Book Description

"Panel flutter tests were conducted on two-full scale vertical stabilizers of the X-15 airplane at a Mach number of 3.0 in the Langley 9- by 6-foot thermal structures tunnel at dynamic pressures from 1,500 psf to 5,000 psf and stagnation temperatures from 300° F to 600° F. Flutter boundaries were obtained for four of the five distinct types of panels which make up the vertical sides of the stabilizers. The boundaries consisted of a flat-panel boundary and a thermally buckled-panel boundary. The flat-panel boundaries were characterized by a reduction in dynamic pressure with increasing skin temperature; whereas, after thermal buckling the trend was reversed. The minimum dynamic pressure for flutter occurred at the intersection of the flat-panel and buckled-panel boundaries and represented a large reduction in the dynamic pressure over the extrapolated, unstressed value. As a result of panel flutter, three of the five distinct types of panels were modified to provide the required flutter margin on the design flight dynamic pressure of the aircraft."--Summary.