LTV A-7 Corsair II

The Ling-Temco-Vought A-7 Corsair II is a carrier-based subsonic light attack aircraft design that was introduced to replace the A-4 Skyhawk in US Naval service and based on the successful supersonic F-8 Crusader aircraft produced by Chance Vought. The A-7 was one of the first combat aircraft to feature a head-up display (HUD), doppler-bounded inertial navigation system (INS), and a turbofan engine. It initially entered service with the United States Navy during the Vietnam War and was then adopted by the United States Air Force to replace their A-1 Skyraiders that were borrowed from the Navy as well as with the Air National Guard. It was exported to Greece (in the 1970s), Portugal and Thailand (in the late 1980s).

LTV A-7 Corsair II
Class Aircraft
Type Attack
Manufacturer Ling Temco Vought
Origin United States of America
Country Name Origin Year
United States of America 1965
ManufacturerName Production From Production To Quantity
Ling Temco Vought 1569 View

In 1962, the United States Navy began preliminary work on VAX (Heavier-than-air, Attack, Experimental), a replacement for the A-4 Skyhawk with greater range and payload. Particular emphasis was placed on accurate delivery of weapons to reduce the cost per target. The requirements were finalized in 1963, announcing the VAL (Heavier-than-air, Attack, Light) competition.

To minimize costs, all proposals had to be based on existing designs. Vought, Douglas Aircraft, Grumman and North American Aviation responded. The Vought proposal was based on the successful Vought F-8 Crusader fighter, having a similar configuration, but shorter and more stubby, with a rounded nose. It was selected as the winner on 11 February 1964, and on 19 March the company received a contract for the initial batch of aircraft, designated A-7. In 1965, the aircraft received the popular name Corsair II, after Vought's highly successful Vought F4U Corsair of World War II. (There was also a Vought O2U Corsair biplane scout and observation aircraft in the 1920s.)

Compared to the F-8 fighter, the A-7 had a shorter, broader fuselage. The wing had a longer span, and the unique, variable incidence feature of the F-8 wing was omitted. To achieve the required range, the A-7 was powered by a Pratt & Whitney TF30-P-6 turbofan producing 11,345 lbf (50.5 kN) of thrust, the same innovative combat turbofan produced for the F-111 and early F-14 Tomcats, but without the afterburner needed for supersonic speeds.

The aircraft was fitted with an AN/APQ-116 radar, later followed by the AN/APQ-126, which was integrated into the ILAAS digital navigation system. The radar also fed a digital weapons computer which made possible accurate delivery of bombs from a greater stand-off distance, greatly improving survivability compared with faster platforms such as the McDonnell Douglas F-4 Phantom II. It was the first U.S. aircraft to have a modern head-up display, (made by Marconi-Elliott), now a standard instrument which displayed information such as dive angle, airspeed, altitude, drift and aiming reticle. The integrated navigation system allowed for another innovation – the projected map display system (PMDS) which accurately showed aircraft position on two different map scales.

The A-7 had a fast and smooth development. The YA-7A made its first flight on 27 September 1965, and began to enter Navy squadron service late in 1966. The first Navy A-7 squadrons reached operational status on 1 February 1967, and began combat operations over Vietnam in December of that year.

The A-7 offered a plethora of cutting-edge avionics compared to contemporary aircraft. This included data link capabilities that, among other features, provided fully "hands-off" carrier landing capability when used in conjunction with its approach power compensator (APC) or auto throttle. Other notable and highly advanced equipment was a projected map display located just below the radar scope. The map display was slaved to the inertial navigation system and provided a high-resolution map image of the aircraft's position superimposed over TPC/JNC charts. Moreover, when slaved to the all-axis auto pilot, the inertial navigation system could fly the aircraft "hands off" to up to nine individual waypoints. Typical inertial drift was minimal for newly manufactured models and the inertial measurement system accepted fly over, radar, and TACAN updates.

Initial operational basing/homeporting for U.S. Navy A-7 squadrons was at NAS Cecil Field, Florida for Atlantic Fleet units and NAS Lemoore, California for Pacific Fleet units. This was in keeping with the role of these bases in already hosting the A-4 Skyhawk attack squadrons that would eventually transition to the A-7.

From 1967 to 1971, a total of 27 Navy squadrons took delivery of four different A-7A/B/C/E models. The Vought plant in Dallas, TX employed up to 35,000 workers who turned out one aircraft a day for several years to support the Navy carrier-based needs for Vietnam and SE Asia and commitments to NATO in Europe. In 1974, when the USS Midway (CV-41) became the first Forward Deployed Naval Force (FDNF) aircraft carrier to be homeported in Yokosuka, Japan, two A-7B squadrons assigned to Carrier Air Wing FIVE (CVW-5) were concurrently homeported at NAF Atsugi, Japan. In 1976, these squadrons (VA-93 and VA-56) finally transitioned to the much more advanced A-7E model. Six Naval Reserve attack squadrons would also eventually transition to the A-7, operating from NAS Cecil Field, Florida; NAS Atlanta/Dobbins ARB, Georgia; NAS New Orleans, Louisiana; NAS Alameda, California and NAS Point Mugu, California. An additional active duty squadron stood up in the 1980s, Tactical Electronic Warfare Squadron 34 (VAQ-34) at NAS Point Mugu, which would operate twin-seat TA-7C and EA-7L aircraft with both a pilot and a naval flight officer in an adversary electronic warfare role.

