The Gurney Flap (or wickerbill) is a small flat tab projecting from the trailing edge of a wing. Typically it is set at a right angle to the pressure side surface of the airfoil, and projects 1% to 2% of the wing chord. This trailing edge device can improve the performance of a simple airfoil to nearly the same level as a complex high-performance design.
The device operates by increasing pressure on the pressure side, decreasing pressure on the suction side, and helping the boundary layer flow stay attached all the way to the trailing edge on the suction side of the airfoil. Common applications occur in auto racing, helicopter horizontal stabilizers, and aircraft where high lift is essential, such as banner-towing airplanes.
Read more about Gurney Flap: History, Theory of Operation, Helicopter Applications
Famous quotes containing the word flap:
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Sporus, that mere white curd of ass’s milk?
Satire or sense, alas, can Sporus feel,
Who breaks a butterfly upon a wheel?’
Yet let me flap this bug with gilded wings,
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—Alexander Pope (1688–1744)