North American Aviation's straight-wing B-45 Tornado, designed during 1944 and 1945, first flew in February 1947. It was the first jet bomber in service with the Air Force and the first four-jet airplane to fly in the United States. Versions included the longer-range B-45C with wingtip tanks and the photoreconnaissance version, the RB-45C. Rated as a light bomber by modern-day standards, it was the first four-jet aircraft to drop an atom bomb and the first to be refueled in midair. It had a wingspan of 89 feet, and it was 75 feet 11 inches long.