Vietnam War ground technology

Vietnam War Ground Technology is not limited to U.S. systems alone., since there are comparisons to examine (e.g., M-16 vs. AK-47, and earlier weapons such as the SKS), and VC/NVA field air defense.

It deals with Army aviation, both fixed- and rotary-wing aircraft, organic to ground units. Forward air controllers deals with the coordination of high-performance U.S. Air Force and U.S. Navy high-performance aircraft in close air support. Special reconnaissance includes the direction, by long-range, clandestine ground penetration teams, of air attack against the Ho Chi Minh Trail.

I do not intend to duplicate other, more general articles, such as air assault. I want to be specific to Vietnam (well, Southeast Asia).

Ground intelligence

Timeliness of sources of intelligence

Personnel detectors

See also: Materials MASINT

A Vietnam-era sensor, the XM2, generally known as the "people sniffer", detected ammonia concentrations in air, which indicated the presence of groups of people or animals. While it was sensitive, but not selective for people, many water buffalo became targets. Nevertheless, it was considered the best sensor used by the 9th Infantry Division, because, as opposed to other MASINT and SIGINT sensors, it could give helicopter-borne troops real-time detection of targets The authors compared the timeliness of a range of sensors [[Image:MASINT-TimelyIntelSniffer.png

Helicopters and Air Mobility

See also: Air Assault

Helicopter mobility is very much associated with the Vietnam War. In air assault, the history of heliborne operations is discussed, and then the Howze Board, attached helicopter operations with the 173rd Airborne Brigade, and the deployment of the 1st Cavalry Division (Airmobile). Apropos of the 1st Cav, separate articles already exist on the Battle of the Ia Drang and the Battle of Bon Son.

Other battles of relevance may include Ap Bac and Lam Son 719.

When the Kennedy Administration took office, Secretary of Defense Robert S. McNamara made exploration of new ways of mobility a high priority. In 1962, he expressed dissatisfaction with Army conservative, and created a well-funded research organization to evaluate extensive air mobility. While it had a formal name, it was generally called the Howze Board after its chief, Hamilton H. Howze.

With McNamara's support, the Board revised its recommendations to create a helicopter-borne combat unit of division size. Large-scale field tests proved it could be effective in battle, and the 1st Cavalry Division (1st Cav) was redesignated the 1st Cavalry Division (airmobile) and sent to Vietnam in July 1965. There had been moderately successful tests in Vietnam by the 173rd Airborne Brigade, arriving in May and first fighting in June, but it became clear that the approach used by the 173rd, attaching helicopters for each mission, was not nearly as effective as a unit that had infantry and helicopters training together as a team. This teaming was a basic aspect of the 1st Cav, which first went into combat in the Battle of the Ia Drang in October 1965.

In the 1st Cav, there were scouts in very light observation helicopters (OH-6), light "Huey" helicopters (UH-1) that could carry 10-12 soldiers into battle or deliver machine gun and rocket fire in direct support, and medium (CH-47) and large (CH-54) helicopters that could lift artillery into firebases supporting the heliborne infantry.

Using scouts and infantry to locate the enemy, and call in artillery and air strikes, was one airmobile tactic. Another was to harass and attrit the enemy with a series of stinging ambushes and raids, using a doctrine now considered swarming. In these and other cases, however, the division name was appropriately chosen -- these were more classically cavalry rather than infantry missions.

Depending on the tactical situation, a LZ might be prepared by artillery, air strikes, or escorting armed helicopters. Since the suppressive fire did not always drive off defenders, there was a balance of stealth vs. fire; small insertions sometimes had the helicopters make several decoy landings, silently landing a team at one quick stop. the first infantry companies landed in "slicks." These were unarmed Bell UH-1D "Hueys" that could carry 12 men and their gear.

