Wing Stall- The wing stall or 'stall' is one of those things that can really catch a pilot by surprise. It can happen at any speed and at any attitude. It is caused when the angle of attack is so great that the air breaks away from the top surface of the wing and lift is lost due to the air being allowed to become turbulent and recompressing to its original state. The most hazardous time for a stall is during take off or landing when the plane is too low for recovery. With very few exceptions, a stall is pilot induced. A plane will usually stall to the left because of p-factor, torque, and prop wash. While a stall that occurs when you don't want it to could be bad news, a desired stall is used in many aerobatic maneuvers. A stall at slow speed is slow and gentle. At high speed it is fast and violent and sometimes can lead to structural damage. By learning how and when a stall can occur it will very seldom be a problem.

The most used method to make a wing stall more gentle is to use washout in the wing. This is accomplished in the following way. The wing is twisted slightly with the root rib being set parallel with the flight path and the tip rib being set with a little bit of negative incidence as shown in figure 2a and 2b. When the angle of attack of the wing is increased it will be greater in the center of the wing than out toward the wing tips. Since the angle of attack is greater in the center section then it will stall first while the tips are still flying. The plane will start losing altitude because of the loss of lift but will still be flying straight and true. If the angle of attack is increased more, the stall will start spreading toward the tips and they will eventually stall also. Wing washout is useful in trainer planes because it gives the beginning pilot more time to recognize that a stall is beginning to occur and take corrective action. Wing washout is present in nearly all civilian and military scale planes because their full scale counterparts use it. Aerobatic planes do not employ wing washout as a general rule because, as mentioned earlier, in these type planes the stall is used in many of their maneuvers and is desirable. There are other methods to control the effects of wing stall such as wing taper , wing sweep, and stall strips. These are a little more complicated and would take up a lot of room in this small pamphlet and will not be covered here but can be covered in discussion. <---Back to Contents