Chengdu J-20 5th Generation Aircraft News & Discussions

[Ultima Thule]

I have always said, from day one, J-20 was using a prototype version that uses WS-15's core mated with WS-10 and AL-31FN technologies that the Chinese are familiar with.

You can call this version whatever you want, like WS-10x. If you said it has a WS-15 core, then I am satisfied.

Then, starting Version 2011, J-20 upgraded to the latest WS-15 engine, which was actually shorter than the prototype. The weapon bay of J-20 is now longer, because of a shorter engine. Now, Tiqiu's latest post has explained why.

And it is this version WS-15 has Thrust Vector Control Nozzles (TVC), and has maximum thrust greater than 21 tons, or 210kN.

And it is entering LRIP with J-20 on schedule as PLAAF Commander predicted in 2009.

Where is my proofs?

I have posted a lot about the WS-15, you can go read my posts.

bro i am agree partially with this post of your from the beginning J-20 first flight WS-10 don't mature enough to WS-15 core on that time, to reduce risk CAC put AL-31 to first 2 or 3 prototype than they put WS-10X when they matures and than they will convert WS-10X with a core of WS-15 late on the project, your thrust estimation about just too much or you have concrete source i would say at-least equal to F-135 or slightly higher no hard feeling bro

 

[Asoka]

bro i am agree partially with this post of your from the beginning J-20 first flight WS-10 don't mature enough to WS-15 core on that time, to reduce risk CAC put AL-31 to first 2 or 3 prototype than they put WS-10X when they matures and than they will convert WS-10X with a core of WS-15 late on the project, your thrust estimation about just too much or you have concrete source i would say at-least equal to F-135 or slightly higher no hard feeling bro

Bro, the F-135 is listed as a 190kN class engine, the exact figure is not released, as it is still classified. The word on the street, is that it is very likely to be higher than 190kN.

The F-135 engine was developed in the early 1990's and became operational in the early 2000's.

Now, more than 20 years later, China has developed an engine that is of the same class, perhaps just a bit more powerful.

I find that credible, based on China's progress in various fields, in the last 30 years.

i don't have hard data like J-20's empty weight to back me. I just estimated that J-20 is at least 2 tons heavier than's F-22's 19.7 tons empty. I find this estimate conservative, since J-20 is at least 3.5 meter longer than F-22, from nose to nozzle.

And I, conservatively, estimated that J-20 was carrying 1/3 of a full tank, or 4 tons of fuel (not a whole lot for a 20+ tons plane) during the sustained vertical climb at the air show, while not using afterburner.

So, I arrived at the flying weight of 22 + 4 = 26 tons for J-20 during that day.

26/2 = 13 tons per engine, it must lift vertically. And since it was not using Afterburner, that means it was using only dry thrust for the vertical climb.

Dry thrust is usually 60% of the maximal thrust.

That is:

Max. Thrust = Dry Thrust / 0.60

So we got,

Max. Thrust = 13 tons / 0.60
Max. Thrust = 21.6 tons, per engine

Is the current Max. Thrust of WS-15 18 tons or 21 tons?

I am not sure. Since my flying weight for J-20, during the air show, was purely a guess.

However, if the Max. Thrust is 18 tons, then J-20 needs to be the same empty weight as F-22's 19.7 tons and carry only 2 tons of fuel for the demo, or something like that.

For a total of 22 tons of flying weight. That would put J-20's max. thrust at 18 tons per engine.

Here is the calculation:

22/2 = 11 tons, dry thrust, each engine must have to lift J-20 vertically, without afterburner.

Max. thrust = 11 tons / 0.6 = 18.3 tons

I find this highly unlikely. That J-20 is the same weight as F-22, despite its at least 3.5 meters longer, nose to nozzle, and carries only 2 tons of fuel during the demo.

So I am comfortable that WS-15 has a max. thrust > 21 tons.

The fact that J-20 did a 5-6 seconds of sustained vertical climb, without the use of Afterburner, is an eye opener for me.

