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-   -   Exceeding the critical angel of attack (https://www.pprune.org/questions/590529-exceeding-critical-angel-attack.html)

waela320 4th Feb 2017 15:24

Exceeding the critical angel of attack
 
Hello

Exceeding the critical angle of attack makes the coefficient of lift drop suddenly and stall will occur , but if we have enough thrust like the fighter jet and we exceeded the critical angle of attack which is approximately 16 degrees can we still have lift ? Is it still called critical angle even if no stall happens ?

barit1 4th Feb 2017 16:13

If the engine thrust exceeds the aircraft weight, then the only issue is controllability.

But flying beyond the critical alpha? Lowering the nose increases lift - Not exactly my cuppa tea; Sorta negative stability time.:eek:

KayPam 4th Feb 2017 16:52

There is still lift well beyond the stalling angle of attack.
That's how your high pitch propeller can deliver thrust at very low speeds.

Piltdown Man 4th Feb 2017 17:11

Yes it is. The definition of critical angle of attack is... but remember, it's only very special aircraft that can fly stalled (for extended periods) because as Barit stated, the issue then becomes controllability. And as KP said, there is still lift well beyond the critical angle.

barit1 4th Feb 2017 17:17

Tes, KayPam, but that's not the problem. With the prop, you just drive on, and as long as the average thrust over 30 seconds or so gets you off the ground - all is well.

HOWEVER - Flying the airplane, keeping it under control in the wing's reverse-slope-alpha regine, is a real challenge for engineers and pilots. Kinda like balancing yourself on top of a basketball!

KayPam 4th Feb 2017 18:01

Yes you're right it would lead to huge instability. That sounds hilarious, in a simulator.


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