July 2015

2015 JulyHiller XH-44 Hiller-Copter
First flight: July 4, 1944 

Stanley Hiller Jr.'s interest in helicopters began in 1941 at age sixteen. The XH-44 coaxial configuration differed dramatically from other helicopters developed during this period in that the layout since a coax did not generate torque, no engine power was wasted driving a tail rotor that produced no lift or forward thrust. Hiller selected a Franklin 90 hp (67 kW) engine, de-rated to 65 hp (48 kW) as the initial power plant for the XH-44.

Ground tests began 1944 with the roar of 65 hp and broken glass when the first engine run-up inside the Hiller workshop sucked the skylights from the ceiling.

On July 4, 1944, Hiller flew the bright yellow aircraft free from its tether for the first time in the stadium. A public demonstration followed less than two months later on August 30, 1944, in San Francisco. His most important improvement was a redesign of the rotor blades and mast to allow each two-blade set to teeter freely. Hiller also installed a more powerful Lycoming O-290 CP engine on December 1, 1945.

The Smithsonian National Air and Space Museum acquired the XH-44 from Hiller in 1953 and then restored the helicopter in 1974. It is now on display at the Smithsonian’s Steven F. Udvar-Hazy Center.

XH-44 Specs:
  • Rotor Diameter: 25 ft (7.6 m)
  • Length: 13 ft 4 in (4.0 m)
  • Height: 9 ft (2.7 m)
  • Weight Empty: 1,244 lb (564 kg)

(Hiller photo via AHS Archives; text by Pete Noell)

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