Chengdu J-20 5th Generation Aircraft News & Discussions

[Asoka]

I must say that your analogy furnished with the matched illustration is thought provoking (as well as your many posts above)... and the picture itself is amusing

It's like using a Toyota Sedan's engine to test a Formula One's racing frame, suspension and tires. Yes, it will drive it. But will it test them to the limit?

I doubt it.

It's very foolish and ignorant to think that it could.

 

[Ultima Thule]

It's like using a Toyota Sedan's engine to test a Formula One's racing frame, suspension and tires. Yes, it will drive it. But will it test them to the limit?

I doubt it.

It's very foolish and ignorant to think that it could.

Its not impossible bro same thing on PAK-FA bro interim engine is 117 but in future main engine for PAK-FA will be izdeliye 30

 

[samsara]

J-20‘s testbed: a modified Tu-204

https://twitter.com/x/status/846607156296110080

Photo by APFSDS

 

[Deino]

Very impressive ... only sad that the front part of this image-series is missing.

 

[j20blackdragon]

Look at the changes made for the F-16/79 fitted for General Electric J79 engine. Shape of air intake was altered. Rear fuselage was extended by 18 inches. But somehow people believe that AL-31 and WS-15 are interchangeable? Give me a break.

Since the J79 engine required a lower airflow than did the F100 turbofan used on all production F-16A/B's, the shape of the air intake was altered. Only external difference between the original, modular designed (and thus easily replaceable) intake section and the new one is the lengthened upper surface of the intake, which extends much further forward, making it an obvious recognition feature. As the J79 engine was also 18 inches (46 cm) longer than the F100, the rear fuselage had to be extended.

In order to limit the required changes to a minimum, the front face of the engine compressor was located at almost the exact same position as with the F100 resulting in a lengthening of the fuselage by 18 inches aft of the stabilator pivot point.

http://www.f-16.net/f-16_versions_article12.html

F-16/79 Demonstrator, YF-16B #75-0752 fitted with the GE J79 engine. Note the extended tailpipe. (LMTAS photo)

 

[Deino]

Look at the changes made for the F-16/79 fitted for General Electric J79 engine. Shape of air intake was altered. Rear fuselage was extended by 18 inches. But somehow people believe that AL-31 and WS-15 are interchangeable? Give me a break.

Funny ... IMO it's exactly an argument that there is NO problem to see the WS-15 with only minor changes mounted into/onto a J-20. Like Your own source stated: what was changed??? The engine itself is longer - therefore the lengthened exhaust - and has a different airflow requirement - therefore a modified intake. Otherwise and especially airframe-wise the F-16-79 is exactly an F-16A and consequently I'm almost sure the current J-20 does not differ much to the final J-10B with the definitive WS-15: Most likely the exhaust will be different and probably the intake too but similar to the F-16 it could easily be a modular design.

That does not mean the WS-15 is interchangeable with the AL-31FN - that was also never with the F100 and the J-79 - but airframe-wise it's not a big issue.

Another example si the F-14 A vs. F-14D. The changes from the original TF30 to the final F110 were also not that huge even if they were not interchangeable; but that also no-one claimed for the final WS-15-equipped J-20.

Deino

 

[j20blackdragon]

Funny ... IMO it's exactly an argument that there is NO problem to see the WS-15 with only minor changes mounted into/onto a J-20. Like Your own source stated: what was changed??? The engine itself is longer - therefore the lengthened exhaust - and has a different airflow requirement - therefore a modified intake. Otherwise and especially airframe-wise the F-16-79 is exactly an F-16A and consequently I'm almost sure the current J-20 does not differ much to the final J-10B with the definitive WS-15: Most likely the exhaust will be different and probably the intake too but similar to the F-16 it could easily be a modular design.

That does not mean the WS-15 is interchangeable with the AL-31FN - that was also never with the F100 and the J-79 - but airframe-wise it's not a big issue.

Another example si the F-14 A vs. F-14D. The changes from the original TF30 to the final F110 were also not that huge even if they were not interchangeable; but that also no-one claimed for the final WS-15-equipped J-20.

