the company was asked to investigate development of a “slim-fuselage” version. The original project, outlined in October, 1938, was designated Type 156 and in March, 1939 it was named “Beaufighter”. Type numbers 157 and 158 were given to a proposed three-seater bomber version with a dorsal turret, and the “slim-fuselage” version (the so-called “sports model”) respectively. Only six months after the first layout had been drawn, the first Beaufighter prototype (R2052) was completed and on 17th July, 1939, made its maiden (light. To convert Beaufort to Beaufighter prototype required only 2,100 drawings, but more than twice as many more were needed to make it fully operational. Consequently, although a production order was placed on 3rd July for 300 “straight ofT the drawing board" (as approved to Air Ministry Specification F. 17/39) it was a year before deliveries to the R.A.F. could begin. The initial contract included four prototypes and one of its requirements was that the design should accommodate the Rolls-Royce Griffon as an alternative to the Hercules, with maximum interchangeability between these engines as removable power-plant installations. The Hercules fitted to the first production Beaufighter Is was the Hercules Mk. III. DEVELOPMENT FEAT U RES Makers' trials of R2052 at Filton resulted in minor changes being made to stiffen the elevator control circuit and increase the fin area. Also the Beaufort's Vickers main oleo-leg assembly was changed to a Below (top): First prototype Beaufighter R2052 with oil-cooler intakes under the engine cowlings, Filton, July, 1939 ajc was then unarmed. (C entre): Third prototype R2054 with oil cooler intakes in wings, green and brown camouflage and black and white under surfaces. (Bottom): R2I86, an early production Beaufighter IF. Compare undercarriage doors with those o f prototypes.