requirement for a small general purpose flying boat and specification R.13/40 was raised for it. Two prototypes were ordered in September 1941 but the situation was reconsidered in December. Its range was insufficient improvement over the Sunderland III, performance on one engine was unacceptable, and land-based patrol aircraft were capable of covering longer ranges. Further, there was little value as an experimental design because the principle had been proven in the B.20 and for an aircraft the size of the B.40 there would not be a significant improvement in drag. With no operational requirement for the B.40, it was therefore cancelled. Specifications (B-20, as designed) See also Notes Bibliography External links "A Teaser in Hydraulics" Flight 1946 p383-384. – details of the float mechanism A photo of the B-20 V8914 on its beaching gear and afloat Dinger's Aviation Pages: Photos and data on Blackburn B20 B-20 1940s British experimental aircraft Floatplanes High-wing aircraft Aircraft first flown in 1940 Twin piston-engined tractor aircraft