Fire bases were set up with medium Boeing CH-47 "Chinook" helicopters, which could transport the 2-ton 105mm light howitzers, light vehicles, and ammunition; the larger CH-54 Tarhe ("the hook") lifted the larger 8-ton 155mm medium howitzers that gave the firebase enormous killing power. Generally, the greater mobility of the 105, and the quick availability of armed helicopters and jet fighter-bombers, made 155s and heavier howitzers less important, unless they were already in a semipermanent base. See tube artillery below for artillery employment doctirne.

Command and control could be very good or very bad. Company-sized forces would often land with their commanding captains, and, as with Moore at X-Ray, sometimes with more senior officers. When the levels of command did not micromanage, a battalion commander (lieutenant colonel) or higher commander could keep an overview of the engagement, and bring in reinforcements, as well as air and artillery strikes, as appropriate.

There were times, however, where the captain might stay airborne, the lieutenant colonel a bit higher, the colonel commanding the brigade at the next altitude, and possibly the major general division commander and lieutenant general corps commander in their own command and control helicopters. When this turned into micromanagement, it was said, ruefully, "never, in the course of human events, have so many, been so supervised, by so few."

Meanwhile the whole operation was covered by helicopter gunships--"Hueys" equipped with rockets, grenade launchers and door-mounted machine guns. Although its maximum speed was only 127 mph, the Huey could dart and dive and swerve with enough agility to evade most ground fire. Close air support from fixed-wing fighter-bombers was readily available.

Individual equipment

Equipment for the individual soldier changed. For some time, there had been an international debate over conventional rather than "assault" rifles. The conventional rifle, such as the M-1 Garand, fired a high-power bullet, had a relatively small magazine, and was best for carefully aimed fire. Assault rifles were an evolution of the less than successful submachine guns of WWII, which fired a low-power pistol bullet, continuously or in bursts. Assault rifles, such as the U.S. M-16 or Soviet AK-47 fired an intermediate power bullet from a large magazine, sometimes in continuous bursts. Many Communist soldiers used the SKS, inferior to the M-16 and AK-47 for use in the conditions of Vietnam.

A consideration for the U.S. was that the M-14 rifle, which had replaced the M-1, was too heavy for many of the smaller Vietnamese allies. The M-16's smaller (5.56mm vs. 7.62mm) bullet allowed a soldier to carry more ammunition, and the trend had been away from carefully aimed fire to suppressive fire that froze the enemy until air and artillery could hit him.

The new M-16 rifle was a shorter, lighter and more versatile assault weapon than the old M-1 or its replacement the M-14. It fired a light bullet at high muzzle velocity, which gave great killing power at ranges under 400 yards. Its rapid fire made it ideal in ambushes, although variations from the designed ammunition, as well as training problems and some mechanical problems, made early versions less reliable than the Communist AK-47. Both the AK-47 and M-16 had advantages and disadvantages; neither was the ideal infantry rifle. The 5.56mm bullet did not always penetrate jungle.

Another individual weapon was a 40mm grenade, which could be fired farther than a hand grenade could be thrown. The grenades could be launched from a M-79 single-shot weapon, rather like a large shotgun and able to fire a shotgun-like round. Alternatively, the M-203 launcher attached to the underside of a M-16 rifle, below the barrel. Limited use was made of a hand-cranked automatic grenade launcher, the Mark 19, primarily on river patrol boats or vehicle-borne troops as it was too heavy for foot soldiers. Other versions were used on helicopters.

The M-60 medium machine gun was powerful and reliable, but suffered from the logistical problem of using different ammunition (7.62mm) than the M-16. In modern U.S. infantry, it has been replaced by the M-249 squad automatic weapon firing 5.56mm.

Heavy weapons

Tube artillery

Beyond what was available from armed helicopters and from fighter-bombers, fire from 105mm howitzers, relatively easy for medium helicopters to lift, was invaluable. 155mm howitzers could be lifted by the heaviest helicopters, but were more likely to be moved, by ground, to a firebase. The long-range 8" howitzer and 175mm gun were only road-mobile, but had sufficient range that their presence did not alert the enemy to impending operations in a specific area.

