Brantly B-1

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.

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

Design and development

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.

Specifications

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)

Performance

• Cruise speed: 113 mph (182 km/h, 98 kn)
• Range: 400 mi (640 km, 350 nmi)