This was a development of the XH-44, of which it retained the co-axial contra-rotating two-bladed rotors, though the latter's diameter was considerably increased.

P.Lambermont "Helicopters and Autogyros of the World", 1958

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J.P.Spencer "Whirlybirds: A History of the U.S. Helicopter Pioneers", 1998

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Technical data for UH-4 Commuter

Engine: Lycoming O-290-0, 150hp, rotor diameter: 10.08m, max ceiling: 3660m, cruising speed: 120km/h, range: 320km