This small and simple tailed delta jet, originally designed as carrier-based (nuclear) bomber, later enjoyed a long career as an extremely versatile attack aircraft. Later developments had a large dorsal spine to make room for electronics. The A-4 was kept in production for 22 years, and is still serving with some air forces. The OA-4 is a two-seat FAC version for the USMC, and the trainer version is known as TA-4. 2960 built.
Type: A-4F Skyhawk
Type: A-4M Skyhawk
MissionThe mission of an A-4 attack squadron is to attack and to destroy surface targets in support of the landing force commander, escort helicopters, and conduct other operations as directed. Developed in the early 1950s, the A-4 Skyhawk was originally designated the A-4D as a lightweight, daylight only nuclear capable strike aircraft for use in large numbers from aircraft carriers. There are numerous models of the A-4 in use. The A-4M and the TA-4F are currently used by Marine Corps Reserve squadrons. All models have two internally mounted 20mm (.8 inch) cannons, and are capable of delivering conventional and nuclear weapons under day and night visual meteorological conditions. The A-4M uses a heads-up display and computer aided delivery of its bomb load with the angle rate bombing system. The Marine Reserve has two squadrons of A-4s with 12 aircraft each. Additionally, each squadron has two TA-4 aircraft.
HistoryThe Skyhawk was designed by Douglas' Ed Heinemann in response to a U.S. Navy call for a jet-powered attack aircraft to replace the A-1 Skyraider. Heinemann opted for a design that would minimize size, weight, and complexity. The result was an aircraft that weighed only half of the Navy's specification and had a wing so compact that it did not need to be folded for carrier stowage. The diminutive Skyhawk soon received the nicknames "Scooter", "Bantam Bomber", "Tinker Toy Bomber" and on account of its nimble performance, "Heinemann's Hot-Rod."
The Navy issued a contract for the type on June 12 1952, and the first prototype first flew on June 22, 1954. Deliveries to Navy and U.S. Marine Corps squadrons commenced in late 1956. The Skyhawk remained in production until 1975, with a total of 2,960 aircraft built, including 555 two-seat trainers. The US Navy began removing the aircraft from its front-line squadrons in 1967, with the last retiring in 1975. The Marines would pass on the Navy's replacement, the A-7 Corsair II, instead keeping Skyhawks in service, and ordering the new A-4M. The last USMC Skyhawk was delivered in 1979, and were used until the mid-1990s until they were replaced by the similarly small, but V/STOL vertical landing AV-8 Harrier.
The Diamondbacks of VMA-131, Marine Aircraft Group 49 retired their last four OA-4Ms on June 22,1994. Trainer versions of the Skyhawk remained in Navy service, however, finding a new lease on life with the advent of adversary training, where the nimble A-4 was used as a stand-in for the MiG-17 in dissimilar air combat training (DACT) It served in that role until 1999, when the last were replaced with the T-45 Goshawk. Their nimble performance also made them suitable to replace the F-4 Phantom when the services downsized their aircraft for the Blue Angels demonstration team, popularized on a 80s rock video, until the availability of the F/A-18 Hornet in the 1980s. The last US Navy Skyhawks, TA-4J models belonging to composite squadron VC-8, remained in military use for target-towing and as adversary aircraft for combat training at Naval Air Station Roosevelt Roads. They were officially retired on May 3, 2003.
The Skyhawk proved to be one of the most popular US naval aircraft exports of the postwar era. Due to its small size, it could be operated from the older, smaller WWII-era aircraft carriers still used by many smaller navies during the 1960s. These older ships were often unable to accommodate newer USN fighters such as the F-4 Phantom II and F-8 Crusader, which were faster and more capable than the A-4, but significantly larger and heavier than older naval fighters.
DesignThe aircraft is of conventional post-WW2 design, with a low-mounted delta-like wing, tricycle undercarriage, and a single turbojet engine in the rear fuselage, with intakes on the fuselage sides. The tail is of cruciform design, with the horizontal stabilizer mounted above the fuselage. Armament consisted of two 20 mm Colt Mk 12 cannon, one in each wing root, with 200 rounds per gun, plus a large variety of bombs, rockets, and missiles carried on a hardpoint under the fuselage centreline and hardpoints under each wing (originally one per wing, later two).
The design of the A-4 is a good example of the virtues of simplicity. The choice of a delta wing, for example, combined speed and maneuverability with a large fuel capacity and small overall size, thus not requiring folding wings, albeit at the expense of cruising efficiency. The leading edge slats are remarkably designed to drop automatically at the appropriate speed by gravity and air pressure, thereby not even needing motors or even a pilot switch. Similarly the main undercarriage did not penetrate the main wing spar, being mounted so that when retracted only the wheel itself was inside the wing and the undercarriage struts were housed in a fairing below the lower wing surface. This meant that the wing structure itself could be lighter for the same overall strength and combined with the lack of a (heavy) wing fold mechanism even more weight was saved. This is the exact reverse of what often happens in aircraft design where a small weight increase in one area leads to a compounding increase in weight in other areas to compensate, leading to the need for more powerful, heavier engines and so on in a tight vicious cycle.
