Dual-mode exit area scheduling?

[perfectz]

dual-mode exit area scheduling?

what is dual-mode exit area scheduling?

 

[mgb_phys]

You leave through the door or the window?

 

[perfectz]

You leave through the door or the window?

Dude I am talking about nozzles of F-22, F-16 ...
Detailed explanation please...

 

[FredGarvin]

I'll have to look at the "dual mode" part (sounds like a controls systems detail) but the exit area scheduling is an automatic control system that varies the exit area of the engine dependent on the flight regime and demands. You'll notice in videos of an aircraft ramping up to take off an aircraft carrier, as the thrust demand is increased, the exit area of the exhaust is opened to allow supersonic flow and increase the exhaust velocity and thus, more thrust. The scheduling is a "calibration" of sorts to provide the best possible engine operation at a given demand.

I would venture a guess that the dual mode aspect is that there are two computer controls that redundantly control the scheduling.

There is an interesting section on the thrust vectoring control nozzle system on a NASA re outfitted F-15 here:
http://www.nasa.gov/centers/dryden/history/pastprojects/Active/pub_online/setp_d6.html

Look under the Nozzle Actuation and Nozzle Control Computer and Control Algorithm sections.

 

[perfectz]

What is supersonic dash capability, and you know something about independent A8 and A9 controls of nozzle in F-16?

 

[FredGarvin]

Supersonic dash is the ability to go to a supersonic speed that is outside or at the edge of the aircraft's normal operating envelope. Most attack have a dash to target so as to get the aircraft in and out very quickly. The actual range and speed of the dash is a part of the overall design and requirements.

As far as the F-16 A8 and A9 controls, a little search shows that the A8 area is the throat area and the A9 area is the exit area of the nozzle. How those controls work I have no idea. Andre should chime in here. He would be able to answer that.

 

[perfectz]

andre where are you?

 

[FredGarvin]

You could try PM'ing him.