Design and testing of an external drag balance for a hypersonic shock tunnel

An external force balance for a hypersonic shock tunnel was developed. The design utilized finite element analysis that identified the dynamics of the balance. A simulated impulse and a step load were applied to the design, the former for determining the simulated transfer function and the latter to validate the design. The numerical modeling showed the feasibility of this approach for designing stress wave force balances. A force balance based on the design was fabricated, calibrated statically and dynamically, and implemented in a shock tunnel for measuring drag of a blunt cone at Mach 9.4. The measured drag compared well with modified Newtonian theory.