The Awesome Power of Air Force Gunships
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The Awesome Power of Air Force Gunships
By Walter J. Boyne
In warfare, timing is critical, and few weapons have
had better timing than the gunship, the epitome of
on-scene firepower in the Vietnam War. History, requirements,
resources, and-most of all-personalities, all came
together at a critical moment to create a piece of
side-firing airborne artillery, a weapon North Vietnam
considered one of the most important of the war.
Whether they were Puffs, Spookys, Spectres, Shadows,
or Stingers, the gunships brought intense, lethally
accurate fire to the enemy's doorstep, busting trucks
and saving the lives of countless friendly personnel.
Putting a fixed side-firing weapon on an aircraft
was first proposed in 1926, when 1st Lt. Fred Nelson
experimented with a de Havilland DH-4 at Brooks Field,
Texas. Nelson mounted a .30-caliber Lewis machine gun
on the wing and flew "pylon turns" to keep
the gun on target, thus demonstrating the very essence
of the concept almost 40 years before it appeared on
the battlefield.
The United States did not have a monopoly on the idea.
In 1932, French military designers installed a fixed
side-firing Schneider P.D. 12 75 mm cannon in a four-engine
Bordelaise A.B. 22 bomber. The A.B. 22 was intended
for use in France's colonial possessions, one of which,
ironically enough, would become the venue for US gunships-Indochina.
In April 1942, 1st Lt. Gilmour C. MacDonald of the
95th Coast Artillery proposed fitting a Piper Cub with
a side-firing machine gun for anti-submarine operations.
MacDonald's gunship idea was passed over, but he resurrected
it in 1961 when, as a lieutenant colonel, he advocated
transverse firing of rockets and machine guns by liaison
aircraft. This time, he was backed by Ralph E. Flexman,
an assistant chief engineer at Bell Aerosystems, who
was intrigued by the challenge of limited war and counterinsurgency
actions and was drawing inspiration from an unusual
source.
Missionary Work
Flexman had heard stories of a missionary named Nate
Saint who had been able to air-deliver mail and supplies
to remote villages by lowering them in a weighted pouch.
The pouch remained stationary over a point on Earth
at the end of a long rope as he flew pylon turns around
the point. Flexman reasoned that the straight line
of the rope would translate into a straight line of
gun fire at a single point on Earth if the gunship
were flown in a similar pylon turn.
The requirement for additional firepower in Southeast
Asia gave impetus to the side-firing idea. Preliminary
tests of the concept were conducted at Air Force Systems
Command's Aeronautical Systems Division at WrightPatterson
AFB, Ohio, by Capt. John C. Simons, as a part of Project
Tailchaser. Simons encountered opposition; many people
believed that a side-firing aircraft, particularly
the C-47, would be far too vulnerable to enemy fire.
There was also doctrinal concern that use of a fixed-wing
gunship was playing into the hands of the Army, which
was becoming ever more dependent upon the helicopter
gunship.
Nonetheless Simons persisted, "bootlegging" missions
in a North American T-28. No guns or sights were fitted,
but Simons was able to validate the concept by marking
the canopy with a grease pencil and flying the pattern.
More experiments were done by Capt. J.D. Boren and
Capt. J.A. Birt in 1964, using a Convair C-131B. Cameras
were used in place of guns, and SSgt. Estell P. Bunch
developed a gun sight for the pilot, Capt. Edwin J.
Hatzenbuehler.
The stage was set for arrival of Capt. Ronald W. Terry
as project pilot. Working with 1st Lt. Edwin Sasaki,
Terry brought a unique combination of skills to the
program. He had great common sense; while using existing
technology, he kept his eye on the latest developments
to improve the system. Terry was able to work the bureaucracy
to his advantage, finding those who could say yes to
his program needs and avoiding those who might say
no.
The results were gratifying; Terry is one of the few
individuals in military history who helped create a
totally new weapon system and tested it in combat himself.
He then went on to create improved systems and test
them in battle, as well. By taking available equipment
and conforming it to new requirements, he was able
to compress development into amazingly brief periods;
as an example, he took the first gunship from project
to combat in only six months.
