An aircraft "stall" can be define this way: When the wing does not produce enough lift to support the weight of the aircraft, gravity takes over! Now that may be an over simplification but it serves the purpose of telling a non-pilot what happens to cause a stall.
Wings, which support the aircraft in flight comes in many shapes and sizes, have different objectives, but one thing holds true: "you can design a wing which will produce a lot of speed, or one which will carry a lot of weight", but not both at the same time. The space shuttle and "Concorde" not with standing, they were the only 2 which were successful in carry a lot of weight very fast. The aircraft here in Aces High are based on world war 2 aircraft, so this topic will concern only them.
The way that I have always described the shape of a wing in simple terms is this: hold a "Hersey bar" on its end and look at it and lo, you have the rough shape of a air foil, which will produce lift. One of the most famous aircraft in WW2 had what was described as a "Hersey Bar" wing and that was the B-17. The aircraft wing produces lift by its shape and the way I have always described it to a non-pilot is this way: A wing produces (2) types of lift: Relative lift and resultant lift, just for purposes of explaining the wings function. The relative lift "holds" the aircraft in flight and the "resultant" lift turns the aircraft. The flight controls do not turn the aircraft or make it climb or descend, they only place the aircraft in the attitude to do the maneuvers that you want it to do.
All aircraft wings have a specific "angle of attack", which if you exceed that angle, the wing will stall. Speed really has nothing to do with it. You can add devices to the wing to reduce the stalling speed such as "slats", (LA-7), or "Fowler" flaps, such as on the B-29, as well as many other aircraft. As air rushes over the wing, things begin to happen, a "separation" point, the point at which the wing is producing lift and not producing lift, is moving towards the rear of the wing. Once that separation point moves far enough to the rear of the wing, to have enough wing area which is producing lift, the wing will begin to fly. If the wings remain level, only relative lift is in effect, but if you start a turn, you now have relative lift which holds the aircraft in flight and resultant lift which will then turn the aircraft. While you can rack an aircraft over into a 90 degree bank and pull the stick back in your lap to produce a turn, this has other aerodynamics in play, which I won't get into here.
As the aircraft slows down, the angle of attack, if your altitude remains constant, begins to increase. The separation point of lift vs non lift is now moving towards the front of the wing, reducing the effective area of lift of the wing. Once that separation point moves forward enough so the wing will no longer produce lift, then gravity takes over and the aircraft will begin to descend. If you are turning the aircraft and as its bank angle increases, the area of relative lift, which holds the aircraft in flight, is now reduced. Example: a 84 foot long wing, when in a 45 degree bank, is now reduced, as far as relative lift is concerned, is reduced to a 42 foot long wing and the result is that your stalling speed increases. But, the resultant lift is "pulling the aircraft in the direction of the bank angle.
Generally speaking, the high wing in a bank will stall first, which will result in the aircraft turning in that direction, which will usually produce a spin, because the wing is no longer producing lift.
Departure Stalls (can be classified as power-on stalls) are practised to simulate takeoff and climb-out conditions and configuration. Many stall/spin accidents have occurred during these phases of flight, particularly during overshoots. A causal factor in such accidents has been the pilot’s failure to maintain positive pitch control due to a nose-high trim setting or premature flap retraction. Failure to maintain positive control during short field takeoffs has also contributed towards accidents.
Arrival Stalls (can be classified as power-off stalls or reduced power stalls) are practised to simulate normal approach-to-landing conditions and configuration. Simulations should also be practised at reduced power settings consistent with the approach requirements of the particular training aircraft. Many stall/spin accidents have occurred in situations, such as crossed control turns from base leg to final approach (resulting in a skidding or slipping turn); attempting to recover from a high sink rate on final approach by using only an increased pitch attitude; and improper airspeed control on final approach or in other segments of the traffic pattern.
Accelerated Stalls can occur at higher-than-normal airspeeds due to abrupt and/or excessive control applications. These stalls may occur in steep turns, pull-ups, or other abrupt changes in flight path. For these reasons, accelerated stalls usually are more severe than un-accelerated stalls and are often unexpected.
The key factor in recovery from a stall is regaining positive control of the aircraft by reducing the angle of attack. At the first indication of a stall, the wing angle of attack must be decreased to allow the wings to regain lift. Every aircraft in upright flight may require a different amount of forward pressure to regain lift. It should be noted that too much forward pressure could hinder recovery by imposing a negative load on the wing. The next step in recovering from a stall is to smoothly apply maximum allowable power to increase the airspeed and minimize the loss of altitude. As airspeed increases and the recovery is completed, power should be adjusted to return the aircraft to the desired flight condition. Straight and level flight should then be established with full coordinated use of the controls. The airspeed indicator or tachometer, if installed, should never be allowed to reach their high-speed red lines at anytime during a practice stall.
