Let's hope so. Could certainly be done for MLU of those first variants. I've read the WS-15 does not have larger dimensions compared to WS-10 but refitting Al-31s with WS-10s are difficult enough already that PLAAF doesn't even bother with. Maybe it's an issue of having spare Al-31s around and not really getting any more benefit by replacing them with WS-10s.
J-20 5th Gen Fighter Thread VI
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Let's hope so. Could certainly be done for MLU of those first variants. I've read the WS-15 does not have larger dimensions compared to WS-10 but refitting Al-31s with WS-10s are difficult enough already that PLAAF doesn't even bother with. Maybe it's an issue of having spare Al-31s around and not really getting any more benefit by replacing them with WS-10s.
I wouldn't assume that.
I think it is much safer to assume that J-20s produced with WS-10s or Al-31s will be using them for their lifetimes. While it is true that J-20 was designed with WS-15 in mind, there would still likely be some structural differences between an aircraft using one engine versus another and at least require some structural modifications, such as the air intake (which is a rather integral part of the aircraft which may or may not be able to be modified on an existing airframe).
But as I said, J-20s using WS-10s or Al-31s are still going to be the PLA's most capable air superiority fighter until a J-20 with WS-15 enters service, and even then, J-20s with the interim engines will be among the most capable air superiority aircraft in the world.
For the PLA, being able to pump out another 100-150 J-20s over the next 5 years is much more important than if they are specifically capable of being refitted with WS-15s sometime in the future.
I think the air intake is fixed, given how integral it is to the design in terms of stealth etc.
The B-21 is having an issue now where the engines need more air than the intakes provide.
But they're having to keep the intake design the same.
One would think the air intakes on the J-20 have already been sized for the larger airflow of the WS-15.
Personally I think the J-20s will use WS-10s and Al-31s to the engine overhaul lifetime, then be replaced with WS-15.
That would be every 5 years, when they have to replace the engine anyway.
I don't think so, the Batch 01 J-11Bs are still flying on AL-31Fs even if all later batches are using the WS-10.
In the case of the J-11B they had to modify the aircraft inlet in order to accommodate the WS-10. I doubt it is practical for the first batch of J-11Bs.
That said, I think we should get back to topic.
It looks like there is no difference in thrust between the WS-10 and AL-31F.
So there is there any need to upgrade the AL-31F?
In comparison, a WS-15 is supposed to generate a lot more thrust than a WS-10.
Correct on all counts.... the WS-15 should have a larger core, and the J-20 was constructed around the WS-15... it was long known that the AL-31F series would initially power the "proof of concept aircraft", when it became apparent that the WS-15 was farther out on the horizon, the inlets of the J-20 were optimized for the AL-31F series engine by shrinking and reshaping them for optimal airflow and engine management... so engine mounts and inlets are indeed different, and while the older birds could be and may be re-engined, I rather doubt that will happen for some time at least...
and as we all know the indigenous WS-10 is a twin to the AL-31F series engines and has become the "place holder of choice", the J-20 actually flies very well with its present power plants, but the Flanker has a higher power to weight ration, likely better acceleration and climb rates, could possibly be faster as well...
the WS-15 will indeed change all of that.....
Would the J-20 inlets really have been shrinked?
Given significantly higher thrust on a WS-15 than a WS-10, wouldn't that mean a much higher air inflow is required?
So instead of shrinking the air inlet for the WS-10, wouldn't it be better to optimise the air inlet for higher WS-15 airflow at the beginning?
The extra air for a WS-10 engine would just go through the bypass, with little impact?
I think you misunderstood 'flight' as 'aircraft'. A flight is 4 aircraft.
So the squadron must be 2-4 flights or 8-16(+ reserves) aircraft.
8-10 of such flights with additional training and reserve units must form a brigade.
USAF fighter squadrons are anywhere from 4-6 squadrons.(+2 reserve aircraft) for a total of 18-26 aircraft.
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