Abstract: An improved air-cooled aviation engine includes a compact combustion chamber having an intake valve opening, an exhaust valve opening, and a generally elliptical shape. The elliptical shape has a major axis and a minor axis, with the major axis intersecting both the intake valve opening and the exhaust valve opening. In some examples, the major axis is the same length or shorter than a diameter of a cylinder bore of the engine, and the minor axis is smaller than the major axis. Combustion is thus constrained to a smaller area than that of the cylinder bore.

Abstract: An improved air-cooled aviation engine includes a compact combustion chamber having an intake valve opening, an exhaust valve opening, and a generally elliptical shape. The elliptical shape has a major axis and a minor axis, with the major axis intersecting both the intake valve opening and the exhaust valve opening. In some examples, the major axis is the same length or shorter than a diameter of a cylinder bore of the engine, and the minor axis is smaller than the major axis. Combustion is thus constrained to a smaller area than that of the cylinder bore.

Abstract: A technique for generating electrical power from an engine in an aerial vehicle includes providing an alternator disk structure (ADS) between the engine and a propeller of the vehicle. The ADS is disposed concentrically with an engine drive shaft that drives the propeller and includes at least two concentric regions, a first region having a stator and a second region having a rotor. The first region is rotationally fixed relative to the engine, and the second region is coupled to a drive shaft of the engine. As the engine rotates the drive shaft, the rotor disposed in the second region spins concentrically relative to the stator disposed in the first region, thereby inducing electrical current in windings of the stator. The rotor and the stator thus work together to generate electrical power, which may be conveyed from the stator to electrical subsystems and controls of the vehicle.