 Following the end of the war, access to the German-built Junkers engines became an issue, and CASA found an alternative with the Rolls-Royce Merlin 500.In April 1956, 173 Merlin engines were ordered and installed on the aircraft in a "power plant" nacelle of a type originally developed by Rolls-Royce for the Beaufighter II and later used on the Avro Lancaster.The newly Merlin-powered bombers and reconnaissance bombers became the 2.111B and 2.111D, respectively; some were re-engined, while others were built new.