A Study of Methods to Increase the Lift of Supersonic Airfoils at Low Speeds

Authors: Pollock, Albert David; Reck, Floyd Francis

Year: 1947

Degree: Engineer's thesis

Advisor: Nagamatsu, Henry T.

Committee Member: Unknown, Unknown

Option: Aeronautics

DOI: 10.7907/J3NG-DD26

Abstract

This thesis presents a study of the problem of improving the lift characteristics of a supersonic wing at low speeds. Trailing edge split flaps, nose flaps, and boundary layer control were investigated singularly and together using the optimum configuration of each.

Results indicate that the nose flap has an appreciable effect on preventing separation and thus increasing the lift. Split flaps give an increment of lift as would be expected. The boundary layer control consisted of blowing a sheet of high velocity air back over the top surface of the wing with very definite improvements of the lift and drag characteristics.

The work on the blowing technique, it is suggested, indicates sufficient promise to warrant much further study. The relatively large increment of lift that can be attributed to the prevention of flow separation at high angles of attack suggests that such boundary layer control could be used to improve controlability and to delay the stall, particularly tip stall, of high speed aircraft with very large sweep back angles.

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