A hybrid-electric aerial vehicle is disclosed comprising: an airframe; a plurality of longitudinal booms extending radially from the airframe; a passively charged internal combustion engine operatively coupled with a fuel tank, a generator operatively coupled with the passively charged internal combustion engine; a battery bank operatively coupled with the generator; and a plurality of motors. The passively charged internal combustion engine has an intake engine valve, an exhaust engine valve, and a combustion chamber, wherein the intake engine valve is delayed to provide an expansion ratio in the combustion chamber that is greater than a compression ratio in the combustion chamber. Each of said plurality of motors may be positioned at a distal end of one of said plurality of longitudinal booms and be operatively coupled with a propeller, wherein the plurality of motors is electrically coupled with the battery bank and the generator.