Supermarine B.12/36

The Supermarine B.12/36, designed by Supermarine as the Type 316, was a British four-engined heavy bomber prototype that was destroyed by enemy action before it was completed during the Second World War. It was built to Air Ministry specification B12/36 of July 1936, which called for a high speed heavy bomber able to fly 3,000 miles and carry 14,000 pounds of bombs or 24 soldiers, and which also required that it be transportable by rail in parts, catapult launched and able to stay afloat at sea for several hours. Supermarine's design was a single-spar mid-wing aircraft with a swept leading edge, carrying bombs in both wings and fuselage and defended by three turrets. It was moved up the Air Ministry's ranking after R. J. Mitchell was interviewed and was selected as the preferred choice by January 1937.