Integrated flow control and power management for vertical take-off and landing (VTOL) aircraft

Novel solutions, such as flying air taxis, are being proposed as a means to resolve intra-city and inter-city travel congestion using, often, vertical take-off and landing (VTOL) aircraft configurations. Such vehicle configurations present unique flight control and aerodynamic challenges particularly during transition phase from hovering to horizontal flight. To achieve smooth transition and avoid aerodynamic stall requires smart coupling of propulsion with flight controls. This project investigates using active flow control to ensure correct operability of VTOL aircraft during transition from helicopter to airplane mode (and back), all whilst utilising minimum energy. The proposed research will develop further knowledge in the physics of the effects of active flow control in alleviating stall during VTOL transition, as well as novel design of integrated flight control and propulsion laws that utilise such flow control techniques to manage overall operability and efficiency of the aircraft.

More specifically, fluid injection active flow control (AFC) has been applied experimentally to mitigate flow separation of an aerofoil at a high angle of attack (the angle between the aerofoil itself and the oncoming airflow) and to thus increase the angle at which the aerofoil stalls. However, there exists limited examples of this being controlled through closed-loop feedback and, additionally, no validation on a flying scaled model. Further, wind tunnel testing of the effectiveness of fluid injection AFC applied to a wing under the effects of a propeller's wake has not presently been done. This project has three primary objectives: 1. Investigate the use of open-loop and closed-loop fluidic flow control through a series of carefully controlled wind tunnel experiments; 2. Design a feedback control methodology that combines the use of classical flight control surfaces with active flow control and apply it to a tiltwing aircraft model. 3. Demonstrate the validity of such a combined approach on scaled tiltwing demonstrator aircraft throughout hover, cruise, and, particularly, transition from vertical to horizontal flight. The design, implementation, and demonstration of such a system would widen a design space for tiltwing aircraft and would contribute towards minimising energy use and maximising passenger comfort in emerging Urban Air Mobility markets.

This project falls within the EPSRC's control engineering and fluid dynamics research areas.