The airfoil aerodynamic characteristics for different Reynolds numbers were determined by XFOIL and corrected for Mach number and post stall effects due to rotation. The electric components were represented via simplified mathematical models while the propeller design was performed by the blade momentum theory with vortex wake deflection including corrections for the tip losses. In this paper a propeller design methodology for a fully electric propulsion system is presented. To obtain a propulsion system with an overall high efficiency one must take into consideration the efficiencies of all individual components as well as their matching meaning that the individual characteristics of all components have to be considered when designing the propulsion system. In most small and medium size UAVs the fully electric propulsion system is implemented. This is not unusual since these systems can provide a large increase in efficiency and reliability while decreasing the carbon footprint. There has been an increased interest in the field of electric power aircraft propulsion systems in recent years mostly due to the technological improvements in power electronics, energy storage and permanent magnet electric motors. Finally, version M4, consisting of about 70% of Dolphin?s original rear domain and 30% of the new nose shape, managed to exceed the NACA?s characteristics, thus paving the way to investigate the Dolphin hybrids that could be suitable for the general aviation industry.
Airfoil shapes series#
A series of the Dolphin?s leading edge modifications has been investigated, gradually improving its aerodynamics. On the other hand, at higher and lower lift coefficients, its aerodynamic characteristics were drastically below those of the NACA section, due to the unfavorable influence of the Dolphin?s sharp nose. Results have shown that the Dolphin has a slightly higher lift/drag ratio in the lift coefficient domain 0.1 ? 0.35 than NACA. The same CFD model has been applied on the counterpart Dolphin 2415. The results were compared with NACA experiments and very good agreements have been achieved in the major domains of lift and polar curves. A CFD calculation model has been established and applied on NACA 2415. The authors of this paper have been motivated to compare the aerodynamic characteristics of widely used NACA 2415 airfoil with Taposu?s dolphin that would have the same principal geometric characteristics. On the other hand, they have not been applied to any commercial general aviation aircraft.
These airfoils are characterized by a sharp leading edge and experiments have proven that they can achieve better aerodynamic characteristics at very high angles of attack than certain classical airfoils, with the nose geometry inclined downwards. Iosif Taposu has formulated a mathematical model and generated a family of airfoils whose geometry resembles the dolphin shape.
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