in 1942, Supermarine planed brand new fighter having a canard foreplane, Type370 Required specifications were these. 1: mount Vickers 40mm as motor cannon. 2: Cruise at 450mph. 3: Reach at 13000ft high. To satisfy these specifications, Supermarine developer team researched new power unit based on RR merlin. it was Combined with large supercharger that made for heavy bomber, was able to earn more than 3000hp and afterburner system equiped aft the surpercharger. Midship engine layout provided smooth variation in cross-sectional area that decrease transonic drag. For smooth developing, many section were from other Supermarine aircraft, such as spitfire.