Hillberg EH1-01 RotorMouse

The Hillberg EH1-01 RotorMouse is an American helicopter that was designed by Donald Gene Hillberg and produced by Hillberg Helicopters of Fountain Valley, California, first flying in 1993. Now out of production, when it was available the aircraft was supplied as a kit for amateur construction.
Design and development.
The EH1-01 RotorMouse was designed to comply with the US "Experimental - Amateur-built" aircraft rules. It features a single main rotor, a two-bladed tail rotor, a single-seat enclosed cockpit with a windshield, skid-type landing gear. The acceptable power range is and the standard engine used is a Garrett AiResearch 36-55 auxiliary power unit (APU).
The aircraft's semi-monocoque fuselage is made from 2024-T3 aluminum sheet. Its diameter two-bladed rotor employs a NACA 0012 airfoil. The aircraft has an empty weight of and a gross weight of , giving a useful load of . With full fuel of , located in a crash-resistant fuel cell, the payload for pilot and baggage is . The cabin width is and the aircraft mounts stub wings similar to the Bell AH-1 HueyCobra.
Operational history.
By 1998 the company reported that one aircraft was completed and flying.
By March 2015 one example had been registered in the United States with the Federal Aviation Administration. The sole one on the registry was in the name of the designer.