The Douglas AD Skyraider, also known as the A-1 Skyraider is an American single-seat attack aircraft in service from 1946 to the early 1980s. The Skyraider had a remarkably long and successful career well into the Jet Age (when most piston-engined attack or fighter aircraft were replaced by Jet aircraft) thus becoming known by some as an "anachronism". The aircraft was nicknamed "Spad", after the French World War I fighter.
It was operated by the United States Navy (USN), the United States Marine Corps (USMC), and the United States Air Force (USAF), and also saw service with the British Royal Navy, the French Air Force, the Republic of Vietnam Air Force (RVNAF), and others. It remained in U.S. service until the early 1970s.
The jet powered A-10 Thunderbolt II was based on specifications for a modernized Skyraider with a heavy payload and good endurance.
The piston-engined propeller Skyraider was designed during World War II to meet United States Navy requirements for a carrier-based, single-seat, long-range, high performance dive/torpedo bomber, to follow on from earlier aircraft such as the Douglas SBD Dauntless, the Curtiss SB2C Helldiver and the Grumman TBF Avenger. Designed by Ed Heinemann of the Douglas Aircraft Company, prototypes were ordered on 6 July 1944 as the XBT2D-1. The XBT2D-1 made its first flight on 18 March 1945, and the USN began evaluation of the aircraft at the Naval Air Test Center (NATC) in April 1945. In December 1946, after a designation change to AD-1, delivery of the first production aircraft to a fleet squadron was made to VA-19A.
The AD-1 was built at Douglas's El Segundo plant in Southern California. In his memoir The Lonely Sky, test pilot Bill Bridgeman described the routine yet sometimes hazardous work of certifying AD-1s fresh off the assembly line at a rate of two aircraft per day for delivery to the U.S. Navy in 1949 and 1950.
A Douglas XBT2D-1 Skyraider prototype
The low-wing monoplane design started with a Wright R-3350 Duplex-Cyclone radial engine which was later upgraded several times. The aircraft had distinctive large straight wings with seven hardpoints apiece. The Skyraider had excellent maneuverability at low speed, and carried a large amount of ordnance over a considerable combat radius. It had a long loiter time for its size, compared to much heavier subsonic or supersonic jets. The aircraft was optimized for ground attack and was armored against ground fire in key locations, unlike faster fighters adapted to carry bombs, such as the Vought F4U Corsair or North American P-51 Mustang, which were retired by U.S. forces before the 1960s.
Shortly after Heinemann began designing the XBT2D-1, a study was issued showing that for every 100 lb (45 kg) of weight reduction, the takeoff run was decreased by 8 ft (2.4 m), the combat radius increased by 22 mi (35 km) and the rate-of-climb increased by 18 ft/min (0.091 m/s). Heinemann immediately had his design engineers begin a program for finding weight savings on the XBT2D-1 design, no matter how small. Simplifying the fuel system resulted in a reduction of 270 lb (120 kg); 200 lb (91 kg) by eliminating an internal bomb bay and hanging external stores from the wings or fuselage; 70 lb (32 kg) by using a fuselage dive brake; and 100 lb (45 kg) by using an older tailwheel design. In the end, Heinemann and his design engineers achieved more than 1,800 lb (820 kg) of weight reduction on the original XBT2D-1 design.
The Navy AD series was initially painted in ANA 623 glossy sea blue, but during the 1950s, following the Korean War, the color scheme was changed to light gull grey and white (Fed Std 595 27875). Initially using the gray and white Navy scheme, by 1967 the USAF began to paint its Skyraiders in a camouflaged pattern using two shades of green, and one of tan.
General characteristics
Crew: 1
Length: 38 ft 10 in (11.84 m)
Wingspan: 50 ft 0.25 in (15.2464 m)
Height: 15 ft 8.25 in (4.7816 m)
Wing area: 400.33 sq ft (37.192 m2)
Airfoil: root: NACA 2417; tip: NACA 4413
Empty weight: 11,968 lb (5,429 kg)
Gross weight: 18,106 lb (8,213 kg)
Fuel capacity: 380 US gal (320 imp gal; 1,400 l) internal tanks
Powerplant: 1 × Wright R-3350-26WA Duplex-Cyclone 18-cylinder air-cooled radial piston engine, 2,700 hp (2,000 kW)
Propellers: 4-bladed Aeroproducts constant-speed propeller
Performance
Maximum speed: 322 mph (518 km/h, 280 kn) at 18,000 ft (5,500 m)
Cruise speed: 198 mph (319 km/h, 172 kn)
Range: 1,316 mi (2,118 km, 1,144 nmi)
Service ceiling: 28,500 ft (8,700 m)
Rate of climb: 2,850 ft/min (14.5 m/s)
Wing loading: 46.6 lb/sq ft (228 kg/m2)
Power/mass: 0.149 hp/lb (0.245 kW/kg)
Armament
Guns: 4x 20 mm AN/M3 cannon with 200 rounds per gun
Hardpoints: 15 external hardpoints with a capacity of 8,000 lb (3,600 kg), with provisions to carry combinations of:
Other: bombs, torpedoes, mine dispensers, unguided rockets, and gun pods.
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