J-20 5th Generation Fighter VII

weig2000 said:

I think that's a hypothesis that fits reasonably well with the observed data, say with 90% confidence level.

CB00-11
CB00-14 DX 787
CB00-18
s/n: 1 - 20
------------------------------------
CB01-21
CB01-34 ETC 9th Bde 62103?
CB01-40 ETC 9th Bde 62200?
s/n: 21 - 40
------------------------------------
CB02-55 NTC 1st Bde
CB02-56 NTC 1st Bde
s/n: 41 - 60
------------------------------------
CB03-69 3rd Training Regt
CB03-70 3rd Training Regt
s/n: 61 - 80
------------------------------------
CB04-xx, no observed data
s/n: 81 -100
------------------------------------
CB05-107 ETC 8th Bde
s/n: 101 - 120
------------------------------------
CB06-xxx, no observed data
s/n: 121 - 140
---------------------------------
CB07-156
s/n: 141 - 160

So if batch #7 is the current batch in production, we have at most 160 J-20s in service now.

Click to expand...

piko1 said:

it can be 20 per batch but if they ramp up the production even more i don't think it wold be 20 actually im amused by the fact that PLAF has so many J-20's it looks at least to me that they use it as pure Interceptor more than Fighter as more i read the more im convinced that the Russian replacement for MiG-31 PAK-DP would look a lot like J-20 ( without the DSI ) if the trumpeter 1/48 kit is correct in size ( big if )
compared to Mig-31 in the same scale they look similar in size

Click to expand...

BoraTas said:

The numbers actually allow 24 aircraft per batch starting with batch 05. Likely? No.

The J-20 is as interceptor as the F-4 was. It definitely sacrificed a bit of turning performance for range, max speed, a larger radar, etc, but it is a fighter. You don't need lifting canards, ventral stabilizers, huge LERXes on a MiG-31-like aircraft. In fact if what we heard about the WS-15 is true, when it gets those WS-15s, it will have by far the highest thrust-to-weight ratio of any aircraft. That means a lot for the climb, acceleration and sustained turn. The J-20 definitely has superb kinematics.

Click to expand...

latenlazy said:

Do we know that it sacrificed turning performance? The whole point of its complex arrangement was to maximize margins on that parameter without sacrificing too much else (because engines were already a penalty).

Click to expand...

BoraTas said:

We don't for sure. It is just a general deduction. It is not one of those high aspect ratio and very low wing-loading fighters like the Su-27, F-15 and F-22 are. We also heard multiple times about its supersonic focus which almost always comes with compromises in subsonic speeds. Its design looks very climb and high-altitude oriented. Delta-wing, lifting all-moving canards, huge LERXes, planned thrust vectoring and an extremely high thrust-to-weight ratio...

Click to expand...

latenlazy said:

Do we know that it sacrificed turning performance? The whole point of its complex arrangement was to maximize margins on that parameter without sacrificing too much else (because engines were already a penalty).

Click to expand...

Scchwerter_ said:

I guess if we think of it in terms of "what could have been if PLAAF had just wanted a thoroughbred BFM machine (or more generally a pure air-superority-oriented jet", then yes the current J-20 does likely have some compromizes in terms of its pure maneuvering capabilities. But again, with aircraft design everything is a compromise, I think they did what they could to give J-20 the best possible maneuverability while satisfying the requirements in other areas.

(sorry if I'm yammering about very obvioys things)

Click to expand...

latenlazy said:

Eh. J-20's wing area is not small. It's actually within ballpark of the F-22's. And *presumably* it actually weighs less than the F-22 as well. So I'm not sure that wing loading is high. Furthermore, wing loading is itself a proxy measure for actual lift to weight performance, which requires accounting for lift coefficient in addition to wing loading to measure actual net force for flight vectors. The original design paper for the J-20 actually emphasized improving supersonic maneuver without penalizing subsonic maneuver. The whole point of 5th generation aerodynamics is expanding the flight envelope performance range so that you're not striking as many compromises across different flight regimes.

Click to expand...

BoraTas said:

Deltas usually are draggier than cropped delta and swept wings at the same level of lift. Especially at higher alpha and subsonic. I am talking generally BTW. None of what I write means the J-20 has a bad subsonic sustained turn. I just say the design is not focused on that, which looks quite obvious to be fair. Look at the profile of this:

View attachment 105239

And this:

View attachment 105240

Click to expand...

latenlazy said:

I feel like the J-20's design study was very clear about what the performance focus of the basic aerodynamic layout was. Even if there were tradeoffs made for different aspects of flight performance I feel like the study itself made it rather clear that there was an emphasis on reconciling rather than trading between supersonic and subsonic maneuvering requirements.

Click to expand...

Scchwerter_ said:

Yep definitely. I wasn’t suggesting that J-20’s subsonic performance is bad (I mean, literally look at air show videos right?), just that if it had initially been designed with different requirements in mind, say less range and supersonic performance requirements and more emphasis on subsonic than what’s currently the case, then in that alternate timeline the J-20 probably would’ve had even better subsonic performance than what it has right now.

Click to expand...