Euro-canards can supercruise
Even the Su-35 has a modest supercruise

The Chinese are not even close.
I don't hate China, it's just time to face facts.
The engine program is stalled.


Sorry, I'm not sure if I was entirely clear earlier. I'm not saying that WS-10C is at 90% the technology of F-119, but rather its thrust with afterburner is about 90% based on publicly available numbers.
According to Pratt https://prattwhitney.com/products-and-s ... gines/f119, F-119 has 35k lb of thrust, which works out to be about 156kN
According to Janes https://www.janes.com/defence-news/news ... ic-engines, WS-10C delivers about 142 kN of thrust. That matches my previous source of 14.5 ton. So, WS-10A is at about 91% of F-119 thrust.

The actual ratio might be lower since F-119's actual thrust is classified. The ratio is probably lower for dry thrust. Aside from that, I'm sure j-20 also has much lower expectations for WS-10's reliability, MTBO and fuel burn compared to F-119. But these are the things that Russia had to sacrifice when it was developing AL-31 and now China has to sacrifice for WS-10 in order to have sufficient thrust. Of course, the difference vs F-135 is even larger. That's exactly why you will not see China with a single engine 5th generation aircraft.

Having said all of that, things in the past 2 years are actually pretty good vs a decade before that when WS-10 first entered service with J-11B. Engine failures were common and often had to be serviced within the first 100 hours. Nowadays, WS-10s are probably more reliable than the AL-31s they are replacing. Thrust has been increased by 16% (from 122kN to 142kN) and is now as good as the latest AL31 variant 117S. The fuel burn is better. China deems that the current thrust and fuel burn of WS-10C to be sufficient for J-20. It's T/W ratio is better than J-10 and flankers. More importantly, they are able to produce a lot of them. There as no way they can mass produce J-20s while relying on Russian factories to build AL-31s. Domestic industrial base and supply chain is very important. Even if WS-15 isn't ready in a couple of years, they could have additional PIP on WS-10 to improve its performance. You can't do that if you rely on import.
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milosh

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Unread post26 Jan 2022, 23:34

jessmo112 wrote:The Chinese are not even close.
I don't hate China, it's just time to face facts.
The engine program is stalled.


Stalled? Really?

In 2000s they could only build copy of RR Spey in 2000s which is British 1960s turbofan (used in their F4 Phantom).

In late 2010s they already make something like F110 GE132, and in 2020s we can expect WS15 which is their equivalent of F119/F135 (F135 is based on F119). So as you can see they have huge jumps in engine tech development and don't be surprise why they are talking about adaptive engine for next gen fighter on which they already work.

This is what you get when you educated huge number of young engineers each year, and you also have huge resources for research and also massive industrial capacity.

It is like you combine USSR institutes and US cold war economy and industry.
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Unread post27 Jan 2022, 01:19

milosh wrote:
jessmo112 wrote:The Chinese are not even close.
I don't hate China, it's just time to face facts.
The engine program is stalled.


Stalled? Really?

In 2000s they could only build copy of RR Spey in 2000s which is British 1960s turbofan (used in their F4 Phantom).

In late 2010s they already make something like F110 GE132, and in 2020s we can expect WS15 which is their equivalent of F119/F135 (F135 is based on F119). So as you can see they have huge jumps in engine tech development and don't be surprise why they are talking about adaptive engine for next gen fighter on which they already work.

This is what you get when you educated huge number of young engineers each year, and you also have huge resources for research and also massive industrial capacity.

It is like you combine USSR institutes and US cold war economy and industry.


And for all of that what do we get?
An engine that's below early F-119 levels of performance even In Reheat.
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Unread post27 Jan 2022, 04:23

Many ways to look at China. Snapshot view is one.

Trend analysis is what Milosh is driving at. Pre-2000s, basically just producing licensed turbojets. Then licensed turbofans in 2000s, then high bypass turbofans to local production of such engines today.

Engine to engine, sure China is behind. However China is playing the 2 engine to 1 engine game, not 1-1. That's the snapshot view of Chinese fighter new builds vs US fighter new builds (exc F-15EX). TW wise, what gap?

Trendwise, US can go to 2 vs 2 and retain superiority. Or US competes on cost with NGAD being single engined. Regardless, it has to move to NGAD. That much is clear.
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Unread post27 Jan 2022, 19:23

Incredible really when it comes to fighter engines, the Chinese are so far behind. I wonder what it is? I mean, I know its engineering but I wonder about the specifics of what they're struggling with. In almost every other arena, the $ and resources/human capital they throw at things has allowed them to either reach parity, exceed some of our capabilities or at least close the gap - fast.

Yet in this one area, it's difficult to establish whether they're closing the gap at all - or at least in any meaningful way. It's very telling how they've stayed away from single engine fighters. At least the very high end ones. The Russians have only just recently even tried to crack that nut with Checkmate, but let's face it - that's still a paper airplane. The last real successful single engine fighter they made was... the Mig-23? Everything since has had a dual engine layout, as no single engine has been "enough" to create a competitive single engine design.

Quite surprising really, after the success of the Mig-21/23. Sure, their engines didn't last long. Yet I think had they kept working at it they might have gotten there by now. As it stands, everything rests on the success (or not) of the Idelyze (or whatever) 30. If they accomplish what they want there, it opens up a world of possibilities.

If it doesn't, they are most certainly doomed to flying rusty Fulcrums and Flankers... until they fall out of the sky.
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Unread post27 Jan 2022, 21:52

Late MiG-23 turbojet engine (R-35 or R-36) wasn't at all bad in fact they had quite decent service life noticeable longer then soviet turbofans.

