 Following World War II, the sleeve valve became utilised less, Roy Fedden, very early involved in the S-V research, built some flat-six single sleeve-valve engines intended for general aviation around 1947; after this, just the French SNECMA produced some SSV engines under Bristol license that were installed in the Noratlas transport airplane, also another transport aircraft, the Azor built by the Spanish CASA installed SSV Bristol engines post-WWII.Bristol sleeve valve engines were used however during the post-war air transport boom, in the Vickers Viking and related military Varsity and Valetta, Airspeed Ambassador, used on BEA's European routes, and Handley Page Hermes (and related military Hastings), and Short Solent airliners and the Bristol Freighter and Superfreighter.The Centaurus was also used in the military Hawker Sea Fury, Blackburn Firebrand, Bristol Brigand, Blackburn Beverly and the Fairey Spearfish.