Chengdu J-20 5th Generation Aircraft News & Discussions

[Asoka]

Strangely, I don't take your insults. Perhaps, its because, I have several Indians and Pakistanis friends, school mates and roomates, and worked with many. I know how they think. I have one Indian rommate, Gaurav, we talks and talks, argues and argues for hours. Sometimes, we won't talk to each other, for days. But several days later, we always acts as if nothing has happen. That's how friends should behave. [

We are here to entertain each others and hoping to find some truths that governments won't tell us.

 

[gambit]

So I stand with my assumption/conclusion/opinion that J-20's BODY is more than 3m longer.

Now, if J-20 is actually the same weight as F-22, 19.7 tons, that means China's engineers had done an amazing feat of engineering to keep J-20 weight down, despite its 3m longer. That's mean China's airframe design has surpassed US.

It means no such thing.

There are so many things you have not considered. What if the J-20's engines are smaller and/or less complex ? The visual size is not indicative of its true nature. I can build a model car out of cardboard and painted it so it looks like the real version. Does that make mine the better 'car' ?

Most of an aircraft -- any aircraft -- is empty space. The J-20's fuselage section may had to be built longer due to aerodynamics demands.

Do you really want to know much -- or little -- is between you and the environment that could kill you ?

The J-20 is supposed to be larger to carry more fuel for longer range because of the lack of air refueling. Designing such an airframe does not mean any leap in architecture and materials.

 

[Asoka]

It means no such thing.

There are so many things you have not considered. What if the J-20's engines are smaller and/or less complex ? The visual size is not indicative of its true nature. I can build a model car out of cardboard and painted it so it looks like the real version. Does that make mine the better 'car' ?

Most of an aircraft -- any aircraft -- is empty space. The J-20's fuselage section may had to be built longer due to aerodynamics demands.

Do you really want to know much -- or little -- is between you and the environment that could kill you ?

The J-20 is supposed to be larger to carry more fuel for longer range because of the lack of air refueling. Designing such an airframe does not mean any leap in architecture and materials.

You quoted me: "That's mean China's airframe design has surpassed US."

Actually the whole passage is:

"Now, if J-20 is actually the same weight as F-22, 19.7 tons, that means China's engineers had done an amazing feat of engineering to keep J-20 weight down, despite its 3m longer. That's mean China's airframe design has surpassed US.

I am a patriotic Chinese, but I just can't believe this is true. F-22 is the world leading, state of the art aircraft design. . . . ."

I don't know why you deliberately misquoted me. To receive respect, one must first respect others. You have said Chinese members at PDF don't respect you. Have you shown respect to anyone of us?

I am sorry that I insulted you and don't respect you. Mostly because what you have said about the J-20 canards being unstealthy and can't possibly made to be stealthy.

In my opinion, you are actually a more informed and more knowledgeable PDF member. I should have checked my temper and responded calmly and politely.

ahojunk said "It takes a man to say sorry", but I think it takes a bigger man to accept the apology. It moved me a great deal that both ahojunk and Deino have accepted my apology graciously. I am actually quite surprised by their gracious responses.

I have apologized to @gambit here and hope to get rid of the hard feelings and restore the harmony.

@Deino, @ahojunk and others can be my witnesses.

"Designing such an airframe does not mean any leap in architecture and materials."
Who has said such thing?

I have said US is the world leader in Airframe design. One can't expect the Chinese to create an airframe that is 3m longer and stays the same weight as F-22. That's why I added 2 tons to J-20's weight, using F-22 as a baseline.

For a passenger plane, the fuselage is mostly empty space, that is true, @gambit. For a fighter plane, it is not. I really don't know what are you trying to say here.

Do you think J-20 is weight less, the same or more than F-22?

The nose to nozzle body length of F-22 is 17m longer, and the plane weights 19.7 tons, that a little more than 1 ton per meter, on average. If J-20 is more than 3m longer, and I assume it added only 2 tons more weight.

That's a very conservative estimate that J-20 is only two tons heavier.

I would honestly expect more, given China's airframe design is not as advanced as US. Other people might have said its 5 tons heavier.

 

[gambit]

For a passenger plane, the fuselage is mostly empty space, that is true, @gambit. For a fighter plane, it is not.

Yes, it is.

I was on two jets: F-111E (Upper Heyford) and F-16A/B/C/D (MacDill).

As in every engineering endeavor, there is always an overhead, a 'margin of error', some 'wiggle room', some 'flex'. Call it whatever you want.

