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An aerodynamic twist can be introduced to the wing with the leading edge near the wing tip twisted downward. This is called washout and causes the wing root to stall before the wing tip. This makes the stall gentle and progressive.
Wing twist is an aerodynamic feature added to aircraft wings to adjust lift distribution along the wing.. Often, the purpose of lift redistribution is 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.
On aircraft with swept wings, wing tip stall also produces an undesirable nose-up pitching moment which hampers recovery from the stall. Washout may be accomplished by other means e.g. modified aerofoil section, vortex generators, leading edge wing fences, notches, or stall strips. This is referred to as aerodynamic washout.
divergence where the aerodynamic forces increase the twist of a wing which further increases forces; control reversal where control activation produces an opposite aerodynamic moment that reduces, or in extreme cases reverses, the control effectiveness; and; flutter which is uncontained vibration that can lead to the destruction of an aircraft.
In early tailless examples, such as the Dunne aircraft, this allowed the outer wing section to act like a conventional empennage (tail) to provide aerodynamic stability. At transonic speeds swept wings have lower drag, but can handle badly in or near a stall and require high stiffness to avoid aeroelasticity at high speeds.
One of a pair of stall strips installed on an American Aviation AA-1 Yankee during manufacture. A stall strip is a small component fixed to the leading edge of the wing of an airplane to modify its aerodynamic characteristics. [1] These stall strips may be necessary for the airplane to comply with type certification requirements.
Twist or washout built into the wingtips can also alleviate pitch-up. In effect, the angle of attack at the wingtip becomes smaller than elsewhere on the wing, meaning that the inboard portions of the wing will stall first. A commonly used solution to pitch-up in modern combat aircraft is to use a control-canard. [9]
The wind frame is a convenient frame to express the aerodynamic forces and moments acting on an aircraft. In particular, the net aerodynamic force can be divided into components along the wind frame axes, with the drag force in the −x w direction and the lift force in the −z w direction. Mnemonics to remember angle names