Aeroelastic design and flight test evaluation of the Ranger 2000 training aircraft

Abstract

The paper describes the aeroelastic analysis for the design, the ground verification tests and the flight test programme, for the Ranger 2000 training aircraft, developed jointly by Dasa and Rockwell International between 1991 and 1994, as a competitor for the next generation US Air Force and Navy Joint Primary Advanced Training System (JPats). Special efforts with respect to the aeroelastic stability were required for the T-tail configuration, for the design of the manual flight control system, and for the establishment of sufficient mass balance for the control surfaces. Several ground vibration tests were performed for the complete aircraft and for individual components for all major design improvements during the flight test evaluation. To minimise the required time for these tests, highly modular test equipment was required. For an efficient flutter flight test programme a reliable excitation system was chosen. This system consists of slotted rotating cylinders, mounted on small vanes, which can be attached to any aerodynamic surface. This equipment creates defined unsteady aerodynamic forces to excite the eigenmodes of the structure.

Quasi-on-line frequency and damping data evaluation between consecutive flight test points was made possible by installing the required hardware and software directly at the flight test quick-look control room, for the direct use of telemetry data. With this approach only a small number of dedicated flutter flights was required.