J-20 5th Generation Fighter VII

minime said:

F22 has a monstrous T:W ratio still unbeaten to this day. Don't think anything gonna top that till a VCE/ACE engine breakthrough.

If I understand correctly, for sustain turn the sub-sonic lift-drag the higher the better with a powerful enough engine but it's a liability for super-sonic cruise because too much drag.
If F-22 is so good at sustain turn which I believe is better than the gold standard F-16,
how does F-22 overcome the drag and maintain supercruise with only dry thrust?

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Mig-29, F-16 have more of the same T:W ratio... supercruise is a lot about drag and thrust at military power.

F110 (f16): 61% maximum thrust at military power, RD-33k (mig29) 61%, AL31F: 62%, WS10a: 64%....
F119 (F22): 74% maximum thrust at military power ! So supercruising is way easier...

Snecma Olympus 593(Concorde ): 82 % and a thrust ratio of less than 0,37 but minimum drag... supercruise like knife in butter.

We will see with WS-15, maximum trust on afterburner means nothing for supercruising. J-20 need an engine with a high military power ratio to be more efficient.

Mohsin77 said:

Not kool man...

The Raptor dominated the skies for 20 years. That's like twice as long as Jordon and the Bulls. The fact that it's still in the conversation of best fighter today is what makes it a legend.

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It didn't dominate the skies against anything though. It entered service when the US was in the prime of its power while the Soviets fell apart and modern China hadn't come of age yet. There was nothing to challenge it so it was basically a very small pond for this fish to dominate and even so (or more likely because of that), it was never really put to the test against any capable enemy fighter. Given those circumstances, it's very easy for the US to paint an aura of invincibility for it regardless of what flaws it may have to use as an intimidation factor. Even so, hints slip out at the cracks that may normally be hidden as the Typhoon reportedly had a "Raptor sandwich" during a NATO dogfighting exercise. (The US did that with the F-15 too over its kill rate on unqualified opponents but I'd put money on a Flanker over the F-15 anytime as they destroyed the F-15s in mock combat over Alaska.) But now, the landscape has changed and China, even Russia are in much better position to put forth their challenges. We should not help American propaganda by perpetuating the mythical golden pedestal that the US wants for its unproven Raptor.

Atomicfrog said:

Mig-29, F-16 have more of the same T:W ratio... supercruise is a lot about drag and thrust at military power.

F110 (f16): 61% maximum thrust at military power, RD-33k (mig29) 61%, AL31F: 62%, WS10a: 64%....
F119 (F22): 74% maximum thrust at military power ! So supercruising is way easier...

We will see with WS-15, maximum trust on afterburner means nothing for supercruising. J-20 need an engine with a high military power ratio to be more efficient.

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Thanks for the input. That's exactly why I think even J-20 has superior Supersonic maneuverability but still can't Supercruise until it gets the proper WS-15 upgrade.

I make a little table just for fun to show my understanding of current 5 gen fighters.
Please let me know if there any major flaw

Deino said:

Impressive ... does he has a FB, Twitter or Weibo account? I would like to contact him.

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I saw these photos from another forum.

But I think you can contact the photographer by his/her id 前站起飞@weibo.com.

minime said:

Thanks for the input. That's exactly why I think even J-20 has superior Supersonic maneuverability but still can't Supercruise until it gets the proper WS-15 upgrade.

I make a little table just for fun to show my understanding of current 5 gen fighters.
Please let me know if there any major flaw
View attachment 96538

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Sorry, I don't mean this as any personal insult and I hope we can laugh about this but this chart is the most worthless thing I've ever seen LOL. The numbers assigned look like you're trying to invent a video or card game for kids. Even analysis using sophisticated software calculating lift, drag, wing loading, TWR, radar cross-section, projected radar capacity down to the node, usually turn out to be total bunk when 2 aircraft actually meet.

manqiangrexue said:

Sorry, I don't mean this as any personal insult and I hope we can laugh about this but this chart is the most worthless thing I've ever seen LOL

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Maybe my method is totally irrelevant or not practical at all for evaluating fighters
But I was hoping for more constructive opinion.
Perhaps you can show me how you do it?

minime said:

Maybe my method is totally irrelevant or not practical at all for evaluating fighters
But I was hoping for more constructive opinion.
Perhaps you can show me how you do it?

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The thing is to realize when there's no way to do something rather than try in crazy and irrelvant ways. This is the official stance of the forum and the mods who are experienced with military aviation all agree. It's better to leave an impossible and contentious task unattempted rather than to have several versions of disinformation out there which actually go against forum rules as it can cause members with opposite views to clash with their own versions of disinformation essentially turning the forum into a dumpster for such useless things. That would severely degrade the professionalism here so the rule is to never undertake A vs B (vs C vs D) comparisons between aircraft. I think the most constructive advice here is to not attempt to do it.

Comparisons between different aircrafts don't make that much of a sense. Its not about weapon vs weapon or even platform vs platform.

It's all about Systems Confrontation. You can have the most garbage plane in the world but if your system beats the opponent's system then you are left satisfied with that "garbage" plane and then go on with singing its praises every day.

I would rather we stay away from such comparisons (J-20 vs F-22/F-35 vs Su-57). Every airforce follows its own doctrine so each aircraft is designed to suit its needs. China is happy with the J-20, the US happy with its F-35 and so on.

siegecrossbow said:

The caveat is that you need to fly at a higher angle of attack to take advantage of the vortex lift. That would slow you down in a turning fight, which admittedly has a very low chance of happening.

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I was aware of this thought when I read the article. The ultimate question is what is the lift coefficients of J-20 and F-22 through the whole range of their AOA. Which we don't have for either J-20 or F-22. So the notion of "F-22 is better in sustained turn than J-20" is unfounded at least.

Here is the wind tunnel test outcome from CAC. Vertical axis is lift coefficient. Horizontal axis is AOA. Note, this is an early model of CAC 4th gen design with underside intake, otherwise same as J-20. The real figure of J-20 may differ. The model's wing AR=3, swept 45 degrees.

I will not use it as an argument but I remember reading another paper saying that J-20's lift coefficient is higher than XXXX or being the highest. I will post it if I find the paper again.

taxiya said:

I was aware of this thought when I read the article. The ultimate question is what is the lift coefficients of J-20 and F-22 through the whole range of their AOA. Which we don't have for either J-20 or F-22. So the notion of "F-22 is better in sustained turn than J-20" is unfounded at least.

Here is the wind tunnel test outcome from CAC. Vertical axis is lift coefficient. Horizontal axis is AOA. Note, this is an early model of CAC 4th gen design with underside intake, otherwise same as J-20. The real figure of J-20 may differ. The model's wing AR=3, swept 45 degrees.

I will not use it as an argument but I remember reading another paper saying that J-20's lift coefficient is higher than XXXX or being the highest. I will post it if I find the paper again.

View attachment 96545

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You are always flying at a non zero angle of attack when you are doing a turn, especially at your maximum turn rates. That’s why the lift *to* drag ratio matters. Not just lift alone or drag alone. This is why all turns bleed energy and speed. What afflicts the J-20 here also afflicts the F-22 and every other fighter.