The Northrop YB-49 was a prototype jet-powered heavy bomber developed by Northrop Corporation shortly after World War II for service with the U.S. Air Force. The YB-49 featured a flying wingdesign and was a turbojet-powered development of the earlier, piston-engined Northrop XB-35 and YB-35. The two YB-49s actually built were both converted YB-35 test aircraft.The YB-49 never entered production, being passed over in favor of the more conventional Convair B-36 piston-driven design. Design work performed in the development of the YB-35 and YB-49 nonetheless proved to be valuable to Northrop decades later in the eventual development of the B-2 stealth bomber, which entered service in the early 1990s.