Dynamic Wind-Tunnel Testing of a Sixty-Degree Delta-Wing Model Without Support Interference

Abstract

The longitudinal dynamic characteristics of a 60 deg sweptback delta-wing model at angles of attack of up to 21 deg were investigated in this study using a magnetic suspension and balance system. The magnetic suspension and balance system can obtain wind-tunnel data without support interference by suspending a model using magnetic forces. Wind-tunnel tests during accurate pitch oscillations were conducted, and the dynamic longitudinal forces and moment data were obtained. We proposed a method to accurately identify the dynamic pitching moment during pitch motions from our data using a dynamic derivative model. In our model, the dynamic derivative due to the pitch rate and pitch acceleration were considered, and these dynamic derivatives were treated as linear functions of angle of attack. Multiple regression analysis was used to identify the coefficients in the model. Our model can separately describe the static and dynamic part of the total pitching moment. The dynamic pitching moment coefficients were precisely identified by our dynamic derivative model with consideration of the acceleration term for low angles of attack. In addition, the pitch acceleration term could be considered to have the same effect as virtually changing the moment of inertia of the delta-wing model.