J-20 5th Gen Fighter Thread VI

[ougoah]

Is that a relevant criticism of my argument? The F-35's original specs indicated that it should be capable of 5G sustained turn at altitude and speed. As it turns out, the aircraft was overweight and the requirements postulated by the Pentagon were downgraded to 4.2 G, if memory serves.

What we know right now is that the J-20 was intended to be supermaneuverable without resorting to TVC or having high thrust engines, and we already know that there's one disappointment: the aircraft is supposed to be able to supercruise with engines as is, but rumors as they come claim that the aircraft needs upgraded engines to supercruise.

Which rumours? Oh yes the ones you made up. Seriously rumours are just that. How do you know so certainly that it's not supercruise-able???????? You make it sound like that's already a certainty and your speculations are based off these rumours by morons. One of these rumour spreaders is a proven moron, liar, and question dodger. I honestly don't know how half the people here even graduated high school. How hard is it to think.

 

[Inst]

Ougoah: Here's the reasoning. You have very aggressive and optimistic (for the Chinese) "sources" like WantWantChina or Tiananmen's Tremendous Achievements. Even these groups claim that the J-20 requires upgraded engines to be capable of "supercruise without afterburners", a pleonasm if there ever was one, but that implies that the J-20 simply can't supercruise in the present configuration. For fanboys, a very basic claim has to be that the J-20 can achieve moderate supercruise loaded with the current engines.

 

[siegecrossbow]

Ougoah: Here's the reasoning. You have very aggressive and optimistic (for the Chinese) "sources" like WantWantChina or Tiananmen's Tremendous Achievements. Even these groups claim that the J-20 requires upgraded engines to be capable of "supercruise without afterburners", a pleonasm if there ever was one, but that implies that the J-20 simply can't supercruise in the present configuration. For fanboys, a very basic claim has to be that the J-20 can achieve moderate supercruise loaded with the current engines.

Hence the need for higher fuel capacity.

 

[vincent]

Ougoah: Here's the reasoning. You have very aggressive and optimistic (for the Chinese) "sources" like WantWantChina or Tiananmen's Tremendous Achievements. Even these groups claim that the J-20 requires upgraded engines to be capable of "supercruise without afterburners", a pleonasm if there ever was one, but that implies that the J-20 simply can't supercruise in the present configuration. For fanboys, a very basic claim has to be that the J-20 can achieve moderate supercruise loaded with the current engines.

Everyone is pulling numbers out of their asses, you included. So stop the fan boy accusations

 

[manqiangrexue]

Ougoah: Here's the reasoning. You have very aggressive and optimistic (for the Chinese) "sources" like WantWantChina or Tiananmen's Tremendous Achievements. Even these groups claim that the J-20 requires upgraded engines to be capable of "supercruise without afterburners", a pleonasm if there ever was one, but that implies that the J-20 simply can't supercruise in the present configuration. For fanboys, a very basic claim has to be that the J-20 can achieve moderate supercruise loaded with the current engines.

Interesting how you scorn these sources as highly unreliable and disconnected from reality but if they say something that you want to hear (J-20 needs upgraded engines to supercruise), suddenly, that's good enough for you to believe...

For me, when I don't trust a source (like those 2 you mentioned), I discount them completely and don't even bother to read them.

 

[ougoah]

Okay I see your reasoning behind no supercruise. May very well be the case but since these are quite unreliable, it's best we keep an open mind about it. It's hardly something we can say with any degree of certainty unlike something for example like the 4 PL-15 capacity of main bay. That we know from pictures and simple dimensions. So speculating on supercruise-ability, is a step too far.

 

[Inst]

My overall point is that you cannot rely on a design document to tell you about the characteristics of an aircraft. Over its development process, aspects are changed and flying characteristics may disappoint.

The idea that since the J-20 is supposed to be maneuverable, it is maneuverable is intellectually unsound. The reports we've obtained suggest that the J-20 in actuality is not significantly superior than the J-11 and J-20 is the subsonic domain, but that it outperforms in the supersonic domain. But think about the implications: the F-22 and Su-57 are known for exceptional subsonic agility. If the J-20 is merely above average, it implies that in the subsonic flight domain it's not as agile as the F-22 and Su-57 in that region.

This is not necessarily a bad thing; remember, with future 180kn engines, a 16000 kg empty weight, and an estimated 28500 loaded weight, the J-20 has a fueled T/W of 1.29 and a 60% fuel T/W of 1.55 .

I think I've used this anecdote before, but consider this: a A6M2 in its ideal flying regime can possibly outturn an F-16. But one of the reasons the A6M2 isn't an air superiority fighter of choice is because its flight regime is easily supersede-able; i.e, the F-16 can go faster and stay faster than the A6M2, so even if we ignore air-to-air missiles the A6M2 is what it is, a World War II aircraft.

