Guns-A-Go-Go; The Boeing Vertol ACH-47A

November 28, 2023

The histories of the US intervention in Vietnam generally start in March 1965, when US Marines stormed ashore at Da Nang…to be met by a bevy of Vietnamese beauties holding signs saying: “Welcome Gallant Marines”.

But in fact, the United States had been deploying considerable forces in the country long before that time, including a new weapon system that was really starting to come into its own and which would soon become a standard feature in militaries everywhere; the helicopter.

The US Army started deploying helicopters to assist South Vietnamese forces in 1961, and these were soon being used to develop ideas on a new concept – Air Assault – that saw infantry delivered directly to their target area to engage immediately. In January 1962 US Army H-21’s conducted a surprise attack on Viet Cong forces, dropping off a thousand ARVN paratroopers in rapid relays and inflicting a heavy defeat on the insurgents.

The idea definitely had huge merit, allowing smaller numbers of troops to be effective over much greater areas, but there was one problem. When coming into the landing zone, the helicopters were horribly exposed to hostile fire and as the Viet Cong adapted to the new threat losses began to mount.

It was swiftly appreciated that suppressive fire was needed during the approach and departure of the vulnerable aircraft and that pintle mounted machine guns mounted on the transports didn’t provide enough by themselves.

A rapid solution was tried when the first of the new Bell HU-1’s, as they were then designated, was deployed to Vietnam in late 1962. This powerful new turbine powered helicopter had better performance than the earlier piston-engine designs but the first models of the new “Hueys” had small cargo compartments which limited their troop-carrying capacity and so a number were converted into a new configuration – gunships.

Initially a field adaption that saw a machine gun and a rocket pod fitted either side of the cabin, the “Hogs” as they would soon be named, became a standard feature in helicopter operations throughout the American intervention.

But though these gunships were built in considerable numbers, including the purpose built UH-1C, they were always recognized as a stop gap. The early conversions, once laden down with weaponry, had difficulty keeping pace with the transports that they were supposed to escort. Plus, as the Huey was designed originally as a transport itself, it was susceptible to battle damage that it had never been intended to endure.

To be honest, the success of the “Hogs” is more a tribute to the brilliance of Bell’s basic design, but it was always a limited aircraft for the role it was shoehorned into. What was required was a properly designed helicopter, very heavily armed and armored, that could escort the more delicate transport helicopters to their landing zone, utterly wreck any enemy on the ground and take a measure of combat damage; an attack helicopter.

Bell, builders of the Huey, had already recognized the problem and were working on a solution.

In December 1962 they began construction of a new helicopter to test out their ideas on this, the Bell 207 Sioux Scout. This laid the groundwork for Bell’s ultimate solution, the Bell 209, today better known of as the Cobra.

Ultimately this would be recognized as the correct approach, and attack helicopters are a standard weapon system in most modern militaries. But in the early 1960s, there was no guarantee that Bell’s concept was the correct one, and so the US Army explored another approach.

And if Bell’s idea was to build a fast, agile hunter of a helicopter, rival Boeing’s was to build…well, I’d call it a Flying Fortress, but that has been done before, so let’s go with “airborne annihilator”.

The ACH-47A.

Mind you, the US Army had their own nickname for the project – “Guns-A-Go-Go”.

In 1964 the US Army convened a commission, the Bush Board, to figure out what would make a better gunship than the then current UH-1B’s that were serving in the role. This considered a number of factors, including current production status and requirements, as well how much armament and weaponry a particular helicopter could be fitted with and still retain worthwhile performance, which was the biggest issue with the UH-1B Hogs.

The board looked at several options, including the Sikorsky S-61 Sea King and Kaman UH-2A Sea Sprite, but determined that the best option was the big CH-47A Chinook. This had only entered service in 1962 and was both one of the most powerful and fastest helicopters in the world at the time. With its comparatively huge lifting capacity and spacious cargo area, the CH-47 could carry both a heavy weapon fit, armour and multiple crew to provide covering fire in just about every direction.

In June 1965 the US Army requested the conversion by Boeing of four CH-47A’s into A/ACH-47A’s – standing for “armed and armored” – which subsequently got shortened to a single “A”, and the first of these was delivered the following November.

The aircraft, who would glory in their individual names of STUMP JUMPER, CO$T OF LIVING, BIRTH CONTROL and EASY MONEY were all modified from standard CH-47A’s by having all but five of the troop seats removed, along with the cargo hook and winch, the main hold and auxiliary loading ramps, crew heaters and sound proofing all stripped from the aircraft.

In their place was added about a ton of specially hardened steel armour plating, fire suppression equipment, an engine fuel cross feed and cutoff system, purpose built armoured seats for the pilot and copilot and an interphone system so that the crew could communicate during combat.

All this meant that the aircraft were all hardened to be able to take heavy machine gun fire but both stay flying and protect the crew to enable them to keep fighting.

But much more conspicuous was the new weapons fit. Two crewed weapon stations were placed on each side of the ACH-47’s with another in the rear. These could be fitted with either an M60 7.62mm machine gun or, more commonly, a .50-calibre heavy machine gun. These allowed the new gunships to engage targets from all quarters, especially after they passed over the target zone after making their initial head on attack.

Because the real teeth of the Guns-A-Go-Go were all intended to savage the enemy up front.

A remotely controlled chin turret contained an automatic 40mm grenade launcher, while added stub wings on either side were equipped to carry a 20mm cannon and pods containing nineteen 70mm rockets.

