Evaluating the feasibility of studying propeller-wing interaction through ground-based high-speed experimental taxi-tests

Abstract

The Dutch Electric Aviation Centre possesses and uses a Cessna Skymaster 337F as an experimental flying testbed to help gain knowledge to aid the transition towards hybrid/ electric aviation. The interaction between the rear propeller slipstream and the horizontal tail has been likened to the interaction of propeller-wing configurations seen on larger regional aircraft. The DEAC intends to study this interaction through ground-based high-speed taxi-tests before any flight tests. By doing so, tests are conducted in a safer and more accessible environment without the need for re-certification, albeit, with changes to both testing environment and aircraft operational settings. This numerical study focused on evaluating the feasibility of such a testing approach to help gain an insight and better prepare for experiments. RANS CFD studies were performed on a simplified self-designed and developed half-airplane half-propeller model of the aircraft in ground-run configuration and free-flight configuration. In this stead-state simulation, the propellers were treated as actuator disks and had a specified constant pressure rise. Vortices being shed from the fuselage and interacting with the tail were discovered. The uncertainties due to the chosen simplifications, the neglect of twin contra-rotating propeller swirls, and the fact that the formation and evolution of the wake vortices, and their interaction with both the rear propeller and the horizontal tail are inherently unsteady effects, precludes a definitive conclusion. A more detailed numerical model is required to address the situation and evaluate the feasibility of this approach.