J-20 5th Gen Fighter Thread V

[Pmichael]

Adding thrust vectoring to J-20 wouldn't only add to weight but also to fuel consumption. Together it might cost 20% of range. That's why the configuration of J-20 was chosen not to need thrust vectoring. I suggest it is just as unnecessary as the swing wing.

eh, where did you get the 20%?

It's like the first time I read that TVC would reduce the range of an aircraft although it could increse the efficiency for supersonic/supercruise (aka increases the thrust and range) of an aircraft.
The reasons why teh J-20 doesn't have TVC is morelikely the plain lack of a workable system right now.

 

[delft]

eh, where did you get the 20%?

It's like the first time I read that TVC would reduce the range of an aircraft although it could increse the efficiency for supersonic/supercruise (aka increases the thrust and range) of an aircraft.
The reasons why teh J-20 doesn't have TVC is morelikely the plain lack of a workable system right now.

The weight would decrease the amount of fuel carried for the same take off weight. The resistance to the flow through the TVC has to be compensated for by a larger engine burning more fuel. Compensated to some extent by a possible reduction in trim drag

 

[latenlazy]

eh, where did you get the 20%?

It's like the first time I read that TVC would reduce the range of an aircraft although it could increse the efficiency for supersonic/supercruise (aka increases the thrust and range) of an aircraft.
The reasons why teh J-20 doesn't have TVC is morelikely the plain lack of a workable system right now.

Uh. Well given what we know what China's research into TVC, I'm not sure lack of a workable system is the sound conclusion to draw.

 

[Pmichael]

The weight would decrease the amount of fuel carried for the same take off weight. The resistance to the flow through the TVC has to be compensated for by a larger engine burning more fuel. Compensated to some extent by a possible reduction in trim drag

Of course such a system would add addtional weight to the aircraft but at the same time you optimize the flow conditions of your engines. A reduction of the range of 20% is baseless at best and would also be an instant kill for such systems.

Uh. Well given what we know what China's research into TVC, I'm not sure lack of a workable system is the sound conclusion to draw.

Maybe I missed a test flight but pretty sure we don't know single test flight of a chinese TVC system. That's pretty much the only conclusion you can draw from this fact.

 

[latenlazy]

Of course such a system would add addtional weight to the aircraft but at the same time you optimize the flow conditions of your engines. A reduction of the range of 20% is baseless at best and would also be an instant kill for such systems.



Maybe I missed a test flight but pretty sure we don't know single test flight of a chinese TVC system. That's pretty much the only conclusion you can draw from this fact.

It's not the *only* conclusion. 1) Just because we haven't heard about a test flight doesn't mean it didn't happen. 2) Not being test flown does not necessarily equate to not being ready. They may simply not find the technology compelling enough to integrate into a design (even a test one). To my knowledge Eurojet has never test flown a TVC engine, but I don't think anyone doubts that they have the technology ready. Similarly we know that there was a TVC version of the WS-10 at one point.

Point 1 as a standalone argument is pretty weak of course, but the body of evidence doesn't suggest that China isn't using the technology because they don't have it, and not using a technology isn't only explainable in the way you're presenting.

 

[Quickie]

TVC is not a must have for all types of fighter jet. The main advantages of TVC are reduction in trim drag and recovery from stalling. Dr. Song's paper specifically mentions about solving the latter problem without the use of TVC. And if the reduction in trim drag can also be reasonably mostly solved with aerodynamic design alone and this compares reasonably well with the reduction in trim drag by way of TVC but without its added weight and maintenance hassle, one can easily see why the J-20 designers choose the former.

 

[Deino]

What do You think guys ... will we see '2101' in the air before new-year / December 31. ?

 

[delft]

I would expect very few days should be needed after roll out to do the necessary tests before the first flight unless something serious happens.

 

[Equation]

What do You think guys ... will we see '2101' in the air before new-year / December 31. ?

I say before the Chinese New Year (Spring Festival) starts.

 

[Blitzo]

I say before the Chinese New Year (Spring Festival) starts.

Heh that's over a month, quite a long span of time. I'd say it will definitely make its maiden flight before Chun Jie, but whether it occurs within a few days from now or a week from now or three weeks from now is another question.