J-10 Thread IV

[Deino]

Yusheng from pakdef just uploaded this hot shot. Is the convergent/divergent nozzle?

I would be careful with the term "convergent/divergent nozzle" for this new TVC-nozzle since the standard AL-31FN also ahs one.

But if You mean the new TVC-one You are wrong, it is clearly a J-10AY from the "Ba Yi".

Deino

 

[Tirdent]

1. In TVC nozzle of Su-35 and Pakfa (before article 30), the vector control part is marked (1). It is partially ball shaped. (2) is the converging part of the nozzle. (3) is the diverging part. The converging and diverging parts work in the same way as a conventional nozzle. The tilting of the nozzle is done by (1). This approach separated the work of converging and diverging from tilting. It is also heavier and longer than conventional counterpart.

Mostly correct. The weight and size penalty is pretty minor though - it's the same length as the non-vectoring AL-31F nozzle AFAIK and compared to Salyut's AVEN/PYBBN-style design, weight increase (per engine) is only about 15kg higher IIRC (for a Flanker, the equivalent of the difference between a skinny or fat pilot in total ). That's pretty inconsequential on a ~1600kg engine (a difference of not even 0.1%!) and the Su-35S configuration has other advantages: all cross sections along the nozzle axis remain almost perfectly circular regardless of vectoring angle, which eliminates a potential source of thrust losses.

BTW, the Izd. 30 nozzle as flown recently appears to follow the same concept as the Izd. 117/117S engine. It's not certain that the Salyut nozzle will be used.

3. J-10's TVC is in the same category as items 2 above, but with different implementation. See the red circles in the following diagram. This does not exists in the all engines in 2. This required the external paddles being constructed in two pieces joined by a hinge. See the red lines in the diagram below and pictures of J-10 further down. Why does the designer make this choice? What difference can be made compared with all other implementation? Maximizing the tilting angle? Further shortening the length of nozzle?

No idea to be honest. It's a relatively minor variation on the basic concept (first used by Salyut), so whatever advantages .or disadvantages it has are likely rather minor.

 

[Inst]

Trident, what do you think about my point regarding fuselage separation? Recall that Daniel's post discusses "enhanced stealth", and as we can see, the Chinese two-piece AVEN does not extend below the bottom of the fuselage when resting. Compare to the F-22 nozzle:

.

This also portends the possibility that the Chinese AVEN is not properly RAM-treated; i.e, with the nozzle blocked by the fuselage at all times, the AVEN does not impact frontal stealth. This presents a choice for Chengdu: they can choose not to treat the nozzles at all, reducing maintenance and engineering costs, but at the same time, if the aircraft is, say, 10 degrees off horizontal, RCS will spike.

Edit: comparing it to the F-22, I think in the F-22's case, the nozzles are blocked by the fuselage on a 0-degree heading. But the two-piece AVEN does permit the use of a thinner fuselage than otherwise--the F-22's engines and nozzles were mostly ready when the demonstrator flew, whereas the J-20 and Su-27's were not.

 

[Tirdent]

I think that patent is more about the blocker than the TVC. As for the two piece petals providing less of a break in the outer mold line when deflected, it's possible that this has stealth benefits, but on the other hand it introduces an additional gap in the surface (like a door). It could go either way.

 

[Inst]

From appearances, it almost looks like one-piece, so the gap is on the inside of the connecting petals, as opposed to between them. That said, I'd agree that it's mostly minor insofar as the F-22 creates a reflector with its TVC and the F-22 is still considered the gold standard of stealth.

 

[taxiya]

Mostly correct. The weight and size penalty is pretty minor though - it's the same length as the non-vectoring AL-31F nozzle AFAIK and compared to Salyut's AVEN/PYBBN-style design, weight increase (per engine) is only about 15kg higher IIRC (for a Flanker, the equivalent of the difference between a skinny or fat pilot in total ). That's pretty inconsequential on a ~1600kg engine (a difference of not even 0.1%!) and the Su-35S configuration has other advantages: all cross sections along the nozzle axis remain almost perfectly circular regardless of vectoring angle, which eliminates a potential source of thrust losses.

BTW, the Izd. 30 nozzle as flown recently appears to follow the same concept as the Izd. 117/117S engine. It's not certain that the Salyut nozzle will be used.



No idea to be honest. It's a relatively minor variation on the basic concept (first used by Salyut), so whatever advantages .or disadvantages it has are likely rather minor.

I think Izd. 30 indeed follows the rest than 117. Take a closer look at its picture, you can see the A8 and A9 actuators are in the similar arrangement with Non-117 nozzles.

And this one on the Su-57. I know there is an angle of photographing, but the length difference is still clearly visible.

 

[SinoSoldier]

Sat photos of the J-10C (or D) along with two JF-17Bs and a J-20A at Dingxin air base on November 30, 2017. Some are suspecting it to be a J-10D since Dingxin is normally reserved for testing prototype or pre-production aircraft instead of those already in production.

 

[Deino]

Sat photos of the J-10C (or D) along with two JF-17Bs and a J-20A at Dingxin air base on November 30, 2017. Some are suspecting it to be a J-10D since Dingxin is normally reserved for testing prototype or pre-production aircraft instead of those already in production.

But this is CAC at Chengdu-Huangtianba and not Dingxin !

 

[Figaro]

New update ... not sure what it means

He wrote this along with the picture on Weibo ...

参考最近的网爆照片，还有论文资料，以及目测，完成矢量菊和其他装置的大致描画，也算基本贴近了。没有高清图的日子，就只好靠它咯。头一次画这么深入画菊，有难度，但也学到很多东西。也重温一下李小龙机务队

，标志性的回忆。向他们致敬。

 

[vesicles]

New update ... not sure what it means
View attachment 44533
He wrote this along with the picture on Weibo ...

参考最近的网爆照片，还有论文资料，以及目测，完成矢量菊和其他装置的大致描画，也算基本贴近了。没有高清图的日子，就只好靠它咯。头一次画这么深入画菊，有难度，但也学到很多东西。也重温一下李小龙机务队

，标志性的回忆。向他们致敬。

The J-10’s thought:” back off! You perv”!