But this earth shattering significance has not caught up to other observers, yet.

All this means J-20 has one hell of aerodynamic airframe, one hell of powerful engine, one hell of state of the art avionics suite, one hell of AESA radar, and one hell of combat range.

And China has the money to produces, several hundreds of those mighty beasts, in the next 20 years, unlike F-22, which is already cancelled.

 

[Han Patriot]

Well at least we all agree J-20 had been using Chinese engines all along. I don't care if it incorporates Russian, American or whatever countries technology, the point is it is Chinese made and designed. AL-31 is out of the picture, now we need to find out which engine was used.

 

[Ultima Thule]

Bro, the F-135 is listed as a 190kN class engine, the exact figure is not released, as it is still classified. The word on the street, is that it is very likely to be higher than 190kN.

The F-135 engine was developed in the early 1990's and became operational in the early 2000's.

Now, more than 20 years later, China has developed an engine that is of the same class, perhaps just a bit more powerful.

I find that credible, based on China's progress in various fields, in the last 30 years.

i don't have hard data like J-20's empty weight to back me. I just estimated that J-20 is at least 2 tons heavier than's F-22's 19.7 tons empty. I find this estimate conservative, since J-20 is at least 3.5 meter longer than F-22, from nose to nozzle.

And I estimated that J-20 was carrying 1/4 of a full tank, or 4 tons of fuel during the susbtained vertical climb at the air show, while not using afterburner.

So, I arrived at the flying weight of 22 + 4 = 26 tons for J-20 during that day.

26/2 = 13 tons per engine, it must lift vertically. And since it was not using Afterburner, that means it was using only dry thrust for the vertical climb.

Dry thrust is usually 60% of the maximal thrust.

That is:

Max. Thrust = Dry Thrust / 0.60

So we got,

Max. Thrust = 13 tons / 0.60
Max. Thrust = 21.6 tons.

Is the current Max. Thrust of WS-15 18 tons or 21 tons?

I am not sure. Since my flying weight for J-20 during the air show, was a guess.

However, if the Max. Thrust is 18 tons, then J-20 needs to be the same empty weight of F-22's 19.7 tons and carry only 2 tons of fuel for the demo, or something like that.

For a total of 22 tons of flying weight. That would put J-20's max. thrust at 18 tons per engine.

Here is the calculation:

22/2 = 11 tons, dry thrust, each engine must have to lift J-20 vertically, without afterburner.

Max. thrust = 11 tons / 0.6 = 18.3 tons

I find this highly unlikely. That J-20 is the same weight as F-22, despite its at least 3.5 meters longer, nose to nozzle, and carries only 2 tons of fuel during the demo.

So I am comfortable that WS-15 has a max. thrust > 21 tons.

The fact that J-20 did a 5-6 seconds of sustained vertical climb without the use of Afterburner is an eye opener for me.

But this earth shattering significance has not caught up to other observers, yet.

All this means J-20 has one hell of aerodynamic airframe, one hell of powerful engine, one hell of state of the art avionics suite, one hell of AESA radar, and one hell of combat range.

And China has the money to produces, several hundreds of those mighty beasts, in the next 20 years, unlike F-22, which is already cancelled.

Brother vertical climbing is not without afterburner of J-20 nothing unusual I can show you lots fighter jets doing that for example PAK-FA doing your vertical climbs without using afterburner with interim engine so what is new for J-20 for vertical climb And not to forget that J-20 using low by pass aka turbojet engine to achieve super cruise High by pass engine has limited super cruise capabilities

 

[帅的一匹]

Bro, the F-135 is listed as a 190kN class engine, the exact figure is not released, as it is still classified. The word on the street, is that it is very likely to be higher than 190kN.

The F-135 engine was developed in the early 1990's and became operational in the early 2000's.

Now, more than 20 years later, China has developed an engine that is of the same class, perhaps just a bit more powerful.

