The North American AJ Savage (later A-2 Savage) is an American carrier-based medium bomber built for the United States Navy by North American Aviation. The aircraft was designed shortly after World War II to carry atomic bombs and this meant that the bomber was the heaviest aircraft thus far designed to operate from an aircraft carrier. It was powered by two piston engines and a turbojet buried in the rear fuselage. The AJ-1 first became operational in 1950 and several were based in South Korea during 1953 as a deterrent against North Korea. Of the 140 built, plus three prototypes, 30 were reconnaissance aircraft. Inflight-refueling equipment was deployed on the Savage in the mid-1950s. The bomber was replaced by the Douglas A3D Skywarrior beginning in 1957. The type was used after its military service for some additional experiments including microgravity test flights and to test a new jet engine in the 1960s and 70s. At the end of World War II, the U.S. Navy began a design competition on 13 August 1945 for a carrier-based bomber which could carry a 10,000-pound (4,536 kg) bomb that was won by North American Aviation. Later that year, the Navy decided that it needed to be able to deliver atomic bombs and that the AJ Savage design would be adapted to accommodate the latest Mark 4 nuclear bomb, the next step in development from the more sophisticated imploding-plutonium-sphere design Fat Man Mk3 used on Nagasaki. A contract for three XAJ-1 prototypes and a static test airframe was awarded on 24 June 1946. The first prototype made its maiden flight two years later on 3 July 1948. That same year the US Navy began an interim capability program employing the Lockheed P-2 Neptune carrying a crash-program reproduction of the smaller, simpler all-uranium 'gun' design Little Boy nuclear bomb as its first carrier-launched nuclear bomber aircraft until the Savage was in service. The Neptune launched using JATO assist but could not land on existing carriers; if launched they had to either ditch at sea after the mission or land at a friendly airbase. The AJ-1 was a three-seat, high-wing monoplane with tricycle landing gear. To facilitate carrier operations, the outer wing panels and the tailfin could be manually folded. It was fitted with two 2,300-brake-horsepower (1,700 kW) Pratt & Whitney R-2800-44W Double Wasp piston engines, mounted in nacelles under each wing with a large turbocharger fitted inside each engine nacelle, and a 4,600-pound-force (20,000 N) Allison J33-A-10 turbojet was fitted in the rear fuselage. The jet engine was only intended for takeoff and maximum speed near the target, and was fed by an air inlet on top of the fuselage that was normally kept closed to reduce drag.[6] To simplify the fuel system, the jet engine used piston engine avgas rather than jet fuel. One 201-US-gallon (760 L; 167 imp gal) self-sealing fuel tank was housed in the fuselage, and another 508-US-gallon (1,920 L; 423 imp gal) tank was located in each wing. The aircraft usually carried 300-US-gallon (1,100 L; 250 imp gal) tip tanks and it could house three fuel tanks in the bomb bay with a total capacity of 1,640 US gallons (6,200 L; 1,370 imp gal). Other than its 12,000-pound (5,400 kg) bombload, the bomber was unarmed. Two of the three prototypes crashed during testing, but their loss did not materially affect the development of the aircraft as the first batch of Savages had been ordered on 6 October 1947. The most significant difference between the XAJ-1 and the production aircraft was the revision of the cockpit to accommodate a third crewman in a separate compartment. The first flight by a production aircraft occurred in May 1949 and Fleet Composite Squadron 5 (VC-5) became the first squadron to receive a Savage in September. The squadron participated in testing and evaluating the aircraft together with the Naval Air Test Center (NATC) in order to expedite the Savage's introduction into the fleet. The first carrier takeoff and landing made by the bomber took place from the USS Coral Sea on 21 April and 31 August 1950, respectively. Many, if not most, surviving AJ-1s had their tails upgraded to the improved AJ-2 configuration. A photo-reconnaissance version of the Savage, initially known as the AJ-1P, but later designated as the AJ-2P, was ordered on 18 August 1950. It had improved R-2800-48 piston engines and the tail was redesigned to add 1 foot (30 cm) of height to the tailfin. The 12° dihedral of the tail stabilizers was eliminated and the rudder enlarged which slightly lengthened the aircraft. Early AJ-2Ps retained the three-man crew, but late-model aircraft added a fourth aft-facing crewman to the upper cockpit. The Savage's internal fuel capacity was also increased. The nose of the aircraft was remodeled with a prominent "chin" to accommodate a forward-looking oblique camera and a variety of oblique and vertical cameras could be fitted in the bomb bay. Photoflash bombs could be carried for night photography missions. The AJ-2 incorporated all of the changes made to the late model AJ-2P and 55 aircraft were ordered on 14 February 1951. The AJ-2 deleted the separate compartment for the third crewman, but retained the third seat in the cockpit from the AJ-2P. For details of operational history an the 13 variants, click here. All up, a total of 143 were built.