US Patent 11267571 Stacked propellers

An aircraft can include a stacked propeller to generate lift during assent and descent. The stacked propeller includes a first propeller and a second propeller that co-rotate about an axis of rotation. In one embodiment, the blades are coupled to a rotor mast that contains an internal cavity. In one mode of operation, the first propeller and/or the second propeller can be stored in the internal cavity in order to reduce drag during flight. The aircraft can include one or more stacked propellers, such as a port propeller and a starboard propeller, which rotate in opposite directions during one or more modes of flight.