For Lt. Col. Jack S. Ballard, author of Development
and Employment of Fixed-Wing Gunships, 19621972,
MacDonald rated as the "originator," Flexman
the "catalyst," Simons the "tester," and
Terry the "seller" of the gunship system.
Terry was the architect of the first and all subsequent
gunship weapon systems, proving them in design, test,
and combat evaluation. His small team designed and
built the installations themselves, scavenging parts
and ideas. They combined the most innovative technology
(first use of low-light-level devices and infrared
sensors in combat) with a 1935-era airframe.
LeMay Says Go
A personal briefing to Gen. Curtis E. LeMay, Air Force
Chief of Staff, on Nov. 2, 1964, secured permission
for Terry to modify a C-47 and test it in combat. The
need was great. With Viet Cong guerrillas and North
Vietnamese regulars infiltrating the South, a flexible,
rapid, and effective means of defense was required.
The gunship offered a solution.
Terry began operations out of Bien Hoa AB, South Vietnam,
during December 1964. The Air Force had created two
FC-47s ("FC" meant "Fighter Cargo," an
unusual designation) by installing GE SUU-11A 7.6 mm
Gatling guns, a gun sight cobbled up from a crosshair
reticle and a 16 mm camera reflex viewfinder, and a
supply of flares. Terry trained crews of the 1st Air
Commando Squadron in techniques of gunship operation,
which involved boresighting the equipment, acquiring
a target, entering an orbit pattern, and then adjusting
it as required to fire on the target.
Dec. 15 marked the first of several successful day
missions with Capt. Jack Harvey as aircraft commander.
Eight days later, the first night mission had a double
success. The first part of the sortie was flown at
Thanh Yend, in the Mekong River Delta, where the FC-47
dropped 17 flares and expended 4,500 rounds of ammunition,
causing the Viet Cong to break off their assault. Then
it was sent to Trung Hung, where, under a barrage of
4,500 rounds of ammunition, the Viet Cong again were
forced to leave.
Reports streamed in validating the usefulness of the
weapon. There were challenges: A night illumination
system was needed, and the flares, some dating to World
War II, often did not work. But no one who saw the
fountain of fire pouring from the FC-47s could ever
forget it. The very sound and fury of the FC-47 raised
South Vietnamese morale even as it "spooked" the
VC, and the aircraft soon got affectionate nicknames
such as "Puff" and "Dragonship." The
call sign "Spooky" was assigned to early
gunship operations.
In summer 1965, Pacific Air Forces asked to have a
16-gunship squadron in place by the following November.
The 7.62 miniguns were excellent weapons but were in
short supply. Terry improvised, getting authorization
from the commander of Air Force Logistics Command,
Gen. Mark E. Bradley, to take 300 old M-2 .30-caliber
machine guns from a McClellan AFB, Calif., warehouse
and install them, 10 at a time, in four C-47s.
The 4th ACS arrived at Tan Son Nhut on Nov. 14, 1965,
and began combat training a week later. It was soon
operating on a full-time basis, defending hamlets in
South Vietnam and flying day armed reconnaissance in
the Steel Tiger area of Laos. By the end of 1965, the
4th ACS had flown 277 combat missions-but had lost
two aircraft. The gunships, now designated AC-47s,
had to operate low, slow, at night, and in bad weather.
Forty-seven AC-47s went to Vietnam, but the courageous
men who flew them were aggressive and determined to
bring the war to the enemy. Casualties were inevitable,
and 12 were lost.
The success of the AC-47s set in motion a dynamic
that continued through the war and beyond. Spooky's
mission expanded to include interdiction of roads,
trails, and rivers, and this greatly increased the
demand for its services.
Communist Reaction
As Terry fought to improve the AC-47s, he pointed
out the advantages a larger, faster aircraft would
bring, particularly in halting supply efforts. On the
other side, the North Vietnamese responded to each
improvement in gunship capability by increasing the
number and the caliber of their anti-aircraft guns
and by positioning them as far south as possible. It
took a maximum effort by Terry and his team to measure
the real requirement for gunships, create their improvements,
get them into the theater within the limitations on
manpower, and then develop the tactics to use them
effectively.
