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Engine flameouts

ToiletDuck

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I've heard of civil jets(or military tankers and such) having flameouts because of turbulent air entering the engine when doing things like pitching back too much without enough power and things like that.

How does a jet like an F-16 turn so darn sharp and not exceed some form of critical angle of attack for the engine? Am i messing up on my ideas here?
 

SIG600

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I've never heard of a tanker or civil jet having problems like that... the two current military jets I can think of that have problems are the Tomcat and T-45. The 'cat just cuz the engines on the -14A sucked... slightly better with the A+ and B models I hear (different engines.) The T-45's problems are with the intake design, and the fact their too small. Carrying too much power at high AOA and low airspeed is just asking for a compressor stall and/or flameout. As far as the -16... it was designed to operate at high AOA/high power. Simply put, the intake is sculpted to provide smooth air at high AOA. I'll let a Viper guy chime in on specifics.
 

spanky2

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What CIG said ... the Viper is designed for high AOA operations. The original P&W-200 motors in the A and early C models required a little more attention when slow / hi aoa to avoid compressor stalls, especially when going from MIL to AB ... but those engines are all gone and replaced by P&W-220 / 229 or GE-110 / 129 engines (most Viper drivers prefer GE = more thrusties) that are user friendly throughout the envelope.
 

scoreboard

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Variable...

Ah, the days of variable intake and compressor vains and stators. The engines actually adapt via movable stators, much like leading edge devices. The F-15 also has a variable intake, the ramps in front of the engine move to account for airflow/AOA. Over the years engine management has improved to the point there are no known restrictions to operating envelope for the F-15 (same for F-16/18/22, etc). You move the throttles, the engine does the rest.
 

ToiletDuck

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well like that CRJ that crashed from 41k feet didn't the engines stall because they were going too slow so there was a high AOA and turbulent air from the wings entered the engine causing it to flameout? Or am I use flameout in the wrong sense?
 

Fury220

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ToiletDuck said:
well like that CRJ that crashed from 41k feet didn't the engines stall because they were going too slow so there was a high AOA and turbulent air from the wings entered the engine causing it to flameout? Or am I use flameout in the wrong sense?
I'm just guessing, but if they were slow at that altitude, they probably were below the minimum mach number at that altitude. Again, I'm just guessing.

I dunno if it's common to most aircraft, but I can comment on the T-38's engines. At high altitudes, the minimum indicated mach number for the engine is altitude/temperature dependent. Stuff like abrupt throttle movements and low power settings can lead to compressor stalls and flameouts, as well as a host of other engine problems (RPM rollback, EGT droop, etc...).
 

SIG600

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ToiletDuck said:
well like that CRJ that crashed from 41k feet didn't the engines stall because they were going too slow so there was a high AOA and turbulent air from the wings entered the engine causing it to flameout? Or am I use flameout in the wrong sense?
They flamed out yes because the engines injested turbulent air off the wings, but they were also way above the capabilities of the airplane for that day (41K is fookin high, the air is thin) and ISA deviation, and the engines corelocked. No amount of airspeed or anything else was going to restart them. From what I understand it's a known issue with those engines, and no one can explain to me why.
 

Fury220

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SIG600 said:
They flamed out yes because the engines injested turbulent air off the wings, but they were also way above the capabilities of the airplane for that day (41K is fookin high, the air is thin) and ISA deviation, and the engines corelocked. No amount of airspeed or anything else was going to restart them. From what I understand it's a known issue with those engines, and no one can explain to me why.
So they were negligently operating the engines out of their known capability? Does that strike anyone as dumb?

BTW, I was up in the 41K range just this morning. Briefly... :)
 
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TonyC

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Fury220 said:
So they were negligently operating the engines out of their known capability? Does that strike anyone dumb?
Actually, I haven't heard of anyone being stricken dumb because of the incident. :)



Does it strike me as dumb? Yepp, but we've already belabored that in several other threads.





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Fury220

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TonyC said:
Actually, I haven't heard of anyone being stricken dumb because of the incident. :)



Does it strike me as dumb? Yepp, but we've already belabored that in several other threads.





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Ah, thanks for pointing out the typo... :)

I must be the only member of this board who doesn't know what happened.
 
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