US Patent 11787551 Vertical takeoff and landing aircraft electric engine configuration

An electric propulsion system for a vertical takeoff-and-landing aircraft having an inverter assembly, a gearbox assembly, an electric motor assembly. The inverter assembly, the gearbox assembly, and the electric motor assembly may be substantially aligned along an axis. The inverter assembly, a gearbox assembly, and electric motor assembly may each abut at least one of the others. The electric engine may use a liquid, such as oil, for cooling and lubricating components of the inverter assembly, gearbox assembly, and electric motor assembly. Further, the electric engine may use volumes of oil for cooling and lubricating components below a threshold volume so that the electric engines do not require a fire protective barrier.