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Stalls depend only on angle of attack, not airspeed. [24] However, the slower an aircraft flies, the greater the angle of attack it needs to produce lift equal to the aircraft's weight. [25] As the speed decreases further, at some point this angle will be equal to the critical (stall) angle of attack. This speed is called the "stall speed".
Platform angle of attack Coefficients of drag and lift versus angle of attack. Stall speed corresponds to the angle of attack at the maximum coefficient of lift (C LMAX) A typical lift coefficient curve for an airfoil at a given airspeed. The lift coefficient of a fixed-wing aircraft varies with angle of attack. Increasing angle of attack is ...
The angle at which maximum lift coefficient occurs is the stall angle of the airfoil, which is approximately 10 to 15 degrees on a typical airfoil. The stall angle for a given profile is also increasing with increasing values of the Reynolds number, at higher speeds indeed the flow tends to stay attached to the profile for longer delaying the ...
The minimum such speed is the stall speed, or V SO. The indicated airspeed at which a fixed-wing aircraft stalls varies with the weight of the aircraft but does not vary significantly with altitude. At speeds close to the stall speed the aircraft's wings are at a high angle of attack. At higher altitudes, the air density is lower than at sea level.
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 ...
Third, assume that the angle of attack α is small enough that cos(α)≈1 and sin(α)≈α, which is typical since airplanes stall at high angles of attack. Similarly, assume that the flight-path angle γ is small enough that cos( γ )≈1 and sin( γ )≈ γ , or equivalently that climbs and descents are at small angles relative to horizontal.
Passive (stall-controlled) wind turbines rely on the fact that angle of attack increases with wind speed. Blades can be designed to stop functioning past a certain speed. This is another use for twisted blades: the twist allows for a gradual stall as each portion of the blade has a different angle of attack and will stop at a different time. [4]
The idea was to increase wingtip efficiency and cause the wing roots to stall first. Angle of attack sensors on the aircraft can also detect when the angle of attack approaches the attitude known to result in pitch-up and activate devices like the stick shaker to warn the pilot, and the stick pusher which overpowers the pilot and forces the ...