A-7D Corsair II
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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. A 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. 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. Theoretically, 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 aircraft with small wings and an afterburner
would burn 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 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.[1] In 1965, the aircraft received the popular name Corsair II, after Vought's highly successful
F4U Corsair of World War II. (There was also a Vought O2U Corsair biplane scout and observation aircraft in 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
wing of the F-8 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,[1] the same innovative combat turbofan produced for the F-111 and early F-14 Tomcats, but without
the afterburner needed for supersonic speeds. Turbofans achieve greater efficiency by moving a larger mass of air at a lower velocity.
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 F-4 Phantom II. It was the first U.S. aircraft to
have a modern head-up display, 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 enjoyed the fastest and most trouble free development period of any American combat aircraft since World War II. 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.
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, announcing 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. Theoretically, 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 aircraft with small wings and an afterburner
would burn 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 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.[1] In 1965, the aircraft received the popular name Corsair II, after Vought's highly successful
F4U Corsair of World War II. (There was also a Vought O2U Corsair biplane scout and observation aircraft in 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
wing of the F-8 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,[1] the same innovative combat turbofan produced for the F-111 and early F-14 Tomcats, but without
the afterburner needed for supersonic speeds. Turbofans achieve greater efficiency by moving a larger mass of air at a lower velocity.
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 F-4 Phantom II. It was the first U.S. aircraft to
have a modern head-up display, 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 enjoyed the fastest and most trouble free development period of any American combat aircraft since World War II. 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.
Improved versions
Secretary of Defense Robert McNamara prodded the Air Force to adopt not only the hugely successful F-4, but also the Navy's A-7
Corsair as a low-cost follow-on to F-105s until the troubled F-111 came online, and as a 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, for Tactical
Air Command. 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 the Navy aircraft. The most important difference from the preceding Navy
versions was the 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. The M61 Vulcan cannon was selected in place of the twin
single-barrel 20 mm cannon. In addition, avionics were upgraded. 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. A total of 459 were built and assigned to tactical fighter wings of the Tactical Air Command
(TAC).
The Navy was so impressed with the performance gain of USAF A-7D that they ordered their own version with the TF41 engine and
M61 cannon, the A-7E, to go along with the new continuous solution weapon systems and sophisticated avionics that was developed in
the A-7C model that was highly advanced for that era. The first prototype flew on 25 November 1968. A-7Es were built in 1970s with
outstanding mission success in the fleet. In 1979 the first around-the-clock night-attack FLIR-capable aircraft were delivered to VA-81
at NAS Cecil Field, Florida. During the 1980s, when defense budgets finally allowed, funding for upgrades various system upgrades and
engineering change proposal mods were incorporated to increase reliability, safety and mission effectiveness. In 1986, 231 A-7Es were
equipped to carry the Low-Altitude Night Attack (LANA) 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). A total of 529 examples were built (not counting
67 A-7Cs).
In 1985, the 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-PW-220 or General Electric F110-GE 100. LTV
responded with the YA-7F, a supersonic version of A-7 powered by an F100-PW-220 with 26,000 lbf (116 kN) 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), the unit horizontal tail was flipped from dihedral to anhedral, and control surfaces were flattened.
Unsurprisingly, the end result resembled the supersonic F-8 Crusader from which the original subsonic A-7 was derived.
The new supersonic A-7 could accelerate with a 17,380 lb (7,880 kg) bomb load from 400 to 550 knots (1,020 km/h) in under 15
seconds and could sustain Mach 1.6 for longer times with the extra fuel. The YA-7F modifications allowed 7-g turn and burn capability
that permitted high-speed sustained evasive maneuvers plus great improvements in high angle of attack performance. As a CAS/BAI
platform to penetrate into enemy territory and return safely, the "Strikefighter" moniker was most fitting. Two A-7Ds were extensively
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 canceled due to improved relations with former adversaries, lower defense budgets, and the Air National
Guard, by then the principal USAF operator of the A-7 generally favoring the in-production F-16 Fighting Falcon.
Production of Corsairs continued through 1984, yielding a total of 1,569 aircraft built. The A-7 Corsair has the distinction of being the
only United States single seat jet fighter-bomber of the 1960s that was designed, built, and deployed directly into the Vietnam War.
Secretary of Defense Robert McNamara prodded the Air Force to adopt not only the hugely successful F-4, but also the Navy's A-7
Corsair as a low-cost follow-on to F-105s until the troubled F-111 came online, and as a 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, for Tactical
Air Command. 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 the Navy aircraft. The most important difference from the preceding Navy
versions was the 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. The M61 Vulcan cannon was selected in place of the twin
single-barrel 20 mm cannon. In addition, avionics were upgraded. 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. A total of 459 were built and assigned to tactical fighter wings of the Tactical Air Command
(TAC).
The Navy was so impressed with the performance gain of USAF A-7D that they ordered their own version with the TF41 engine and
M61 cannon, the A-7E, to go along with the new continuous solution weapon systems and sophisticated avionics that was developed in
the A-7C model that was highly advanced for that era. The first prototype flew on 25 November 1968. A-7Es were built in 1970s with
outstanding mission success in the fleet. In 1979 the first around-the-clock night-attack FLIR-capable aircraft were delivered to VA-81
at NAS Cecil Field, Florida. During the 1980s, when defense budgets finally allowed, funding for upgrades various system upgrades and
engineering change proposal mods were incorporated to increase reliability, safety and mission effectiveness. In 1986, 231 A-7Es were
equipped to carry the Low-Altitude Night Attack (LANA) 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). A total of 529 examples were built (not counting
67 A-7Cs).
In 1985, the 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-PW-220 or General Electric F110-GE 100. LTV
responded with the YA-7F, a supersonic version of A-7 powered by an F100-PW-220 with 26,000 lbf (116 kN) 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), the unit horizontal tail was flipped from dihedral to anhedral, and control surfaces were flattened.
Unsurprisingly, the end result resembled the supersonic F-8 Crusader from which the original subsonic A-7 was derived.
The new supersonic A-7 could accelerate with a 17,380 lb (7,880 kg) bomb load from 400 to 550 knots (1,020 km/h) in under 15
seconds and could sustain Mach 1.6 for longer times with the extra fuel. The YA-7F modifications allowed 7-g turn and burn capability
that permitted high-speed sustained evasive maneuvers plus great improvements in high angle of attack performance. As a CAS/BAI
platform to penetrate into enemy territory and return safely, the "Strikefighter" moniker was most fitting. Two A-7Ds were extensively
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 canceled due to improved relations with former adversaries, lower defense budgets, and the Air National
Guard, by then the principal USAF operator of the A-7 generally favoring the in-production F-16 Fighting Falcon.
Production of Corsairs continued through 1984, yielding a total of 1,569 aircraft built. The A-7 Corsair has the distinction of being the
only United States single seat jet fighter-bomber of the 1960s that was designed, built, and deployed directly into the Vietnam War.
