Throughout World War 2 (1939-1945) the United States Navy (USN) - like the United States Air Force (USAF) - undertook a myriad of programs in an effort to find more modern, capable solutions to meet wartime requirements. Beyond its crop of fighters, the service looked to improve its stock of dive bombers and torpedo bombers as the war in the Pacific expanded. Additionally, the ground strike role was evolving and many existing fighters were quickly turned into fighter-bombers but lacked a hefty ordnance-carrying capability and the ranges needed to cover the vast expanse of the Pacific Theater.
Douglas had attempted to sell the USN on several "large" carrier-based aircraft designs in an effort to keep USN interest in Douglas aircraft products for as long as could be had. However, many projects became stillborn or forgotten ventures so an all-new approach was taken with the next attempt. The initiative was born through talks with USN authorities in June of 1944 and veteran Douglas engineers (including famous aircraft designer Ed Heinemann) immediately went to work, producing a large fighter concept in short order. The presented proposal from Douglas was enough to win over the USN and order for fifteen (later increased to twenty-five) prototypes under the "XBT2D-1" designation was handed down on July 21st.
The speed at which the war evolved also dictated development windows of wartime aircraft ventures and the XBT2D-1 proved no different. The design team had the mockup completed in August for review and a premium was placed on expediency so many existing components and proven design elements were incorporated into the new aircraft. Much thought was also given to the design based on first-hand accounts from pilots in the field and company personnel bringing these notes back stateside. The prototype was unveiled in February of 1945 and the aircraft flown for the first time on March 15th of that year - the XBT2D-1 coming in both under weight and some four months ahead of the intended development schedule.
The XBT2D-1 appeared as if an oversized fighter and was, on the whole, a most conventional looking aircraft for the time. Engineers did away with the idea of an internal bomb load to open space for fuel and other applicable equipment. Ordnance carrying capability came from the straight wing appendages which provided for seven hardpoints each. Additionally there lay a single hardpoint under the fuselage. At least two underwing positions and the fuselage centerline hardpoint were also plumbed for external fuel stores while internal fuel all resided in a single tank. A powerful Wright R-3350-8 supercharged radial piston engine of 2,300 horsepower was fitted in the nose and this drove a large four-blade propeller unit. Immediately aft of the engine compartment lay the single-seat cockpit under a bubble canopy offering elevated views over the nose and wings. As the aircraft was expected to fly in low against enemy air defenses the cockpit was protected with over 200 lb of armor plating. The wings were fixed ahead of amidships bringing most of the aircraft's mass forward. The fuselage was largely tubular in shape though somewhat deep (and awkward looking) in profile. The lower rear fuselage sides were slab-sided and contained dive brake panels with a third panel added to the belly. The tail unit utilized a rounded vertical fin and low-set horizontal planes. A typical "tail-dragger" undercarriage arrangement was used with the main legs retracting rearwards under the wings. An arrestor hook was fitted under the tail and the wing mainplanes were designed to fold outboard of the main legs for carrier storage.
The fifteen total hardpoints - coupled with the massive engine output - allowed for up to 6,000 lb of external stores to be carried. Standard armament included 2 x 20mm cannons (later four) installed in the wings. These weapons could be used as both an offensive and defensive measure by the pilot (as seen in the wars to follow).
The USN received the aircraft for trials in April of 1945 and, beyond some slight issues, the aircraft won over test pilots and authorities. With the war in Europe over in May of that year - and Japan to follow in August - the XBT2D-1 product was allowed to survive and was not cancelled as so many other programs were in the post-war drawdown. Instead, the USN cut its production order to help ease delivery of the product which was adopted as the AD-1 "Skyraider".
As such, the Skyraider missed out on combat actions in World War 2.
Skyraiders Over Korea
Nevertheless, the Skyraider was acquired in numbers significant enough to make up the strike arm of United States Navy carrier groups heading into the Korean War (1950-1953). It was also taken on by the United States Marine Corps (USMC) who could appreciate a heavy ordnance hauler for Close-Air Support (CAS). As the AD-1, Skyraider aircraft received their baptism of fire over the Korean Peninsula despite the arrival of jet fighters by this time - Skyraiders showcased better range and loitering times as well as ordnance flexibility when compared to thirsty jet fighters with limited air-to-ground armament. First actions for AD-1s were on July 3rd, 1950 from the deck of USS Valley Forge (CV-45). The Skyraider recorded its only air kill of the war on June 16th, 1953 when a USMC Skyraider claimed a Polikarpov Po-2 "Mule" biplane. Beyond its traditional bombing sorties, Skyraiders accounted for other missions inthe theater including radar jamming and night strikes. The Hwacheon Dam was struck by a torpedo released by a Skyraider back on May 2nd, 1951 - torpedo delivery being one of the Skyraiders original battlefield roles when developed. Skyraider losses in Korea totaled 128 aircraft though 27 of this total was to non-combat-related incidents - particularly tricky handling of the powerful aircraft.
