Vertical Lift by Series Hybrid Power

Multi-rotors (e.g. quad-copters) typically have direct electric drive, where the electric motor shaft is directly coupled to the propeller shaft. The benefit of this configuration is simple and high fidelity control. But electric drive for vertical lift typically relies on lithium polymer batteries for energy storage, and battery specific energy is extremely low compared to internal combustion fuels; Gasoline has about a 15X advantage over rechargeable batteries and diesel has about an 18X advantage. Current unmanned multi-rotor aircraft do not have the endurance or payload capability to act in place of manned observatory platforms (rechargeable batteries deliver at most two hours of endurance for multi-rotor aircraft with no payload). However, frequency response requirements tend to prohibit direct drive from an internal combustion engine. Aurora proposes to develop a reformulated Miller Cycle engine in Series Hybrid Architecture for use in small unmanned vertical lift aircraft to combine the benefits of both direct electric drive and internal combustion engine technology. The reformulated Miller Cycle will also confront the fuel mixing issues associated with sUAS sized small engines. More »