Pilots of the early A-7s lauded the aircraft for general ease of flying (with the exceptions of poor stability on crosswind landings and miserable stopping performance on wet runways with an inoperative anti-skid braking system) and excellent forward visibility but noted a lack of engine thrust. This was addressed with A-7B and more thoroughly with A-7D/E. The turbofan engine provided a dramatic increase in fuel efficiency compared with earlier turbojets – the A-7D was said to have specific fuel consumption one sixth that of an F-100 Super Sabre at equivalent thrust. An A-7D carrying 12 x 500 lb (227 kg) bombs at 480 mph (775 km/h) at 33,000 ft (10,000 m) used only 3,350 lb (1,500 kg) of fuel per hour. Typical fuel consumption at mission retrograde during aircraft carrier recovery was approximately 30 pounds per minute compared to 100+ pounds per minute for the Phantom F-4J/N series. The A-7 Corsair II was tagged with the nickname "SLUF" ("Short Little Ugly Fucker") by pilots.

Southeast Asia carrier use

In Vietnam, the hot, humid air robbed even the upgraded A-7D and A-7E of power. Takeoff rolls were lengthy, and fully armed aircraft struggled to reach 500 mph (800 km/h). For A-7A aircraft, high density altitude and maximum weight runway takeoffs often necessitated a "low transition", where the aircraft was intentionally held in "ground effect" a few feet off the runway during gear retraction, and as much as a 10-mile (16 km) departure at treetop altitude before reaching a safe flap retraction speed. (A-7A wing flap systems were either fully extended or fully retracted. The A-7A flap handle did not have the microswitch feature of later models that permitted the flaps to be slowly raised by several degrees per tap of the flap handle as airspeed slowly increased during max-weight takeoffs.)

Carrier catapult launches at maximum weight under these performance-robbing conditions were not significantly better and were characterized by the aircraft decelerating by as much as 20 knots (37 km/h) immediately after launch. As a result, A-7A units operated their aircraft 4,000 pounds below the max-rated takeoff weight for the A-7E.

In a sortie against the Thanh Hoa bridge, four A-7Cs from VA-82 successfully delivered 8,000 lbs of high explosives with two planes carrying two 2,000 lb (910 kg) Walleyes, while two others also carried 2,000 lbs in Mk 84 GP bombs. In a simultaneous attack, the center piling on the bridge's west side was hit and broke the span in half. After this, the Thanh Hoa bridge was considered permanently destroyed and removed from the target list.

A total of 98 USN A-7 Corsairs were lost during the war.

United States Air Force A-7D

The United States Army has not been permitted to operate fixed-wing combat aircraft since the establishment of an independent United States Air Force in 1947. To meet its need for close air support of its troops in South Vietnam, the Army pressured the Air Force to procure a specialized subsonic close air support fixed-wing aircraft that would suit its needs better than the general-purpose supersonic aircraft that the USAF preferred.

The Vought A-7 seemed to be a relatively quick and inexpensive way to satisfy this need. However, the USAF was initially reluctant to take on yet another Navy-designed aircraft, but Secretary of Defense Robert McNamara was insistent. On 5 November 1965, Secretary of the Air Force Harold Brown and USAF Chief of Staff General John P. McConnell announced that they had decided to order a version of the Corsair II, designated A-7D, for the Tactical Air Command.

The A-7D differed from the Navy's Corsair II in several ways. For one, the Air Force insisted on significantly more power for its Corsair II version, and they selected the Allison TF41-A-1 turbofan engine, which was a license-built version of the Rolls-Royce Spey. It offered a thrust of 14,500 pounds, over 2000 pounds greater than that of the TF30 that powered the Navy's Corsair IIs. Other changes included a head-up display, a new avionics package, and an M61A1 rotary cannon in place of the two single-barreled 20-mm cannon. Also included was a computerized navigation/weapons delivery system with AN/APQ-126 radar and a head-up display.

Two YA-7D prototypes were completed with TF30-P-6 engines, and the first of these flew on 6 April 1968. The first Spey-powered A-7D (67-14854) flew for the first time on 26 September 1968. The seventeenth production aircraft introduced a provision for boom flight refueling in place of the Navy's probe/drogue system, with the boom receptacle being on the top of the fuselage behind the cockpit and offset to port.

The A-7D first entered service in 1970 with the 57th Fighter Weapons Wing at Luke AFB Arizona, and the 354th Tactical Fighter Wing at Myrtle Beach AFB, South Carolina was equipped with four squadrons of A-7Ds by 1972; the 355th TFW at Davis-Monthan AFB was equipped with four squadrons in 1972, and in 1973, the 23d TFW at England AFB, Louisiana was fully equipped with A-7Ds.

