J-20 5th Gen Fighter Thread VI

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Brumby

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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.
The problem is in the translation of the word "队". The vernacular meaning is not "squadron:" but a "unit" or "section" but the numerical number associated with that word is subject to the context in usage. The relationship in sizing in that example is differentiated though the words "中" and "大" which means "medium" and "large".
 

Tirdent

Junior Member
Registered Member
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?
Depends...

5th generation engines designed for super cruise significantly increase specific thrust (thrust per mass flow) for high non-reheated thrust at supersonic speed. Typically, bypass ratio is lowered and turbine inlet temperature increased to achieve this, whether the WS-15 can do so sufficiently to obtain the desired thrust hike without higher mass flow than the WS-10/AL-31F is difficult to say.

As the J-20 inlet is fixed, there would be a drag penalty if WS-15 air flow requirements cause the inlets to be oversized for the interim engines, though probably not serious, especially if it has a bleed that can be scheduled to reduce spillage.
 

Inst

Senior Member
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.
Dadui is defined as flight group according to this resource. So a dadui has 8-10 planes.

But you're right that a 中队 maps to flight, while a 大队 seems to map to squadron.
 

stannislas

New Member
Registered Member
Depends...

5th generation engines designed for super cruise significantly increase specific thrust (thrust per mass flow) for high non-reheated thrust at supersonic speed. Typically, bypass ratio is lowered and turbine inlet temperature increased to achieve this, whether the WS-15 can do so sufficiently to obtain the desired thrust hike without higher mass flow than the WS-10/AL-31F is difficult to say.

As the J-20 inlet is fixed, there would be a drag penalty if WS-15 air flow requirements cause the inlets to be oversized for the interim engines, though probably not serious, especially if it has a bleed that can be scheduled to reduce spillage.
If you compare j-20 2001 and 2017, you can see the inlet was modified
 
Depends...

5th generation engines designed for super cruise significantly increase specific thrust (thrust per mass flow) for high non-reheated thrust at supersonic speed. Typically, bypass ratio is lowered and turbine inlet temperature increased to achieve this, whether the WS-15 can do so sufficiently to obtain the desired thrust hike without higher mass flow than the WS-10/AL-31F is difficult to say.

As the J-20 inlet is fixed, there would be a drag penalty if WS-15 air flow requirements cause the inlets to be oversized for the interim engines, though probably not serious, especially if it has a bleed that can be scheduled to reduce spillage.
As most everyone here realizes the inlet is an integral part of the aircraft induction system, and that induction system must be tailored to the power plant in order for the power plant to perform at its maximum thrust and responsiveness.....

As well comparing the "proof of concept" birds 001 and 002/004, and their respective inlets with the pre-production/LRIP aircraft, it's obvious that the inlets have been reduced in order to optimize performance with the AL-31F/WS-10.

Had they not reduced the flow, they would have increased drag and decreased thrust, when the WS-15 does come along, it will have inlets that have been optimized increase flow and reduce drag, I suspect it will indeed super cruise....
 

Inst

Senior Member
As most everyone here realizes the inlet is an integral part of the aircraft induction system, and that induction system must be tailored to the power plant in order for the power plant to perform at its maximum thrust and responsiveness.....

As well comparing the "proof of concept" birds 001 and 002/004, and their respective inlets with the pre-production/LRIP aircraft, it's obvious that the inlets have been reduced in order to optimize performance with the AL-31F/WS-10.

Had they not reduced the flow, they would have increased drag and decreased thrust, when the WS-15 does come along, it will have inlets that have been optimized increase flow and reduce drag, I suspect it will indeed super cruise....
Increased drag is a function of speed and altitude, i.e, when the Mass Airflow is greater than what the engine can process, you get drag. So in theory, you can have high low-altitude drag but increased thrust at medium altitudes and speeds.

From actual measurements of the J-20's inlets, they seem to be tailored for Al-31 mass air flows, not WS-15 or F135 class airflows.
 
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