An Investigation of the Pressure Distributions on a 45 ' Swept Half Wing , including the Effects of Upper Surface Spoilers

SUMMARY Pressure measurements, flow visualisation tests and force measurements have been made on 45' swept half wings, to examine the flow conditions which prevail, particularly in relation to the effectiveness of an upper surface spoiler as a roll control. Tests were made on l/10 scale half-models in the 3ft x 3ft wind tunnel over a Mach number range 0.5 to 0.9. The wing flow is characterised by attached flow at low incidence and then at 4' to 5 0 , the occurrence of leading edge separation near the tip and consequent formation of an upper surface vortex. As incidence is increased the separation point mcwes inboard and the vortex strength increases. An unvented spoiler on the upper surface of the wing 1s effective under attached flow conditions but loses effectiveness as it comes under the influence of vortex flow. Venting the spoiler reduces its effectiveness under attached flow conditions but increases its effectiveness under vortex flow conditwns.