A major fact of the war was that Communist troops,
trucks, and supplies all moved along the extensive
Ho Chi Minh Trail, which in various forms had been
used for centuries. Some 1,500 square miles of territory
were woven together by the complex and ever more sophisticated
network of roads, supply depots, truck stops, barracks,
hospitals, repair yards, and other elements necessary
to keep the rice and bullets moving south. Most of
the route was covered by a jungle canopy that made
reconnaissance difficult by day and almost impossible
by night.
Nonetheless, the US had to try to interdict the flow
of supplies, and the best tool for the job was obviously
an improved gunship. In the meantime, the pitifully
few AC-47s (parceled out in twos, threes, and fours
at five different bases) valiantly defended the strategic
hamlets. It was the air commando's proud boast that
none was ever lost when a gunship was overhead.
A surprisingly wide variety of aircraft, ranging from
the Cessna Model 337 to the Boeing B-47, were considered
for the role of improved gunship. The goal was an aircraft
that could carry more equipment for longer times with
greater safety. A high wing was preferred for ease
of gun and sensor installation.
Terry proposed Project Gunboat, based on a converted
C-130A with improved sensors and weapons, more ammunition,
and immensely improved performance. (The maritime Gunboat
designation was soon replaced by the more logical Gunship
II title.) Four 7.62 miniguns and four M-61 Vulcan
20 mm cannons were installed in Gunship II, along with
a side- and forward-looking radar, a Starlight scope
night observation device, and a computerized fire-control
system linking sensors and guns. Also installed were
overt and covert illuminators, armor plate, and better
navigation equipment. Fuel tanks were "inerted" against
ground fire.
Gunship, Times Three
A prototype arrived at Nha Trang AB, South Vietnam,
on Sept. 21, 1967, for combat evaluation. It was a
resounding success. After a brief refurbishment, Gunship
II re-entered combat in February, flying out of Ubon
RTAB, Thailand, against the Ho Chi Minh Trail in Laos.
Code-named Spectre, the AC-130 was an unmitigated success,
destroying hundreds of trucks. It was then returned
to operations in South Vietnam. Analysis of results
showed that the AC-130 was about three times as effective
as the AC-47.
Air Force Secretary Harold Brown had authorized the
C-119G as the AC-47 replacement. Gen. John P. McConnell,
Chief of Staff, continued to press for the AC-130,
stressing it had a "search and destroy" capability
in addition to a close-support mission. The two most
telling arguments for the AC-130 were its survivability
and its effectiveness. It cost $5,100, on average,
for Gunship II to destroy or damage a truck. For an
F-105, the cost per vehicle was $118,000.
The opposing views were ultimately reconciled in a
costly compromise that led to the creation of three
types of gunships in the fleet-AC-47s, AC-119s (Gs
and Ks), and AC-130s.
In December 1968, four Gunship II aircraft arrived
at Ubon. Operated by 16th Special Operations Squadron,
the four AC-130s were pressed into combat and forced
to adapt to a variety of missions, but they concentrated
on night interdiction. (The Air Commando Squadron designation
changed to Special Operations Squadron Aug. 1, 1968.)
Within three months, the four aircraft, with still-inexperienced
crews, had destroyed 607 trucks, more than a quarter
of the theater total.
The 16th SOS continually experimented and improvised
as it gained experience in operating the advanced Gunships.
As massive numbers of anti-aircraft guns moved in to
defend the Ho Chi Minh Trail, new tactics were devised.
Among them were the F-4AC-130 teams that operated
together to kill trucks and suppress anti-aircraft
fire. It was an unlikely combination, given the vast
difference in their performance, and the tactics were
inherently dangerous. When the guns opened up on the
Spectre, the Phantoms would pass through the AC-130's
orbit twice, first to drop its cluster bomb unit, then
again on the climb back to altitude. The combination
proved effective against both trucks and the defending
anti-aircraft guns.
It was hazardous work, and an AC-130 was hit by anti-aircraft
fire March 3, 1969. Only a few weeks later, Gunship
II strength was reduced by a quarter when on May 24
the Air Force lost its first Spectre. Severely hit
by 37 mm anti-aircraft, the AC-130 crashed on landing
at Ubon. Two crew members were killed, and the aircraft
was destroyed.