And thrust was superb, over 130kN, and in some scenarios it could push 160kN :shock: at low altitude for one minute.

Shame they didn't test Su-27 prototype with that engine, but with AL-21 turbojet, Sukhoi cooperated with Luyka while MiG cooperated with Tumansky.

If they put R-35-300 in Su-27 it would be lot more logical, I mean 3000km range was consider waste even in USSR.
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Unread post28 Jan 2022, 16:36

milosh wrote:Late MiG-23 turbojet engine (R-35 or R-36) wasn't at all bad in fact they had quite decent service life noticeable longer then soviet turbofans.

And thrust was superb, over 130kN, and in some scenarios it could push 160kN :shock: at low altitude for one minute.

Shame they didn't test Su-27 prototype with that engine, but with AL-21 turbojet, Sukhoi cooperated with Luyka while MiG cooperated with Tumansky.

If they put R-35-300 in Su-27 it would be lot more logical, I mean 3000km range was consider waste even in USSR.


Yes good point Milosh..

That engine always impressed me, although I think it got overshadowed by the Mig-25's monster Tumansky R-15's. It (the R-35/36) was crazy powerful, especially for its size. It's said that captured Mig-23's could easily "walk away" from the F-14A in a drag race. I wonder how much of that was due to the engine and how much was due to the fully swept variable geometry wing?
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sferrin

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Unread post29 Jan 2022, 23:24

mixelflick wrote:It's said that captured Mig-23's could easily "walk away" from the F-14A in a drag race. I wonder how much of that was due to the engine and how much was due to the fully swept variable geometry wing?


It was said by an F-14 pilot. (Watched the video yesterday.) And it was a TF-30 powered F-14A. Not exactly a hot rod. His recounting of his experience with the Mig-23 did make me wonder if it could have had a realistic chance of beating the Red Baron Starfighter's low-altitude speed record. (988 mph.)

Re the Mig-25's engines, I always thought it strange that it could only produce 22,500lbs of thrust yet had those huge nozzles. I suspect it was getting a huge bump from the ram effect when at speed. By comparison, the Mach 3 XF-108's J93 produced about 30,000lbs thrust and had a relatively small nozzle.
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milosh

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Unread post30 Jan 2022, 15:43

mixelflick wrote:[
Yes good point Milosh..

That engine always impressed me, although I think it got overshadowed by the Mig-25's monster Tumansky R-15's. It (the R-35/36) was crazy powerful, especially for its size. It's said that captured Mig-23's could easily "walk away" from the F-14A in a drag race. I wonder how much of that was due to the engine and how much was due to the fully swept variable geometry wing?


F-14A fly against MiG-23 with R29 not R35, R29 max thrust is ~113kN, R35 is ~130kN. What is more strange is R35 service life wasn't bad at all especially when compared to R29 and even AL-31, it have probable twice longer service life of R29 and 1.5time of AL-31.

So it wasn't classic soviet catch, reduce service life of engine to get as much as possible thrust.

@sferrin

Right, ramjet afterbuner.

Advanced variable afterburner is used in R15 similar in concept as J58 one but different design, for example here is graph which showed that well:
http://www.leteckemotory.cz/motory/r-15 ... r_fors.gif

So at H=11km and speed Mach 2.2 its max thrust is 17tons or 173kN, which is lot higher then 100kN which you see when look wiki or other sites, that is max thrust at test bench.
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Unread post30 Jan 2022, 15:46

milosh wrote:Late MiG-23 turbojet engine (R-35 or R-36) wasn't at all bad in fact they had quite decent service life noticeable longer then soviet turbofans.

And thrust was superb, over 130kN, and in some scenarios it could push 160kN :shock: at low altitude for one minute.

Shame they didn't test Su-27 prototype with that engine, but with AL-21 turbojet, Sukhoi cooperated with Luyka while MiG cooperated with Tumansky.

If they put R-35-300 in Su-27 it would be lot more logical, I mean 3000km range was consider waste even in USSR.


There was only R-35-300 fighter engine.
The R-36-35FVR was the lift engine for the Yak-38 VTOL aircraft. The R-36-51A was the main engine of the Tu-144D SST.

The R-35-300 maximum dynamic thrust was 160-180kN, but it has no time limitation, like the R-25-300 (MiG-21bis) "ChR" regime had. It was just the thrust maximum, which came from the max inlet pressure ratio and max airflow.

The R-15-300 was designed for the Mach 1.5 - 2.8 operation, that's why it had a first and the secondary afterburner. The only five stages compressor had an extremely moderate pressure ratio, which caused the very low efficiency below supersonic. However, due to the dynamic pressure ratio above Mach 1.5, the entire system generated a much more effective thrust, this is the reason, why the R-15-300 had much less specific fuel consumption above Mach 1.5/11000 meters, than at low speed low level operation.
The R-35-300 was unable to support the MiG-25 at high speed.

Please compare the diagrams and the specs:
http://www.leteckemotory.cz/motory/r-35/
http://www.leteckemotory.cz/motory/r-15/

The AL-21F-3A had similar mounting dimensions, as the AL-31F had, so it was obvious to use as a temporary engine in the early months of the Su-27 program. The AL-21F-3A had the quite similar configuration, as the GE J79 had, but it was slightly bigger and way more powerful. The R-35-300 was not fit into the Su-27 prototype rear fuselage, not just because the size, but because of te nozzle system either. The R-35-300 had a ejector nozzle, where the outer nozzle was attached to the fuselage, while the inner nozzle was the engine's own. The AL-21F-3A had a Laval nozzle, like the AL-31F has, so it was easy to fit into the T-10 engine bay.
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