Aviation News - February 2016 UK

thrust. The first trainer version evolved as the

TA-7C featuring a tandem cockpit for student

and instructor. These aircraft were made

up of 24 existing A-7Bs and 36 new build

airframes. Two-seaters of the A-7H and A-7P

followed and were known as the TA-7H and

TA-7P repectively, however 30 two-seaters

for the Air National Guard (ANG) had the

deignation A-7K.

The D/E series were a significant

enhancement on previous versions. The D

featured the M61A1 Vulcan Gatling rotary

cannon (other versions had two 20mm Colt

Mk12 cannons). The D model also had a

new anti-skid braking system plus could be

in-flight refuelled (all subsequent versions

were capable of this).

Two YA-7D prototypes were built and

used the TF30-P-6 engine, the first flight of

this type taking place on April 6, 1968. Both

these aircraft were later retrofitted with the

Allison TF41-A-1 engine which were licence

built copies of the Rolls-Royce RB162-256

Spey with 14,250lb of thrust.

The Navy’s E-variants were generally

similar, but with the notable difference of a

more powerful Allison TF41-2 with a thrust of

15,000lb. Internal fuel capacity was greater

than on the D version, but at the expense of

the D’s greater foam protection of the main

fuel tanks.

At the heart of both D/E versions was

the IBM Corporation AN/ASN-91 (V) tactical

computer, which calculated bomb aiming

based on inputs from the aircraft’s various

sensors including the Doppler radar, Garrett

Corp CP-953A/AJQ air data computer and

AN/APQ-126(V) forward-looking radar.

In 1985 following USAF requests for

proposals for an aircraft to take over the

Fairchild Republic A-10 Thunderbolt II’s

interdiction role the concept of a supersonic

A-7 materialised powered by a single Pratt

& Whitney F100-PW 220 engine developing

26,000lb of thrust. To accommodate this

powerplant the aircraft was lengthened by 4ft

(1.2m). The vertical stabiliser also gained 10in

(25cm) in height. Two aircraft A-7Ds 71-0344

and 70-1039 were modified (designated

YA-7Fs) and subsequently operated by 445th

Flight Test Squadron at Edwards AFB in

California. The role they had been designed for

was, however, filled by F-16 Fighting Falcons.

In 1982 eight TA-7Cs were modified to

serve as EA-7L electronic aggressor aircraft

and were operated by VAQ-34 at NAS Point

Mugu in California from 1983 until as late as

November 1994 when the last aircraft was

sent for storage at Davis-Montham AFB.

VIETNAM

The A-7 Corsair II set records almost from

the off. On its first combat deployment with

the US Navy in South East Asia, the aircraft

had a daily availability rate of ten-12 out

of 14 available aircraft in each squadron.

Furthermore, in the type’s first 4,000 hours of

missions not a single aircraft was lost. The

USAF bettered that statistic with only three

accidents in 50,000 flight hours.

In the lead-up to these impressive figures,

the A-7A first entered combat in Vietnam on

December 4, 1967 with VA-147 performing

attacks against bridges and highways

around Vinh. In the coming months USS

Ranger made four regular line periods on

Yankee Station in the Gulf of Tonkin. The

aircraft made strikes against the Nui Long

Lau tunnels in December 1967, sealing the

entrances with 500lb, 1,000lb and 2,000lb

bombs. Other targets included railways,

coastal shipping, vehicles and roads and

bridges between Vinh and Haiphong and VA-

147 also flew air support for the US Marines

during the siege of Khe Sanh.

The destruction of the Thanh Hóa Bridge

by aircraft of VA-82 from USS America proved

the wisdom of the targeting systems on

board the A-7. The bridge had until this time

remained resolutely intact despite repeated

attacks, but it finally succumbed to the

combined efforts of four A-7Cs and 8,000lb of

Walleye and Mk84 General Purpose bombs.

The free flow of ideas and experience

with the US Navy and USAF led to the

formation of a joint project called Coronet

Stallion. The USAF embarked three pilots,

one maintenance officer and 20 specialists

onboard USS Ranger to assess the A-7. The

USAF’s chief officer, Maj Charles McClaren

made a formal summary of his findings. “We

found the A-7A very rugged, stable and long-

legged aircraft,” he said. “Performance was

not impressive with the small engine (TF30),

but fuel economy was astounding...our

maintenance people thought the A-7A one of

the most easily maintained aircraft that they

had encountered.”

The hot and humid air of Vietnam robbed

the engine of much of its power. Such was

the effect that fully armed aircraft sometimes

struggled to reach 432kts (800km/h). For the

earliest A-7A models, high density altitude

and maximum weight runway take-offs often

necessitated a ‘low transition’ where the plane

was intentionally held in ground effect during

wheel retraction and also as much as ten

miles at treetop level before the aircraft had

achieved a satisfactory speed for safe flap

retraction. Launches from carriers were

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LTV A-7B 154363 taxies at the manufacturer’s Dallas, Texas facility. The main difference between

the A and B variants was the more powerful TF-30-P-8 engine which replaced the P-6. via author

A US Navy A-7 performs a catapult launch from a carrier. Key Collection

48-55_a7DC.mfDC.mfDC.mfDCDC.mf.indd 51 07/01/2016 16:18