Profile – Douglas Skyraider

Douglas already had a long association with the US Navy which extended as far back as 1921 to the company’s DT-1 torpedo-carrying biplane. The Navy was also well acquainted with the name ‘Dauntless’ because the Douglas SBD Dauntless was the service’s standard dive-bomber and it had been largely responsible for victory over the Japanese aircraft carriers during the Battle of Midway in June 1942. There had already been a competition to find a replacement for this dive-bomber but the Douglas company had lost to Curtiss which had presented its SB2C Helldiver. The Curtiss aircraft had not lived up to expectations and Ed Heinemann’s team had afterwards won an order for two prototypes of their SB2D-1 Destroyer, a powerful two seat, inverted gull wing design which featured heated leading edges for removing ice buildup, a large internal weapons bay, huge dive brakes, remotely controlled twin 0. 5in (12. 7mm)gun turrets and a tricycle undercarriage for the first time on a carrier aircraft. It proved to be far too heavy and would have been very expensive to produce because it had been decided that most parts which were not sheet metal were to be forgings. This aircraft, although unsuccessful, was the first antecedent of the Skyraider.

There were two other aircraft in the Skyraider’s direct ancestry, the BTD-1 Destroyer and the TB2D Skypirate. The new Destroyer was a redesigned SB2D with most of its predecessor’s forged parts replaced by cheaper to produce built up fabrications, the gun turrets deleted and its weapons bay modified to accommodate two torpedoes. Additions included large air brakes in the fuselage and two forward firing cannons mounted in the wings. It retained the tricycle undercarriage and gull wings. This aircraft was in line with the Navy Department’s new BT designation for a single seat machine for the primary role of dive bombing with the secondary capability of torpedo attack.

A separate parallel venture, the TB2D Skypirate was a large three seat torpedo bomber powered by a 3,350hp (2,499kw) Pratt Whitney R-4360-8 Wasp Major engine driving two big contra-rotating propellers to eliminate torque and with an internal bay capable of housing four 2,000Ib (907kg) torpedoes. It was too specialised to attract navy interest and did not proceed beyond the building of two prototypes.

The future for the BTD-1 Destroyer had at first looked promising with orders for 358 being received by the end of February, 1944, but this was short-lived. In fact, although 28 were delivered, they never became operational with the US Navy. There were numerous teething troubles and aerodynamic deficiencies in the inverted gull laminar flow wing which could not be overcome. Furthermore, there was now stiff competition looming with the Kaiser-Fleetwings BTK and Martin’s BTM, later caller the Mauler.

It was to discuss the BTD-1 Destroyer’s future that Heinemann and the others had gone to Washington in mid-June, 1944. It was here late on the 16th that Heinemann had dramatically requested to cancel the BTD contract and use unexpended leftover funds to build “an entirely new and superior airplane”. He had requested 30 days but had been given only until 9. 00am the following day, thus triggering off the frantic overnight effort!

Heinemann’s last minute presentation to the US Navy’s BuAer was convincing. Under an amendment to the BTD contract, he and his team were rewarded with the go-ahead to build 15 experimental XBT2D-1 aircraft but there was a new time limit too . . . In nine months the first prototype had to be ready.

Other requirements for the new aircraft were equally tough. It had to weigh only 16,000lb (7,484kg) loaded, some 2,500lb (1,134kg)lighter than the BTD; it had to carry more in a lighter airframe without losing out on the toughness required of any carrier-borne aircraft; and it had to be designed in such a way that the time required for rearming, refuelling and maintenance had to be reduced by 50%.

The Douglas team was only one day late! It W:?S . . cm March 18, 1945, that the new XBT2D-1 (BuAer No. 09085)took off from Mines Field, California, the old airfield which is now LA International Airport, for the first time. Test pilot LaVerne Brown flew his bright silvery Dauntless II for an hour over Los Angeles and landed to tell everyone that it was a “real winner”.

In appearance the new. machine was a sturdy, somewhat angular, low-wing monoplane with clean lines and a stubby profile. It had ended up half a ton lighter than initially guaranteed and was like a big fighter with no internal weapons bay and a single seat cockpit housed by a sliding teardrop canopy. The laminar section wings had large Fowler flaps, a single fold and the main legs of the landing gear folded backwards to lie under the unbroken wing skin with the wheels recessed to sit behind the main spar. The cockpit, which was large and roomy, had been designed for efficiency with controls positioned for convenient operation and pilot comfort during long missions. There was a forward and downward vision angle of 15 degrees, twice the amount previously considered acceptable. The machine’s large tailplane was pivoted and hydraulically powered. Its fuel system consisted of one large protected tank which filled the middle fuselage behind the pilot’s seat. For armament, it had two 20mm cannons, one in each wing, capable of firing 400 rounds per minute; 2081b (94kg) of armour plate; and three bomb racks, one under each wing and one under the fuselage.

