The designation AD-5 was initially reserved for a proposed late-1948 version of the Skyraider to be powered by a turbo-compound version of the R-3350 engine. Several other aircraft of the era were also being considered for such an engine, including the B-36 and the B-50. However, the turbocompound engine was so heavy and large that it would have required a major airframe redesign, and since the production run of the Skyraider was thought to be nearing its end, the project was not proceeded with.
The designation AD-5 was used instead for a December 1949 proposal for an aircraft which would combine the antisubmarine hunter-killer role in a single airframe and with side-by-side seating for two crew members. In order to accommodate the side-by side seating, the aircraft was lengthened by 1 feet 11 inches and the upper fuselage was broadened. The dive brakes on the fuselage sides were deleted, but the ventral dive brake was retained. Improved and larger underwing bomb racks were installed. The leading edges of the underwing racks were moved further forward, their leading edges extending well forward of the wing leading edge. Provisions were made for a new and more sturdy centerline pylon. The wing armament of 4 20-mm cannon was made standard. An air scoop was added to the leading edge of the vertical fin.
The most noticeable change was the wider and longer cockpit area, with side-by-side seating for two crew members. The two crew members were seated underneath a much larger canopy which slid to the rear. The area immediately behind the cockpit was covered by additional transparent areas, which were often tinted a deep blue. Additional crew members could be carried here, but the area was usually occupied with electronics.
The prototype AD-5 was created by converting AD-4 BuNo 124006. It lacked the radar and electronics planned for the production AD-5, and was first flown on August 17, 1951. It was followed by 212 production aircraft. Although originally intended as an antisubmarine hunter-killer aircraft, most AD-5s were operated as two-seat day attack aircraft. On many missions, the planes were flown as single-seaters.
The aircraft could be fitted with field conversion kits to to make it possible for it to fulfill several different roles. Among these were medical evacuation with four casualty litters, VIP transport with four backward-facing seats, twelve-seat troop transport, utility cargo transport capable of carrying up to 2000 pounds of cargo, photographic reconnaissance, and target towing.
In 1956, the Navy suggested that that the AD-5 be converted into a midair refuelling tanker. However, a Douglas study showed that it would be impractical to store a lot of extra internal fuel inside the airframe of the AD-5 because of weight distribution problems. Instead, Douglas engineers came up with an idea of an external fuel storage package containing a 300-gallon tank plus a hydraulic pump, a hydraulically-driven hose reel, and a 50-foot refuelling hose with a drogue. However, this system was very rarely used on the Skyraider, but was later used in the A4D-2 Skyhawk and the LTV A-7 Corsair II.
In September of 1962, surviving AD-5s were redesignated A-1E when used in the attack role and UA-1E when
used in the utility role.
Engine: One Wright R-3350-26WA Duplex Cyclone 18-cylinder air-cooled radial engine, rated at 2700 hp for
takeoff and 2100 hp at 14,500 feet.
Performance: Maximum speed 330 mph at 15,200 feet, 310 mph at sea level. Cruising speed 200 mph., initial climb rate 2300 feet/min,
Combat ceiling 26,200 feet. Initial climb rate 2860 feet/min. Combat range 524 miles with 4500 lbs of
bombs. Maximum ferry range 3030 miles
Weights: 12,300 pounds empty, 18,800 pounds normal loaded, 25,000 pounds maximum.
Dimensions: Wingspan 50 feet 0 1/4 inches, length 40 feet, height 13 feet 9 inches,
wing area 400.33 square feet.
Armament: Four 20-mm cannon in the wing. One underwing bomb rack just outboard of each main landing gear, six
bomb racks on each outer wing, plus one centerline underfuselage pylon.
132392/132476 Douglas AD-5 Skyraider c/n 9409/9493. 132478 Douglas AD-5 Skyraider c/n 8873. 132392/132476 Douglas AD-5 Skyraider c/n 9409/9493. 133854/133929 Douglas AD-5 Skyraider c/n 9544/9619.