What's new

Chengdu J-20 5th Generation Aircraft News & Discussions

"You can swap to WS-15 if it was on purpose designed with the same spacial dimensions as the one that it would be replacing. There is no logical reason the WS-15 cannot be externally an exact replica of either the AL-3L or WS-10X engine."

Name an instance, in the world history of modern aircraft development, that was successfully done, as you just have said, that an new engine and new aircraft was "as on purpose designed, with the same spacial dimensions", to replace "externally an exact replica" of an older, much less powerful engine.

Otherwise, the Mod. will level, the charge of, groundless speculation, at you.

Even, that's possible and desirable, it still won't explain, why a 130kN-140kn engine, like WS-10b or AL-31FN could lift, a plane weighting +20 tons plus fuel, in a sustained vertical climb, without the use of AB, in front of thousands of international spectators.

I got a feeling, that this crucial point, still don't mean anything to you, and to many other readers.
Mr. @Asok , it's so true that NOT every one who reads this thread does really understand the aircraft engine power (Dry Thrust etc). You may ask, how many do understand the calculation between the required "engine power" and the "total weight of the aircraft"? You may wish to create a quiz poll with multiple choice answer: A, B, C, D, E... see if many know the right answer. :D I see PDF has the polling facility, we usually apply it at sports forums.

I guess just a few do really know the "engine things". Inevitably you may see strange questions or remarks.
 
"You can swap to WS-15 if it was on purpose designed with the same spacial dimensions as the one that it would be replacing. There is no logical reason the WS-15 cannot be externally an exact replica of either the AL-3L or WS-10X engine."

Name an instance, in the world history of modern aircraft development, that was successfully done, as you just have said, that an new engine and new aircraft was "as on purpose designed, with the same spacial dimensions", to replace "externally an exact replica" of an older, much less powerful engine.

Otherwise, the Mod. will level, the charge of, groundless speculation, at you.

....


It does not have to have be "externally an exact replica". and it also does not require a complete redesign.

An aircraft engine is like a tailored suit for a man. The engine is custom built for the airframe and vice versa.

Similarly, since the WS-15 is likely to be larger, heavier and needs more airflow to operate than the AL-31, the aircraft would need to have its intakes fundamentally redesigned. Internal bulkheads would need to be redesigned in the airframe midsection to accommodate the increased diameter of the larger engine. The airframe may need to be lengthened. Other components in the engine bay like actuators, fuel control, harnesses, tubing, gearbox, FADEC would need to be redesigned. Total weight of the aircraft would increase. Theses would not be cheap modifications. The entire aircraft would need to be retested and re-certified. Therefore, any theoretical upgrade from AL-31 to WS-15 would not be a simple "plug & play" either. Ideally, you either design an aircraft for AL-31 or WS-15. You don't do both. If you do both, you would almost be building a new aircraft.

....


The Russians make the same with the current 117 engine, which will be replaced by the izd. 30. Similar the F-14 flew with TF-30 and later F110´, similar the later F-15/-16 blocks were able to handle both the F100/110 engines. And another example is the AL-31F/FN and WS-10 for the J-11-series.

As such You do not need to completely redesign an aircraft to fit a new engine as long as the new type is designed and build to fit that aircraft. Surely additional changes are necessary to adjust this new engine to the different weight, airflow and so on specifications, but it's not that an issue.

Impossible however is it to "Frankenstein" an engine from different parts aka core, fan and AB.
Consequently I indeed expect certain modifications when the WS-15 will be flight test for the first time and later adopted for operational use, however if the WS-15 is designed to fit the same external dimensions - what I expect - it is not an issue. Your example that a F-135 is larger than a F100 or F110 is moot since it was designed and build for different aircrafts. The A.320's engine is also different to a B777's engine since both are completely unrelated.

Deino

Deino
 
"You can swap to WS-15 if it was on purpose designed with the same spacial dimensions as the one that it would be replacing. There is no logical reason the WS-15 cannot be externally an exact replica of either the AL-3L or WS-10X engine."

Name an instance, in the world history of modern aircraft development, that was successfully done, as you just have said, that an new engine and new aircraft was "as on purpose designed, with the same spacial dimensions", to replace "externally an exact replica" of an older, much less powerful engine.

Otherwise, the Mod. will level, the charge of, groundless speculation, at you.

Even, that's possible and desirable, it still won't explain, why a 130kN-140kn engine, like WS-10b or AL-31FN could lift, a plane weighting +20 tons plus fuel, in a sustained vertical climb, without the use of AB, in front of thousands of international spectators.

I got a feeling, that this crucial point, still don't mean anything to you, and to many other readers.

I am not trying to say that the J-20 is equipped with the AL-3L currently at all - my point is that it is simple to swap out one engine to another if this was the intention all along.

Actually it is not even a requirement for the external dimensions of the engine to be exactly equal to have an almost "plug and play" scenario.

