Bristol B.149

Bristol B.160 Blenheim / Bolingbroke

The outcome was the Bristol Type 142M, the most important changes being to provide armament, a bomb aimer's position, internal bomb stowage and more powerful 626kW Mercury VIII radial engines. To make room for a bomb bay in the lower fuselage, the low-wing configuration of the civil Type 142 was changed to mid-wing for the military version, which became named Blenheim. The prototype made its first flight on 25 June 1936, and initial deliveries went to No 114 Bomber Squadron in March 1937.

The requirement for longer range led to evolution of the long-nosed, increased tankage and strengthened landing gear version, named originally Bolingbroke I. These began to enter RAF service in March 1939, by then designated Blenheim IV.

By the outbreak of World War II Blenheim Is had been superseded by Mk IVs in the UK, but remained in first-line service in Greece and the Western Desert. A Blenheim made the first aerial sortie of the war when, on 3 September 1939, a machine of No 139 Squadron made a photo reconnaissance flight over the German fleet in the Schillig Roads. On the following day Blenheims and Well-ingtons joined in a mast-height bombing of the pocket battleship von Scheer.

Blenheim IF night-fighters had their armament of two machine-guns supplemented by a four-Browning under-fuselage gun pack. It was these aircraft which pioneered British airborne radar, serving throughout the blitz of 1940-41. The Blenheim would equip the first ever nightfighting unit in the world for the No.25 Squadron.

The Blenheim IV with which the RAF entered the second World War was an all-metal monoplane powered by two Bristol Mercury radial engines, each giving 920 hp. Carrying a crew of three, the Blenheim had a span of 56 ft 4 in (17.17 m). Maximum speed was 262 mph (422 km/h) and range 1,800 miles (2,895 km). A 1,000-lb (454-kg) bomb load could be carried and defensive armament included a pair of guns in a dorsal turret.

On 24 February 1941 a modified Blenheim, known originally as the Bisley, made its first flight. Powered by two 708kW Mercury 30 engines, it featured an extensively modified nose and other changes. As the Blenheim V, a total of 940 production aircraft were eventually built in several variants. Although not popular with its crews it remained operational in the Far East until the latter part of 1943.

The Bolingbroke was the Canadian-built version of Bristol Aircraft (Britain) Company's Blenheim Mk IV bomber. Bolingbrokes were manufactured by Fairchild Aircraft Ltd., Longueil, PQ. Canada built a total of 687 Bolingbrokes between 1939 and 1943.
The RCAF first used the Bolingbroke in 1939. In total, eight maritime squadrons in Canada flew the "Boly" on anti-submarine patrols off the east and west coasts. The majority of the Bolingbrokes served as training aeroplanes at the BCATP's Bombing and Gunnery Schools and Wireless Schools.

Bristol Blenheim IF
Engines: 2 x Bristol Mercury XV radial, 920hp.
Length: 42.59ft (12.98m)
Width: 56.33ft (17.17m)
Height: 9.81ft (2.99m)
Maximum Speed: 266mph (428kmh; 231kts)
Maximum Range: 1,454miles (2,340km)
Service Ceiling: 27,264ft (8,310m; 5.2miles)
Armament:
1 x 7.7mm machine gun in wing system
2 x 7.7mm machine guns in manually-operated dorsal turret.
Up to 1,000lbs of internal stores.
Optional:
2 x 7.7mm rear-firing machine guns
Accommodation: 3
Empty Weight: 9,800lbs (4,445kg)
Maximum Take-Off Weight: 14,412lbs (6,537kg)

Bristol 160 Blenheim Mk IV
Engine : 2 x Bristol Mercury XV, 893 hp
Length: 42.585 ft / 12.98 m
Height: 9.843 ft / 3.0 m
Wingspan : 56.332 ft / 17.17 m
Wing area : 468.987 sqft / 43.57 sq.m
Max take off weight : 14403.1 lb / 6532.0 kg
Weight empty : 9792.4 lb / 4441.0 kg
Max. speed : 231 kts / 428 km/h
Cruising speed : 172 kts / 319 km/h
Service ceiling : 27264 ft / 8310 m
Wing load : 30.75 lb/sq.ft / 150.00 kg/sq.m
Range : 1269 nm / 2350 km
Crew : 3
Armament : 5x cal.303 MG (7,7mm), 454kg int, 145kg ext.

Blenheim IV
Engines: 2 x Bristol Mercury, 920 hp.
Wing span: 56 ft 4 in (17.17 m).
Max speed: 262 mph (422 km/h).
Range: 1,800 miles (2,895 km).
Crew: 3.
Bomb load: 1,000-lb (454-kg).
Armament: 2 x mg.

Bristol Blenheim Mk IV
Engines: 2 x Bristol Mercury XV, 675kW
Take-off weight: 6532 kg / 14401 lb
Empty weight: 4441 kg / 9791 lb
Wingspan: 17.17 m / 56 ft 4 in
Length: 12.98 m / 42 ft 7 in
Height: 3.0 m / 9 ft 10 in
Wing area: 43.57 sq.m / 468.98 sq ft
Max. speed: 428 km/h / 266 mph
Cruise speed: 319 km/h / 198 mph
Ceiling: 8310 m / 27250 ft
Range: 2350 km / 1460 miles
Crew: 3
Armament: 5 x 7.7mm machine-guns, 600kg of bombs

Blenheim V
Speed: 303 mph at 15,000 ft
Operational range: 1900 miles
Armament: 3 x .303 mg
Bombload: 1000 lb

Bolingbroke
Engines : Two 920hp Bristol Mercury XV, 920 hp
Wing Span : 56ft 4in
Length : 42ft 9 in
Height : 12ft 10 in
Speed : 266mph
Seats: 3
Armament: One 0.303 Vickers K, four 0.303in Brownings. Four fixed brownings. 1000lbs bomb

Blenheim 5