Measurements of Aerodynamic Forces

Design, Fabrication and Testing of a Balance, Sting and Model Configuration.

This project is a part of the plan to expand existing capabilities in aerodynamic testing, by designing and constructing a balance able to provide aerodynamic coefficients of drag, lift and moments in the range of Mach number of 5 to 6. Balance systems in conventional supersonic wind tunnels are routinely available. Force measurements in short duration facilities, like the present one, are not available and they are particularly challenging.

In the past several methods have been developed to overcome these problems or occurrences. In the present work the technique of Jessen and Gronig (1993) was adopted. In this arrangement a strain gauge balance has been designed and implemented to operate without acceleration compensation. A model and balance system of low mass with high stiffness reaches its natural frequency at about 1 Khz. The balance is part of the sting, virtually independent of the model and it thus can be calibrated statically. The models for this balance do not need any acceleration gauges installed and no inertia matrix has to be determined.

Test Projectile

Test Projectile

Cross Balance with Attached Strain Gauges

Cross Balance with Attached Strain Gauges