Preliminary Wind-Tunnel Investigation of an N.A.C.A. 23012 Airfoil with Various Arrangements of Venetian-Blind Flaps.

摘要

A investigation has been made in the N.A.C.A. 7-by-10 foot wind tunnel of a large-chord N.A.C.A. 23012 airfoil with several arrangements of venetian-blind flaps to determine the aerodynamic section characteristics as affected by the over-all flap chord, the chords of the slats used to form the flap, the slat spacing, the number of slats, and the position of the flap with respect to the wing. Complete section data are given in the form of graphs for all the combinations tested. The optimum arrangement of the venetian-blind flap was a combination in which the flap was located near the wing trailing edge. These arrangements of the venetian-blind flap were superior to any flaps previously tested for producing lift and giving low drag coefficients at high lift coefficients. The wing with this flap, however, had very large pitching-moment coefficients. When operated as split flaps, the venetian-blind flaps were inferior to the simple split flap in producing lift.