So, I tried reading the wikipedia article covering the subject, but nothing made sense; so if y’all could explain the critical attack and things like that as well, it would be great!!
In: Physics
A stall in aviation is when there isn’t enough air going past the wings for them to provide enough lift to keep the plane in the air. .
It could be because the plane is flying too slow or the nose is pitched up too high.
lots of people have already answered your question but if you’re interested in learning more, [this guy](https://youtu.be/Kg6jV5mkf-8?t=85) makes great videos about aviation.
Airplanes fly by shoving air down really hard. Forget about Bernoulli’s principle, if the shape of the wing was that important, planes couldn’t fly upside down and they do.
In a stall, because of either the position of the wing, or the speed of the plane, enough air is not being shoved down.
That’s bad because you start to fall. Falling is different from flying downwards in the same way that sinking is different from swimming downwards.
When you fall, that also means you’re not controlling the plane. That’s bad because you use the ability to control the plane to stop falling.
The balance between the speed of air passing over the wing and under the wing changes. This speed differential is what creates lift, keeping the plane aloft. If the differential is lost, so is lift. This is called a stall.
A stall is when the aerodynamic forces acting on an aircraft’s wings are no longer providing sufficient lift to keep it airborne. This is dangerous for what I hope are obvious reasons. If there’s no lift acting on the plane, there’s nothing keeping it in the air.
The critical angle of attack (how much the aircraft is pointed upward) is the maximum angle at which a plane’s wings can be angled upward before they stall and stop providing lift.
An aircraft needs to travel at a certain speed or above (that means air flows over its wings at a certain speed). This air travelling *over* the wings causes something called “lift”. Lift is the upward force which causes the aircraft to stay in the air. Lift can only happen when the air travels over the wings at or above this speed. Hence why aircraft need to reach this speed when on a runway. If an aircraft drops below this speed when in the air, the amount of air travelling over the wings drops, meaning the lift is no longer sufficient to keep the aircraft in the air. This is what is called a stall. The cause of the drop in speed can either be too little power (engine problem), or the aircraft is pitched too high (pointing upwards too steep).
Imagine a paper airplane – you must throw it forward at a certain speed for it to keep airborne, otherwise it will fall out of the sky. It is a similar concept (although it is the shape of the wing on the real aircraft which is key to generating lift), but it should help you to imagine.
Now for critical angle of attack… imagine the same paper airplane, if you throw it angled towards the ceiling, it would immediately fall from the sky regardless of how fast you’d thrown it. This is because it’s angle is above it’s critical angle.
All of the above is filled with very complicated mathematics, but I’ve tried to ELI5, hope it helps.
While it is possible for the aircraft’s engine to stall (meaning it no longer provides power to the propellers, in the same way a car will stall, I’ll probably need to ask my own ELI5 to find out how that works), this specific problem is when airflow over the wings does not produce sufficient lift to keep the plane airborne. There’s a few ways I can think of for this to happen: the plane’s just slowed down enough, either through trying to gain altitude or for coming in for a landing, or the wind around the airplane lowers the flow over the wings – a plane with a tail wind has less flow going from front to back. If the plane has enough altitude, it’s not *extremely* dangerous, so long as the plane is front heavy / aerodynamically shaped to point forward, because as it falls to the ground, it will gain speed and eventually the wings will produce lift – being low enough that that *eventually* is too late is the problem
As a wing’s angle of attack (the angle between the relative wind and the wing) increases, the lift increases until a certain point, after which the angle of attack becomes so high that it introduces turbulence before the air is past the wing, which causes lift to start going back down again. The angles of attack that are greater than peak lift are considered stalled.
How dangerous a stall is depends on two things:
1. How controllable the airplane is during stall. Usually planes are designed so that the part of the wing with control surfaces (ailerons) stall last, so that the pilot can still roll the plane in a stall. For pitch, it is important that the plane be balanced so that the nose goes down during a stall, which causes the angle of attack to decrease until the wing is no longer stalled. If the center of mass is too far back and the turbulent wake of a stalled wing covers the tail to the point where the tail has no control, it is called a “deep stall,” which is very difficult to recover from. Most of the time, a deep stall means that the plane will lose altitude until it crashes into the ground.
2. How close to the ground a plane is when it stalls. Student pilots stall on purpose at high altitude to learn how to recover and return to non-stalled flight (angle of attack on the low side of the lift curve discussed at the beginning). Recovering from a stall involves pointing the nose down and diving briefly, to reduce angle of attack, and then returning to level flight. If you are too close to the ground when you stall, you will crash during stall recovery.
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