Consider the Euro-fighter flight timeline:

1994 27 March - maiden flight of first development aircraft, DA1 from DASA at Manching with RB199 engines.
19946 April - maiden flight of second development aircraft, DA2 from BAe Warton. DA2 also flew with RB199s.
1995 4 June - maiden flight of Italian DA3, the first with EJ200 engines.

Dimensions of the two engines:

EJ200 -
Length: 4 m (160 in)
Diameter: 737 mm (29.0 in)

RB199 -
Length: 3,600 millimetres (142 in)
Diameter: 720 millimetres (28.3 in)

So the engines need to be similar in dimension but do not have to be exactly equal - the diameter is really the most important as that affects the fuselage much more than it's length.

FYI, I believe that the current J-20 operates on a special WS-10X that gives enough power to allow 1:1 T/W ratio at dry thrust - it will be swapped out before end of decade by the WS-15.

@Deino
 
Last edited:
@Deino, @UKBengali, @52051

Engineering, a new engine and new plane, to be compatible, with an old engine, seems backward to me. Even that's possible. I wouldn't go through that kind of trouble and complicate my life.

I would just make, a quick prototype, with the new engine core, by "adapting" proven existing technology. This way I would have time, to test the design, of the new engine core, thoroughly, while I wait for the actual new engine to be ready, for flight testing. This way, I could have the best of both world.

This way,
1.) will reduce risk by using as much existing technology as possible in initial flight testings.
2.) will, actually test the new engine core, to flush out the potential problems, as early as possible, so the engineers have time to solve them.
3.) will give the engineers, additional time to finish, the complete design of the new engine, and have more time to do ground testings, before it is put on the new plane, for flight testing.
4.) This is by far, the best and safest way, to keep the testing and development schedule. IMO.

Remember, the engineers and management and test pilots, wants to play it safe too, they don't want their new planes crashed, regularly, but they have a very tight schedule to keep too, otherwise, they lose their jobs.

The idea that J-20, is still using an old engine, after 6 years of testing (and the new engine, never made it, to flight testing on J-20, yet), while going to LRIP, seems crazily stupid to me.

But that's just me.

By insisting J-20 was flying with (and still is flying with) WS-10 or AL-31FN, you guys, seems proving my suspicion, that some people, don't care (or don't understand) about the fact ,that total engine thrust, must be greater than plane's flying weight, for it to fly in a sustained vertical climb.

And if Afterburner was not used, in the sustained vertical climb, it's Dry Thrust, must be greater than, it's flying weight.

I guess not everyone took a basic Physics course in his life, or remember what he has learned in that class.

If it were not for, the sustained vertical climb demonstration, back in November 1, 2016, I wouldn't have a firm opinion, that J-20 is already using WS-15, perhaps, as early as the first day of the testing, in 2011.

This is a sticking/stinking point, isn't it? :mad: :( :o: o_O :undecided:

Anyone, who is ignoring, this amazing demonstration, is putting his head, in the sand, like an ostrich.
 
Last edited:
Honestly ... Your Quick-Prototype theory is BS.

Name any case in aviation histoty for such a case. You either use a proven older type for the first prototypes and replace it in later serial aicrafts or you use already the new engine from tge beginning. But never, never your theoretical approach was used - simply since it is not possible - to quickly frankenstein a prototype engine and later use the definitive powerplant.
 
Last edited:
Honestly ... Your Quick-Prototype theory is BS.

Name any case in aviation histoty for such a case. You either use a proven older type for the first prototypes and replace it in later serial aicrafts or you use already the new engine from tge beginning. But never, never your theoretical approach was used - simply since it is not possible - to quickly frankenstein a prototype engine and later use the definitive powerplant.
FC-31 V2 do you agree is using a new engine? It is smokeless so more or than proves its not RD-93 engine. Or you want to claim V2 is flying with RD-33MKB engine which has never reported to be export to China?
 
FC-31 V2 do you agree is using a new engine? It is smokeless so more or than proves its not RD-93 engine. Or you want to claim V2 is flying with RD-33MKB engine which has never reported to be export to China?


Yes, but Pardon how is the FC-31V2 related to the point above ? We are discussing the J-20 ...

Anyway Even if V2 uses a WS-13 it is still a RD-93 based design that at least Dimension-Wise matches the original engine. As such it is neither Asok's proposed quick-prototype Frankenstein-design nor a completely new powerplant.

Even more the Ws-13 was surely always the planned engine.
 
Yes, but Pardon how is the FC-31V2 related to the point above ? We are discussing the J-20 ...

Anyway Even if V2 uses a WS-13 it is still a RD-93 based design that at least Dimension-Wise matches the original engine. As such it is neither Asok's proposed quick-prototype Frankenstein-design nor a completely new powerplant.

Even more the Ws-13 was surely always the planned engine.
Why would franken not possible? It has less new design and therefore easier implementation than a new design with less failure and less testing require.
 
It does not have to have be "externally an exact replica". and it also does not require a complete redesign.




