Flight tests of new or modified aircraft are a necessary part of the design process and provide the final validation of the full scale aircraft design. Flight testing for certification is a critical phase as all trials proving compliance with specifications and regulations must be completed in the shortest possible time, while maintaining high quality standards in the certification process. Usually a heavy instrumentation is installed to validate the predicted behaviour of the aircraft and also to detect unforeseen problems so that, if necessary, fast modifications can be done.
Optical measurement techniques can minimize the installation effort and reduce the testing time as they are able to capture a huge amount of parameters within a short time. The preceding project AIM Advanced In-flight Measurement Techniques proved the principal feasibility to apply modern optical measurement techniques as being used in industrial wind tunnels to flight testing.
The AIM² project intends to further develop these measurement techniques to be easily and routinely applied to in-flight testing with industrial demands. Thus, AIM² focuses on developing reliable and easy to use dedicated measurement systems and on defining design and application rules for these new in-flight measurement techniques. The prime objective is to enable aerospace industries to use such mobile measurement systems in future to reduce testing time and costs.
AIM² will be structured in progressive steps. Starting with basic studies on challenges discovered in the preceding project, leading to optimized measurement systems to be tested under research conditions and finally to be proven in an industrial environment. To do these steps in an effective way the partnership of AIM² will comprise four partners from aerospace industries, including one SME, three research organisations and three universities with expertise in optical measurement techniques, flight testing and training.
Flight tests and resulting data analysis demonstrate that AIM2 technology captures better deformation measurements on wings and control surfaces. The team has also designed hardware for measuring propeller deformation spanning 360 degrees and the flight test setup is ready to go.
Better surface and strain measurements have been recorded in lab and wind tunnel tests thanks to development of advanced sensors and a new data acquisition system. Investigators also improved in-flight air speed measurements through application of advanced particle image velocimetry (PIV) and a light detection and ranging or LIDAR setup.
A handbook on advanced in-flight measurement techniques has been published and Euronews broadcast a documentary on AIM2’s PIV techniques. The mobile technology and easy-to-use guide should enable non-experienced users to apply optical measurement techniques to flight tests. This should substantially reduce the time and cost of the certification process while enhancing overall safety.