But in aviation, mass and weight matters more than most engineering endeavors. In flight, weight is a penalty. That amount of 'overhead' or 'margin' is even more scrutinized at the conceptual level, meaning even before the jet's design was put on paper.

A jet fighter, a cargo, a bomber, is no different than an airliner. In fact, in the military, aesthetics is irrelevant.

This is what the interior of C-5 looks like...

Look at the 'ceiling' over the troops. You can see exposed aircraft components. Electrical conduits and even exposed wiring cablings, ducts, and insulation. Nothing covering them.

A jet fighter is no different. In fact, a jet fighter is even structurally more austere than any other aircraft design.

An aircraft is mostly empty space.

I really don't know what are you trying to say here.

Do you think J-20 is weight less, the same or more than F-22?

The nose to nozzle body length of F-22 is 17m longer, and the plane weights 19.7 tons, that a little more than 1 ton per meter. If J-20 is more than 3m longer, and I assume it added only 2 tons more weight.

That's a very conservative estimate that J-20 is only two tons heavier.

I would honestly expect more.

I am not going to get into a pointless debate on which jet is heavier. I am only pointing out the flaw in your argument that just because the J-20's empty weight MAYBE less than the F-22, somehow that translated into a more 'advanced' airframe design.

You want to be patriotic ? Fine. I have no problems with that. But do not strain logic in cheerleading for China.

 

[Asoka]

Yes, it is.

I was on two jets: F-111E (Upper Heyford) and F-16A/B/C/D (MacDill).

As in every engineering endeavor, there is always an overhead, a 'margin of error', some 'wiggle room', some 'flex'. Call it whatever you want.

But in aviation, mass and weight matters more than most engineering endeavors. In flight, weight is a penalty. That amount of 'overhead' or 'margin' is even more scrutinized at the conceptual level, meaning even before the jet's design was put on paper.

A jet fighter, a cargo, a bomber, is no different than an airliner. In fact, in the military, aesthetics is irrelevant.

This is what the interior of C-5 looks like...

Look at the 'ceiling' over the troops. You can see exposed aircraft components. Electrical conduits and even exposed wiring cablings, ducts, and insulation. Nothing covering them.

A jet fighter is no different. In fact, a jet fighter is even structurally more austere than any other aircraft design.

An aircraft is mostly empty space.


I am not going to get into a pointless debate on which jet is heavier. I am only pointing out the flaw in your argument that just because the J-20's empty weight MAYBE less than the F-22, somehow that translated into a more 'advanced' airframe design.

You want to be patriotic ? Fine. I have no problems with that. But do not strain logic in cheerleading for China.

"I am only pointing out the flaw in your argument that just because the J-20's empty weight MAYBE less than the F-22, somehow that translated into a more 'advanced' airframe design."

You got it in reverse.

My whole point is China's airframe design is not as advance as US, so it doesn't make sense to assume J-20 weights LESS than F-22.

 

[gambit]

My whole point is China's airframe design is not as advance as US, so it doesn't make sense to assume J-20 weights LESS than F-22.

Really...??? Try to keep up with your own arguments...

That's mean China's airframe design has surpassed US.

Source: https://defence.pk/threads/chengdu-...ews-discussions.111471/page-499#ixzz4Urut3M00

We can take a look at the entire comment...

Now, if J-20 is actually the same weight as F-22, 19.7 tons, that means China's engineers had done an amazing feat of engineering to keep J-20 weight down, despite its 3m longer. That's mean China's airframe design has surpassed US.

Source: https://defence.pk/threads/chengdu-...ews-discussions.111471/page-499#ixzz4UrvvzLhb

Note the highlighted 'if'.

Even as speculation, the idea that the J-20's airframe design is more advanced than the F-22 is absurd by virtue of lower weight despite longer length is absurd. There are so many things that are not airframe related that could produce a lower weight without making said airframe more 'advanced'.

 

[Asoka]

Really...??? Try to keep up with your own arguments...

Yes, really.

Here is really what I said:

"That's mean China's airframe design has surpassed US.
I am a patriotic Chinese, but I just can't believe this is true."

You can read that whole section again. I don't think China has surpassed US airframe design, not by a long, long, long shoot.

"It really is amazing how much efforts the Internet Chinese will go in straining logic and the laws of physics in trying to make the J-20 the superior."

How is claiming J-20 is 2 tons heavier makes it more superior?

What is your logic here?

 

[Deino]

...
The J-20 is supposed to be larger to carry more fuel for longer range because of the lack of air refueling. ....

