On 27 April 1946, the McDonnell XHJH Whirlaway takes to the skies for its maiden flight, becoming the largest helicopter yet flown in the United States and the first American twin-rotor helicopter ever to lift off.
Developed for the U.S. Navy, the Whirlaway—formally designated the XHJH-1—emerges from a wartime drive to expand rotary-wing aviation beyond small, single-rotor designs. At a time when helicopters remain experimental and largely confined to niche roles, the Whirlaway represents a bold step into heavy-lift capability and multi-passenger transport. Unlike conventional helicopters such as the Bell Model 47, which received FAA civilian certification just weeks ago, which we covered in our 8 March post, McDonnell's new machine explores a very different engineering path: the transverse-rotor system.
The XHJH Whirlaway is built around two horizontally opposed, intermeshing rotors mounted at the ends of short wing-like outriggers. This transverse-rotor layout eliminates the need for a tail rotor, which in traditional designs counters torque produced by the main rotor. By using two counter-rotating rotors on either side of the fuselage, the Whirlaway inherently balances torque while also improving lateral stability. The aircraft is powered by two 450-horsepower Pratt & Whitney R-985 Wasp Junior radial engines—each driving one of the rotors—allowing it to lift heavier loads than any other American helicopter to date.
The Whirlaway’s fuselage is large and boxy, designed to carry up to 10 passengers or bulky cargo. Its rear loading ramp and internal layout suggest the Navy’s interest in using it for air-sea rescue, medical evacuation, and cargo transport—tasks unmanageable with the compact Bell 47 or Sikorsky R-4. In testing, the XHJH-1 demonstrates promising handling characteristics and robust lift performance, though its size and mechanical complexity raise concerns about maintenance and operational costs.
Nevertheless, today, test pilot Charles R. Wood showcases the Whirlaway's flight capabilities.
Picture: The world’s first twin-engine helicopter, the XHJD-1, also was the largest. Source: U.S. Naval Institute Photo Archive
World War Two
On 27 April 1946, the McDonnell XHJH Whirlaway takes to the skies for its maiden flight, becoming the largest helicopter yet flown in the United States and the first American twin-rotor helicopter ever to lift off.
Developed for the U.S. Navy, the Whirlaway—formally designated the XHJH-1—emerges from a wartime drive to expand rotary-wing aviation beyond small, single-rotor designs. At a time when helicopters remain experimental and largely confined to niche roles, the Whirlaway represents a bold step into heavy-lift capability and multi-passenger transport. Unlike conventional helicopters such as the Bell Model 47, which received FAA civilian certification just weeks ago, which we covered in our 8 March post, McDonnell's new machine explores a very different engineering path: the transverse-rotor system.
The XHJH Whirlaway is built around two horizontally opposed, intermeshing rotors mounted at the ends of short wing-like outriggers. This transverse-rotor layout eliminates the need for a tail rotor, which in traditional designs counters torque produced by the main rotor. By using two counter-rotating rotors on either side of the fuselage, the Whirlaway inherently balances torque while also improving lateral stability. The aircraft is powered by two 450-horsepower Pratt & Whitney R-985 Wasp Junior radial engines—each driving one of the rotors—allowing it to lift heavier loads than any other American helicopter to date.
The Whirlaway’s fuselage is large and boxy, designed to carry up to 10 passengers or bulky cargo. Its rear loading ramp and internal layout suggest the Navy’s interest in using it for air-sea rescue, medical evacuation, and cargo transport—tasks unmanageable with the compact Bell 47 or Sikorsky R-4. In testing, the XHJH-1 demonstrates promising handling characteristics and robust lift performance, though its size and mechanical complexity raise concerns about maintenance and operational costs.
Nevertheless, today, test pilot Charles R. Wood showcases the Whirlaway's flight capabilities.
Picture: The world’s first twin-engine helicopter, the XHJD-1, also was the largest.
Source: U.S. Naval Institute Photo Archive
2 days ago | [YT] | 2,362