Blackburn B.7 from the Right |
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The Blackburn B-7 was a general purpose army co-operation aircraft that was designed to a 1931 specification that didn’t result in any production aircraft.
Specification G.4/31 of July 1931 called for a two or three seat general purpose aircraft to carry out a mix of duties, including army co-operation, day and night light bombing, diving bombing and reconnaissance. The new aircraft was to replace the Westland Wapiti and Fairey Gordon.
When the specification was issued, it was expected to lead to a fairly large number of orders, so most major aircraft companies submitted a design. Official prototypes of the Vickers 253, Parnall G.4/31 and Handley Page H.P.47 were built. Five more aircraft were built as private ventures – the Bristol 120, Westland P.V.7, Hawker P.V.4, Fairey G.4/31 and Armstrong Whitworth A.W.19.
In October 1931 the Air Ministry added coastal defence and torpedo bombing to the already long list of requirements. This interested Blackburn, and in 1933 they built the prototype B-7. This was built on the same production line as the Blackburn Shark I torpedo bomber, and was very similar to that aircraft. Both aircraft were powered by a 700hp Armstrong Siddeley Tiger IV engine. They had a semi-monocoque fuselage clad in Alclad, and divided into a series of waterproof compartments to give it good buoyancy. The B-7 was an uneven span biplane, with an unusual system of diagonally sloped wing struts. The wingspan was the same as on the Shark, but the chord was increased to give it bigger wings and increase its payload. Unlike the Shark it didn’t have folding wings, as one of the few tasks it wasn’t being asked to perform was carrier operations. It could carry bombs under the wings, a torpedo under the fuselage, and had one fixed forward firing gun and one flexibly mounted rear gun.
The B-7 made its maiden flight at Brough on 28 November 1934 and began its manufacturer’s trials on 5 January 1935. It went to Martlesham on 28 May, ready for the competitive trials. However by this point the original specification was outdated, and several requirements had been dropped. The trials were still carried out, ending in October 1935, but none of the nine aircraft were ordered into production.
Engine: Armstrong-Siddeley Tiger IV
Power: 700hp
Crew: 2-3
Span: 46ft 0in
Length: 35ft 4 5/8in
Height: 12ft 9in
Armament: One fixed forward firing machine gun, one flexibly mounted rear machine gun
Bomb load: Bombs under wings, torpedo under fuselage
As Bomber
All-up weight: 7,027lb
Speed: 150mph at 6,000ft
Climb Rate: 1,200ft/ min
Service ceiling: 20,000ft
Range: 540 miles
As General Purpose Aircraft
All-up weight: 7,762lb
Speed: 149mpg at 6,000ft
Climb Rate: 1,150ft/ min
Service ceiling: 18,000ft
Range: 540 miles
As Torpedo Bomber
All-up weight: 8,338lb
Speed: 145mpg at 6,000ft
Climb Rate: 980ft/ min
Service ceiling: 10,500ft
Range: 475 miles