The new machine completed a strenuous and extensive test programme at Patuxent Naval Air Test Center, Maryland. Results indicated that at medium altitude it could fly at 375mph (603km/ h), could climb at 3,680 feet (1,669m) per minute and had an absolute ceiling of 33,200 feet (10,120m). In mock combat it was found to be almost a match for the Vought F4U Corsair and Grumman F6F Hellcat below 20,000 feet (6,095m).

Included among the first 25 airframes built were 6 which were completed as prototypes for future versions. These were two XBT2D-1Ns equipped with underwing pods housing radar (port side) and a searchlight (starboard) and room for 2 radar operators in the fuselage behind the pilot; one XBT2D-1P for photographic reconnaissance; one XBT2D-1Q for electronic countermeasures with under wing pods containing radar (port) and chaff (starboard) and a single electronics operator within the fuselage; one XBT2D-1W as an airborne early warning aircraft equipped with search radar in a large bubble fairing under the fuselage and 2 radar operators behind the pilot in the enlarged cabin; and finally an upgraded version of the basic design with several minor changes, designated the XBT2D-2.

Aircraft carrier trials on the USS Sicily began early in 1946 amid an atmosphere which suggested that an order for 548 machines signed by the US Navy back in March, 1945, would not go ahead because the Second World War had ended. In February the new aircraft was christened ‘Skyraider’ and in April the US Navy changed its system of designations so that the BT2D was modified to AD. This meant that the BT2D-1N version was now the AD-1N, the BT2D-1P was now the AD-1P and so on. The carrier trials proved the Douglas design team’s claims of ease of serviceability and maintenance.

The Skyraider began service with the navy with VA-19A at Naval Air Station (NAS) Alameda in December, 1946. However, early in 1947 the USN reported some aircraft were suffering severe buckling of the wings in the vicinity of the landing gear. This was attributed to continual heavy landings on carrier decks. Research indicated that the recommended sinking speed of 14 feet (4. 3m) per second contact velocity was consistently being exceeded. Eventually, after a major modification programme on the wing and fuselage structure, the fault was rectified. When later AD-2 models were tested they were found capable of withstanding a sinking speed of 23. 3 feet (7. 1m) per second without yielding.

At first it seemed in the dawning jet age that the future of any piston-engined design would be very limited. Prior to 1947 deliveries were slow but then things began to pick up. A total of 332 AD-1s of all variants were delivered that year plus 7 more XBT2D test aircraft. The excellent endurance, adaptability and weapons carrying capabilities were being recognised so the company’s contracts were secure but there was no realization yet of how large those contracts would finally be. The second principle version of the Skyraider, the AD-2, appeared early in 1948 and was delivered to the fleet with strengthened wings, greater fuel capacity and its R-3350-26W engine with increased horsepower from 2,500hp (1,865kw) to 2,700hp (2,014kw). A total of 156 of this version were delivered together with 22 AD-2Q electronic countermeasures aircraft. For the pilot’s ease of identification, the cockpit controls of this model were shaped to resemble the systems that they worked, eg. , the dive brake control resembled a miniature dive brake instead of a knob and so on . . .

The AD-2 and AD-3 were basically the same type of aircraft except for a number of modifications. The latter had an increased undercarriage oleo strut travel from 10 to 14 inches (25. 4 to 35. 5cm), a redesigned cockpit, a few minor changes in the structure and an improved tailwheel. One hundred and twenty five were built but the number of variants exceeded the AD-2 model and they performed a large variety of duties for the navy. These included versions of the ‘E’ , ‘N’, ‘Q’ , ‘S’, and ‘W’ types. The AD-3S aircraft was used as an anti-submarine hunter/killer in combination with the AD-3E early warning machine but probably the most interesting was the AD-3W ‘Guppy’ which carried a large radar scanner screen dome underneath the fuselage giving it a very awkward appearance. Initially, the shape presented numerous aerodynamic problems but these were successfully resolved to the extent that pilots who flew the AD-3W were surprised to discover that it was probably the easiest of all Skyraiders to land on an aircraft carrier. Like the AD-3N, the AD-3W had a 3 seat arrangement with two radar operators side by side in a compartment just behind the fuel tank in the rear portion of the fuselage.

