In response to the German U-boat campaign in the Atlantic during World War II, the McDonnell Aircraft Corporation submitted a proposal to the U.S. Navy for a large antisubmarine helicopter. It would be the firm’s first rotary-wing aircraft and the world’s first helicopter with twin engines and twin rotors.1
The Navy responded with a letter of intent in May 1944 for the design and construction of one XHJD-1 aircraft, with a formal contract for the helicopter awarded to McDonnell in March 1945. It would be a large aircraft, exceeding even the Focke-Achgelis Fa 223, probably the largest helicopter flown to that time. The single-engine, twin-rotor Focke-Achgelis Fa 223, which entered German Luftwaffe service in 1942, was 7,055 pounds empty and had a loaded weight of 9,502 pounds. Only ten of that aircraft were flown.
The XHJD-1, designed by Constantine M. Zakhartchenko, was first flown on 27 April 1946, at Lambert Field in St. Louis. Given the McDonnell name Whirlaway, the aircraft was fitted with twin engines mounted outboard from the fuselage on short “wings.” Pylons extended out from both engine nacelles for the twin rotors. (The general configuration was similar to the Fa 223.) The rotors initially had a diameter of 46 feet, later increased to 50 feet.
Among its innovative features, the configuration enabled either engine to send power to both rotors by transmissions and gear boxes. Thus, the helicopter could maintain level flight at full gross weight on the power of one engine turning both rotors. Also, the three-blade rotors were counter-rotating, which eliminated torque and hence the need for a tail rotor. The helicopter was provided with fixed, tail-wheel landing gear; the main landing gear extended down from the engine nacelles and was externally braced.
In 1946, the aircraft was changed from XHJD-1 to XHJH-1 when the McDonnell letter designation was changed from “D” to “H” in the Navy classification system. The letter “D” was reserved for Douglas aircraft.2
Despite the aircraft’s size, lift capability, and other advanced features, with World War II ended, there would be no production of the McDonnell helicopter. Although the Navy and other U.S. services showed great interest in rotary-wing aircraft after the war, the size and configuration of the HJH-1 likely would have made it a difficult “bird” to handle on board ship.
Thus, from April 1946 to June 1951, the prototype was employed in various flying research projects. There were several modifications to the XHJH-1 during those five years, with changes in the rotor blades and horizontal control surfaces installed on the tail fin. When those research efforts were completed, the XHJH-1 passed into history, not having been a progenitor, but still an interesting aviation development.3
1. This column is based in part on René J. Francillon, McDonnell Douglas Aircraft since 1920 (London: Putnam, 1979).
2. The McDonnell and Douglas firms were merged in 1967 to form the McDonnell Douglas Corporation.
3. The XHJH-1 was donated to the National Air and Space Museum in Washington, DC.