WING GLOVE TEST BED FEASIBILITY STUDY

Abstract

Wind tunnels are at present used to obtain the bulk of the experimental data on airfoils and on the properties of the boundary layer. In-flight testing is being used increasingly, however, to promote knowledge of laminar flow technology, to calibrate wind tunnels which in general suffer specifically from wind tunnel type turbulence and to obtain experimental data at high Reynolds numbers. In particular, inflight testing has been used to evaluate boundary layer transition prediction schemes. In-flight testing has been carried out using a number of different configurations of test bed. The University of Braunchweig, Germany has, for example, used a " glove" containing pressure sensing equipment which fitted very closely over the wing of an LFU 205 propeller aircraft. This aircraft was used intensively for laminar flow investigations and the experimental transition data obtained used to find a limiting value of N in the "N-factor method" for predicting boundary layer transition. Flight testing in this manner is limited, however, in that only the characteristics of the wing airfpil section may be investigated and a wake survey is not possible. This gtove should allow better measurement of the lift drag and transition region than can currently be carried out by many wind-tunnles. In addition, test Reynolds numbers in excess of 5.5 x10^6 are possble - larger than those achievable by many research facilities. The following sections discuss the design of the glove, the istrumentation used within it and assess the feasibility of the aircraft/wing giove combination boih aerodynamically and structurally. The cost effectiveness and flexibility of the concept in comparison vith oiher forms of in flight testing are also investigated.