Abstract: A model rotary wing aircraft is provided that includes a fuselage, a power plant, a main rotor, a tail rotor, and a drive apparatus. The power plant includes a passive cooling system to transfer heat produced by the power plant to the atmosphere. The passive cooling system consumes less than about five percent of the power produced by the power plant. The main rotor is driven by the power plant at a main rotor speed of rotation and the tail rotor is driven by the power plant at a tail rotor speed of rotation. The drive apparatus transfers power from the power plant to the main rotor and tail rotor to rotate the tail rotor at a tail rotor speed of rotation that is about three times greater than the main rotor speed of rotation to minimize the amount of power used by the tail rotor.

Abstract: A fuselage structure for use on a model helicopter includes a longitudinally extending keel defined by a vertical flat plate oriented to lie in parallel relation to a longitudinal axis of the model helicopter. A radio control system component is mounted to the vertical flat plate. The fuselage structure also includes a laterally extending floor perpendicular to the keel, a front bulkhead appended to the keel and a forward end of the floor, and a firewall appended to the keel and a rearward end of the floor. A landing gear assembly is coupled to the fuselage structure at a junction positioned to lie adjacent to a forward portion of a bottom edge of the keel.

Abstract: A device for stabilizing yaw motion is provided for use on a helicopter having a main rotor rotatable about a main rotor axis, a power source, and a tail rotor boom with a longitudinal axis. The device includes a tail rotor and a gyroscopic mechanism. The tail rotor is mounted to the tail boom of a helicopter and is rotated about a tail rotor axis by the power source to generate a thrust force transverse to the tail boom and offset from the main rotor axis. The gyroscopic mechanism automatically varies the thrust force generated by the tail rotor to oppose yaw motions. The gyroscopic mechanism includes first and second variable pitch gyro arms extending along first and second gyro arm pitch axes, respectively, a support mechanism, and a pitch adjustor linkage.