Abstract: Aircraft comprising an airframe having a forward end, an aft end opposite the forward end, a top extending between the forward end and the aft end, and a bottom opposite the top side. The aircraft further includes a power plant mounted on the airframe. In addition, the aircraft includes at least two propellers rotatably mounted on the airframe and powered by the power plant for moving the aircraft in a generally forward direction during operation of the propellers. Also, the aircraft includes at least two counter-rotatable fan sets mounted on the airframe and powered by the power plant for providing upward lift to the aircraft during operation of the fan sets.

Abstract: A face-gear forging die which can be used to near-net forge face gears is disclosed. The face-gear forging die is constructed from a blank, and is cut to specification using a wire electrical discharge machining (EDM) process. The wire electrical discharge machining process is computer controlled, according to pre-specified instructions. Accordingly, a variety of different-shaped face-gear forging die may be constructed by merely changing the specification's input to the wire Electric Discharge Machining apparatus. The wire Electric Discharge Machining process can also be used to cut the face gear tooth directly, to thereby circumvent the forging procedure. The complex, curved surfaces of the face gear teeth are mathematically approximated with a ruled surface, and the mathematical approximation is input to the wire Electric Discharge Machining apparatus for subsequent execution and forming of the die.