J-20 5th Gen Fighter Thread V

[Air Force Brat]

Its the question if China is ready to produce and deploy J-20 aircraft with non-WS15 engines. There are all kind of documents and leaks which claim that China is exactly doing that but most also claimed that we would see more J-20 prototype evalutations or even a low-rate production in the near future, claims which don't get supported by the things we are seeing right now.

If China wants to push the J-20 with the WS-15 then further prototypes without WS-15 engines wouldn't make sense right now and the focus should be on several parts like avionics, EW, radar/sensors etc. which can be tested on ground or with the already known prototypes.

China will continue to test fly the J-20 with the present AL-31Fs until the WS-15 is ready to fly and fully support the flight test program, to assume that the WS-15 is what is delaying the flight test is to misunderstand that the engines are "interchangeable", and have been designed from the beginning to be so. The WS-15 is likely testing on transport category aircraft now as it matures through the flight test regimen.

The WS-15 won't change any of the flight test characteristics except to make everything, "Mo Betta", of course it will take some minor tweaking to install and flight test this engine in the J-20, and once the J-20 is operating with a fully mature WS-15, top end, climb, and supercruise will all be a part of
"opening up the envelope" for the J-20.

 

[Pmichael]

Engines - body interaction, different physical characterstics and different performance data and profile in transonic, supersonic and different altidudes etc. are all things which make swapping two engines family barely a trivial act.
There is a reason why one of the things first prototypes of aircraft are getting is the planned engine or it can happen that one can run into the same problems like India with the Tejas.

 

[A.Man]

Engines - body interaction, different physical characterstics and different performance data and profile in transonic, supersonic and different altidudes etc. are all things which make swapping two engines family barely a trivial act.
There is a reason why one of the things first prototypes of aircraft are getting is the planned engine or it can happen that one can run into the same problems like India with the Tejas.

Please to say something that you know and we don't know.

 

[thunderchief]

IMHO, best course of action for China would be to produce new airframe with lessons learned from previous examples, and to continue testing avionics, weapons integration etc ... with old engines . On the other hand, they could modify one of existing prototypes (already at the end of its usefulness ) to carry WS-15 . So, even if something happens and airframe is lost, it would not be such a great loss .

 

[antiterror13]

Engines - body interaction, different physical characterstics and different performance data and profile in transonic, supersonic and different altidudes etc. are all things which make swapping two engines family barely a trivial act.
There is a reason why one of the things first prototypes of aircraft are getting is the planned engine or it can happen that one can run into the same problems like India with the Tejas.

same problems like India with Teja ????? I am not sure what are you talking about?

 

[Pmichael]

same problems like India with Teja ????? I am not sure what are you talking about?

You mean the several years delay because of design rework because of the way too late decision which engine to use for it.
The airframce and engines of the aircraft are intregrated parts of the J-20 and can't be develope seperately until the last days or even after it if the claims of a low-initial production line with AL-31F are true without that it will affect the J-20 negatively.

 

[manqiangrexue]

On the other hand, they could modify one of existing prototypes (already at the end of its usefulness ) to carry WS-15 . So, even if something happens and airframe is lost, it would not be such a great loss .

LOL I really don't think that's how they do things.

"Hey, Lao Li, you ready to go? Remember, if you feel a violent rumble followed by a cracking sound, go on and hit the eject; that would be the engines leaving the nacelles. Not sayin' it's gonna happen, just sayin' it's something you might wanna keep in mind. Also, whatever you do, do not let it go down over Sichuan Darling Lil' Angels middle school; my kid goes there. Jus' tryna keep the fam alive, nomsayin'? Alright, buddy, good luck!" [turns around] "You guys have all the firetrucks ready and the fire department on hold like I told you, right? Cool. If his ejector fails, I get dibs on his Yao Ming autographed basketball; I already called it."

Next day, headlines on every American paper:
"Chinese copied stealth jet with new Chinese (probably) copied engine, the pride of China crashes and burns in a heap, paying testament to Chinese quality! Chinese aviation permanently crippled. New holiday, National 'Murca Day to be designated on this day annually"
LOLOL

 

[thunderchief]

Next day, headlines on every American paper:
"Chinese copied stealth jet with new Chinese (probably) copied engine, the pride of China crashes and burns in a heap, paying testament to Chinese quality! Chinese aviation permanently crippled. New holiday, National 'Murca Day to be designated on this day annually"
LOLOL

Prototypes do crash occasionally , and I don't think China cares much about opinion of yellow press. What matters is how to test new engine on one hand and not to endanger development of whole aircraft on the other . You could do only so much with testbed aircraft like Il-76 , eventually you wold need to fit them on real thing .

 

[manqiangrexue]

Prototypes do crash occasionally , and I don't think China cares much about opinion of yellow press. What matters is how to test new engine on one hand and not to endanger development of whole aircraft on the other . You could do only so much with testbed aircraft like Il-76 , eventually you wold need to fit them on real thing .

Yeah, of course they'll need to test it on a J-20, but they'll make extremely ample preparations for that test, and invest as much as they have during every other test, just like the first flight of J-10 or J-20. When prototypes crash, it's because the team did absolutely everything they could and were very confident that everything would go fine, but they were wrong. It's not because they said, "Screw it; what do we still need 2001 around for anyway? Put WS-15 on it and see what happens."

In general, I think the same as you, that the prototypes were designed to carry WS-15 and they could remove AL-31 and put WS-15 to test it without the need for designing new prototypes made to carry WS-15. But I don't think they have the attitude of, "Let's just test it and even if we lose a prototype, it's not a big deal."

 

[thunderchief]

Well, of course they would not just strap new engines on old airframe . This would be done after careful calculations and possibly modifications. Still, something could go wrong and that's why is better to do that with old prototype reaching the end of its usefulness .