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In aerodynamics, hysteresis can be observed when decreasing the angle of attack of a wing after stall, regarding the lift and drag coefficients. The angle of attack at which the flow on top of the wing reattaches is generally lower than the angle of attack at which the flow separates during the increase of the angle of attack. [8]
In fluid dynamics, angle of attack (AOA, α, or ) is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is moving. [1] Angle of attack is the angle between the body's reference line and the oncoming flow.
[1] [2] Unlike fixed-wing aircraft, of which the stall occurs at relatively low flight speed, the dynamic stall on a helicopter rotor emerges at high airspeeds or/and during manoeuvres with high load factors of helicopters, when the angle of attack(AOA) of blade elements varies intensively due to time-dependent blade flapping, cyclic pitch and ...
An angle-of-attack indicator for light aircraft, the "AlphaSystemsAOA" and a nearly identical "lift reserve indicator", are both pressure-differential instruments that display margin above stall and/or angle of attack on an instantaneous, continuous readout. The General Technics CYA-100 displays true angle of attack via a magnetically coupled vane.
Spins are characterized by high angle of attack, an airspeed below the stall on at least one wing and a shallow descent. Recovery and avoiding a crash may require a specific and counter-intuitive set of actions. A spin differs from a spiral dive, in which neither wing is stalled and which is characterized by a low angle of attack and high ...
The phugoid, for moderate amplitude, [1] occurs at an effectively constant angle of attack, although in practice the angle of attack actually varies by a few tenths of a degree. This means that the stalling angle of attack is never exceeded, and it is possible (in the <1g section of the cycle) to fly at speeds below the known stalling speed.
For this reason the angle of attack is stable when it is less than the stalling angle. [1] [3] The aircraft displays damping in roll. [4] When the wing is stalled and the angle of attack is greater than the stalling angle, any increase in angle of attack causes a decrease in lift coefficient that causes the wing to descend. As the wing descends ...
Above this angle flow over the airfoil becomes detached and lift decreases, a condition commonly called a stall. When a fixed-wing aircraft exceeds its critical angle of attack the entire aircraft loses lift and enters a condition called a stall. The usual consequences of a fixed-wing stall are a sharp drop in aircraft altitude and a dive.