The 354th TFW first deployed two squadrons of A-7Ds to Korat Royal Thai AFB, Thailand in September 1972 as part of Operation Cornet Dancer, The A-7Ds were quickly assigned the "Sandy mission" of providing air cover for Combat Search and Rescue missions of downed pilots.

Taking over for Douglas A-1 Skyraiders (and adopting their call sign of "Sandy"), the A-7's higher speed was somewhat detrimental for escorting the helicopters but the aircraft's high endurance and durability were an asset and it performed admirably.

On 18 November 1972, Major Colin A. Clarke led a successful CSAR mission near Thanh Hoa to rescue a downed F-105 Wild Weasel crew. The mission lasted a total of 8.8 hours during which Clarke and his wingman took a number of hits from 0.51 cal (12.7 mm) anti-aircraft fire. For his actions in coordinating the rescue, Clarke was awarded the Air Force Cross, the USAF's second-highest decoration for valor, and his A-7D (AF Serial No. 70-0970) was eventually placed on display on 31 January 1992 at the National Museum of the United States Air Force at Wright-Patterson AFB, Ohio.

With the end of US involvement in South Vietnam, the 354th TFW (Deployed) at Korat began flying combat sorties in Cambodia to support the Lon Nol government in support of Khmer National Armed Forces against the Khmer Rouge. Rotational deployments began to Korat from the 355th TFW and 23d TFW, with pilots and support personnel beginning six-months deployment cycles. In March 1973, the 354th transferred a squadron of A-7Ds to the 388th TFW, the host wing at Korat RTAFB at the time, which re-established the 3d Tactical Fighter Squadron and created a permanent USAF A-7D presence in Southeast Asia. A-7Ds from both wings stationed at Korat engaged in combat operations in Cambodia until 15 August 1973 when an A-7D of the deployed 353d TFS/354th TFW carried out the last air support mission. In March 1974, the 354th TFW transferred several more aircraft to the 3d TFS prior to its return to Myrtle Beach AFB.

The USAF A-7D flew a total of 12,928 combat sorties during the war with only six losses – the lowest of any U.S. fighter in the theater. The aircraft was second only to Boeing B-52 Stratofortress in the amount of ordnance dropped on Hanoi and dropped more bombs per sortie with greater accuracy than any other U.S. attack aircraft.

Role Attack aircraft
Manufacturer Ling-Temco-Vought
First flight 26 September 1965
Introduction February 1967
Retired 1991 (USAF, USN); 1993 (ANG)
1999 (Portuguese Air Force)
2014 (Hellenic Air Force)
Status Retired
Primary users United States Navy (historical)
United States Air Force (historical)
Portuguese Air Force (historical)
Hellenic Air Force (historical)
Produced 1965–1984
Number built 1569
Unit cost US$2.86 million
Developed from Vought F-8 Crusader
Variants LTV A-7P Corsair II
Vought YA-7F


General characteristics

  • Crew: 1
  • Length: 46 ft 1.5 in (14.06 m)
  • Wingspan: 38 ft 9 in (11.81 m)
  • Height: 16 ft 0.75 in (4.90 m)
  • Wing area: 375 ft (34.8 m)
  • Airfoil: NACA 65A007 root and tip
  • Empty weight: 19,915 lb (9,033 kg)
  • Loaded weight: 29,040 lb (13,200 kg)
  • Max takeoff weight: 42,000 lb (19,050 kg)
  • Powerplant: 1 x Allison TF41-A-1 turbofan, 14,500 lbf (64.5 kN)

Performance

  • Maximum speed: 606 knots (698 mph, 1,123 km/h at sea level)
  • Cruise speed: 465 knots (535 mph, 860 km/h)
  • Combat radius: 621 NM (715 mi, 1,150 km)
  • Ferry range: 2,485 NM (2,860 mi, 4,600 km (with 4-300 gal external tanks))
  • Service ceiling 42,000 ft (12,800 m)
  • Rate of climb: 15,000 ft/min (76 m/s)
  • Wing loading: 77.4 lb/ft (379 kg/m)
  • Thrust/weight: 0.50

Armament

  • Guns: 1 x 20 mm (0.787 in) M61 Vulcan gatling gun with 1,030 rounds
  • Missiles: 2 x AIM-9 Sidewinder, on one each side of fuselage
  • Bombs: 20,000 lb (9,080 kg) on six external hardpoints, compatible with a wide range of general-purpose bombs, including:
    • Up to 30 x 500 lb (230 kg) Mark 82 bombs
    • Rocket pods
    • Paveway laser-guided bombs
    • AGM-45 Shrike, AGM-62 Walleye, AGM-65 Maverick, AGM-88 HARM, and GBU-15 electro-optical glide bombs
    • 1 x B28, B57, or B61 nuclear bomb

End notes