REPUBLIC OF SERBIA

MINISTRY OF DEFENCE

www.mod.gov.rs

MINISTRY OF DEFENCE

Material Resources Sector

Defensive Technologies Department

Military Technical Institute

www.vti.mod.gov.rs

COMPARASION OF THE T-38 WIND TUNNEL DATA OBTANED
BY STATIC AND DYNAMIC TESTS

Marija Samardžić,

Military Technical Institute, Belgrade, Serbia, majasam@ptt.rs

Zoran Anastasijević,

Military Technical Institute, Belgrade, Serbia, anastaz@eunet.rs

Dragan Marinkovski

Military Technical Institute, Belgrade, Serbia, marinkovskid@ikomline.net

Abstract: Comparison of aerodynamic data obtained in measurements with an internal strain gauge balance in static and dynamic wind tunnel tests are presented. Normal force coefficients, pitching moment coefficients and static stability derivatives are compared for the missile calibration model. The tests were performed in the T-38 wind tunnel of the Military Technical Institute (VTI) in Belgrade. Forced oscillation technique was used in the dynamic measurements. Static stability derivatives in the dynamic tests were determined from the model moment of inertia, model angular velocity, amplitude of model angular oscillatory motion, amplitude of the excitation moment and phase shift between model oscillatory motion and excitation moment. Static stability derivatives in the static wind tunnel tests were obtained from the slopes of a curve drawn through the moment coefficients vs model angle of attack data. The same semiconductor five-component strain gauge balance was used in the static and dynamic tests. This balance is primarily intended for dynamic tests.

Keywords: wind tunnel, dynamic measurement, stability derivatives, strain gauge balance.