In May, 1948 with full production into its stride BuAer requested that a new AD-4 programme be started. This became the major production version of the Skyraider series. It was powered by a 2 700 horsepower {2,014kw) R-3350-26WA radial engine and had a new P-1 autopilot. In general, the changes required were relatively minor with only a cockpit mock-up being necessary. The initial order was for 386 machines and of these 226 were to be AD-4s, 29 were to be AD-4Ns, 39 were to be AD-4Qs and 52 were to be AD-4Ws. This total was later reduced by 30 aircraft. This series also included the AD-48, a specialised machine with its armament increased to four 20mm cannon in the wings and provision for carrying a nuclear weapon. It was intended that this would be delivered to its target using the tossbombing technique. There were 24 conversions from standard AD-4 configuration and 165 were built.

The Korean War

Towards the end of 1949 the probability of obtaining funds for future Skyraider development seemed doubtful. A proposal for a new AD-5 programme had not been accepted by BuAer and, as of June, 1950, the production rate of the remaining order was only 4 aircraft per week. These were AD-4Ws and AD-4Ns. Gradual phasing out of the AD seemed inevitable until suddenly, at the end of June, war broke out in Korea. The situation began to change almost overnight as the Able Dogs began to prove their outstanding combat capabilities, especially in close ground support. The bomb load they could carry was both enormous and varied and they could stay to finish the job properly long after fuel hungry jet fighter-bombers were obliged to leave.

The Skyraiders operational life in Korea began on July 3 flying from the USS Valley Forge. By the end of the war in July, 1953, no less than fifteen navy squadron had operated the type, seven of them having flown two operational tours and VA-55 had three tours, the first on the USS Valley Forge, the second on the USS Princeton and the third between July, 1952, and January, 1953, on the USS Essex. In addition, three US Marine squadrons also used the type and one of these, VMA-121, was credited with delivering the greatest weight of bombs onto the enemy during the war. Amid their other achievements, on May 1, 1951, AD-4 Skyraiders from the USS Princeton successfully breached the Hwachon dam in a raid which marked the last recorded use of aerial torpedoes. Increased orders for the Skyraider began to snowball in 1951. These included AD-4Bs as well as the newly developed AD-5s, which was perhaps the most versatile Skyraider variant. As already noted, the initial AD-5 proposed by Douglas was a 1948/49 venture. This was powered by an R-3350 turbo compound engine but because it required a large amount of fuselage redesign BuAer had refused funds. The AD-5 designation therefore went to a variant which combined within one airframe the hunter/killer roll for anti-submarine warfare. For this the forward airframe was widened so that two crew members could be seated side by side and the fuselage length was increased by 1’11” (. 58m). Other changes included the elimination of the fuselage dive brakes, an increase in the area of the vertical tail surface and increasing armament to standardise four 20mm cannon in the wings.

Through various weapons and equipment packages the AD-5 proved capable of undertaking a multitude of roles from aircraft carriers. These included a conversion into an ambulance aircraft with accommodation for 4 litters; troop transport with bench type seats for carrying 12 personnel; VIP/staff transport with 4 rearward facing seats; cargo transport capable of carrying up to 2,000Ib (907kg) of freight; photographic reconnaissance; and target tug. In 1953, Douglas developed an external in-flight refuelling system for the Skyraider using the probe and drogue technique at the time to make it the only carrier based aircraft capable of being an aerial tanker. Altogether, 212 of these conversions were made.

When production of the AD-5 ceased in 1956, a total of 670 had been built. An interesting experimental aircraft in this series was the AD-5S built to evaluate the anti-submarine role using Magnetic Anomaly Detection (MAD) equipment but the type never reached production.

The AD-6 was essentially an improved version of the earlier AD-4B with a few minor changes and simplification of its electrical equipment for easier maintenance. Changes included a canopy which could be jettisoned; a hydraulically, instead of manually, operated arresting hook; and the provision of special equipment for low level bombing. Power was still provided by a Wright R-3350-26WA engine of 2,700hp (2,014kw) and altogether 713 were built.

