Radio Telemetry of Stagnation Pressure from a Wind Tunnel Model Magnetically Supported in Supersonic Flow

During a set of aerodynamic tests in a Mach number 2. 4 wind tunnel, it was proven feasible to telemeter stagnation pressure measurements from within a magnetically suspended, ferromagnetic model. State-of-the-art, f-m radio telemetry, developed for hypervelocity range use, was employed. Although data at the outset of each of three trials reflect errors of less than three percent, inordinate frequency vs temperature interaction introduced intolerable shifts in telemeter center frequency as testing progressed. Several methods may be used to reduce these interactions. Magnetogasdynamic effects arising from the use of the magnetic model suspension technique are discussed in an appendix, and are shown to be negligible in most wind tunnel testing.