F-15 Inlet-Design Questions

[KJ_Lesnick]

I know the F-15 features a moving lip that can hinge up and down depending on speed which I'm guessing is to increase capture area at supersonic-speed. It also features a porous ramp.

My question is, is the porous-ramp fixed, or does it move as well (narrowing down the throat at high-speeds) in addition to the moving lip?


Kendra

 

[rousseau]

Arh, my friend, if my understanding of which you mean porous-ramp is right, my answer is yes.
Only lip moving, will cause a turbolent flow in the inlet, so we need an incline to conform the air-flow after the lip down.

 

[KJ_Lesnick]

Arh, my friend, if my understanding of which you mean porous-ramp is right, my answer is yes.
Only lip moving, will cause a turbolent flow in the inlet, so we need an incline to conform the air-flow after the lip down.

I'm confused here exactly as to what you said.

It would seem you either said...
- 1.) Only the lip moves
- 2.) The lip moves with the ramp and the lip would produce turbulent flow in the inlet if only the ramp moves

Which one is correct?

 

[rousseau]

Sorry, English is not my native language.
What I wanted to say is, both of them would moving responsively, not only one part moving factually. If you get a cutaway of F-15, you will find a board for release/discharge air pressure after the lip of inlet.

sorry for my clumsy express.

 

[flateric]

That's how it looks

 

[KJ_Lesnick]

flateric,

Thank you for the drawing! It really helps when you can actually see it.


Kendra Lesnick

 

[KJ_Lesnick]

Out of curiosity, was the basic inlet concept, using the moveable-lids, patented by McDonnell Douglas around the time the F-15 was developed, built and flown?

Kendra Lesnick
(BTW: I know later on in 1999, they did patent the mission adaptive inlet, but I don't know if they patented anything before that)