In 1958, the RCAF wanted to replace their aging C-47 Dakotas with a turbo powered aircraft. Their choice was the Vickers Viscount, but the Canadian government decided against this aircraft. Instead, Canadair offered a series of CV-540 variants powered by Napier Eland turboprops. The project was given the number CL-66 and three versions were considered. The CL-66A was to be a 48/64 passenger aircraft. The CL-66B designed to be a cargo/passenger configuration with a payload of 14200 lb. The CL-66C used the Convair-built CV-440s, having only their new engines fitted at Canadair.