I find that credible, based on China's progress in various fields, in the last 30 years.

i don't have hard data like J-20's empty weight to back me. I just estimated that J-20 is at least 2 tons heavier than's F-22's 19.7 tons empty. I find this estimate conservative, since J-20 is at least 3.5 meter longer than F-22, from nose to nozzle.

And I estimated that J-20 was carrying 1/4 of a full tank, or 4 tons of fuel during the susbtained vertical climb at the air show, while not using afterburner.

So, I arrived at the flying weight of 22 + 4 = 26 tons for J-20 during that day.

26/2 = 13 tons per engine, it must lift vertically. And since it was not using Afterburner, that means it was using only dry thrust for the vertical climb.

Dry thrust is usually 60% of the maximal thrust.

That is:

Max. Thrust = Dry Thrust / 0.60

So we got,

Max. Thrust = 13 tons / 0.60
Max. Thrust = 21.6 tons.

Is the current Max. Thrust of WS-15 18 tons or 21 tons?

I am not sure. Since my flying weight for J-20 during the air show, was a guess.

However, if the Max. Thrust is 18 tons, then J-20 needs to be the same empty weight of F-22's 19.7 tons and carry only 2 tons of fuel for the demo, or something like that.

For a total of 22 tons of flying weight. That would put J-20's max. thrust at 18 tons per engine.

Here is the calculation:

22/2 = 11 tons, dry thrust, each engine must have to lift J-20 vertically, without afterburner.

Max. thrust = 11 tons / 0.6 = 18.3 tons

I find this highly unlikely. That J-20 is the same weight as F-22, despite its at least 3.5 meters longer, nose to nozzle, and carries only 2 tons of fuel during the demo.

So I am comfortable that WS-15 has a max. thrust > 21 tons.

The fact that J-20 did a 5-6 seconds of sustained vertical climb without the use of Afterburner is an eye opener for me.

But this earth shattering significance has not caught up to other observers, yet.

All this means J-20 has one hell of aerodynamic airframe, one hell of powerful engine, one hell of state of the art avionics suite, one hell of AESA radar, and one hell of combat range.

And China has the money to produces, several hundreds of those mighty beasts, in the next 20 years, unlike F-22, which is already cancelled.

Don't forget the building technology of J20 is much more advanced than F22, such as more composite material and 3D printing. If one day what you said proved to be true, I will apologize to you first. I hope what you said is true.

Bro, the F-135 is listed as a 190kN class engine, the exact figure is not released, as it is still classified. The word on the street, is that it is very likely to be higher than 190kN.

The F-135 engine was developed in the early 1990's and became operational in the early 2000's.

Now, more than 20 years later, China has developed an engine that is of the same class, perhaps just a bit more powerful.

I find that credible, based on China's progress in various fields, in the last 30 years.

i don't have hard data like J-20's empty weight to back me. I just estimated that J-20 is at least 2 tons heavier than's F-22's 19.7 tons empty. I find this estimate conservative, since J-20 is at least 3.5 meter longer than F-22, from nose to nozzle.

And I estimated that J-20 was carrying 1/4 of a full tank, or 4 tons of fuel during the susbtained vertical climb at the air show, while not using afterburner.

So, I arrived at the flying weight of 22 + 4 = 26 tons for J-20 during that day.

26/2 = 13 tons per engine, it must lift vertically. And since it was not using Afterburner, that means it was using only dry thrust for the vertical climb.

Dry thrust is usually 60% of the maximal thrust.

That is:

Max. Thrust = Dry Thrust / 0.60

So we got,

Max. Thrust = 13 tons / 0.60
Max. Thrust = 21.6 tons.

Is the current Max. Thrust of WS-15 18 tons or 21 tons?

I am not sure. Since my flying weight for J-20 during the air show, was a guess.

However, if the Max. Thrust is 18 tons, then J-20 needs to be the same empty weight of F-22's 19.7 tons and carry only 2 tons of fuel for the demo, or something like that.