Ähhhhm ... No airrefueling ?

 

[Asoka]

Ähhhhm ... No airrefueling ?

View attachment 366066

Even J-10 has a refueling prod.

 

[Deino]

Even J-10 has a refueling prod.

View attachment 366067

Yes I know, but I was surorised about Gambit's reply that the J-20 should lack that capability. It is known since years ...

 

[randomradio]

Yes I know, but I was surorised about Gambit's reply that the J-20 should lack that capability. It is known since years ...

Gambit overestimates the US and underestimates others.

 

[Asoka]

Gambit overestimates the US and underestimates others.

"Overestimates the US, and underestimates others."
It's now an American patent. They have copy-righted it. Hubris is not a sin, anymore. It's quite fashionable both among the Left and Right.

 

[randomradio]

"Overestimates the US, and underestimates others."
It's now an American patent. They have copy-righted it. Hubris is not a sin, anymore. It's quite fashionable both among the Left and Right.

Now, Gambit, you, me etc are irrelevant when we consider the big picture. But it's a huge problem if the US establishment has the same line of thinking.

Only a few months ago, I pointed out to him that quantum based technologies have matured a lot, to the point they are making prototypes, and that will render shaping based stealth wholly obsolete. He claimed it was all nonsense, that it is still decades away, and then just a few weeks later the Chinese reveal a quantum satellite and a radar.

From what I've heard, the J-20 is expected to carry a Digital AESA radar with GaN. If it's true, then it's a massive upgrade, difficult for anybody else to counter, definitely not something the F-22 can handle. As it stands today, only the Rafale likely has a digital radar, although based on GaAs for now. I just hope the F-35 has a digital radar that can compete with the J-20's radar or the US is going to be fighting the Chinese with outdated technology.

 

[grey boy 2]

 

[gambit]

Ähhhhm ... No airrefueling ?

My bad. I will rephrase my original thoughts. The original intent for the J-20 was to have less dependency on air refueling than Western fighters primarily because the PLAAF is not as capable as the US in terms of mastery of the skills involved.

Air refueling is not easy like everyone thinks it is.

The PLAAF's air refueling fleet is drogue equipped. This method has serious limitations in terms of refueling rates which affects how many aircrafts, even though they maybe small fighters, per event. Drogue delivers a lower rate of fuel flow than probe. Even though the receiver aircraft is a small fighter, it still consumes its own fuel while it is taking on fuel.

The US uses two methods: probe and drogue.

The probe method delivers a higher rate of fuel flow which is necessary for large receivers like the bombers and cargo jets.

The US Navy is an expeditionary force that must be as self reliant as possible uses the drogue method. Its lower fuel flow rate is adequate for its fleet of small aircrafts which came from aircraft carriers.

Using the US as example. The probe method can transfer up to 6,000 lbs/min. The drogue method is up to 2,000 lbs/min.

The J-20's size is no accident. The PLAAF realized its shortcomings in the air refueling area, but the need to have a 5th gen platform outweighs the need to have a comprehensive air refueling capability.

Note...

http://www.ausairpower.net/APA-PLA-Tanker-Programs.html

With a total fuel uplift at MTOW about one half of a KC-135E/R, each Badger in practical terms can adequately support only two fighters.

That is not two fighters at a time. But simply -- two fighters. Based upon its MTOW, as a modified platform, the air refueler Badger can carry only enough fuel to service only two fighters.

Remember, the client is burning fuel at the same time he is taking on fuel. If fuel flow rate in equals to fuel flow rate consume, you will NOT be refueling him. Your delivery must be higher than his consumption. If it is not high enough, the refueling time will take longer, but at the same time, you cannot cram fuel down his receptacle.

Assuming the J-20 is in full service. What this mean is that for every J-20 sortie, and we are looking at a typical four-ship sortie, if there is a need to air refuel this sortie, the PLAAF will have to assign its largest air refueler in inventory for that day.

Most people do not know it, but if you cannot provide that air refueling, that strike mission will be cancelled. That happened many times in Desert Storm when planners conflicted each other in terms of scheduling air refuelers.

At the current time, the US have 50 KC-10s, the largest of the air refuelers, and for the smaller KC-135s...

http://www.af.mil/AboutUs/FactSheets/Display/tabid/224/Article/104524/kc-135-stratotanker.aspx

Inventory: Active duty, 167; Air National Guard, 180; Air Force Reserve, 67

How many air refueler modified IL-78s does the PLAAF have in order to support a typical four-ship sortie to patrol the SCS, for example ?