Sir Frank Whittle's jet aircraft engine was patented in 1932. This W.1X non-airworthy engine unofficially became the first British turbojet to be airborne when the E.28/39 made short, straight hops. The W.1X and drawings of the W.2B production engine were delivered to the General Electric Company on October 1, 1941. GE's improved and uprated version, the IA, powered the first U.S. jet aircraft, the Bell XP-59A Airacomet on October 2, 1942.