21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-1.1.4

DEVELOPMENT, QUALIFICATION AND FLIGHT TESTING OF A WINGGRID ON A JET-POWERED TESTBED

La Roche U., MeyerˇPiening H. R.*, Stengele I.*, Bircher T.**
La Roche Consulting, Switzerland; *ETHZ, Switzerland; **BITANX, Switzerland

Keywords: flight testing, winggrid, jet-powered testbed

The WINGGRID consists of a grid of identical and parallel winglets mounted to the tip of an aircraft wing for reduction of induced drag. At the ICAS Conference Sorrento 1996 [1] the fundamentals of such an aerodynamic device had been presented. With the conclusive results of the wind-tunnel tests reported, full-scale flight tests of the WINGGRID using an existing aircraft as test-bed were conducted. The expected performance figures of the Sorrento 1996 [1] paper were reproducibly confirmed full scale. The question, how storcks use their fingerfeathers for achieving high glide-numbers with low aspect ratio, worked on since Otto Lilienthal, has found an answer. The tests revealed good handling and safety features of the device. The actual tests were performed in 97. They comprised the formal airworthiness tests for qualification followed by performance testing. The available results point to an important breakthrough, not the least because applications open a new design-philosophy for wings. The paper analyses the validity of the experimental evidence obtained and identifies major conclusions for applications.

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