Deino

My example was meant to illustrate the changes to the intake and engine bay when fitting a new engine. But for you to compare the F-16/79 to the J-20 is absurd.

1. The J79 engine was a thrust downgrade for the F-16, while the WS-15 will be a massive thrust upgrade for the J-20. More thrust means more stress on the airframe throughout a variety of different flight envelopes. More thrust means more heat from the engine. The WS-15 also needs to produce enough dry thrust for the J-20 airframe to supercruise. The F-16 didn't need to supercruise with the J79 engine (or any engine).

2. The F-16 is a conventional aircraft. The J-20 is a STEALTH aircraft. Changes to the airframe (however small in your opinion) will change the radar cross section of the J-20. The intake, for example, is a major radar reflector. Airflow is not the only concern when designing an intake for a stealth aircraft.

 

[Ultima Thule]

My example was meant to illustrate the changes to the intake and engine bay when fitting a new engine. But for you to compare the F-16/79 to the J-20 is absurd.

1. The J79 engine was a thrust downgrade for the F-16, while the WS-15 will be a massive thrust upgrade for the J-20. More thrust means more stress on the airframe throughout a variety of different flight envelopes. More thrust means more heat from the engine. The WS-15 also needs to produce enough dry thrust for the J-20 airframe to supercruise. The F-16 didn't need to supercruise with the J79 engine (or any engine).

2. The F-16 is a conventional aircraft. The J-20 is a STEALTH aircraft. Changes to the airframe (however small in your opinion) will change the radar cross section of the J-20. The intake, for example, is a major radar reflector. Airflow is not the only concern when designing an intake for a stealth aircraft.

Its not impossible bro,look the PAK-FA currently its using 117 engine, intended or main powerplant for PAK-FA will IDEALIZE-30 or ADZ-30, same will goes to J-20 as well bro, no bro your intake theory is wrong, their is some kind of airflow diverter system inside the J-20 to take away excess airflow from the engine let's ask from the expert @gambit, @Oscar , @Rashid Mahmood , @Horus, @Bilal Khan (Quwa) , @Bilal Khan 777 am I right or wrong sir?

 

[Asoka]

My example was meant to illustrate the changes to the intake and engine bay when fitting a new engine. But for you to compare the F-16/79 to the J-20 is absurd.

1. The J79 engine was a thrust downgrade for the F-16, while the WS-15 will be a massive thrust upgrade for the J-20. More thrust means more stress on the airframe throughout a variety of different flight envelopes. More thrust means more heat from the engine. The WS-15 also needs to produce enough dry thrust for the J-20 airframe to supercruise. The F-16 didn't need to supercruise with the J79 engine (or any engine).

2. The F-16 is a conventional aircraft. The J-20 is a STEALTH aircraft. Changes to the airframe (however small in your opinion) will change the radar cross section of the J-20. The intake, for example, is a major radar reflector. Airflow is not the only concern when designing an intake for a stealth aircraft.

"More thrust means more stress on the airframe throughout a variety of different flight envelopes. "

I think this very important point, don't mean anything, to a lot of people here at PDF. That's why they keep thinking AL-31FN and WS-15, are interchangeable with J-20. All you need to do, is loose a few screws and pop in the other one, and everything will work just fine, they believe.

 

[Deino]

I think this very important point, don't mean anything, to a lot of people here at PDF. That's why they keep thinking AL-31FN and WS-15, are interchangeable with J-20. All you need to do, is loose a few screws and pop in the other one, and everything will work just fine, they believe.

Sorry to disappoint You in Your believe that there is anyone who thinks that "AL-31FN and WS-15, are interchangeable with J-20" and even more by onlyto "loose a few screws and pop in the other one". No-one - at least I don't know anyone here claiming such a stupid thing - ever said that.

But in fact - and You again simply did not read properly - it is not that difficult to develop another version using the WS-15 say in a J-20B, while the current A-models uses - uups; You don't wanna hear it - an AL-31FNMXYZ or whatever.
It will surely be a new version but if the new WS-15 has at least not extremely different dimension, what I don't expect it could be a quite similar development as projected with the T-50 which now uses the Type 117 engine and later will use the izd. 30 and long, long ago the development from the F-14A using TF-30 progressed to the F110-euqipped F-14B and D.

