J-20 5th Gen Fighter Thread IV (Closed to posting)

[ahadicow]

Can mod move this section into a different thread? We want to know about J-20, not how russian planes achieve incredible aerodynamic feats. And Mig 29, you argument sounds like "Russian planes can achieve this, so J-20 can achieve no more than this." May I suggest you resovle your "china inferior" complex somewhere else?

 

[Engineer]

In this picture of Graph 12 they show you the angle of deflection of the tailplane.

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Angles of deflection are not random, they even say after positioning the stabilizer the forces will start.

That does not contradict anything I have said. Once the Cobra maneuver is initiated, the tailplane becomes non-functional until the aircraft recovers. That is because the tailplane loses effectivenes at high angle of attack. Canard does not have such issues.

Triplane configurations or canard delta or tailplane configuration are not what make design better but the balance of the design it self, on Su-35 the Sukhoi bureax achieved a design that can do Kolokol, "hook" which basicly has not been replicated by any other fighter without Thrust vectoring.

The reliance on thrust vectoring actually illustrates inferior aerodynamics on the part of Su-35. Without that thrust vectoring, Su-35 couldn't sustain flight at high angle of attack anywhere close to what F-35 can do, eventhough tailplane is used by both aircraft.

Show me Kolokol by J-10 or J-20 and you will prove your point Cobra is not even proven by J-10 in air shows after almost 16 years of its first flight.

F-22 has shown it, F-16 too, but with thrust vectoring, the rest is the myth of the forum lore, no video.

I have already proved my point. Multiple sources have all stated that aircraft relying on tailplane lose controllability at high angle of attack while aircraft with canard can maintain controlled flight. So far, your claims to the contrary are just empty words, not factually supported in any manner.

You simple do not understand that stealth fighters are compromised and they need TVC nozzles or HMS as the Eurofighter pilot says.

Is either HMS and highly offbored missiles or Thrust vectoring what F-22 and F-35 use.
Eurofighter and SU-35 are more aerodynamic fighters.

Not so. While stealth features do impose design constrains, those contrains have clearly been overcame given how stealth aircraft have better performance than their non-stealth counterparts. Even without thrust vectoring, F-22 can fly faster and has a larger flight envelope than any non-stealthy aircraft.

The true compromise lies in aircraft such as the Su-35. These aircraft have a 40-year-old airframe, so they employ aerodynamic techniques that are only state of the arts 40 years ago. They are aerodynamically inferior to new generation of aircraft, which is why the Su-35 has to rely on thrust vectoring. For PAKFA, the design is compromised by the use of the tailplane, as controllability of the aircraft is lost at high angle of attack. For Sukhoi, there is no other choice but to use thrust vectoring.

J-20 is not different, its aerodynamics are compromised, its canard positioned ina way it limits its max effectivity, while Rafale has a better position.

Actually, the canard on J-20 is positioned very well. As long-coupled canard, it is able to provide large pitch authority using only small deflection. The Rafale uses short-coupled canard so the pitch authority from the canard is nearly non-existence. The LERX of the J-20 boosts the strength of vortices generated by the canard, allowing the long-couple canard to enhance lift as short-couple canard does. In short, the canard on the J-20 achieves what Rafale's canard does, and does so better.

Its large frontal cross section its huge, the jet has huge bumps on the intake increasing the cross section swelling the aircraft frontal cross section add to that the large nose and large and long body.

The frontal cross section on the J-20 is not any bigger than that of F-22 and PAKFA. At the same time, it is big enough for the installation of a big radar which allows the aircraft to see better. The longer fuselage gives the J-20 a better finess ratio as compared to the other fifth generation aircraft, thereby reducing drag. The bumps on the intake significantly reduce weight as compared to traditional intakes, while maintaining an equal level of efficiency.

If the jet adds external wing pylons the performance will reduce substantially.

Like other stealth aircraft, the J-20 can store its weapon internally. This reduces drag significantly as compared to non-stealth aircraft. It also reduces radar cross section, making it harder for an opponent to detect the J-20. The thing is, stealth aircraft have the option to use external stores, while non-stealthy aircraft have no choice but to use external stores and accept the associated performance penalities.

It is just a big F-35 with canards

This is actually a big compliment to the F-35, one that I don't feel this particular American aircraft deserves. Still, the F-35 can at least sustain flight at 50° angle of attack, while we know Flankers cannot.

In fact Su-35 carries L band UHF radar on the wing to detect Stealth fighters


It means simply Europe and the Russians are relying on aerodynamics and UHF radars to design a counter stealth force.

Europe has passive radars.

In reality, that's a compromise from the fact that the level of Russia's steath technology is mediocre, even when compared to China. This is pretty clear when one looks at the exposed air inlets on the PAKFA. Due to that backwardness in stealth, the PAKFA has to carry extra radars with weight that could have allocated to more weapons or fuel. The fact that these radars stick out of the aircraft hurts aerodynamics inaddition to increasing radar cross section.

Your are thinking J-20 has advanced while others are not trying to go other ways, the american concept of stealth is not followed as many think, in Europe and Russia are going for cheap alternatives.

Quite the opposite, the American concept of stealth is highly regarded by Russia and Europe. For Russia, this high regard is reflected in the PAKFA as the country attempted to make the plane as stealth as possible. For Europe, the high regard is shown in various stealthy UCAV projects. The issue is that neither Russia or Europe have enough money for a fully fedge stealth fighter. That is why Russia came up with a semi-stealthy aircraft while Europe focus on unmanned stealth aircraft.

