Inflight-Measurements of Aircraft Undercarriage Vibration during Deployment

Kurzfassung

Within the EU funded Project AFLoNext (http://www.aflonext.eu/) flow-induced vibrations of aircraft components are under investigation. Aerodynamic or structural devices are designed to mitigate the vibration response levels especially of the deployed landing gear doors. The nose landing gear is emitting vorticity which impacts the downstream located main landing doors. To verify the results of unsteady complex flow simulations of the undercarriage conducted by different project partners, flight tests shall provide a database for calibration of numerical investigations and verify the results. Different types of sensors were installed on the undercarriage of the Advanced Technology Research Aircraft operated by the German Aerospace Center DLR, comprising accelerometers, strain gauges, travel and pressure sensors. To get detailed knowledge of the dynamic interaction of pressure loads and structural response on the nose and main landing gear doors, the simultaneous data acquisition of all signals at high sample rates up to 2 kHz was mandatory during deployment. In addition, monitoring of critical response levels was essential to stay in defined limits during flight. The presentation will give an overview of the selected Flight Test Instrumentation and the preparation of the test aircraft including the documentation and substantiation to get the flight approval.