A-7 Corsair II
The
Ling-Temco-Vought A-7 Corsair II was a light
attack aircraft based on the
F-8 Crusader. The A-7 was one of the first combat aircraft to feature a
head-up display (HUD), doppler-bounded inertial navigation system, and a
turbofan engine. It served with both the
United States Navy and the
United States Air Force, and later with the
Air National Guard. It was exported to
Greece (in the 1970s),
Portugal, and
Thailand (in the late 1980s).
In
1962,
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. A particular emphasis was placed on accurate delivery of weapons to reduce the cost per target. The requirements were finalized in
1963 and in
1964 the Navy announced the
VAL (Heavier-than-air, Attack, Light) competition. Contrary to USAF philosiphy, which was to employ only supersonic fighter bombers such as the
F-105 Thunderchief and
F-100 Super Sabre, the Navy felt that a subsonic design could carry the most payload the farthest distance. One story illustrated that a "slow fat duck" could fly nearly as fast as a supersonic one, since carrying dozens of iron bombs also restricted its entry speed, but a fast plane with small wings and an afterburner would burn up a lot more fuel. To minimize costs, all proposals had to be based on existing designs.
Vought,
Douglas Aircraft,
Grumman, and
North American Aviation responded. The Vought proposal, based on a blunted
F-8 Crusader 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
F4U Corsair of
World War Two.
Compared to the
F-8 Crusader fighter, the A-7 had a shorter, broader fuselage. The wing was made larger, so the unique variable incidence wing was deleted. To achieve the required range, A-7 was powered by a
Pratt & Whitney TF-30-P-6
turbofan producing 11,345 lbf (50.5 kN) of thrust, the same innovative combat turbofan produced for the
F-111, but without the afterburner need for supersonic speeds. Turbofans achieve more efficiency by moving unburned air at a lower velocity.
The aircraft was fitted with an
AN/APQ-116 radar 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
F-4 Phantom. It was the first US aircraft to have a modern heads-up display
HUD, 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) accurately showed aircraft position on two different map scales.
The A-7 enjoyed the fastest and most trouble-free development period of any American combat aircraft since the second world war. 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 operation status on
1 February 1967, and began combat operations over
Vietnam in December of that year.
Secretary of Defence
Robert McNamara is best remembered among fighter circles for the
F-111 commonality debacle, but he also prodded the Air Force to adopt not only the hugely successful
F-4 Phantom, but also the Navy's
A-7 Corsair as a low cost follow-on to F-105s until the troubled F-111 came online. The Air Force installed a fixed high speed refueling receptacle behind the pilot optimized for the
KC-135's flying boom rather than the folding long probe, they opted for their M61 gatling gun rather than the twin single-barrel 20mm cannon, and changed to the Allison TF41-A-1 engine which was a licenced version of the British Spey. The TF41-A-1 engine produced 14,500 LBS of thrust. Later Navy versions would retain the gun and engine.
Production of Corsairs continued through
1984. A total of 1,569 aircraft were built.
[[image:corsair.sideview.fairford.arp.jpg|thumb|left|250px|LTV TA-7C Corsair II of the Greek Air Force, on ramp at the Royal International Air Tattoo, Fairford, England, in 2005]]
Pilots of the early A-7s lauded the aircraft for general ease of flying (with the exception of poor stability on cross-wind landings) 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 six times less than
F-100 Super Sabre at equivalent thrust. An A-7D carrying 12x 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. The integrated weapons computer provided highly accurate bombing with
CEP of 60 ft (20 m) regardless of pilot experience. The doppler navigation system required a mere 2.5 minutes on the ground for partial alignment, a big improvement over 13 minutes required in
F-4 Phantom II. In addition, the A-7 required only 11.5
man hours of maintenance per mission resulting in quick turnaround and high number of combat-ready aircraft.