The A-4 pioneered the concept of "buddy" self air-to-air refueling. This allowed the aircraft to be used as a tanker for others of the same type, removing the need for entirely different tanker aircraft - a particular advantage for small air arms or when operating in remote locations. This worked by designating a tanker aircraft and fitting it with a centre-mounted "buddy store" that was a large external fuel tank with a hose reel in the aft section and an extensible drogue type refueling bucket. This aircraft was fuelled up without armament and launched prior to the attack aircraft. The attack aircraft were then armed up to the maximum and given only just enough fuel to bring them up to the maximum take-off weight. Once airborne, they would then proceed to top up their fuel tanks from the tanker using the A-4's inbuilt re-fuelling probe on the starboard side of the aircraft nose. They could then proceed to the target with both full armament and fuel loads. While rarely used in service since the KA-3 Skywarrior tanker was available, every Boeing, formerly McDonell Douglas F-4 Phantom when the services downsized their aircraft for the Blue Angels demonstration team, popularized on a 80s rock video, until the availability of the F/A-18E/F Super Hornet is now built with this capability with the retirement of dedicated tankers imminent in the 2000s.
The A-4 was also designed to be able to make an emergency landing, in the event of a hydraulic failure, on the two drop tanks nearly always carried by these planes. Such landings resulted in only minor damage to the nose of the aircraft which could be repaired in less than an hour. The wings had automatic leading edge slats, operated by aerodynamic pressure alone, again a simple but effective and weight saving feature. Ed Heinemann is credited with having a large "K.I.S.S." sign put up on the wall of the drawing office when the aircraft was being designed. Whether this is true, the A-4 certainly is a shining example of the application of that principle to aircraft design.
CombatSkyhawks were the Navy's primary light bomber over both North Vietnam during the early years of the Vietnam War while the USAF was flying the supersonic F-105 Thunderchief. They would be supplanted by the A-7 Corsair II in the Navy light bomber role. Skyhawks carried out some of the first air strikes by the US during the conflict and a Marine Skyhawk is believed to have dropped the last US bombs on the country. On one occasion, an A-4C Skyhawk, piloted by LCDR Ted Swartz from attack squadron VA-76, shot down a MiG-17 with an unguided rocket (In May 1970, an Israeli Skyhawk piloted also shot down a MiG-17 with unguided rockets, over south Lebanon).
Lt. Cmdr John McCain flew A-4s, once having to clamber out over the refueling probe of a Skyhawk stationed on the carrier USS Forrestal in order to escape a devastating flight deck fire caused by a rogue Zuni rocket, which eventually cost the lives of 134 sailors. John McCain escaped from his jet by climbing out of the cockpit, walking down to the nose of the plane, and jumping off the refueling probe. Video tape shot aboard the Forrestal shows McCain narrowly escaping the explosion. He would ultimately be shot down over Vietnam while flying another Skyhawk.
Shortly afterwards, Israeli Air Force Skyhawks would be the primary ground attack aircraft in the War of Attrition and the Yom Kippur War. They cost only 1/4 what a Phantom cost and carried more bombs and had longer range than the air superiority fighters they replaced. The Skyhawks bore the brunt of losses to sophisticated SA-6 missile batteries. They have been replaced by F-16s.
During the Falklands Conflict, in spite of being armed with just iron bombs and lacking any electronic or missile self defense, Argentine Air Force Skyhawks sunk HMS Coventry (D118), HMS Antelope (F170) and RFA Sir Galahad (1966) besides producing heavy damage to several others like HMS Glasgow (D88), HMS Argonaut, HMS Broadsword and RFA Sir Tristram. Argentine Navy A-4Q's also played a role in the bombing attacks against British ships, destroying HMS Ardent (F184).
In all, 22 Skyhawks were lost or shot down during the war to a mixture of surface to air missiles such as the Sea Dart and the Sea Harriers guns and missiles.
More recently, Kuwaiti Air Force Skyhawks fought in the first Gulf War. Of the 36 that were delivered to Kuwait in 1970s, 23 survived the war and the Iraqi invasion, with only one being destroyed in combat.
Skyhawks were well loved by their crews for being tough and agile. These attributes, along with its low purchase and operating cost and easy maintenance, have contributed to the popularity of the A-4 both with American armed forces and internationally.