A method is described to measure the performance of fixed-wing aircraft with wing tip propellers, using a scaled (33.3%) version of the electric two-seater e-Genius aircraft at the University of Stuttgart. The use of wing tip propellers has been shown in previous studies to reduce the wing tip vortex, both decreasing the induced drag and converting some of the energy in the vortex into thrust. The test platform is shown and a measurement concept to individually quantify these two effects is presented. Flight-testing in real conditions, however, introduces a number of measurement errors through the effects of atmospheric disturbances and control input. The problems that were encountered during the test design are described and a method is presented to calculate the expected measurement error. Both atmospheric disturbances and control input are found to potentially introduce considerable measurement errors, making a repeatable test setup difficult. Solutions to reduce the performance measurement errors are then shown and consist of a linear-quadratic regulator to minimize the effects of atmospheric turbulence and control input, as well as guidelines for the test campaign. The presented method can readily be applied to other configurations relying on electric propulsion.
展开▼
