The fuselage was completely redesigned by Canadair, going from the pressure cabin used in the Britannia to an unpressurised one with two long bomb bays fore and aft of the wings. The powerplants werre also changed from the Bristol Proteus turboprop engines to Wright R-3350 turbo-compound piston radial engines, which had lower fuel consumption necessary for extended missions at low level. At the design stage the Napier Nomad, another turbo compound engine was also considered, although the Nomad was later cancelled.