The Design and Manufacture of a Dedicated Aeroelastically Scaled Flutter Demonstrator Aircraft

The aeroelastic behavior of aircraft wings is an area of extensive research. High aspect ratio wings are commonly used to achieve a high lift-to-drag ratio. These slender wings become very flexible in practice, leading to increased aeroelastic phenomenon like flutter. Flutter occurs after a perturbation in the airstream disrupts the wing of an aircraft and an oscillation of increasing amplitude results. This oscillation can lead to unique loading conditions for the aircraft and in extreme cases cause structural failure. The threat of flutter has led to a number of small-scale demonstrator aircraft aimed at gathering aeroelastic data without risking the destruction of full-scale aircraft. While these demonstrators have seen success collecting data, they are often designed with a foam core composite layup wing structure not representative of current aircraft. The lack of representative demonstrators has created a need for a new demonstrator to be designed using a traditional rib and spar wing structure more accurately representing full-scale aircraft. To accomplish this structure, laser cut balsa wood will be used for the internal wing construction. Balsa wood allows a rib and spar structure to be used while maintaining the high flexibility wing characteristics most susceptible to flutter. In addition, a programmed control sequence will deflect the aircraft’s ailerons ten degrees in opposite directions five times over a period of a half second exciting the wing into oscillation. This control sequence will be used prior to, at, and past the critical flutter onset speed allowing data to be collected throughout all flight conditions. Accurate aeroelastic data will be collected through nine Inertial Measurement Units mounted in the wing, fuselage, and tail sections of the aircraft. These data will then be used to validate a novel flutter prediction technique developed by the Aero-Servo-Thermo-Visco-Elasticity Laboratory at Clarkson University. Once validated this technique will accurately predict the onset speed and corresponding aeroelastic behavior of full-scale aircraft. Accurate predictions will enable the design of new high efficiency aircraft as well as improve the understanding of current aircraft behavior.