Landgraf Helicopter Co. Model H-2 Lateral-Twin Helicopter
First flight: November 2, 1944
This attractive, single-seat, lateral-twin experimental helicopter was first flown on Nov. 2, 1944 at Army Lomita Air Strip near Torrance, California. The H-2 preliminary design started in 1933 and construction began in 1940. Fred Landgraf quit his job at Douglas Aircraft-Northrop Division in El Segundo, California, in 1943 and established the Landgraf Helicopter Co. in order to work on his project full time.
The entire fuselage and wing/lateral-boom structure consisted of molded plywood with glued joints. A single British-built 7-cylinder, 85 hp (65 kW) Popjoy R air-cooled radial engine powered the rotors by tension rod linkages directly to disks attached to the rotor hubs. These “power disks” were connected by 12 sets of carbon steel rods (for each rotor) with maximum tension on any rod under full power reaching 400 lb (1.8 kN).
The 16 ft (4.9 m) diameter 3-bladed rotors were contra-rotating, synchronized, and intermeshing. Directional control was achieved by cyclic operation of the blade tip-mounted ailerons. A later rotor design achieved yaw control by actuation of spoilers on the rotor blades via yaw pedals in addition to the ailerons. The aircraft had a gross weight of 850 lb (386 kg). It was also one of the earliest helicopters to feature a retractable tricycle landing gear.
The maiden flight was on Nov. 2, 1944. Despite several successful early flights, the aircraft crashed on Nov. 17 when one of the wooden rotor hubs failed inflight. The pilot was injured. Landgraf then began a redesign with a steel rotor hub.
In the spring of 1945, the U.S. Army awarded Landgraf Helicopter Co. a $50,000 contract to develop a rigid rotor blade system and by the spring of 1946 the rebuilt H-2 was ready to fly and made several flights at Central Airport near Compton, California, and Vultee Field in Downey, California. Additional Army funding was received in January 1948.
A fatal crash in 1948 ended the program. Despite plans for a larger 3-seat H-3 and 5-to-8-seat H-4 variants, the company was dissolved in 1949 with program assets and patent rights sold to the British company, Firth Helicopters; unfortunately, the new owners did not complete their version and the project was abandoned.
Fred Landgraf was later employed at Ryan Aeronautical in San Diego, California, as a project engineer.
Photos: via www.skynet.be
Text: Ken Bartie
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