Aircraft Factfile and Recognition Guide – A-7
Corsair
Background
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 philosophy, 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 was based on the successful F-8 Crusader
fighter, having an identical configuration, but more short and 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 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 of the F-8 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 II. It was the first US
aircraft to have a modern heads-up display, now a standard instrument,
which displayed information such as dive angle, airspeed, altitude,
drift, and aiming reticule. 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 Defense Robert McNamara prodded the Air Force to adopt not
only the hugely successful F-4 Phantom II, 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 ordered the A-7D with a fixed high speed
refueling receptacle behind the pilot optimized for the KC-135's flying
boom rather than the folding long probe of Navy aircraft. They opted
for the M61 Vulcan gattling gun rather than the twin single-barrel 20 mm
cannon, and changed to the Allison TF41-A-1 engine, which was a
licensed version of the British Rolls-Royce Spey. The TF41-A-1 engine
produced 14,500 lbf (64 kN) of thrust. Later Navy versions would adopt
this gun and engine. Production of Corsairs continued through
1984. A total of 1,569 aircraft were built.
The A-7 Corsair II was tagged with the nickname "SLUF" (Short Little
Ugly Feller) by pilots. 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 one sixth that of an 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.
US Navy A-7 Corsairs were phased out of the fleet during the 1980s,
being replaced in large part by the McDonnell Douglas (Now Boeing)
F/A-18 Hornet. The last Navy A-7s were retired by fleet operational
squadrons (VA-46 and VA-72) in May 1991.
By 1981, the Fairchild A-10 Thunderbolt II took over the Air Force
close air support (CAS) role from the A-7s with active duty units. With
the exception of the A-7s used in the F-117 program, the last active
duty Corsairs were used by the 23d Tactical Fighter Wing at England Air
Force Base Louisiana in 1981. Many active-duty pilots missed the
performance and sophistication of the Corsair.
Active duty US Air Force A-7Ds were transferred to Air National Guard
(ANG) units beginning in 1974, with new twin seat A-7K's built starting
in 1979 being sent directly to the ANG. The last USAF Air National
Guard Corsairs were retried in 1993 by the ANG units at Rickenbacker
ANGB (Ohio), Des Moines (Iowa), Tulsa (Oklahoma) and Springfield (Ohio).
Some of these surplus aircraft were passed to Greece, Thailand and
Portugal, however by the end of 1998, with the exception of some
airframes used as static displays, all US A-7s were disposed of by
AMARC.
The Portuguese Air Force A-7s (designated A-7P, TA-7P) were 20
converted Navy A-7As and 6 TA-7C airframes powered by the TF30-P408
engine and were equipped with A-7E avionics. Deliveries to Portugal
began in May 1981 and were completed by May 1986. These aircraft were
retired in 2001.
Recognizing
the A-7 Corsair
The A-7 is an unmistakable aircraft to identify on the ground or in the air. Here's tips on how to identify one:
Wings:. High-mounted,
swept-back, and tapered with blunt tips and a negative slant. Sawtooth
in the leading edges on some models.
Engine: One turbofan inside
the body; oval air intake under a round nose. Single exhaust.
Fuselage: Wide, thick body
with rounded nose and blunt tail section. Bubble canopy is located well
forward on the nose.
Tail: Flats mid-mounted on
the body, swept-back and tapered, with a positive slant. The fin is
swept-back with a curved tip.
Specifications - A-7D Corsair
Primary Function:
Attack
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)
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×
Allison TF41-A-1 turbofan, 14,500 lbf (64.5 kN)
Maximum speed: 606
knots (698 mph, 1,123 km/h at sea level)
Cruise speed: 465
knots (535 mph, 860 km/h)
Service ceiling:
42,000 ft (12,800 m)
Crew: 1
Armament:
Guns:
1× 20 mm (0.787 in) M61 Vulcan gattling gun with 1,030 rounds
Missiles:
2× AIM-9 Sidewinder, on one each side of fuselage
Bombs:
15,000 lb (6,800 kg) on six external hard points, compatible with a wide
range of general-purpose bombs, including:
Up to 30×
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× B28,
B57, or B61 nuclear bomb
Sources: GlobalSecurity.org
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