Forward observers helped control artillery fire, and computers supported artillery. The Field Artillery Digital Automatic Computer (FADAC), went into development in 1958, and remained usable into the 1980s.

Gunships

Especially for night defense of fixed positions such as Special Forces/CIDG camps, fixed-wing gunships, originally "Puff, the Magic Dragon," an Air Force AC-47 transport fitted with three miniguns firing 100 bullets per second, provided critical illumination, as well as an ability to deliver massive amounts of machine gun fire. The fixed-wing gunship idea worked well and continued to improve; the first versions of the modern AC-130 were later deployed in Vietnam. AC-130 aircraft were used, most heavily, against the Ho Chi Minh trail. Fire control methods of the time made use of the fixed-wing gunships dangerous in close proximity to friendly forces at location that was not precisely known; Special Forces camps' position was known.

High-performane attack aircraft

Flown by the Air Force, Navy, and Marines, versions of the F-4 Phantom II were the primary high-performance aircraft used in close support. Navy and Marine A-4 Skyhawk aircraft operated in the northern areas, both from carriers and land bases.

B-52

In the South, B-52 support was originally targeted from TACAN beacons. A radar-guided drop technique was subsequently use, especially at the Battle of Khe Sanh. B-52D aircraft, intended for nuclear strike missions, were modified to maximize their ability to carry gravity bombs. B-52F models were then modified to In 1964, the Air Force decided to improve the B-52F's conventional bombing capability by modifying it to carry 12 standard 340 kilogram (750 pound) bombs on multiple ejector racks fitted to each Hound Dog pylon, along with the existing conventional warload of 27 bombs in the bombbay, for a total of 51 bombs.

The Buff gradually became an important weapon in the war, providing a form of "flying artillery" that could dump overwhelming firepower, making a profound impression on the enemy. General Westmoreland commented: "We know, from talking to prisoners and defectors, that the enemy troops fear B-52s, tactical air, artillery, and armor ... in that order."

Three B-52s could cut a swath miles long through the jungle, with the aircraft flying so high that the enemy had no idea they were under attack until the bombs began to hit. The shock of such concentrated high explosive was tremendous, with tales of scouts on the ground finding entire enemy units dead, without a mark on them, simply killed by concussion. Survivors of such attacks were demoralized or shellshocked. The Buff would also ultimately take on the jungle tunnel complexes that frustrated the Americans for so long, carpeting them with heavy bombs fitted with delayed action fuzes. The bombs would bury themselves deeply into the ground and then detonate, caving in the tunnels.

"The B-52 was devastating when targets could be found, but in many cases the enemy was elusive and all the bombers accomplished was to level stretches of jungle and kill lots of monkeys

Initial operations

The initial "South Bay" conventional bombing upgrade program was completed in 1964, with 28 B-52Fs refitted. It was followed by the similar "Sun Bath" program in 1965, which performed the upgrade on 46 more aircraft. 46 more B-52Fs were transferred to Anderson in June 1965, with these aircraft upgraded by the Sun Bath program in great haste. The first B-52 bomb raid in Southeast Asia, codenamed "Arc Light", took place on 18 June 1965.

27 B-52Fs left Anderson to perform a tactical strike on a concentration of Viet Cong forces north of Saigon. The mission was a disaster. Two B-52Fs collided in midair, with both aircraft lost and eight of the twelve crewmen killed, and technical problems forced one Buff to return to base. The enemy had already left the area by the time the survivors dropped their bombs.

That was the only B-52 raid conducted in June. Five more Arc Light raids, totalling 140 B-52F sorties, were conducted in July 1965, and five more, totalling 165 sorties, took place in August. Although no B-52s were lost in these ten actions, the Buffs were still ineffective. One of the problems was that Arc Lights had to be approved by the White House. By the time a request had been sent from the tactical commander back to Washington DC, run through the approval process, then passed back to Anderson for execution, the enemy had usually moved on.

