TU-Flex: A Very-Flexible Flying Demonstrator with a Generic Transport Aircraft Configuration

Abstract

In the continuous search to increase efficiency in fuel consumption and reduce environmental impact, the aeronautical industry is getting more interested in enabling and developing higher aspect ratio wings. However, the increase in flexibility tends to deteriorate flying qualities making it necessary to implement more complex controllers and to develop more complex numerical models to capture the real flight dynamics of the aircraft. Nevertheless, there are not enough demonstrators to provide validation data for such models. For these reasons, the Chair of Flight Mechanics, Flight Control, and Aeroelasticity of the TU-Berlin in cooperation with the DLR's Institute of Aeroelasticity is working on the development of TU-Flex, a remotely piloted vehicle designed to gather coupled flight and structural dynamics data to validate flexible/very flexible aircraft models with a typical transport aircraft configuration. This paper shows that it is feasible to attain the levels of deformations required to study the dynamics of flexible and very flexible aircraft in a low-cost scaled demonstrator. The aircraft was designed using an in-house development process that includes the use of DLR's ModGen/NASTRAN for dimensioning the main structural components, and the DLR's software Loads Kernel for the load analysis of the free-flying aircraft. The current geometry of the TU-Flex allows performing experiments in an available wind tunnel facility, and in flight test experiments for a gradual validation process. This demonstrator is capable to attain all main design requirements and it is in a detailed design process and construction. Time-domain simulations are in development with an in-house code for the flight dynamics of very flexible aircraft.