In Vietnam, the hot, humid air robbed even upgraded A-7D and A-7E of power. Takeoff rolls were lengthy and fully-armed aircraft struggled to reach 500 mph (800 km/h). Pilots quipped that the Corsair "is not very fast, but it sure is slow" (Higham 1978). For
dissimilar air combat training, and the Blue Angels, the Navy would chose the more nimble
A-4 Skyhawk as a subsonic maneuvering platform, as some considered the SLUF to be a "
grape" in air combat. The Marine Corps would also pass on the Corsair, they would opt instead for the
V/STOL vertical landing
AV-8 Harrier as their light attack fighter.
The first US Navy A-7As were deployed to Vietnam in 1967 with
VA-147 Argonauts aboard
USS Ranger (CVA-61). The aircraft made their first combat sortie on
4 December 1967. In the following months, VA-147 made around 1,400 flights losing only one aircraft. In January 1968, USS Ranger participated in the incident surrounding the capture of
USS Pueblo (AGER-2) in the
Sea of Japan by
North Korea. Improved A-7B arrived in Vietnam in early 1969, with A-7E following in 1971.
The USAF A-7Ds were also widely used in Vietnam with
354th Tactical Fighter Wing,
Korat RTAFB, Thailand, entering action in October 1972. The aircraft attacked targets as far as 500 mi (800 km) from airbases, extensively utilizing mid-air refueling. The A-7Ds were quickly assigned the "Sandy mission" of providing air cover for rescue of downed pilots. Taking over for
A-1 Skyraiders (hence the name "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 1971, Major
Colin A. Clarke led a successful 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 13 mm (0.51 cal) anti-aircraft fire. For his actions in coordinating the rescue, Clarke was awarded the
Air Force Cross, the USAF's second-highest medal. The A-7D flew a total of 12,928 combat sorties during the war with only 4 losses -- the lowest of any US fighter in the theatre. The aircraft was second only to
B-52 Stratofortress in the amount of ordnance dropped on
Hanoi and dropped more bombs per sortie with greater accuracy than any other US attack aircraft.
Navy A-7s also provided air support during the
U.S. mission in
Lebanon in
1983. One A-7, along with an
A-6 Intruder, were shot down by
Syrian missiles on
December 4, 1983.
USAF Corsair IIs were phased out of front-line service by the late 1970s, after a trial against the slow but rugged
A-10 Thunderbolt in the close air support role. Many aircraft passed to the
Air National Guard, while many pilots missed the performance and sophistication of the Corsair. The 4450th Tactical Group stationed at Nellis AFB, NV had the unique distinction of being the last active USAF unit to operate the A-7D Corsair II. While USAF A-7s stayed home in favor of A-10s,
Navy aircraft participated in
Operation Desert Storm where the A-7Es of squadrons
VA-46 and
VA-72 operated from the aircraft carrier
USS John F. Kennedy as one of the few aircraft with the range to reach all the way to Bagdhad from carriers. The
F-16 Fighting Falcon would also largely replace the A-7 as the Air Force's high performance attack fighter, while the Navy replaced them with the supersonic
F/A-18 Hornet in the 1980s. Even with an advanced technology afterburning turbofan, some still remark that the F-16 lacks the range of the old A-7. The complaint that the Hornet lacked range reached such a level that the even larger
F/A-18E/F Super Hornet was scaled up to carry more fuel. The last US Corsairs were retired not long after Some surplus aircraft were then passed to
Greece and
Portugal, where they remain in service.
A re-engined variant was proposed with near-sonic performance with afterburners, but this concept would lose out to the
F-16 Fighting Falcon and
F/A-18 Hornet (see below).
The A-7 Corsair II was tagged with the nickname "SLUF" (Short Little Ugly F*cker) by pilots.
*
A-7A - First production version. Early USN Corsair IIs had two 20 mm
Colt Mk 12 cannons with 250 rounds per gun. Maximum ordnance, carried primarily on the wing pylons, was theoretically 15,000 lb (6,804 kg), but was limited by maximum takeoff weight, so the full weapon load could only be carried with greatly reduced internal fuel. 199 built.
*
A-7B - Uprated TF30-P-8 engine with 12,190 lbf (54.2 kN) of thrust. In 1971, surviving A-7B were further upgraded to TF30-P-408 with 13,390 lbf (59.6 kN) of thrust. 196 built.
