Experimental aerodynamics of delta wing mini UAVs and their scaling

摘要

This paper describes experimental aerodynamics of remotely controlled delta wing mini UAV prototypes (empty weight ca. 100g, payload 70g, wing span ca. 500mm) with a view to scaling down the design to the micro UAV size. Flight tests of one prototype revealed unexpectedly low performance, in particular a low gliding ratio and poor elevon's effectiveness. Wind tunnel tests were performed to elucidate the reasons for this behaviour using the following five models: Model A - typical all wing configuration with thick aerofoils (good performance in flight tests); Model B - delta wing configuration with thick aerofoils (low performance in flight tests); Model C - all wing configuration and thin aerofoils; Model D - delta wing configuration and thin aerofoils; Model E - delta wing configuration and modified thin aerofoils. Of particular interest is the "mid span vortex" discovered on model B which seems to be specific to low Reynolds numbers aerodynamics. It was probably responsible for low performance results in flight tests of this model. Wind tunnel tests of models A, C, D and E seem to suggest some methods to overcome this problem. They are analysed at the end of the paper.