Test techniques for small-scale research aircraft

Abstract

Small-scale aircraft provide a powerful tool for investigating the flying qualities of novel aircraft configurations. Testing procedures have been developed and applied to two small-scale research vehicles, the Blended Wing Body Flight Control Testbed (BWB) and the Oblique All Wing Unstable Demonstrator (OAW). These aircraft carry digital data acquisition and stability augmentation computers that support graphical analysis of flight data, enabling inthe-field evaluation and modification of control laws. The ability to evaluate dynamic behavior in the testing environment supports a creative, hands-on, iterative approach to aerodynamic experimentation and control law design. Methods developed for this research include several bench-top and static tests, an error analysis for measurement of the mass moments of inertia, and characterization of static engine performance. Dynamic car-top testing is used to simulate the dynamics and aerodynamics of flight, without the risks associated with free flight. Important differences between car-testing and free flight have been identified through analytic and experimental methods. A non-linear piloted simulation has been developed for use in control law design and pilot training. A symbiotic interaction between nonlinear simulation and car testing illuminates aspects of the dynamics that neither technique can independently address. Flight test procedures are developed and debugged using a mule aircraft as a placeholder in