Performance Flight Testing of a Single Engine Powered Lift Aircraft

This paper describes a low cost flight test program and presents the results for evaluating the performance of the Ball-Bartoe JETWING upper surface blown powered lift aircraft with and without the thrust augmenting ejector installed. The program included a ground test series for thrust calibration by dynamometer and by measuring the velocity profile with laser velocimeter followed by performance flight testing to obtain lift coefficient vs. angle of attack and lift coefficient vs. excess thrust coefficient. Stability and handling characteristics were also evaluated. Flight test results when compared with wind tunnel data generally showed good agreement although the lift curve slope obtained by flight test is somewhat less than that from wind tunnel primarily testing because of inaccuracies involved in measuring angle of attack in flight.