The five-seater Model 305 helicopter is based on the smaller two-seat Brantly B-2 that was designed by Newby O. Brantly. The helicopter is powered by a Lycoming IVO-540 flat six piston engine.^[1] The enlarged cabin has room for five passengers, two side-by-side forward-facing seats and a bench seat at the rear for three passengers.^[1] The Model 305 first flew during January 1964 and FAA type approval was received 29 July 1965.^[2] 45 were built during the mid 60's by Brantly and Brantly-Hynes produced an improved version in 1985 of which 4 were built. The Brantly 305 suffered from a ground resonance problems.^{[citation needed]} Hynes developed a more powerful and streamline version in 1993, none were produced.^{[citation needed]}

Data from Jane's All The World's Aircraft 1976-77 ^[3]

General characteristics

• Crew: 1
• Capacity: 4 passengers
• Length: 32 ft 11 in (10.03 m) (overall length, rotors turning), 24 ft 5 in (7.44 m) (fuselage length)
• Height: 8 ft 0+1⁄8 in (2.442 m)
• Empty weight: 1,800 lb (816 kg)
• Max takeoff weight: 2,900 lb (1,315 kg)
• Fuel capacity: 43 US gal (36 imp gal; 160 L)
• Powerplant: 1 × Lycoming IVO-540-A1A air-cooled flat-six engine, 305 hp (227 kW)
• Main rotor diameter: 28 ft 8 in (8.74 m)
• Main rotor area: 35.8 sq ft (3.33 m²)

Performance

• Maximum speed: 120 mph (190 km/h, 100 kn) at sea level
• Cruise speed: 110 mph (180 km/h, 96 kn) at sea level
• Range: 220 mi (350 km, 190 nmi)
• Service ceiling: 12,000 ft (3,700 m)
• Rate of climb: 975 ft/min (4.95 m/s)

Related development

• Brantly B-2

• Taylor, John W.R. Jane's All The World's Aircraft 1976-77. London:Jane's Yearbooks, 1976. ISBN 0-354-00538-3.
• The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985), 1985, Orbis Publishing.