All this added up to a considerable amount of firepower that the ACH-47’s could deliver to target, following up with a thorough dosing of machine gun fire as the gunships passed overhead. Indeed, I called this type a Flying Fortress earlier, but it was more like a flying First World War tank; bristling with machine guns and anti-personnel weapons and resistant to return fire from standard infantry weapons.

Army evaluations took place in March 1966 and with such positive assessments that three of the aircraft were delivered to Vietnam to begin combat testing that June. Unfortunately, one of the ACH-47’s, Stump Jumper was destroyed in an accident when it hit another Chinook while taxiing.

As a result the helicopter that had been left in the United States for weapon testing was also rushed to Vietnam for deployment.

In December the three ACH-47’s were designated as the 1st Aviation Detachment (Provisional) and attached to the 1st Cavalry Division to support their airborne operations. The division had begun deploying Chinook’s in a transport capacity in 1965, but had soon come to appreciate the types heavy lift capabilities; not just for the CH-47’s ability to shift artillery pieces and quantities of munitions and troops, but also the way they could roll literally tonnes of napalm in drums out of the back ramp and onto unfortunate enemy troops below.

So, they certainly seem to have taken to the ACH-47’s, and the gunships were soon employed in supporting the 1st Cav’s operations.

However, such heavy use in combat inevitably led to losses and the Co$t of Living went down on 5 May 1967 when it suffered a rather tragic system failure. While making a gun run in the vicinity Bong Son, a location that the 1st Cav had been fighting in for months, the retention pins on one of Co$t of Living’s 20mm cannons came loose, allowing the gun to swing upwards and shoot into the aircraft’s front rotor, destroying it and causing the aircraft to crash in flames.

The tragedy did not stop the operational tempo for the remaining two ACH-47’s though. Their ability to soak up enemy fire and deliver devastating and accurate support meant that the soldiers of the 1st Cavalry came to hugely respect the gunships and their crews. And this really came to be demonstrated in the type’s final mission, which took place on the 22 February 1968.

On the 31st of January, as part of the Tet Offensive, Communist forces seized the city of Hue, digging in deeply and leading to a month of intensive street fighting as the US and their South Vietnamese allies fought to clear the city.

While the Battle of Hue is most famously associated with the US Marine Corps,  the 1st Cav was also committed to the fight and with them the ACH-47’s, which because of their ability to act almost like a flying tank/bunker were especially valuable. In fact, because the weather was often bad during the battle, restricting air support by attack aircraft, the ACH-47’s were often the most formidable air attack asset available in the efforts to retake Hue.

On February 22 the ACH-47’s were engaged in attacking communist positions on the edge of the city when Birth Control came under heavy and sustained fire. The gunship had to make an emergency touch down in a dry paddy field within rifle range of the Citadel of the ancient city, an area that bristled with communist positions and anti-aircraft guns.

Despite this its partner aircraft Easy Money swung in under heavy fire, laying down its own return barrage and landing next to its stricken sister. The seven-man crew of Birth Control managed to scramble aboard and Easy Money lifted off, taking more fire and, according to some sources, suffering several of its crew being wounded.

Attempts began to mount a recovery effort for Birth Control but the Viet Cong had other ideas, hitting the downed aircraft with mortar fire and destroying it.

This left Easy Money as the final remaining ACH-47A and as the operational doctrine had been for the Guns-A-Go-Go gunships to always operate in pairs, this spelt the end for the type. No reported attempts to team the last ACH-47 up with other gunships seem to have been attempted, and Easy Money was sent to be converted back into a standard CH-47 for transport duties.

Unfortunately, the extensive alterations that she had undergone made such a conversion far too impractical, and she languished as a maintenance trainer at Boeing’s facility in Vietnam. The end of the war saw her sent back to the US, where she carried on serving as a trainer, before in 2000 being restored back to her Vietnam configuration and being placed on display at the Redstone Arsenal in Alabama.

The effectiveness of the ACH-47A’s does rather make one wonder why the program wasn’t carried on, though the attempted reconversion of Easy Money gives the main clue – the US Army really needed as many Chinooks as it could for transport duties to replace its far inferior predecessors.

Because truth be told, the Guns-A-Go-Go gunships were tremendously successful, despite their limited numbers. Individually they carried as much ordnance as three of the UH-1 Hogs and had both far more ability to absorb punishment and to sustain combat operations because of the greater amounts of ammunition that the big aircraft could carry.

Indeed, their formidable capabilities were recognized by General John Tolson, commander of the 1st Cavalry during their tenure with the division and one of the key instigators of the whole air mobile concept of warfare. He said of the ACH-47’s that:

“Though anything but graceful, it had a tremendous effect on the friendly troops which constantly asked for its support. From an infantryman’s viewpoint, when the “Go-Go Bird” came the enemy disappeared.”

But with the heavy demands for transport Chinooks, plus the commissioning of more powerful aircraft gunships such as the AC-130, the ACH-47, despite their obvious success, was passed over and became a rather intriguing footnote in the history of airmobile warfare.

 

Sources / Related

https://chinook-helicopter.com/chinook/gunsagogo.html

https://en.wikipedia.org/wiki/Boeing_CH-47_Chinook#Variants

https://www.armyaviationmuseum.org/ach-47a-guns-a-go-go/

https://chinook-helicopter.com/chinook/Guns_A_Go_Go_Mohr_Info.pdf

https://chinook-helicopter.com/chinook/Guns_A-Go_Go_Info.pdf

https://en.wikipedia.org/wiki/Bell_UH-1_Iroquois_variants#UH-1B

https://www.thearmorylife.com/huey-hog-gunship/

https://www.airvectors.net/avhuey_1.html

https://en.wikipedia.org/wiki/Air_assault

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