Evaluation of Flight Agility/Departments Characteristics with a New Multi-Axis Text Rig

The evaluation of lateral/directional stability departure boundaries for combat aircraft in preliminary design has historically been based on the knowledge of certain static aerodynamic coefficients. For aircraft operating at high angles of attack and high yaw and roll rates, these criteria are inadequate. A new criteria including yaw and roll rate dependent terms has been developed by Eidetics. To use the criteria, numerical values for these terms must either be calculated or determined from specific dynamic wind tunnel tests covering a large matrix of independent variables such as angle of attack and sideslip, oscillation frequency and amplitude, etc. An alternative to determining the values of these individual parameters is an innovative experimental approach utilizing a multi-axis rotational wind tunnel apparatus. This experimental technique would directly determine the stability and controllability tradeoffs of a model in "constrained flight" in response to control inputs from conventional surfaces, thrust vectoring, or other aerodynamic control effectors such as forebody vortex control. Phase I will determine the feasibility and utility of such a device, and, if judged to be beneficial, an operational apparatus would be designed, built and demonstrated in Phase II.