Advanced optical in-flight measurements on deformation of wings and propeller blades

Abstract

During certification of a new aircraft the loads and thus the deformations occurring in free flight have to be measured to prove the safety of the structure. Strain gauges and accelerometers are commonly applied to measure the deformation and the movements of the structure. The installation of these sensors and their cables however, is very time consuming and often yields to strong modifications of the air-craft structure. To minimize this effort the DLR develops advanced optical measure-ment techniques for in-flight testing. One of these non-intrusive measuring tech-niques is the Image Pattern Correlation Technique (IPCT). Within the EU funded Specific Targeted Research Project AIM (Advanced In-flight Measurement Tech-niques) of the 6th framework the DLR and Piaggio Aero Industries are using an IPCT measuring system to investigate the in-flight deformation of the wing and of the pro-peller blades of the Piaggio P180 aircraft. The present paper will give a short introduction to IPCT and describe the stereoscopic camera setup for the flight tests. The results of the pretests done at the Piaggio P180, as well as possible solutions of major problems of optical in-flight test-ing will be presented.