Novel wing designs for tractor-propeller aircraft theory, CFD and wind tunnel test results

Abstract

This thesis proposes novel wing designs with lower drag for propeller/rotor driven aircraft in tractor configuration with particular emphasis on a method of designing wings with lower induced drag by exploiting the propeller slipstream. With the increasing dynamism in short-haul regional air traffic, which tends to be inherently more expensive compared to inter-continental flights on larger aircraft on a passenger-km basis, it becomes necessary to explore new designs that may cut down fuel burn. In this scenario a turboprop is a particularly attractive option, as a propeller is an inherently more efficient producer of thrust than a turbojet or even turbofan. Beginning in the early 1990’s there was a decline in the usage of turboprops in civil aviation because of the availability of cheap oil, and jets have been preferred as they became affordable, faster and quieter, there is now a revival of interest in turboprops owing to climate change concerns and connectivity demands. Turboprops continue to be favoured for large cargo transport aircraft, military or civil, and for unmanned air vehicles requiring long endurance. There is therefore a need to explore new technologies associated with turboprops and other rotor-driven aircraft and optimize them for better performance. In particular, technologies associated with current propeller-driven aircraft do not take adequate account of the potential to exploit the effects of the propeller slipstream to design better wings; more generally the benefits of taking an integrated view of propeller and air frame together have not been fully realized.