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

[tphuang]

I wonder how many more flying prototypes of this pre-production will be built. We got 2011 to 2013 so far with 2014 coming. They built 4 J-10s in the pre-production phase after the 9 that were built in initial developmental phase. J-10 project probably needed more of those initial prototypes to correct design and such, so that accounts for the more number of initial prototypes (9 for J-10 vs 4??? for J-20). But I would also think they have an improved design process in this project vs the J-10 project. I'm guessing it really depends on whether they need to do any kind of redesign to the aircraft. And also they would need new prototypes to be tested with improved engines. It certainly seems like if they intend for this to go into service by 2018, then they will flight test these 4. Possibly make minor changes and free design and build new one by end of 2015/early 2016. And then go ahead with low rate production sometimes in 2017.

 

[Player99]

I wonder how many more flying prototypes of this pre-production will be built. We got 2011 to 2013 so far with 2014 coming. They built 4 J-10s in the pre-production phase after the 9 that were built in initial developmental phase. J-10 project probably needed more of those initial prototypes to correct design and such, so that accounts for the more number of initial prototypes (9 for J-10 vs 4??? for J-20). But I would also think they have an improved design process in this project vs the J-10 project. I'm guessing it really depends on whether they need to do any kind of redesign to the aircraft. And also they would need new prototypes to be tested with improved engines. It certainly seems like if they intend for this to go into service by 2018, then they will flight test these 4. Possibly make minor changes and free design and build new one by end of 2015/early 2016. And then go ahead with low rate production sometimes in 2017.

Here on ifeng.com they were talking about "there might be 8 to 10 prototype flying..."

 

[LesAdieux]

there's a problem here, the J-20 is still waiting for the ws-15, it's using the AL31 as substitute for the moment. since the two engines got quite different thrust, they are supposed to have different size, does it mean they've got to redesign the J-20 later? then what's the point to make so many prototypes now?

 

[Blitzo]

there's a problem here, the J-20 is still waiting for the ws-15, it's using the AL31 as substitute for the moment. since the two engines got quite different thrust, they are supposed to have different size, does it mean they've got to redesign the J-20 later? then what's the point to make so many prototypes now?

They've probably tried to design the plane so they only need minimal redesign for later engines and to get as much valid data for WS-15 equipped models despite using interim engines.

Basically, it's not quite optimal, but it's definitely not a show stopper, especially if they've started from the outset knowing the plane would use different engines later on

 

[by78]

A clear shot of the "2013". I don't spot any visible change from "2013".

(2048 x 1331)

 

[latenlazy]

there's a problem here, the J-20 is still waiting for the ws-15, it's using the AL31 as substitute for the moment. since the two engines got quite different thrust, they are supposed to have different size, does it mean they've got to redesign the J-20 later? then what's the point to make so many prototypes now?

I've always thought that the reason why the nacelles look a bit weird with the J-20 is due to the fact that they're using smaller diameter engines than the final design intends, and that the nacelles will probably be redesigned when the WS-15 is installed.

 

[Deino]

A clear shot of the "2013". I don't spot any visible change from "2013".

It no longer has a pitot !

 

[LesAdieux]

They've probably tried to design the plane so they only need minimal redesign for later engines and to get as much valid data for WS-15 equipped models despite using interim engines.

Basically, it's not quite optimal, but it's definitely not a show stopper, especially if they've started from the outset knowing the plane would use different engines later on

unlike the ws-10/AL31 case, the two are pretty much exchangable; the difference between ws-15 and AL31 are significant, ws15 got 30% more thrust than AL31, so it could be significantly larger by size, which means its not going to be a minimal redesign. also because the J-20 is badly under power with the AL31, many of the fly test cannot be carried out.

 

[latenlazy]

unlike the ws-10/AL31 case, the two are pretty much exchangable; the difference between ws-15 and AL31 are significant, ws15 got 30% more thrust than AL31, so it could be significantly larger by size, which means its not going to be a minimal redesign. also because the J-20 is badly under power with the AL31, many of the fly test cannot be carried out.

It shouldn't be significantly bigger. A portion of the thrust increase will come from increased mass flow, but a portion will also come from increased inlet temperatures.

Flight tests should be fine actually, because they can just reduce the weight of the aircraft with less fuel to simulate the appropriate T:W ratio.

 

[delft]

It no longer has a pitot !

That shouldn't be a surprise. By using a number of static ports at well chosen places and use a suitable ccomputer program you can get more information and avoid the trouble of having a pitot tube which as we know might include people trying to hang on them and so bending them.