Meanwhile, Terry had become chief of the AC-130 Gunship
Program Office. He and a small band of enthusiasts
in July 1969 proposed the first of a series of improvements
to the Spectre. Their aim was to improve lethality
and survivability.
They did so with heavier armament, a digital fire-control
system, an air-to-ground moving target indicator system,
and a low-light-level television to improve target
acquisition at night. The four 7.62 miniguns were replaced
by two 20 mm Gatling guns and two 40 mm Bofors guns.
A two-kilowatt illuminator and a Paveway I laser designator
were added to facilitate cooperation with tactical
aircraft. The location of detected targets could be
stored in an inertial navigation system, for later
use.
Surprise Package
Terry's proposal received quick approval. The improved
aircraft, dubbed "Surprise Package," was
tested at Eglin AFB, Fla., in late October 1969. Things
went so well that it was deployed to Southeast Asia
on Nov. 25, where it proved to be a great advance over
the earlier AC-130.
The advanced AC-130 was less vulnerable because it
was able to operate at higher altitudes and was better
armored. Its 40 mm guns and laser designators made
it far more lethal; it destroyed or damaged trucks
at a rate of 7.34 per sortie. The standard AC-130 was
its closest competitor, with an average of 4.34.
The success of Surprise Package altered opinions in
the Pentagon. Estimates were that about 200 trucks
per day were sent down the trail. Previous interdiction
efforts peaked at 30 truck kills per day. Now, a force
of 18 AC-130s and 26 AC-119K aircraft could kill 100
to 200 trucks per night.
In these days, there was a running bureaucratic debate
about the proper number of gunships and the degree
to which they should be modified. By the summer of
1970, no fewer than five AC-130 gunship programs were
under way.
A fleet of six "new" AC-130 gunships entered
combat in November 1970, initially with disappointing
results. The aircraft were more advanced and the new
crews did not have sufficient experience in operating
them. Terry, now a lieutenant colonel, was assigned
to correct the situation, and under his tutelage, the
success rate on truck kills rapidly improved.
Interdiction efforts in Laos were intensified, and
the war was expanded to include missions in Cambodia.
As experience was gained, the success of the gunships
continued to rise; by March 1971, they were destroying
an average of 13 trucks per sortie, with as many as
3,240 destroyed and 787 damaged per month, almost 90
percent of the number attacked. By June, a total of
almost 14,000 trucks had been destroyed and damaged,
three times as many as in the previous year. The claims,
doubted at first as being too high, were subsequently
validated as accurate. Unfortunately, trucks were less
expensive than gunships, and the Soviet Union supplied
them in quantity, with as many as 8,000 per month rolling
down the trail.
In 1971, a decision was made to acquire six additional
AC-130Es, and the need to decrease further their vulnerability
resulted in the Pave Aegis program. The Pave Aegis
aircraft received a 105 mm gun in addition to the 40
mm and two 20 mm guns. It also had improved radar and
was provided with a Mk 24 flare capability, to counter
the Surface-to-Air Missile threat.
It should be noted that the unusual monsoon cycle
of weather in Southeast Asia allowed gunship modifications
to be made during the rainy season and available for
combat as soon as the weather cleared.
"Move Back 18 Feet"
Brig. Gen. Carl A. Hagan of US
Army Forces Command, speaking at an Air Force
Association symposium in February 1990, shared
a soldier's view of the awesome power of the
Air Force gunship. Hagan's son Steve, a captain
in the 82d Airborne Division, had taken part
in Operation Just Cause in Panama in December
1989. On the first night, his unit found itself
in a difficult spot.
Fortunately, the captain told
his father, there was an AC-130 gunship overhead: "We
explained our situation and the guy [in the
gunship] said, 'Where are you?' and we showed
him, and he said, 'Where are the bad guys?'
and we showed him that. There was a pregnant
pause for a couple of seconds, and then he
said, 'You need to move back 18 feet.' "
"They did that," the
elder Hagan reported, "and the AC-130
did its thing and eliminated all opposition.
