DYNAMIC SUPPORT INTERFERENCE IN HIGH-ALPHA TESTING

Dynamic test results of aircraft models at high angles of attack are analyzed with regard to the support interference effects. Single-degree-of-freedom oscillatory tests in pitch or yaw of aircraft configurations are subject to the same type of support interference through the near-wake recirculatory region as is experienced by slender bodies of revolution. Consequently, the measurements can be corrected for support interference using the same methodology. The support interference associated with rotary rigs used in coning experiments is of a different type, being stationary in nature rather than unsteady, with the coning motion inducing a displacement of the vortex wake similar to that caused by side slip in a static test. Performing static tests at varying incidence and side-slip angles with two alternate supports can provide the information needed to correct coning experiments for support interference.