New Configuration Design and Analysis for a Vertical Take-off/Hovering Solar Powered Aircraft

According to the assumption making use of the propeller slipstream to increase the lift of the aircraft, two new configurations, i.e., the over-the-airfoil propeller aerodynamic configuration and the new double airfoil configuration coupled with a propeller, are investigated for the purpose of improving the performances of the vertical take-off aircraft during the phases of cruise, hovering and vertical take-off. The Computational Fluid Dynamics (CFD) technology is utilized to investigate the change regulations of these two new configurations affected by the configuration parameters in a two dimensional flow The simulated results indicate that the lift coefficients of these two configurations can be apparently augmented by using the propeller slipstream correctly and the maximum of the lift coefficient increment can be achieved by 14.8%. However, the drag coefficients are reduced significantly, even to be a minus value. With a zero free stream velocity, the axial acceleration of the propeller slipstream still has the ability of inducing some lift on the airfoil for the propeller-coupled double airfoil configuration, as a result, the necessary engine power at the phases of cruise and vertical take-off can be decreased, respectively. Meanwhile, the generation of the induced lift can proof that the assumption described above is practicable.