For a total of 22 tons of flying weight. That would put J-20's max. thrust at 18 tons per engine.

Here is the calculation:

22/2 = 11 tons, dry thrust, each engine must have to lift J-20 vertically, without afterburner.

Max. thrust = 11 tons / 0.6 = 18.3 tons

I find this highly unlikely. That J-20 is the same weight as F-22, despite its at least 3.5 meters longer, nose to nozzle, and carries only 2 tons of fuel during the demo.

So I am comfortable that WS-15 has a max. thrust > 21 tons.

The fact that J-20 did a 5-6 seconds of sustained vertical climb without the use of Afterburner is an eye opener for me.

But this earth shattering significance has not caught up to other observers, yet.

All this means J-20 has one hell of aerodynamic airframe, one hell of powerful engine, one hell of state of the art avionics suite, one hell of AESA radar, and one hell of combat range.

And China has the money to produces, several hundreds of those mighty beasts, in the next 20 years, unlike F-22, which is already cancelled.

Don't forget the building technology of J20 is much more advanced than F22, such as more composite material and 3D printing. If one day what you said proved to be true, I will apologize to you first. I hope what you said is true.

We even adopt smart skin technology in J20.

The RAM coating of J20 is a generation ahead of F22, its doomed to be a F22 killer.

We shall concentrate all resource to churn out J20 for airforce. Leave the J31 for navy.

Well at least we all agree J-20 had been using Chinese engines all along. I don't care if it incorporates Russian, American or whatever countries technology, the point is it is Chinese made and designed. AL-31 is out of the picture, now we need to find out which engine was used.

Say good bye to AL31.

 

[j20blackdragon]

I said it before and I'll say it again...the size of a fixed intake is directly related to the airflow requirements of a specific engine. Different engines will have different airflow requirements, and different intake sizes.

There is no such thing as 'one size fits all' when it comes to a fixed intake.

CAC has 20+ years of experience designing the J-10 and the aircraft designers know the airflow requirements of the AL-31FN.

CAC also knows the airflow requirements of the AL-31FN Series 3 along with a fixed DSI intake.

The J-20 intakes (also fixed DSI) are noticeably larger than all previous planes designed by CAC.

For the sake of argument, let's assume the WS-15 isn't ready at the moment. Why would CAC purposely design oversized intakes for a plane that will initially enter service with AL-31? Oversized intakes add weight and drag to an already gargantuan J-20 airframe. Why would the CAC engineers design such a stupid plane? Why would the PLAAF accept such a plane?

If the WS-15 shows up later, CAC has the option of redesigning a new intake for the new engine.

The F-16 (fixed intake) is the best example. When the General Electric F110 was adopted, the intake was redesigned and enlarged to accommodate the increased airflow requirements of the new engine. The F-16 currently has two different intakes!

I'm aware that the F-14A's TF30 engine was replaced with the F110 engine with no apparent intake redesign. But that is because the F-14 has a variable geometry intake with moving ramps that can control the speed and volume of airflow reaching the engine.

The J-20 has a fixed DSI intake and the DSI bump doesn't move. I assume there are no internal ramps hidden behind the DSI bump. The J-20 has no mechanical means to control the volume of airflow reaching the engine. Therefore, the size of the J-20 intakes must be the correct size from the very beginning.

This is perfectly normal because both the F-22 and F-35 have fixed intakes too. There is a reason why all stealth fighters have fixed intakes.

CAC is fully capable of redesigning the intake of an aircraft.

Look what the J-10 intake used to look like in 1991.

However, when the domestic engine didn't pan out, the intake was enlarged to accommodate the increased airflow requirements of the Russian AL-31FN. An engine change leads to an intake change.

DSI intake and AL-31FN Series 3 adopted for J-10B.

Also note in the above two pictures that the overall size of the intake remained approximately the same when the J-10 upgraded from AL-31FN to the increased thrust AL-31FN Series 3. In other words, the adoption of DSI did not drastically increase the size of the intake, even with the slightly increased thrust AL-31FN Series 3.