Eurofighter and rafale can lightly armed with the right sensors perhaps give a good run for its money to stealth fightyers like J-20, J-31 or F-22

The fact that your scenario necessitate Eurofigher and Rafale to be lightly armed while engaging the F-22 already shows the superb performance of stealth fighters. I rest my case.

 

[Deino]

Guys ... please stay on topic !

and most of all @ MiG-29: PLEASE not in each and every post pages of text, numbers of links only to state Your claims.

Plase continure this looooooooooong discussion in the aerodynamics tread, THANK You.

Deino

 

[MiG-29]

That does not contradict anything I have said. Once the Cobra maneuver is initiated, the tailplane becomes non-functional until the aircraft recovers. That is because the tailplane loses effectivenes at high angle of attack. Canard does not have such issues.


The reliance on thrust vectoring actually illustrates inferior aerodynamics on the part of Su-35. Without that thrust vectoring, Su-35 couldn't sustain flight at high angle of attack anywhere close to what F-35 can do, eventhough tailplane is used by both aircraft.



I have already proved my point. Multiple sources have all stated that aircraft relying on tailplane lose controllability at high angle of attack while aircraft with canard can maintain controlled flight. So far, your claims to the contrary are just empty words, not factually supported in any manner.


Not so. While stealth features do impose design constrains, those contrains have clearly been overcame given how stealth aircraft have better performance than their non-stealth counterparts. Even without thrust vectoring, F-22 can fly faster and has a larger flight envelope than any non-stealthy aircraft.

The true compromise lies in aircraft such as the Su-35. These aircraft have a 40-year-old airframe, so they employ aerodynamic techniques that are only state of the arts 40 years ago. They are aerodynamically inferior to new generation of aircraft, which is why the Su-35 has to rely on thrust vectoring. For PAKFA, the design is compromised by the use of the tailplane, as controllability of the aircraft is lost at high angle of attack. For Sukhoi, there is no other choice but to use thrust vectoring.



.

Kolokol does not need TVC nozzles is a pure aerodynamic maneouvre.
You problem the way you see J-20 as many of the people here is you see it as an all dancing and doing jet.

It has compromised, Stealth is only good for X band wavelength, so what the other nations are doing is use passive or UHF radars.

Su-35 uses L and decimetric wavelength which detects Stealth aircraft.

J-20 needs TVC, it will need HMS and the right engine, that does not mean UHF radars, can not see it, specially new radars, like those in europe by cassidian.

This radar sees not only F-22, J-20 but also T-50.




well if you want to continue the talk go to the aerodynamics thread.

 

[Engineer]

Kolokol does not need TVC nozzles is a pure aerodynamic maneouvre.

Irrelevant, as It is not related to sustained flight at high angle of attack which I brought up in relation to the J-20.

You problem the way you see J-20 as many of the people here is you see it as an all dancing and doing jet.

No. The problem is that you joined this board with the very intention of putting down the J-20. Your last few posts are not much different than the posts you have made when you first joined the board. They involve listing any feature on the J-20 and claiming that feature to be bad. There is no logic, objectivity, or reference to relevant facts whatsoever.

It has compromised, Stealth is only good for X band wavelength, so what the other nations are doing is us passive or UHF radars.

Su-35 uses L and decimetric wavelength which detects Stealth aircraft.

In your own words, the necessity of installing extra radars would be a compromise. Those radars exist because Su-35 cannot see aircraft such as the F-22 at the range that F-22 can detect the Su-35. That's a compromise. The weight of those extra radars means less weight can be allocated to fuel and payload. That's also a compromise.

J-20 needs TVC, it will need HMS and the right engine

PLAAF is already equipped with HMS. Yes, the J-20 is still waiting for the WS-15. However, the J-20 has no need of thrust vectoring. The canard can provide the required pitch authority at high angle of attack. At the same time, the combination of canard, LERX and body-lift significant enhance lift as compared to a conventional aircraft, giving the J-20 excellent maneuverability. Furthermore, thrust vectoring offers little to no tactical advantages,

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whom you have quoted.

that does not mean UHF radars, can not see it, specially new radars, like those in europe by cassidian.

This radar sees not only F-22, J-20 but also T-50.




well if you want to continue the talk go to the aerodynamics thread.

UHF radar is only useful for detection. It cannot be used for fire control purposes. Nothing defeats stealth better than stealth itself.

 

[AssassinsMace]

Anyone know what that is?

 

[Deino]

Anyone know what that is?

Hmmm ... if I would not know better I would say a launch rail of an AAM from the side bay !??

Deino

 

[AssassinsMace]

Here's a guy's RC model that's closer than the ones seen before.

[video=youtube;kmTR1_UEinc]http://www.youtube.com/watch?v=kmTR1_UEinc[/video]

 

[AssassinsMace]

Hmmm ... if I would not know better I would say a launch rail of an AAM from the side bay !??

Deino

Here's the Youtube version of Siegecrossbow's video link earlier. At 4:26 is where this pic came from. I can't tell if the side door is open but when it lands you can see those markers on the side right where that rail would be.

[video=youtube;lzlAwi6Qna0]http://www.youtube.com/watch?v=lzlAwi6Qna0[/video]

 

[Engineer]

Anyone know what that is?

It appears to be the door to side weapon bay. It becomes obvious when you pause the video at around 4:32.