4
$\begingroup$

In this video a stall happens at 1:40 upon reaching the critical angle of attack. The air flow is now detached from the upper part of the wing, resulting in higher pressure above the upper part of the wing, thus eliminating the major factor of lift.

enter image description here

Let's imagine that we have extremely powerful engines and enough tail stabilizer authority to maintain horizontal flight with any speed.

Is it possible to maintain horizontal flight when:

  1. wings have high angle of incidence (let's assume some experimental design)*
  2. aircraft has zero pitch condition (straight and level flight)
  3. permanent state of high angle of attack (as the consequence of the 1 and 2)

*high angle of incidence is an angle between wing chord and longitudinal axis of the plane (fuselage)

I assume, the lift that we will get in this case, will be generated mostly by Newton's law by deflecting air ONLY by the LOWER side of the wing.

$\endgroup$
  • $\begingroup$ Given your edit, I feel like the only answer can be "given a big enough engine, even a brick can fly" $\endgroup$ – Federico Dec 5 '17 at 15:06
4
$\begingroup$

That is kind of what the mechanism of lift of a flat plate does: the sharp leading edge destroys the upper flow pattern almost immediately. This question has more info on it.

The lower side of the wing does provide as much or more lift, even when stalled, at AoA of 45°, so lift would not be the problem. Drag would be:

enter image description hereImage source

On this scale, drag for the NACA 0012 profile is very close to zero until the aerofoil stalls, after which it jumps up and continues climbing. At AoA of 45° the C$_D$ is 1.1 instead of about 0.02 when not stalled - you need over 50 times the thrust to maintain the stalled condition you are describing!

$\endgroup$
  • 3
    $\begingroup$ I fly a plane that doesn't stall... With power and half flaps, you pull the stick gradually and the plane ends up with its longitudinal axis almost vertical. One can't stay that way for long, because the engine can't have adequate lubrication in that position and –besides– the prop can't keep the altitude, so it starts to fall tail first... But it doesn't stall... It's a STOL single-engine 'Savannah', an Italian clone of the Zenith CH701... $\endgroup$ – xxavier Dec 4 '17 at 20:11
  • $\begingroup$ @Koyovis, Thanks, I understand that there's will be lot's of drag and the thrust requirements is much higher. What kind of speed increase is needed to maintain horizontal flight in this condition? (assuming the wing area stays the same). $\endgroup$ – Electric Pilot Dec 5 '17 at 15:09
  • $\begingroup$ If you mean a horizontal flight path - same speed as just before the stall, but at an angle of attack of 45 degrees. $\endgroup$ – Koyovis Dec 5 '17 at 15:23

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.