Brantly B-1

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Brantly B-1
Role light coaxial-rotor helicopter
Manufacturer Brantly Helicopter Corporation
Designer Newby O. Brantly
First flight 1946
Status abandoned

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.

Design and development[edit]

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 a tailwheel under the tailfin.[1]

Unfortunately, the design was too heavy and complex and was abandoned.


Data from [2]

General characteristics

  • Crew: 1
  • Capacity: 1
  • Length: 17 ft 6 in (5.33 m)
  • Height: 7 ft 9 in (2.36 m)
  • Empty weight: 1,325 lb (601 kg)
  • Gross weight: 2,000 lb (907 kg)
  • Powerplant: 1 × Franklin O-335 6-cyl. air-cooled horizontally=opposed piston engine, 150 hp (110 kW)
  • Main rotor diameter: × 29 ft 6 in (9 m)


  • Cruise speed: 113 mph; 98 kn (182 km/h)
  • Range: 398 mi; 346 nmi (640 km)


  1. ^ Simpson, R.W. (26 May 1998). Airlife's Helicopters and Rotorcraft. The Crowood Press Ltd. ISBN 978-1853109683. 
  2. ^ Lambermont, Paul Marcel; Pirie, Anthony (1970). Helicopters and autogyros of the world (Illustrated, revised ed.). Barnes. 

External links[edit]