Wing twist
From Wikipedia, the free encyclopedia
Wing twist is an aerodynamic feature added to aircraft wings to ensure that the wing tip is the last part of the wing surface to stall, for example when executing a roll or steep climb; it involves twisting the wingtip a small amount downwards in relation to the rest of the wing. This ensures that the effective angle of attack is always lower at the wingtip than at the root, meaning the root will stall before the tip. The reason this is desirable is because the aircraft's Flight control surfaces are often located at the wingtip, and the variable stall characteristics of a twisted wing alert the pilot to the advancing stall while still allowing the control surfaces to remain effective, meaning the pilot can usually rescue the aircraft from the stall before control is completely lost. It is also sometimes referred to as washout.
Wing twist can also, rarely, refer to the deflection of the wing when it is made of insufficiently stiff materials; actuation of the flaps can, instead of deflecting air as intended, cause the wing itself to be deflected and is related to compressibility effects; this problem has mostly been eradicated however, with modern high-strength alloys and composites.
