Some Experimental Investigations on Transonic Flutter Characteristics of Thin Plate Wing Models with Sweptback and Tapered Tips

Some experimental investigations on the transonic flutter characteristics have been conducted using thin plate cantilevered wing models with sweptback tapered tips, which were elastically supported at the root, in the NAL 0.6m×0.6m transonic blowdown wind tunnel for flutter testing in the range of Mach numbers from 0.804 to 1.171. The wing models have the tip planform of sweptback angels of 35deg at the leading edge and 30deg at 1/4 chord line, and an aspect ratio of 1.017 and a taper ratio of 0.6. It is concluded that the flutter boundaries of the wing models have been obtained and the boundaries expressed by the “experimental flutter speed coefficient” are characterised as having minimum values at around Mach number 1.0. It is also concluded that the considerable increase in the flutter instability area is caused by the decrease in the stiffness of the elastic support at the root of the model.