You are correct, both engines were very much different, esp. the later one much more powerful with different specifications and airflow and both are surely not interchangeable but the airframe changes were only minimal; and the same I expect for the WS-15-powered J-20XYZ.

Deino

 

[j20blackdragon]

I would like to change the subject slightly.

The only piece of circumstantial evidence that supports the AL-31 theory for the J-20 is the appearance of the nozzle. Nobody has actually seen a J-20 engine removal or installation with AL-31. Nobody can verify an AL-31FM2 contract with Russia.

Some people have also claimed that the so-called "Frankenstein" engine theory is impossible. Is it?

I want to put some facts out there and let people decide.

The F100 engine has five major modules that can be removed from the engine for repair or overhaul, serviced separately, and then reassembled to produce a whole engine:

(1) inlet/fan
(2) core (compressor, combustor, and compressor-drive turbine)
(3) fan-drive turbine
(4) augmentor and exhaust nozzle
(5) gearbox

Each module is completely interchangeable from engine-to-engine at the intermediate maintenance level.

The modular concept allows for minor engine problems to be fixed directly on the flightline. For example, let's say the F100 has suffered slight damage from a minor birdstrike. You change the fan module, test, and return the engine to service within a short time period without the need for a long shipment and wait time for another location to address your issue. A supply of modules are kept on base. In more serious cases, the engines go to an Air Force depot.

The photo below is the F-15 engine shop at RAF Lakenheath airbase (48th Fighter Wing). All the F100 augmentor/exhaust nozzle modules are separated before your very eyes.

My point is that the augmentor/exhaust nozzle is not some sort of inseparable element of the engine. Some engines don't even have augmentors. Other engines (like in the X-35 prototype) combined the F119 core with an interim nozzle. The F135 continues to share a common core with the F119.

So the "Frankenstein" engine theory is impossible? Why is it impossible? China could have easily created a lookalike AL-31 augmentor/nozzle module to expedite testing of the WS-15 core and other more critical components. As long as the module is tailor-made to fit the engine, everything should be fine. Perhaps the final stealthy, thrust vectoring augmentor/nozzle is still in development. It is far easier to create different modules that are interchangeable than different whole engines that are interchangeable. When the final stealth augmentor/nozzle module is ready, they remove the interim AL-31 module, and pop in the new one. Some additional testing will be required, but the intakes and engine bays can stay the same. The WS-15 core was being tested inside the engine bay the whole time.

What have we seen so far from the J-20? Sometimes the nozzles look like AL-31. Sometimes they are black. Sometimes they are silver. Are they applying different coatings to the nozzles, or are they rapidly changing augmentor/nozzle modules? I have no idea.

But I will be watching closely at several things. The size of the intakes do not lie because they are directly tied to the airflow requirements of the engine. The rear fuselage will change if they change the dimensions of the engine bays. Lastly, look at the nozzles.

 

[Asoka]

"But in fact - and You again simply did not read properly - it is not that difficult to develop another version using the WS-15 say in a J-20B, while the current A-models uses - uups; You don't wanna hear it - an AL-31FNMXYZ or whatever."

Whatever this version J-20B, with the new WS-15 engine is, when it fly, it must be tested like a new plane, from the ground up.

This is the point of my contention.

If it took J-20A, 5-6 years to get into LRIP, it will also take J20-B, similar amount of time (5-6 years of intensive testing), after WS-15 is ready to be tested on J-20B, which could be 10-20 years from now.

Also, J-20A with a WS-10 or AL-31FN engine is NOT a 5th generation plane, meeting the 4S requirements. It can not do Supersonic Cruise, nor possess Supersonic Maneuverability.

It's a 4th Generation plane, with Stealth characteristics.

So until J-20B with WS-15 is ready (another 10-20 years from now) , China do not possessed a 5th Generational Fighter.

So the CIA is more than right, in its estimate, that China will not possessed such plane before 2020. In fact, China might not have such plane before 2030, at the rate of WS-15 is progressing as you and others believed.