The final production version of the Skyraider was the AD-7 powered by an improved Wright 2,800hp (2,088kw) R-3350- 26WB radial engine. This machine also had local strengthening of its landing gear, engine mountings and outer wing panels in accordance with the findings of tests carried out by Douglas in 1953 into fatigue problems encountered in AD-2s, AD-3s and AD-4s. A total of 72 were built and production came to an end on February 28, 1957, when the last AD-7, No. 143133, rolled off the assembly line at El Segundo. It was the last piston-engined bomber to be produced in the USA and during its 12 years of production 3,180 Skyraiders had been built in 28 different configurations. The last machine was delivered to VA-215 at Moffett Field, California, but although production had ceased, the Skyraider story was still far from over.

Foreign Service

The first Skyraiders to be used by a country other than the USA were AD-4Ws ordered by Britain for the Royal Navy. These British machines carried the designations AEW-1 and the first 20 were delivered to 778 Squadron late in 1951 for operational training. When this was complete the aircrew and aircraft were assigned to 849 Squadron for sea duty. Additional Skyraiders were supplied under the MDAP programme until a total of 50 had been delivered. Two of these, WV-106 AND WT-121, are currently held by the RN Fleet Air Arm Museum.

France became the second European country to use the type in 1959. Asthe US Navy phased out its AD-4s, France purchased 100 flyable aircraft for deployment in Algeria. The Armee de l’. Air formed three squadrons which were attached to the 20th Escade and these continued to use Skyraiders until 1965. In that year the French Government gave its remaining machines to the Cambodian Air Force.

Sweden became the third European country to fly the Skyraider beginning in 1963. A British-operated company in Sweden, Scottish Aviation Ltd, purchased former Royal Navy aircraft and supplied a dozen to the Swedish Army plus two airframes for spare parts. The AD-4Ws were modified from their original configuration. Their radomes were removed from under the fuselage and a large bubble window added, placed just aft of the door which led to the radar operator’s compartment behind the cockpit. They were used as target towing aircraft for the army’s anti-aircraft batteries.

The next major user of the Skyraider was the air force of South Vietnam . . .

Change of Designation

By September, 1955, the US Navy had on its strength a total of 29 Skyraider squadrons and it remained on this peak until mid 1957. From then on numbers gradually declined so that by 1965 only 10 squadrons were still flying the type. Meanwhile, the US Marine Corps had phased it out by the end of 1958. In September, 1962, all Skyraiders still in service were redesignated and became the A-1 series: the AD-5 became A-1E; AD-SW = EA-1E;AD-5Q = EA-1F;AD-SN= A-1G;AD-6 = A-1H; and AD-7 = A-1J.

Vietnam Service

A-1 Skyraiders carried out a variety of roles in the Vietnam War including flying cover for rescue missions, close air support operations and forward air control(FAC) sorties. It was one of the most hard working and versatile aircraft used in the war, re-earning for itself the accolades it won over Korea. The US Navy used several variants including electronic countermeasure versions. In 1967 the navy retired its old ‘Spads’ from the conflict leaving the USAF and VNAF as the remaining users of the type. Many exNavy A-1s were refurbished and sent back to active units for still more operations.

In March, 1966, Major Bernard Fisher, a Skyraider pilot of the First Air Commando Squadron observed one of his comrades make an emergency landing on the A Shau airstrip as North Vietnamese were invading the area. In spite of enemy fire, Fisher landed his aircraft, taxied it down the battered runway, picked up the stranded airman and took off again. For his courageous rescue he received the Congressional Medal of Honour.

Probably the most remembered Spad mission took place on June 20, 1965, when four Skyraiders of VA-25 from the USS Midway were attacked by two MiG-17s while on a RESCAP mission. The Americans managed to outmanoeuvre the jets in a five minute contest and shot one of them down. As if to prove this feat was not a fluke, a flight of Skyraiders from the USS Intrepid managed to repeat the performance on November 1, 1966, by shooting down another MiG-17 and damaging two others in a clash between four Spads and four MiGs.

At the time of the truce in January, 1973, about a hundred A-1s were turned over to the VNAF. Several of these squadrons were still operational during the collapse in 1975. Meanwhile, the USAF had disbanded the last of its Spad units in the winter of 1974. In its long and distinguished service career the Skyraider was known: AD; AbleDog; A-1; Spad; Sandy; Flying Dump Truck; and so on . . . It has to have far exceeded every expectation that Ed Heinemann, Leo Devlin and Gene Root could have possibly envisaged in their Washington hotel room on that fateful night way back in June, 1944.