Measurement of Steady and Unsteady Airloads on a Stiffness Scaled Model of a Modern Transport Aircraft Wing.

Kurzfassung

Extensive wind tunnel tests have been carried out on a modern transport aircraft wing in transonic flow. The objective was to measure steady and unsteady pressure distributions, and to investigate the influence of the variable twist distribution of an elastic wing. For this purpose the wind tunnel model was scaled in stiffness, so that the twist distribution was similar to a representative aircraft, and changed with loads variation. The extensive model instrumentation consisted of opto-electronical equipment to measure the actual wing twist distribution. The forced model oscillation in pitch and bending up to a reduced frequency of about 0,7 (based on a reference chord) was measured with conventional accelerometers. A piezo-electrical balance was used for steady and unsteady forces measurement. Steady and unsteady pressures were measured simultaneously with 290 pressure transducers. Investigated parameters were Mach number, stagnation pressure, angle of incidence, reduced frequency and oscillation amplitude.