Chengdu J-20 5th Generation Aircraft News & Discussions

[Deino]

NO !

 

[AlyxMS]

People who aruges that J-20 used TVC nozzles always posts pictures that might make you think the nozzles aren't pointing straight if you squint your eyes real hard.

While any proper TVC nozzle will vector over 20 degrees which are easily recognizable beyond dispute.

Think about it:
If J-20 does have TVC, where are the images with the nozzles that are obviously vectoring? (<10deg.)
If J-20 does have TVC but it's disabled to hide this ability, why do we have images that looked like the nozzle is slightly (>5deg.) off center? Is CAC that incompetent that shutting down TVC is not possible?
Why woud CAC give J-20 a TVC at the cost of extra weight just to allow a maximum of >5 degree of vectoring?

There's only one logical conclusion:
There's no evidence to suggest J-20 is equipped with TVC nozzles. The pictures people use to argue that there is are likely illusions caused by lighting, camera lenses or two nozzles at different closed/open state.

 

[gambit]

NO !

Do you see now -- why debating these guys are so entertaining ?

 

[cirr]

http://www.bilibili.com/video/av6935520/

 

[siegecrossbow]

http://www.bilibili.com/video/av6935520/

This was an early video posted on October 2nd.

 

[Asoka]

The top two pictures show former Chinese President Jiang Zemin visiting the engine testing facility and trying out the control of the vector thrusting nozzle with a joy stick. The information about the VT nozzle was displayed at the Chinese Air show in 2000 and 2004.

Here these pictures clearly show the nozzles are turned to the left. If it is merely an optical illusion, what or how caused this illusion?

This pictures shows the Chinese aviation experts approved the design of the engine with the thrust to weight ratio of 10 (WS-15). The date is Feb, 27, 2006.

It seems before the final design of the WS-15 was approved the core of the engine was already tested successful in April, 22, 2005. And the reports say the designers worked 15 years for that result. The Chinese were learning from the West that design and test of the core engine should be done separately before the design of the overall engine, not as one big step.

These reports indicated the WS-15 project was started in 1990, and the core was successfully tested in 2005, the design was approved in 2006, and the maturity of the overall engine is probably reaching acceptable level after 10 years of development.

 

[Globenim]

矢量噴管 Folks, does these pictures look like J-20 has thrust vectoring to you.

The last picture clearly shows the nozzles are pointing downward to me.

No looks closer. Its just looks tilted because of the reflection on top of the nozzle and the shadow at the bottom.

 

[Asoka]

No looks closer. Its just looks tilted because of the reflection on top of the nozzle and the shadow at the bottom.

What about another picture with several green, red and yellow reference lines drawn?

 

[Globenim]

What about another picture with several green, red and yellow reference lines drawn?

Unequally expanded nozzles, right (in picture left) iris is simply bigger, and the iris center is generaly not on same level as the bottom red line so at this angle of the photoshot it will appear perpendicular shifted to the left because of perspective and well just generally perspective and possibly some lens distortion too

 

[Asoka]

The original yellow reference line seems skewed to me, so I drawn a white line straight down vertically along the middle of the two engines. The left engine appears even more tilted toward the left. I do not believe lens distortion has anything to do with it. I am still not sure whether this is due to the perspective effect.

We have seen many times that the J-20 nozzle's iris expansion can be controlled individually. May be the vector thrust nozzles can also be controlled or altered individually. What kind of flying can be achieved with kind of fine controls, I am not sure.

 

[Asoka]

http://www.bilibili.com/video/av6935520/

The 180 degree turn demonstrated by J-20 is extraordinarily tight with no visible loss of significant speed. It is doubtful any other aircraft can do it without the use of vector thrust.

People who aruges that J-20 used TVC nozzles always posts pictures that might make you think the nozzles aren't pointing straight if you squint your eyes real hard.

While any proper TVC nozzle will vector over 20 degrees which are easily recognizable beyond dispute.

Think about it:
If J-20 does have TVC, where are the images with the nozzles that are obviously vectoring? (<10deg.)
If J-20 does have TVC but it's disabled to hide this ability, why do we have images that looked like the nozzle is slightly (>5deg.) off center? Is CAC that incompetent that shutting down TVC is not possible?
Why woud CAC give J-20 a TVC at the cost of extra weight just to allow a maximum of >5 degree of vectoring?

There's only one logical conclusion:
There's no evidence to suggest J-20 is equipped with TVC nozzles. The pictures people use to argue that there is are likely illusions caused by lighting, camera lenses or two nozzles at different closed/open state.

The extraordinary tight 180 degrees turn demonstrated by J-20 in the recent video posted in this page is strong evidence of vector thrust. In fact one of the commentator, a former Chinese General said that.

 

[AlyxMS]

The extraordinary tight 180 degrees turn demonstrated by J-20 in the recent video posted in this page is strong evidence of vector thrust. In fact one of the commentator, a former Chinese General said that.

Arguing a good turn radius = TVC is like good score in olympics = PED. It could've been executed without TVC. (Also that turn is not that spectacular, a J-10 could've easily done it)
Besides, that turn is 100% documented via HD video, not in a single frame did we see the nozzles turning. (Or if the nozzles did turn, they turned so slight that it's completely unnoticeable) Therefore J-20 did that turn without using TVC, didn't this fact just defeated your point?

 

[Asoka]

Arguing a good turn radius = TVC is like good score in olympics = PED. It could've been executed without TVC. (Also that turn is not that spectacular, a J-10 could've easily done it)
Besides, that turn is 100% documented via HD video, not in a single frame did we see the nozzles turning. (Or if the nozzles did turn, they turned so slight that it's completely unnoticeable) Therefore J-20 did that turn without using TVC, didn't this fact just defeated your point?

I have never seen a fighter with TVC could turn like that in high speed. Show me some videos.

One major reason that I don't believe all J-20 are using AL-31 engines is that its engine sound is completely different to Su-27 and Su-30. And its much louder too.

 

[SQ8]

I have never seen a fighter with TVC could turn like that in high speed. Show me some videos.

One major reason that I don't believe all J-20 are using AL-31 engines is that its engine sound is completely different to Su-27 and Su-30. And its much louder too.

From 3:08 on wards

TVC only effect post stall manoeuvrability.

 

[AlyxMS]

I have never seen a fighter with TVC could turn like that in high speed. Show me some videos.

One major reason that I don't believe all J-20 are using AL-31 engines is that its engine sound is completely different to Su-27 and Su-30. And its much louder too.

I assumed you meant "without TVC".
Here goes:

The same engine can make different sound depending on a lot of variables. A few as examples: Throttle setting, after burner, altitude, speed(doppler effect) even the tail structure of a plane.

Whether it's louder or quiter: same thing, with the added factor of "your speaker's volume settings".

Also you gotta have insanely good ears to conclude "this is not AL-31" just by hearing it(which were recorded in a open space with loads of ambient noises by the built in mic of a handheld camera).

Please address my second point regarding my previous post if you'd like to.