As smooth as gliding: flutter testing

Recently, my colleague Al narrated how the Simcenter software was used for prediction of the flutter behavior of the innovative Perlan 2 glider. With Simcenter, truthful prediction of flutter behavior also encompasses accurate flutter tests – using the smart and compact Simcenter SCADAS XS data acquisition system.

Flutter is a phenomenon that can affect any structure subjected to aerodynamic forces. It is an oscillation caused by the interaction of aerodynamic forces, structural elasticity and inertial effects. Not only the long and slim Perlan 2 glider can suffer from a flutter effect. The phenomenon can affect any glider or aircraft in flight, with potential dramatic consequences. This is why flutter testing is an essential step of any aircraft certification process, making sure that the aircraft is safe to fly in the defined flight envelope.

 Idaflieg flutter instrumentation with SCADAS XS 2.JPGFlutter instrumentation with LMS SCADAS XS

I only flew once in a glider and, apart from the terrifying catapult launch, I really enjoyed the quiet flight over a landscape of lakes and forests. It’s easy to understand why so many pilots nurture a passion for this activity. Uniting their professional goals with their hobbies is a dream for many students. This is exactly what  Idaflieg offered to engineering students joining its Sommerschule (summer school) program. Idaflieg is an institution that regroups several Akaflieg associations. In these academic associations, engineering students from various German technical colleges and universities bring together innovative ideas to the aviation industry. The summer camp took place last august in the south of Germany and gathered about 30 students united by the same passion. During 3 weeks, the students executed flight performance measurements and testing of over 15 airplanes, amongst which models of new gliders, Akaflieg prototypes and serial models. Measurement projects are run in cooperation with the Deutschen Zentrum für Luft- und Raumfahrt (National Aeronautics and Space Research Centre – DLR).

For flutter testing, the student teams relied on the Simcenter SCADAS XS system for in-flight data acquisition. Light and compact, the Simcenter SCADAS XS is easy to fit in an airframe as slender as the one of a glider. The video below shows the glider instrumented for a flutter test.

Instrumentation of the D-43 video

In flight, the pilot acted to excite the natural frequencies of the airplane with the effect of creating a flutter phenomenon. The two videos show the excitation inside the aircraft and the resulting effect. Quite impressive to watch!

 Flutter test of the D-40 up to 160km/h video

 On the Idaflieg Sommerschule blog, you’ll find more information about the performed tests. At Siemens, we’re quite proud to have supported this initiative and worked with engaged students who will  surely shape the future of aviation.

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