Steady and unsteady force testing of fighter aircraft models in a water tunnel

Abstract

The force testing of small-scale models in a water tunnel was investigated as an inexpensive and quick means to obtain static and dynamic force and moment data representative of full-scale fighter aircraft maneuvering in the post-stall regime. Force tests of flat plate and three-dimensional full span models were conducted in General Dynamicsf 24 x 24 in2 horizonal flow water tunnel using a special balance developed and built by General Dynamics. Steady incidence sweeps and unsteady pitch-pulse motions to a maximum angle of 90 deg were YKvestigated for several planforms and models. Some specific objectives of this study were to: (1) verify that static and dynamic force and moment measurements from water tunnel testing were representative of large-scale wind tunnel tests; (2) demonstrate the importance of model three-dimensionality; (3) evaluate the effects of planform geometry; and (4) investigate dynamic stability and controllability aspects of the Cobraw maneuver performed by Pougachev in a Russian SU-27.