But suddenly the J-20 (DSI same as J-10B) intakes are very noticeably larger than all previous J-10 intakes.

Those that believe the J-20 is using AL-31 need to explain why the J-20 intakes are oversized. Don't skirt around this question.

 

[Asoka]

Brother vertical climbing is not without afterburner of J-20 nothing unusual I can show you lots fighter jets doing that for example PAK-FA doing your vertical climbs without using afterburner with interim engine so what is new for J-20 for vertical climb And not to forget that J-20 using low by pass aka turbojet engine to achieve super cruise High by pass engine has limited super cruise capabilities

I don't see a telltale sign of a long, hot, and bright exhaust coming out of the nozzles, so I just assume it's not using the Afterburner. The keyword is "sustained" vertical climbing, not just a loop or near vertical climbing.

If other planes can do a "sustained" vertical climbing, without Afterburner, it means its TWR in dry thrust is > 1. That's great.

J-20 is probably not the first one to do it. Some smaller and lighter planes like F-16, Rafael, probably did it a lot time ago.

I just used this fact to calculate J-20 engine's max. thrust. It's very significant that a large and heavy plane like J-20 to have a TWR > 1, with just dry thrust alone.

It means a very significant advantages in dog fighting. It means it has enough thrust, so that it does not need to use, the fuel intensive AB, to keep up with its opponents, and does not leave a long hot and very visible exhaust stream for your opponent's heat seeking missiles to go after.

This is a very very important advantage.

If your opponent can't see you, or lock onto you, that means he can't shoot you down.

Remember, the internal fuel capacity for F-22 and F-35 is around 8-9 tons, and for J-20 is near 12 tons.

If J-20 has a much larger internal fuel capacity, and don't need to use AB during combat, but you do, because it has a much higher dry thrust, the chance that you can out last this beast in fuel consumption, and out fight it, to tell a tale, is ZERO.

 

[Deino]

OMG ... not again !

That climb is for a few 100-feet ... if the horizontal Speed is fast enough, every aircraft do such a decent climb.

Did You ever try to post this BS in a forum with serious experts in propulsion, aerodynamics and aerospace technology?

But - UPPPS - Sorry I'm wrong:

From now on I admit, the J-20 can reach Mach 3 in level flight, it has a super-duper-hyper mega-powerful engine based on technology no other nation on earth has mastered in the thrust class exceeding the PW2000 even if much smaller ... So stronk, all others are total loosers!

... oh Lord I'm stupid !! Please forgive me, I'm stupid indeed and will never tell any contrary to the last paragraph; never ever.

 

[Asoka]

Mr. Deino can't even grasp basic concepts such as Thrust to Weight Ratio (TWR), Afterburner, sustained vertical climb, and he can't even read or write a single Chinese word, yet he has written several books on "Chinese Combat Aircrafts", and contributes to several aircraft magazines.

This is mind-boggling to me.

Mr. Deino is a typical know nothing "journalist". I almost want to order a copy of his book on Amazon, just to see, what he writes.

Mr. Deino has lost his bet that J-20 is using a Russian made AF-31-FN-M2 engine, yet he is still refuse to honor his promise to resign the position of Moderator.

I must say my opinion of the German people has dropped a notch because of Mr. Deino's shamelessness.

 

[nang2]

Mr. Deino is a typical know nothing "journalist". I almost want to order a copy of his book on Amazon, just to see, what he writes.

Mr. Deino has lost his bet that J-20 is using a Russian made AF-31-FN-M2 engine, yet he is still refuse to honor his promise to resign the position of Moderator.

I must say my opinion of the German people has dropped a notch because of Mr. Deino's shamelessness.

I think Deino is a fine mod. It isn't hard to estimate it wrong, especially about Chinese weaponry, thanks to Chinese elusive way of information sharing.

