Two-dimensional Tests on a 15 percent. Thick Symmetrical Roof-top Aerofoil with 20 per cent. Plain Flap in the National Physical Laboratory 13 ft. x 9 ft. Wind Tunnel

摘要

A series of tests was carried out in the 13 ft. X 9 ft. wind tunnel at the National Physical Laboratory on a 15 per cent, thick symmetrical roof-top aerofoil fitted with a 20 per cent, plain flap, in order to obtain information about the increase of the low-drag range to be gained by deflecting the flap and to extend to higher Reynolds numbers earlier work on the relations between theoretical and experimental characteristics of a wing with flap.nWith flap at 0 deg. the lift, drag, and pitching moments up to the stall were measured at speeds up to 180ft./sec. (R = 2.88 X 106). A few tests were also made with small flap deflections and incidences up to 4 deg. With the flap at 0 deg. the low-drag range is small (CL =ca ± 0-125 at R = 2-88 X 106) and at 180 ft./sec. the wing stalls at 12 deg, incidence (CL = 1 -05). Deflection of the flap increased the low-drag range, but this series of tests was not completed owing to failure of the model.