The F-86, the USAF's first swept-wing jet fighter, made its initial flight on October 1, 1947. The first production model flew on May 20, 1948, and on September 15, 1948, an F-86A set a new world speed record of 670.9 mph. Originally designed as a high-altitude day-fighter, it was subsequently redesigned into an all-weather interceptor (F-86D) and a fighter-bomber (F-86H).  As a day fighter, the airplane saw service in Korea in three successive series (F-86A, E, and F) where it engaged the Russian-built MiG-15. By the end of hostilities, it had shot down 792 Migs at a loss of only 76 Sabres, a victory ratio of 10 to 1.  More than 5,500 Sabre day-fighters were built in the U.S. and Canada. The airplane was also used by the air forces of 20 other nations, including Japan, Spain, Britain, and Australia.