 

[Shotgunner51]

@wanglaokan @Asok @j20blackdragon @grey boy 2 @pakistanipower @Tiqiu @ChineseTiger1986

I have had great experience working together with fellow mod - Deino - he is a fair man, critical to details, dedicated to his work, and just as emotional as any normal man like all of us. Let us all have a friendly and peaceful coexistence aka all sides stop with their name-calling, personal attacks against nationality or profession (and these include certain smileys that's sometimes perceived as provocation, use some manner please). I suggest everyone only argue on technical matters, if anything is not confirmed it is admitted as such (until the true facts are confirmed, with data from credible sources). Personal opinions are allowed, personal analysis/investigations are encouraged (putting bits and pieces together, and reach one's own conclusion or assumption), so feel free to express, and do respect others' rights to do the same. Thanks and best regards, Shotgunner51

 

[Deino]

@wanglaokan @Asok @j20blackdragon @grey boy 2 @pakistanipower @Tiqiu @ChineseTiger1986

I have had great experience working together with fellow mod - Deino - he is a fair man, critical to details, dedicated to his work, and just as emotional as any normal man like all of us. Let us all have a friendly and peaceful coexistence aka all sides stop with their name-calling, personal attacks against nationality or profession (and these include certain smileys that's sometimes perceived as provocation, use some manner please). I suggest everyone only argue on technical matters, if anything is not confirmed it is admitted as such (until the true facts are confirmed, with data from credible sources). Personal opinions or views are encouraged, so feel free to express, and do respect others' rights to do the same. Thanks and best regards, Shotgunner51

Thanks a lot for these words and I admit that I'm surely emotional, indeed no longer impartial, maybe even biased.
But I think in the same way others can admit the same ... only from their own side of perception and understanding.

I promise to stick to these suggested rules so that the discussion can return to be rational and objective until the facts are actually openly confirmed and there is no room for further interpretation.

Deino

 

[Ultima Thule]

@wanglaokan @Asok @j20blackdragon @grey boy 2 @pakistanipower @Tiqiu @ChineseTiger1986

I have had great experience working together with fellow mod - Deino - he is a fair man, critical to details, dedicated to his work, and just as emotional as any normal man like all of us. Let us all have a friendly and peaceful coexistence aka all sides stop with their name-calling, personal attacks against nationality or profession (and these include certain smileys that's sometimes perceived as provocation, use some manner please). I suggest everyone only argue on technical matters, if anything is not confirmed it is admitted as such (until the true facts are confirmed, with data from credible sources). Personal opinions are allowed, personal analysis/investigations are encouraged (putting bits and pieces together, and reach one's own conclusion or assumption), so feel free to express, and do respect others' rights to do the same. Thanks and best regards, Shotgunner51

But why deino said that China can't install WS series of engine and insisting this indeginous engine is AL-31 M2

 

[That Guy]

But why deino said that China can't install WS series of engine and insisting this indeginous engine is AL-31 M2

Why are you offended by that? He's making a technical call, based upon his own knowledge. Disagree? Explain why.

 

[Ultima Thule]

Why are you offended by that? He's making a technical call, based upon his own knowledge. Disagree? Explain why.

Based on knowledge for what? he has a eye catching assessment with no base, he is no technical background, the biggest reason is that all Chinese senior members telling indigenous engine is install on J-20 @Deino can't agree with other Chinese senior members and Call its a home made AL-31M2 with no Prove if China make AL-31M2 it call reverse engineered not indigenous engine thats why i can't agree with him

Why are you offended by that? He's making a technical call, based upon his own knowledge. Disagree? Explain why.

Based on knowledge for what? he has a eye catching assessment with no base, he is no technical background, the biggest reason is that all Chinese senior members telling indigenous engine is install on J-20 @Deino can't agree with other Chinese senior members and Call its a home made AL-31M2 with no Prove if China make AL-31M2 it call reverse engineered not indigenous engine thats why i can't agree with him