The Bristol Blenheim originally was constructed as a private venture. The Bristol Aeroplane Company in 1934 was ordered to construct a high speed six to eight seater twin engined aircraft by a Lord Rothermere as a civil aircraft. It was a low wing all metal monoplane and in 1935 it managed 307mph at 14,000 feet, had excellent flying characteristics and a retractable undercarriage. It is said that Lord Rothermere donated the aircraft to the nation because of it was an aircraft ahead of its time. It had a number change from G-ABCZ to K-7557 and in 1935 was submitted to meet Specification B.28/35 which was called for at the time.
To meet the specified requirements of Specification of B.28/35 the wings were raised to mid fuselage position, the Mercury 6.S.2 640hp radial engines were replaced by 840hp Mercury 8s and it was accepted as the Blenheim Mk I light bomber. But by the time it would be put into service as a war fighting machine, it was found to be slow and would be vulnerable to enemy fighter attack aircraft. In 1938 the decision was made to convert the Blenheim 1 to a long range fighter. But although it was found to be just as cumbersome and its fire power was to prove quite inadequate, the Air Ministry at the time thought that it was better to put the aircraft into service than nothing at all.
Model Scale 1:38
Blenheim Mark I
Blenheim Mark I Bundle
Blenheim Mark IV / Bolingbroke
Formal work on an extended-range reconnaissance version started as the Blenheim Mk II, which increased tankage from 278 gal to 468 gal. Only one Blenheim Mk II was completed as flight tests revealed the increase in speed to be marginal and thus not warranting further development. Another modification resulted in the Blenheim Mk III, which lengthened the nose, and thereby dispensed with the "stepless cockpit" format of the Mk.I in introducing a true windscreen in front of the pilot, to provide more room for the bombardier. This required the nose to be "scooped out" in front of the pilot to maintain visibility during takeoff and landing. However both of these modifications were instead combined, along with a newer version of the Mercury engine with 905 hp and the turret acquired a pair of Brownings instead of the Vickers K; creating the Blenheim Mk IV.