Now, that's close air support."
Project Hornet
A contract was awarded in 1968 for project Combat
Hornet, for a total of 52 additional gunships. The
first 26 were to be AC-119Gs, equipped with four 7.62
GAU-2B/A miniguns, gun sight, armor, night observation
sight, DPN-34 and SPR-3 radars, 20 kw airborne illuminator,
and an LAU-74/A flare launcher. The second 26 were
to be AC-119Ks, with similar equipment plus two 20
mm Vulcan guns, AN/APQ-133 beacon tracking radar, FLIR,
and a Doppler navigation system. The AC-119Ks were
almost five times as expensive as the AC-119Gs.
The Gunship III program was not without its difficulties,
but four AC-119G Shadows arrived at Nha Trang by the
end of December 1968, along with advance elements of
the 71st SOS, whose personnel were largely called up
from reserve units. Combat operations began Jan. 5,
with the Shadows operating in South Vietnam. All 18
aircraft assigned arrived by March 1, and the AC-119Gs
proved acceptable in all the roles accomplished by
the AC-47 except for that of forward air control. (In
June 1969, the 71st SOS became the 17th SOS.)
In 1969, the AC-119Gs would fly more than 3,700 sorties
over 14,251 combat hours, fire almost 35 million rounds
of ammunition, and expend 22,000 flares. They killed
some 1,500 enemy troops and, most important, had allowed
no outpost to be overrun while they were overhead.
Flying the Shadow was not without hazard; many recorded
hits from AAA. One was lost to ground fire, and another
crashed on takeoff.
By the end of 1970, the AC-119s were spread over four
bases: Phan Rang (seven AC-119Gs and three AC-119Ks),
Tan Son Nhut (nine AC-119Gs) and Da Nang (seven AC-119Ks)
in South Vietnam, and Nakhon Phanom (six AC-119Ks)
in Thailand. The 17th SOS had been replaced by the
activation of the 18th SOS, which was given duties
primarily in the Steel Tiger area of Laos. The 18th
SOS distinguished itself in truck-killing operations
from the very first. By April 1970, less than two months
after the arrival of the last AC-119K, the unit claimed
its 1,000th disabled truck.
Countless men and supplies poured down an expanded
Ho Chi Minh Trail, now defended by heavier anti-aircraft
guns and SAMs. In March 1972 two AC-130s were shot
down in the Steel Tiger area in Laos. In May, the brand
new SA-7 Strela was introduced. This SAM was a shoulder-fired
weapon with an infrared seeker for which there was
no immediate defense. The North Vietnamese also responded
to American technology with more sophisticated techniques,
including better camouflage, better convoy discipline,
and the increased use of waterways.
Airpower became increasingly important as North Vietnam
began its spring 1972 offensive. The most sophisticated
methods were employed to oppose it. The Spectres and
Stingers worked from their Thai and South Vietnamese
bases against targets in Cambodia, South Vietnam, and
Laos. As North Vietnam stepped up its efforts, the
work of the gunships expanded to provide more close
support of the South Vietnamese army. The Pave Aegis
AC-130s were particularly successful, using their 105
mm gun to destroy tanks and the increasingly heavy
artillery being deployed. There were many instances
when the heavy fire from gunships halted overwhelming
assaults on South Vietnamese positions, as in the defense
of An Loc.
The importance of the gunship had grown out of all
proportion to its numbers. It was a hands-on, into-the-teeth-of-the-storm
weapon, flown by courageous crews under hazardous conditions.
And the gunship continued to distinguish itself in
USAF service after Vietnam. Today, eight AC-130Hs and
13 AC-130Us form a vital part of the Air Force Special
Operations Command. If the need arises for a new generation
of gunships, the technology is available.
Walter J. Boyne, former director of the National Air
and Space Museum in Washington, is a retired Air Force
colonel and author. He has written more than 400 articles
about aviation topics and 29 books, the most recent of
which is Beyond the Horizons: The Lockheed Story. His
most recent article for Air Force Magazine,
"El
Dorado Canyon," appeared in the March 1999
issue.
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