Skyraiders Over Vietnam
Despite the growing stock of American Navy jets, the Skyraider remained a primary player in USN service heading into the latter part of the 1950s. As such, they were once again pressed into combat service during the Vietnam War (1955-1975) where their endurance and ordnance-hauling proved the aircraft an excellent prop-driven design for the attack role. Initial operations involving Skyraiders was on August 5th, 1964. Its air-to-air prowess was exemplified somewhat when a pair of NVAF Mikoyan-Gurevich MiG-17 jet fighters were claimed to cannon fire during June of 1965 and October of 1966 - the slower-moving Skyraiders gaining the advantage over the faster-moving jets. Inherently good loitering times also allowed Skyraiders to stay on station over downed pilots to provide CAS until rescue helicopters arrived. By the end of the war, Skyraiders began to give way to the inbound stock of Douglas A-4 Skyhawk, Grumman A-6 Intruder, and Vought (LTV) A-7 Corsair II jet-powered strike platforms. Ex-USN Skyraiders made it into the inventory of the USAF and the South Vietnamese Air Force (SVAF) by the end of the war and - from 1973 onwards - all in-theater Skyraiders were strictly under SVAF usage. Total Skyraider losses in the Vietnam War were 266 aircraft - 201 of these under the USAF banner.
As USN jets took over Skyraider territory, other Skyraider operators began to emerge. The South Vietnamese Skyraiders were reconstituted by the North following the end of the Vietnam War (some also ended their service days in Cambodia and Thailand). The French Air Force purchased over 100 former USN Skyraiders for colonial defense duty where they were used in the Algerian War of Independence (1954-1962). The British Royal Navy took on a stock of 50 aircraft for the Airborne Early Warning (AEW) role from 1951 onwards and knew these as the "Skyraider AEW.Mk 1". Fourteen RN models were then sold off to Sweden and these served from 1962 to 1976 before ending their tenures as target tugs. Other foreign operators became the Central African Republic, Chad, and Gabon. The last Skyraiders in service were retired from the Gabonese Air Force in 1985.
Total production of Skyraiders was 3,180 aircraft manufactured during the span of 1945 to 1957. The turbo-prop-powered Douglas A2D "Skyshark" was born from the Skyraider line as a possible USN attack aircraft product - though only twelve were ever completed. First flight of a prototype was on March 26th, 1950.
Skyraider Variants and Designations
Because of the wide reaching 1962 redesignation of American warplanes, the Skyraider carried several major designations and served under many marks. XBT2D-1 was the original single-seat dive bomber / torpedo bomber prototype for USN consideration which begat the alternative three-seat XBT2D-1N prototype of which three were completed. XBT2D-1P was a one-off prototype for a photographic reconnaissance mark. XBT2D-1Q was another one-off to provide the basis for a two-seat Electronic CounterMeasures (ECM) platform. A single prototype was also made for BT2D-2 as the XAD-2 with increased fuel capacity and intended as an improved attack platform.
Original production models were the AD-1 which numbered 242 in all. The AD-1Q became a two-seat ECM platform based on the AD-1 production model and 25 examples followed. AD-1U was outfitted with radar countermeasures and could tow aerial targets while lacking engine water injection and armament capabilities. XAD-1W was a prototype made to serve in the AEW role and became 31 examples of the AD-3W in service.
AD-2 followed as an improved mark over the AD-1. These introduced the Wright R-3350-26W radial engines of 2,700 horsepower output. 156 aircraft were built to this standard. AD-2D was a little-remembered variant used in post-nuclear data collection and were operated by remote control. AD-2Q was built in 21 examples from the AD-2 as a two-seat ECM aircraft. AD-2QU was a radar countermeasures platform in the same vein as the AD-1U before it (lacking armament and water injection) - only one example was realized.
The AD-3 became the aforementioned A2D Skyshark experiment with turboprop engine so the AD-3 designation was later reused as a continuation of the direct AD Skyraider line with reinforced fuselage, longer landing gear legs, and a new canopy design. 125 of this mark were produced. The AD-3S became an Anti-Submarine Warfare (ASW) platform though only two prototypes of this model existed. Fifteen AD-3N three-seat night attack forms were produced. The AD-3Q was another ECM model of which 23 examples followed. AD-3QU became a target tower and AD-3W served in the AEW role through 31 aircraft.
AD-4 brought about reinforced landing gear legs, navigational improvements, cockpit upgrades, new radar, support for underwing rockets, and 4 x 20mm cannon as standard armament. 372 of this mark were completed. AD-4B was a special mission model capable of delivering a nuclear bomb and existed in 165 new-build aircraft as well as 28 converted models. AD-4L was a winterized model for Korean service and 63 aircraft were acquired. AD-4N were 307 examples of a three-seat night attack model. AD-4NA designated 100 AD-4N aircraft with their night mission equipment removed. The AD-4NL were 36 conversions of AD-4N aircraft. AD-4Q existed as a two-seat ECM aircraft and saw 39 examples procured. AD-4W was a three-seat AEW platform of which 168 were delivered. 50 of these later came under British Royal Navy service as the Skyraider AEW Mk.1
The AD-5 model used a unique side-by-side cockpit layout and completed without the usual dive brake arrangement. 212 of this type were realized. 239 examples of te AD-5N, a four-seat night attack platform, were seen. The AD-5Q was a four-seat ECM model and converted from 54 existing airframes. AD-5S served as a one-off prototype for Magnetic Anomaly Detector (MAD) ASW equipment testing. AD-5W was a three-seat model for AEW service and 218 were completed. UA-1E was a utility-minded variant of the AD-5 mark.
AD-6 was built in 713 examples as a single-seat attack platform with ordnance carrying capabilities up to 3,500 lb. The AD-7 followed though outfitted with the Wright R-3350-26WB engine and life extension improvements added. This marked the last official Skyraider production model with 72 being completed.
In the 1962 revision, the AD-1 Skyraider became the A-1 Skyraider and its various marks followed. A-4D became the A-1D, AD-5 was the A-1E, AD-5N was the A-1G, AD-5Q was the EA-1F, AD-6 was the A-1H, and AD-7 was the A-1J.