The Russians make the same with the current 117 engine, which will be replaced by the izd. 30. Similar the F-14 flew with TF-30 and later F110´, similar the later F-15/-16 blocks were able to handle both the F100/110 engines. And another example is the AL-31F/FN and WS-10 for the J-11-series.

As such You do not need to completely redesign an aircraft to fit a new engine as long as the new type is designed and build to fit that aircraft. Surely additional changes are necessary to adjust this new engine to the different weight, airflow and so on specifications, but it's not that an issue.

Impossible however is it to "Frankenstein" an engine from different parts aka core, fan and AB.
Consequently I indeed expect certain modifications when the WS-15 will be flight test for the first time and later adopted for operational use, however if the WS-15 is designed to fit the same external dimensions - what I expect - it is not an issue. Your example that a F-135 is larger than a F100 or F110 is moot since it was designed and build for different aircrafts. The A.320's engine is also different to a B777's engine since both are completely unrelated.

Deino

Deino

Bad examples.

The current PAK FA T-50 is a technology demonstrator using an interim engine, the 117. The final version of that aircraft using izdeliye 30 is something we haven't seen yet. The izdeliye 30 is a clean-sheet design and we don't know the dimensions of that engine. F100/F110 are both engines from the same generation, with similar dimensions, similar thrust, designed to be interchangeable with each other. Same for AL-31 and WS-10.

Look at the dimensions of the F100 and compare it to the F135. This is the difference between 4th and 5th generation engines.

F100

Length: 191 in
Inlet Diameter: 34.8 in
Maximum Diameter: 46.5 in

http://www.pw.utc.com/F100_Engine

F135

Length 220 in (5.59 m)
Inlet Diameter 43 in (1.09 m)
Maximum Diameter 46 in (1.17 m)

https://www.pw.utc.com/Content/F135_Engine/pdf/B-2-4_F135_SpecsChart.pdf

The F-135 is also heavier. The F-135 also requires significantly more airflow to generate that extra thrust. You won't be fitting the F135 into the F-15 or F-16 without major redesign of the aircraft. I don't know the dimensions of the WS-15, but I assume the same laws of physics apply for the AL-31 and WS-15. I assume China is facing the same technological constraints as Pratt & Whitney when designing a next generation engine.

The F-35 was suffering from bulkhead and engine mount cracks not too long ago, and the aircraft was designed from the beginning to accept the F135. Can you imagine the problems you will have when you take an aircraft designed and tested for AL-31 and try to make the jump to WS-15?
 
huitong latest rumors:

It has been speculated that either all prototypes are powered by AL-31F-M1, or 200x technology demonstrators are powered by AL-31F-M1, then 201x prototypes and LRIP J-20s are powered by AL-31F-M2 (A Configuration?).

The latest rumor (March 2017) suggested that J-20 is preparing for the integration of the new WS-15 turbofan engine.


http://chinese-military-aviation.blogspot.com/
 
huitong latest rumors:

It has been speculated that either all prototypes are powered by AL-31F-M1, or 200x technology demonstrators are powered by AL-31F-M1, then 201x prototypes and LRIP J-20s are powered by AL-31F-M2 (A Configuration?).

The latest rumor (March 2017) suggested that J-20 is preparing for the integration of the new WS-15 turbofan engine.


http://chinese-military-aviation.blogspot.com/


Uppps ... so it seems that strange German is maybe correct !!! :smitten:
How could that be with his head still in the sand ?:dance3:

Even more I was discussing my theory with OedoSoldier at Twitter and he too thinks I'm correct.
 
Last edited:
Uppps ... so it seems that strange German is maybe correct !!! :smitten:
How could that be with his head still in the sand ?:dance3:

Even more I was discussing my theory with OedoSoldier at
Uppps ... so it seems that strange German is maybe correct !!! :smitten:
How could that be with his head still in the sand ?:dance3:

Even more I was discussing my theory with OedoSoldier at Twitter and he too thinks I'm correct.

Yes ... but first of all even if Huitong is IMO a remarkable source of information, he's not free of faults (just look at the WS-15 he posted too), as such I beg to wait until we call it confirmed.

Even you yourself claim Huitong is not error free. Huitong just like you , is based on eyeball observation and rumour only. Take this info of J-20 engine with a pinch of salt. There is no comfirmation from official regarding the engine used on J-20 currently.
 
Uppps ... so it seems that strange German is maybe correct !!! :smitten:
How could that be with his head still in the sand ?:dance3:

Even more I was discussing my theory with OedoSoldier at Twitter and he too thinks I'm correct.

Hmm...I have to disagree, Deino, but there is no way the WS-15 could be integrated this early. 2025 at the earliest.
 
According to a very trustful military insider, Pupu, J-20A will soon to be equpipped with WS-10B engine, with a thrust of 142kn.

This is consistent with the senior fellower of China academy of engineering's comments on how China will soon fit J-20 with home-made engines during the recent congress meeting.
I noticed that too.
 
Back
Top Bottom