J-20 goes operational again

Military aircraft - Post cold war aircraft, including for example B-2, Gripen, F-18E/F Super Hornet, Rafale, and Typhoon.
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Unread post09 Oct 2019, 17:33

weasel1962 wrote:The tomcats may have benefited from the F-111 experience.

On YT you have excellent F-14 presentation done by back then Grumman vice president he was clear they learned a lot from F-111, he said if there wasn't F-111 we wouldn't be able to make F-14 as good as it is.


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Unread post16 Oct 2019, 01:48

One topic that's pissed off both Chinats and neutral observers of the J-20 on SDF recently is discussion of the J-20's inlets.

We know that the Al-31 cannot provide sufficient thrust at altitude for the Su-27 with its variable inlets. The drag estimated for about 35,000 FT to at the Mach barrier is about 20,000 lbs. To reach Mach 1.4, you'd need about 25,000 pounds. The AL-31, at best, can do something like 60.5 kN with 2 engines (13,500 pounds) at that altitude and at Mach 1.1.

Is it possible that the Al-31 / WS-10 can do so at altitude given larger inlets (greater initial airflow), longer inlet length (greater space for the diffuser to do its work), as well as bypass ducts (as on the F-22) to bleed off low-speed excess airflow?

The total inlet length, ignoring geometry, is around 8-8.5 meters on the J-20, vs about 5 meters on the F-22.

Suspected bypass ducts on the J-20:


https://www.quora.com/What-are-these-op ... of-an-F-22

Known bypass ducts on the F-22:

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Unread post16 Oct 2019, 13:19

inst wrote:Suspected bypass ducts on the J-20:


Where? And suspected by who? All I'm seeing are panel edges. Bypass doors are pretty obvious.

"There I was. . ."

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