22nd Congress of International Council of the Aeronautical Sciences, Harrogate, UK, 28 August - 1st September, 2000
Paper ICAS 2000-P5.4

PROTOTYPE DESIGN AND TESTS OF A COMMERCIAL UL-AIRCRAFT EQUIPPED WITH WINGGRID WINGTIPS

U. La Roche, Switzerland
La Roche Consulting Dynaero & Onera

Keywords: flight testing and wing design, subsonic, ul-aircraft

Based on the reported successful fullscale testing of the Winggrid device in 1997 an existing production model UL-aircraft has been adapted to this device. Adaption of the device to the given airplanes constraints is decribed. We describe first the special structural considerations for adaption of the device to a standard product. Then we give the performance precalculation, followed by the test results for confirmation of the design calculations. To the classic perfomance enveloppe comprising cruise performance, modified landing and take-off behaviour is added and a soaring speed range with motorglider performance. For this additional performance no additional controls or add-ons (such as change of wing-pairs, etc.) are required. The performance increase in L/D attained for the optimum speed range gets the UL-aircraft to be classified as a regular motorglider. Extensive test results including comparison to aircraft of the same type with same span, but equipped with different wingtip arrangements are reported. The relevant tests are executed under guidance of ONERA.

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