Magnetic suspension and balance system for high-subsonic wind tunnel

A magnetic suspension and balance system (MSBS) was successfully developed for suspending a model against a high-subsonic flow. In the high-subsonic regime, the aerodynamic loads acting on the model increase with increasing flow speed and the fluctuation forces increase accordingly. The pitch/yaw directional instability of the model increases in the high-subsonic regime. To solve these problems, the power of the amplifiers and the controlling frequency of an MSBS for a 10 cm low-speed wind tunnel were increased to improve the control system response. A magnetic field was also introduced to compensate for the directional instability of the model by increasing the output of the front drag coil and decreasing that of the rear drag coil. This modification of the magnetic field enabled an ogive-cylinder model with a diameter of 10 mm and a length of 156 mm to be suspended in the MSBS up to a Mach number of 0.6.