The Blackburn Type B-7 was a private venture from the Blackburn Aircraft Company response to Specification G.4/31, which sought a general-purpose aircraft to replace the Westland Wapiti. This requirement attracted ten different designs, including officially supported entries from Handley Page with the HP47, Parnall with the G.4/31 and Vickers with the Type 253.
Private venture prototypes were also offered by Armstrong Whitworth Aircraft with the AW19, Bristol Aeroplane Company with the Bristol Type 120, Hawker Aircraft with the PV4 and Westland with the PV7. Fairey Aviation meanwhile, submitted two types with the F-1 biplane and the G.4/31 monoplane.
The 'jack-of-all-trades' nature of the specification included requirements to carry / drop a torpedo and to conduct dive bombing. Additionally, there were a range of other subsidiary duties which included casualty evacuation.
With the Blackburn Shark already in production and already carrying essentially similar armament, Blackburn’s entry was in effect, a land-based Blackburn Shark (with no wing fold or arrestor hook). It did however, feature an increased wing chord to suit the higher weights, as required to meet the requirement.
Power for the Blackburn B-7 was provided by the 700 hp Armstrong Siddeley Tiger IV, the same engine as that fitted to the Blackburn Shark. The aircraft also shared a number of other components such as the fuselage and wing, with its 'Warren Truss' style bracing.
The Blackburn B-7 was first flown at Brough on 28th November 1934, thereafter being flown to Martlesham Heath for official competitive trials between 28th May and the end of October 1935.
The type was found to have the lowest performance of the various G.4/31 contenders although by then official interest in the Specification was waning quickly. Because of this, none of the prototypes originally offered received a production order. The removal of the need for a torpedo carriage from the requirement (met by Blackburn B-7) undoubtedly damaged its chances in any case.
The Blackburn B-7 was returned to Brough at the end of the official trials in October 1935, where it was scrapped shortly afterwards.
Variants & Numbers Built
One prototype only carrying Class B registration B-7.
|Powerplant||One 700 hp Armstrong Siddeley Tiger IV|
|Span||46 ft 0 in|
|Maximum Weight||7,027 lb (bomber), 7,762 lb (GP), 8,338 lb (Torpedo)|
|Capacity & Armament||Two crew; fixed forward-firing Vickers gun, defensive Lewis gun fired from rear cockpit, two 500lb bombs carried on underwing racks, one 1,800 lb 18 in torpedo carried between undercarriage legs.|
|Maximum Speed||147 mph at 7,000 ft|
|Cruise speed||100 mph|
|Range||540 miles (475 miles with torpedo)|
None - The sole prototype was scrapped following its return from official trials.