Flight tests at transonic speeds on freely falling models. Parts I to V

Abstract

In the past decade the problems associated with high-speed flight have increasingly occupied the minds of many workers in aerodynamics and aircraft structures. The possibility of achieving supersonic flight has introduced a number of new problems not the least of which has been that of obtaining aerodynamic information throughout the transonic range of speeds. This report deals with one of the early test techniques developed for this purpose. Basic bodies carrying the aerofoils to be tested were released from an aircraft flying at height, and accelerated under the influence of gravity through the transonic speed range. Radar recorded the flight path and telemetering equipment carried within the body transmitted information to a ground station during the free fall. The work on this method of test which was started in 1943 was brought to a close in 1949. The main reason for abandoning the experiments was the limiting accuracy of the telemetering equipment although other contributing causes were present. Part I of this report is a historical precis of the Work and Part II a description of the models and the technique itself. In Part III the drag measurements on nine wings are presented and in Part IV the application of the technique to flutter tests is considered. Part V discusses the accuracy of the technique.