Hiller XH-44

Stanley Hiller became interested in helicopters in the late 1930s, when he saw pictures of the Focke-Wulf Fw 61 and the Vought-Sikorsky VS-300.[1] He bought every book on helicopter development that he could find, and in the early 1940s he began design work on the XH-44, at the age of 17.[2]

The XH-44 featured a pair of contra-rotating rotors which, in its original form, was powered by a 65 hp Franklin engine (de-rated from its original 90 hp).[3] The engine was later swapped for a 125 hp Lycoming engine. It was the first successful coaxial rotor helicopter to be built in the United States, as well as the first helicopter to use all-metal rotor blades.[3]

The XH-44 tipped over on its first tethered test flight with Hiller at the controls, resulting in minor damage. On July 4, 1944, the XH-44 made its first untethered flight at the University of California's football stadium at Berkeley.[3] The helicopter made an appearance during a public demonstration at San Francisco on August 30, 1944.[3][4]

The success of the XH-44 caught the attention of Henry J. Kaiser, who funded further development of Hiller's rotor system.[3]

Hiller donated the XH-44 to the Smithsonian National Air and Space Museum in 1953.[5] The helicopter was restored in 1974, and in 1997 it was lent back to Hiller and displayed at the Hiller Aviation Museum.[5] The original XH-44 is no longer displayed at the Hiller Aviation Museum, although a replica is currently on display at the museum.[6]

Data from [3]

General characteristics

• Crew: 1
• Length: 13 ft 4 in (4.06 m)
• Empty weight: 1,244 lb (564 kg)
• Powerplant: 1 × Franklin piston engine, 65 hp (48 kW) (original)
• Powerplant: 1 × Lycoming piston engine, 125 hp (93 kW) (after modification)
• Main rotor diameter: 2× 25 ft (7.6 m)

Aircraft of comparable role, configuration, and era

• Brantly B-1
• Gyrodyne RON Rotorcycle
• Kamov Ka-25
• Yakovlev EG