The Brantly B-1 was a 2-seat, coaxial-rotor helicopter designed by Newby O. Brantly and constructed by the Pennsylvania Elastic Company, Brantly's employer.
3-501: In 1946, Brantly started flight testing the B-1 prototype (NX69125), which used a 150 hp Franklin O-335 engine in the fabric fuselage and two three-bladed rotors that rotated at 320 rpm and were fitted coaxially. The collective, cyclic, and differential controls were enclosed in the rotor hubs and ran in an oil-bath. Each rotor blade weighed 5.5 kilos. It also had a fixed wheel undercarriage with
6-540: A tailwheel under the tailfin. Unfortunately, the design was too heavy and complex and was abandoned. Data from General characteristics Performance Franklin O-335 The Franklin O-335 (company designations variations on 6A and 6V ) was an American air-cooled aircraft engine of the 1940s. The engine was of six-cylinder, horizontally-opposed layout and displaced 335 cu in (5.5 L). The power output of later variants
9-511: Was 225 hp (168 kW). These engines were commonly vertically mounted and used to power many early helicopters in the United States. They were closely related to the 2A4 and 4A4 2- and 4-cylinder engines. In various subtypes, the 6A4 remained in continuous production from 1945 to the time Franklin's United States operations ceased in 1975, with versions continuing in Polish production into
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