The HRH was designed to comply with the US experimental – amateur-built rules. It features a single main rotor, a single-seat enclosed cockpit with a windshield, skid-type landing gear and a four-cylinder, air-cooled, four-stroke, 1650NaN0 Subaru EJ25 automotive engine. It is the high power to weight ratio that gives the aircraft its name.
The aircraft fuselage is made from a mix of welded 4130 steel tube and bolted-together aluminum tubing, with a composite cabin shell. Its 251NaN1 diameter two-bladed Waitman composite rotor has a chord of 80NaN0. The tail rotor has a 460NaN0 diameter. The aircraft has an empty weight of 10000NaN0 and a gross weight of 13500NaN0, giving a useful load of 3500NaN0. With full fuel of the payload is 2390NaN0. The HRH can hover in ground effect at 70000NaN0 and out of ground effect at 50000NaN0
By January 2013 there was one example, the 2001 prototype, registered in the United States with the Federal Aviation Administration.[3]