The Development And Evaluation Of The Cal Air Force Dynamic Wind Tunnel Testing System PDF Download

The Cornell Aeronautical Laboratory (CAL) system provides a unique mounting through which a model can be forced precisely in any desired planar sinusoidal motion. The versatility and overall accuracy of the CAL/Air Force dynamic testing system was demonstrated during a series of wind-tunnel tests. These tests permitted, for the first time, a measurement of the separate components of the rotary damping moment. The moment due to rate of change of angle of attack was measured by oscillating the model in pure plunging motion. The moment due to pitch rate was measured during pitching motion. The sum of these is compared with the total rotary damping moment as measured in rotation. Comparisons of data taken at two frequencies and four Mach numbers indicate that the components are accurate to within plus or minus ten percent of the total rotary damping moment. The results are compared with theory, flight test data, and other wind-tunnel measurements on the same and similar models. Future applications of this equipment are reviewed, particularly with regard to its use as a research tool to support basic investigations for the development of theoretical or semiempirical methods for predicting dynamic stability characteristics of aircraft at transonic speeds. (Author).