*
A-7C - first 67 production A-7E with TF30 engines.
*
TA-7C - two-seat trainer version for US Navy, 24 converted from A-7B, 36 from A-7C. Upgraded to A-7E standard in 1984.
*
A-7D - In the footsteps of recently adopting another Navy design, the
F-4 Phantom II, USAF requested a version of A-7 for
Tactical Air Command to fulfill the need for an inexpensive close-air support replacement for
A-1 Skyraider. On
5 November 1965 the USAF announced that it would purchase a version of the A-7, designated the
A-7D. The most important difference from Navy versions was adoption of the
Allison TF41-A-1 turbofan, a license-built version of British
Rolls-Royce Spey. With 14,500 lbf (64.5 kN) of thrust, the engine offered a considerable boost in performance. In addition, avionics were upgraded, internal armament was changed to a single 20 mm
M61 Vulcan gatling cannon, and the in-flight refueling method was changed from probe-and-drogue to the boom. The
YA-7D prototype with TF30 flew on
6 April 1968, with the first TF41 aircraft taking to the air on
26 September 1968. The aircraft were later updated to carry the
Pave Penny laser spot tracker to add the capability to drop guided bombs. 459 built.
*
A-7E - the Navy was so impressed with the performance gain of USAF A-7D that they ordered their own version with the TF41 engine. The first prototype flew on
25 November 1968. In
1986, 231 A-7E were equipped to carry the
LANA (Low-Altitude Night Attack) pod which projected amplified light image on the HUD and, in conjunction with radar, provided terrain following down to 460 mph (740 km/h) at 200 ft (60 m). 529 built (not counting 67 A-7C).
*
YA-7F (A-7D Plus, A-7 Strikefighter) - In
1985, USAF requested proposals for a fast strike aircraft because of concerns that
A-10 Thunderbolt II was too slow for interdiction. The design called for a new engine, either the
Pratt & Whitney F100 or
General Electric F110. LTV responded with a supersonic version of A-7 powered by a F100-PW-220 with 26,000 lbf (115.7 kN) of thrust. To accommodate the new engine, the
fuselage was lengthened about 4 ft (1.22 m). New fuselage sections were inserted in both the forward and aft fuselage - a 30 in (76 cm) section in front of the wing and an 18 in (46 cm) section behind the wing. The wing was strengthened and fitted with new augmented flaps, leading edge extensions and automatic maneuvering flaps. The
vertical stabilizer height was increased about 10 in (25 cm). Ironically, the end result resembled the F-8 Crusader from which the A-7 was originally derived. Two A-7D were modified, the first one flying on
29 November 1989 and breaking the
sound barrier on its second flight. The second prototype flew on 3 April 1990. The project was cancelled in favor of the
F-16 Fighting Falcon.
*
A-7G - proposed version for Switzerland, none built
*
A-7H - Modified A-7E for Greece without air-refuelling capability, 60 built.
*
TA-7H - two-seat trainer version for Greece
*
EA-7L - 8 TA-7C modified into electronic aggressor aircraft used by
VAQ-34, upgraded to A-7E standard in 1984
*
TA-7K - two-seat trainer version for Air National Guard, 30 built
*
A-7P - rebuilt ex-Navy A-7A for Portugal
*
TA-7P - two-seat trainer version for Portugal
*
YA-7E or
YA-7H - two-seat prototypes built by Ling-Temco-Vought as a private venture.
* Greece, Portugal, Thailand, United States (Air Force, Navy),
*Also see
List of units using the A-7 Corsair II |
Orthographically projected diagram of the A-7E Corsair II. |
*
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*
355th Tactical Fighter Wing A-7D Corsair II Era{{aircontent|sequence=
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A-4 -
A-5 -
A-6 -
A-7 -
AV-8 -
YA-9 -
A-10|related=
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F-8 Crusader|similar aircraft=
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Nanchang Q-5*
Sukhoi Su-17*
A-6 Intruder|lists=
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List of attack aircraft*
List of military aircraft of the United States|see also=
