Blackburn B.3/40 B.28 High Speed Bomber

British Secret Projects: Fighters and Bombers 1935-1950 Tony Buttler

This private venture high-speed light bomber and reconnaissance design first proposed in 1939, was based on the Botha torpedo bomber. It was powered by two Griffins and had a span of 54ft 9in and length (tail down) of 39ft 0in. Specification B.3/40 was written around the project and indicated a maximum speed of at least 400mph at 18,000ft, with the warload to include two 500lb or four 250lb bombs; there was also an allowance to fit a four-gun turret. This seems to have been a quite long-lived project and one prototype, X8500, was ordered in 1940; a mock up was also built but the B.28 was eventually abandoned.

How accurate do you the speed projections are?