But the China's PLAAF Commander, has predicted back in 2009, China's 5th Generation Fighter will be flying shortly, and will be operational by 2017-2019.

Who is going to be right, here, the CIA or the PLAAF Commander?

Your ludicrous claim that J20A is flying with a non WS-15 engine, simply do not make any sense, nor anyone has provided any evidence, that it is flying with, a WS-10 or AL-31FN engine.

No evidence, whatsoever.

Your theory is groundless, baseless, and completely evidence-free.

Your emperor has no clothes, Mr. Deino.

 

[Ultima Thule]

"But in fact - and You again simply did not read properly - it is not that difficult to develop another version using the WS-15 say in a J-20B, while the current A-models uses - uups; You don't wanna hear it - an AL-31FNMXYZ or whatever."

Whatever this version J-20B, with the new WS-15 engine is, when it fly, it must be tested like a new plane, from the ground up.

This is the point of my contention.

If it took J-20A, 5-6 years to get into LRIP, it will also take J20-B, similar amount of time (5-6 years of intensive testing), after WS-15 is ready to be tested on J-20B, which could be 10-20 years from now.

Also, J-20A with a WS-10 or AL-31FN engine is NOT a 5th generation plane, meeting the 4S requirements. It can not do Supersonic Cruise, nor possess Supersonic Maneuverability.

It's a 4th Generation plane, with Stealth characteristics.

So until J-20B with WS-15 is ready (another 10-20 years from now) , China do not possessed a 5th Generational Fighter.

So the CIA is more than right, in its estimate, that China will not possessed such plane before 2020. In fact, China might not have such plane before 2030, at the rate of WS-15 is progressing as you and others believed.

But the China's PLAAF Commander, has predicted back in 2009, China's 5th Generation Fighter will be flying shortly, and will be operational by 2017-2019.

Who is going to be right, here, the CIA or the PLAAF Commander?

Your ludicrous claim that J20A is flying with a non WS-15 engine, simply do not make any sense, nor anyone has provided any evidence, that it is flying with, a WS-10 or AL-31FN engine.

No evidence, whatsoever.

Your theory is groundless, baseless, and completely evidence-free.

Your emperor has no clothes, Mr. Deino.

What is the prove? You are assuming too much bro, as per chinese senior members on PDF like @wanglaokan, @cirr, @ChineseTiger1986, @Beast and others saying that either J-20 using WS-10B or hybrid version of WS-10 you are too much bashing in the favor of China, get real bro, you are relatively new in the engine development field as copmare US, Russia, Germany, UK, and France

 

[UKBengali]

Whatever this version J-20B, with the new WS-15 engine is, when it fly, it must be tested like a new plane, from the ground up.

This is the point of my contention.

If it took J-20A, 5-6 years to get into LRIP, it will also take J20-B, similar amount of time (5-6 years of intensive testing), after WS-15 is ready to be tested on J-20B, which could be 10-20 years from now.

This is not true.

All the elements of the flight characteristics apart from super-cruise and supersonic manoeuvrability can be tested on a non-WS-15 engine. Avionics and weapons(minus super-cruise firings) can also be tested.

 

[Asoka]

This is not true.

All then elements of the flight characteristics apart from super-cruise and supersonic manoeuvrability can be tested on a non-WS-15 engine. Avionics and weaponns(mius super-cruise firings) can also be tested.

You are right that the electronics equipments need not to be re-tested all over again.

What I am saying is that at the rate of WS-15 is progressing as some people have suggested. China will not have a true 5th generation fighter in operation before 2030, proving CIA's estimate, to be right, and the PLAAF Commander's prediction, very wrong.

I, doubt, very much that the PLAAF Commander, don't know, what he was saying, and the CIA was right about China's J-20' progress.

I highly doubt, when the PLAAF Commander said "the J-20 will be operational by 2017-2019", he meant it will be flying with a WS-10 or AL-31FN.

The PLAAF Commander also said, he is very satisfied with J-20's performances.

I highly doubt PLAAF will be very satisfied with J-20's performances, if it was flying with WS-10 or AL-31FN.