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Old October 31st 19, 02:50 PM posted to
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Default Bristol Bolingbroke

The Bristol Fairchild Bolingbroke was a maritime patrol aircraft and trainer
used by the Royal Canadian Air Force during the Second World War. Built by
Fairchild-Canada, it was a license-built version of the Bristol Blenheim Mk IV

In 1935, the British Air Ministry issued Specification G.24/35 to procure a
coastal reconnaissance/light bomber to replace the Avro Anson. Bristol proposed
the Type 149, based on its Blenheim Mk I, with Bristol Aquila engines to give
greater range. While the Air Ministry rejected this proposal, a Blenheim Mk I,
retaining its Mercury VIII engines, was converted as a Type 149 (Blenheim Mk
III) for the general reconnaissance role. The nose was lengthened to provide
more room for the bombardier, with the upper left surface of the nose being
scooped out to maintain pilot visibility during takeoff and landing.

The longer range also fulfilled a Canadian requirement for a maritime patrol
aircraft. Consequently, Fairchild Aircraft Ltd. (Canada) of Quebec started
production of the Blenheim Mk IV as the Bolingbroke (the originally intended
name for the Blenheim IV). This type was nicknamed the "Bolly". After a small
run of aircraft constructed to British specifications, as the Bolingbroke Mk I,
Fairchild switched production to the Bolingbroke Mk IV with Canadian and
American instruments and equipment. These versions also included anti-icing
boots and a dinghy. One of the early Mk IV variants was the Bolingbroke Mk IVW
which was powered by two 825 hp (615 kW) Pratt & Whitney SB4G Twin Wasp Junior
engines. Incapable of maintaining altitude on one engine, the normal bomb load
was reduced to 500 pounds on these aircraft to compensate for the low engine
power. The most-produced variant was the Bolingbroke Mk IVT trainer, of which
457 were completed. A total of 626 Bolingbrokes were produced.

Maritime patrol aircraft/trainer

Bristol Aeroplane Company
Fairchild Aircraft Ltd. (Canada)

First flight
14 September 1939

15 November 1939

Primary user
Royal Canadian Air Force


Number built

Developed from
Bristol Blenheim

Most of the 151 Mk IVs built served in their intended role as patrol bombers on
the Atlantic and Pacific coasts of Canada between 1940 and 1944. Two squadrons
of these aircraft also served in Alaska during the Aleutians campaign. The Mk
IVT trainers saw extensive use in the British Commonwealth Air Training Plan

Specifications (Bolingbroke Mk IV)

General characteristics
Crew: three
Length: 42 ft 9 in (13.03 m)
Wingspan: 56 ft 4 in (17.17 m)
Height: 9 ft 10 in (3.00 m)
Wing area: 469 ft2 (43.6 m2)
Empty weight: 9,835 lb (4,470 kg)
Loaded weight: 13,750 lb (6,250 kg)
Max. takeoff weight: 14,500 lb (6,591 kg)
Powerplant: 2 Bristol Mercury XV nine-cylinder air-cooled radial engine, 920
hp (685 kW) at 9,250 ft (2,820 m) each

Maximum speed: 250 knots (288 mph, 464 km/h) at 15,000 ft (4,570 m)
Cruise speed: 174 knots (200 mph, 322 km/h)
Range: 1,617 nm (1,860 mi, 2,995 km) at 170 mph (274 km/h)
Service ceiling: 27,000 ft (8,230 m)
Rate of climb: 1,480 ft/min (7.5 m/s)
Wing loading: 29.3 lb/ft2 (143 kg/m2)
Power/mass: 0.14 hp/lb (0.24 kW/kg)


Guns: 1 fixed forward firing .303 in Browning machine gun and one .303 in
Browning machine gun in power operated dorsal turret, alternately in the IVT,
two Browning machine guns in a Bristol Type B1 Mk IV turret
Bombs: 2 500 lb (230 kg) or 4 250 lb (114 kg) bombs