An evaluation of aerodynamic prediction methods applied to the XB-70 for use in high speed aircraft stability and control system design

A key consideration in the development of flight control systems early in the design stage is the availability of aerodynamic information for different candidate configurations. Aerodynamic estimation methods must be available to provide the connection between the configuration geometry and its stability and control characteristics. The accuracy of current estimation methods is studied in this paper through application of DATCOM and APAS to available XB-70 wind tunnel and flight test data. The study was carried out for the subsonic approach condition and three supersonic conditions. Tables and charts are presented to provide a quantitative assessment of the accuracy of the predictions, and areas requiring improvement are identified. Results show that APAS and DATCOM predictions are good for most lateral/directional stability and control derivatives. Estimations for the pitching moment slope, yaw damping and yawing moment due to flap deflection derivatives are only fair. The most difficult derivative to predict is the rolling moment due to sideslip.