In the same way, the J-20, if the report of empty weight is credible, can force engagements at higher speeds than what its rivals are comfortable with.

 

[latenlazy]

My overall point is that you cannot rely on a design document to tell you about the characteristics of an aircraft. Over its development process, aspects are changed and flying characteristics may disappoint.

The idea that since the J-20 is supposed to be maneuverable, it is maneuverable is intellectually unsound. The reports we've obtained suggest that the J-20 in actuality is not significantly superior than the J-11 and J-20 is the subsonic domain, but that it outperforms in the supersonic domain. But think about the implications: the F-22 and Su-57 are known for exceptional subsonic agility. If the J-20 is merely above average, it implies that in the subsonic flight domain it's not as agile as the F-22 and Su-57 in that region.

This is not necessarily a bad thing; remember, with future 180kn engines, a 16000 kg empty weight, and an estimated 28500 loaded weight, the J-20 has a fueled T/W of 1.29 and a 60% fuel T/W of 1.55 .

I think I've used this anecdote before, but consider this: a A6M2 in its ideal flying regime can possibly outturn an F-16. But one of the reasons the A6M2 isn't an air superiority fighter of choice is because its flight regime is easily supersede-able; i.e, the F-16 can go faster and stay faster than the A6M2, so even if we ignore air-to-air missiles the A6M2 is what it is, a World War II aircraft.

In the same way, the J-20, if the report of empty weight is credible, can force engagements at higher speeds than what its rivals are comfortable with.

The program tender and design documents for the J-20 stated that supermanueverability was a requirement. Do we have cause to believe the requirements for the J-XX’s tender has changed or shifted?

We have comments from other pilots that the F-22’s subsonic maneuverability isn’t outstanding compared to, say, the Eurofighter’s. The consistent theme in comments on the F-22’s performance in mock fights seems to be that they don’t stay in the subsonic regime for very long, their main advantage is in transient energy conversation, their radar evasion makes it difficult for opponents to get a lock window on them. Meanwhile, comments we have on the J-20’s subsonic maneuverability only says that it was “pretty good”. I don’t recall anyone making any comparisons to other fighters. Not sure where you get the impression that it was only as good as a J-11 from.

 

[Blitzo]

Meanwhile, comments we have on the J-20’s subsonic maneuverability only says that it was “pretty good”. I don’t recall anyone making any comparisons to other fighters. Not sure where you get the impression that it was only as good as a J-11 from.

This.

It was mentioned in key forum just earlier today as well and I have no idea where this idea of J-20's performance compared to XYZ came from.

All we have from the J-20 pilot's interview after the parade regarding J-20's performance is how well it performs subsonic and supersonic. They mention nothing about its performance relative to J-11 or any other aircraft.

 

[Engineer]

My overall point is that you cannot rely on a design document to tell you about the characteristics of an aircraft. Over its development process, aspects are changed and flying characteristics may disappoint.

You are essentially arguing that reality falling short of expectation invalidates everything else that did meet expectation. Your argument is a fallacy.

Let's replace the word "J-20" with "bridge" to illustrate the absurdity of your argument. Architect designed a bridge. Over its construction process, aspects are changed and the bridge characteristics disappoint. That means it isn't a bridge anymore.

One can absolutely rely on design documents to infer aircraft characteristics, because that's the entire purpose of design documents.

The idea that since the J-20 is supposed to be maneuverable, it is maneuverable is intellectually unsound. The reports we've obtained suggest that the J-20 in actuality is not significantly superior than the J-11 and J-20 is the subsonic domain, but that it outperforms in the supersonic domain. But think about the implications: the F-22 and Su-57 are known for exceptional subsonic agility. If the J-20 is merely above average, it implies that in the subsonic flight domain it's not as agile as the F-22 and Su-57 in that region.

This is not necessarily a bad thing; remember, with future 180kn engines, a 16000 kg empty weight, and an estimated 28500 loaded weight, the J-20 has a fueled T/W of 1.29 and a 60% fuel T/W of 1.55 .

I think I've used this anecdote before, but consider this: a A6M2 in its ideal flying regime can possibly outturn an F-16. But one of the reasons the A6M2 isn't an air superiority fighter of choice is because its flight regime is easily supersede-able; i.e, the F-16 can go faster and stay faster than the A6M2, so even if we ignore air-to-air missiles the A6M2 is what it is, a World War II aircraft.

In the same way, the J-20, if the report of empty weight is credible, can force engagements at higher speeds than what its rivals are comfortable with.

No. It is your argument here that is intellectually unsound. J-20 does not have to be significantly superior in manoeuvrability than Su-27 as a prerequisite for J-20 to be manoeuvrable. J-20 being at least as manoeuvrable as Su-27 already means J-20 is manoeuvrable. Period.