A REDUCED ORDER MODEL TO ESTIMATING PROPELLER/WING INTERACTION IN SOLAR POWERED AIRCRAFT PRELIMINARY DESIGN

The recent improvements in electric motor technology and battery energy density are making electric propulsion a valid alternative for non-conventional aircraft design. The adoption of this new propulsive system is changing the design of new aircrafts and distributed propulsion seems to be a good way to exploit the advantages of electric propulsion. In order to minimize the power required, an efficient aerodynamics coupled with high efficiency propeller capable of working at low Reynolds numbers has to be developed. Reduced order models are useful in the preliminary design phase to define the best thrust distribution because they allow the analysis of different configurations in an acceptable time. The model presented is a modified lifting line that takes into account the flow acceleration due to the propeller disk and the swirl component due to the propeller rotation. The reduced model was validated with available wind tunnel results and applied for the analysis of the lift distribution of the Heliplat solar energy aircraft. Differences between the presented model and a panel code CFD analysis are also illustrated.