By late August, decision-making authority for Arc Lights had been moved down slightly, to the Joint Chiefs of Staff, which simplified that issue a bit. More importantly, the Air Force had revised their tactics. Although large raids were still conducted with 30 or so Buffs, the tendency was now to commit them in smaller numbers -- eventually settling on three as more or less the norm -- and conduct raids on multiple locations simultaneously. The B-52s also began to expand their area of operation, performing raids into Laos to pound the Ho Chi Minh Trail, which the enemy used to supply the war in South Vietnam. The first raid on Laos took place on 12 December 1965, with the number of strikes rising from that time.

The B-52F remained in combat service in Southeast Asia for less than a year, being replaced in March 1966 by the B-52D, which had been optimized for the role. Beginning in late 1965, all B-52Ds had been given the "high density bombing (HDB)" or "Big Belly" upgrade, which modified the aircraft to carry 84 225 kilogram (500 pound) or 42 340 kilogram (750 pound) bombs in the bombbay. The upgraded B-52Ds could also carry 24 340 kilogram bombs on the pylons, for a total maximum warload of an astounding 27,200 kilograms (60,000 pounds) of conventional bombs.

The B-52Ds also sported a new paint scheme, with the black underside as used on the B-52F, and the top surfaces painted in a disruptive jungle camouflage scheme with tan and two shades of green. About 42 B-52Ds were initially committed to the war, the number gradually rising to twice that number, with crews serving six-month combat tours. Aircrews from other B-52 variants were included in the rotation to make sure everyone got their fair share of combat.

Basing

For missions in Vietnam, the principal airfield was Anderson AFB in Guam, which took significant refueling. Advanced basing, starting on April 10, 1967, at U Tapao Royal Thai Air Base, helped the times, but did not offer more than basic B-52 maintenance.

Navigation and radar bombing

The first radar drop guidance used the Strategic Air Command AN/MSQ-77 "Skyspot" radar bombing scoring system, which was precise enough for such targets as airfields. By 1967, five MSQ-77's were in SVN and one in Thailand. They had an 175 mile range and needed line of sight. Even when the A solution of sorts appeared in 1966 with an adaptation of Strategic Air Command’s radar bomb scoring system. This modification, called the MSQ-77, guided aircraft to a precise point in the sky where ordnance was released. It wasn’t pinpoint accuracy, but it was good enough for targets such as airfields and industrial areas.

By 1967, the Air Force had five MSQ-77 radars working in South Vietnam and one in Thailand. However, none of these sites covered the North Vietnamese heartland around Hanoi. That required putting the radar where it would have an unobstructed line of sight to the airspace over Hanoi. Also, the target area had to be within 175 miles of the radar, which was the effective range of the system. There was also a helicopter-transportable AN/TSQ-81.

Radar for the North

While radar bombing is outside our immediate scope, the information is being preserver here should this be useful. A site, with a rough airstrip, was on Phou Pha Thi, a very steep-sided mountain in Laos, where a TACAN. The mile-high facility had line-of-sight on Hanoi. The airstrip, Lima Site 85, was an airstrip and environs, one of several hundred Lima sites used in the CIA-Hmong unconventional warfare against the Pathet Lao.

The basic operation element were elements of 3 or 6 B-52

Airmobile operations

In mid-1965, the 11th Air Assault Division (Test), the experimental force in AIR ASSAULT II, was reflagged as the 1st Cavalry Division (Airmobile) and sent to Vietnam. Their first assignment was to crush Giap's buildup around the Ia Drang river; there are indications that Giap intended to meet the 1st Cav and learn techniques to fight the airmobile forces.

The 1st Cav learned lessons in the Battle of the Ia Drang in October and November 1965, and refined its techniques at the Battle of Bong Son in December 1965 through February 1966.

Well handled airmobile forces could dominate at the tactical and operational levels, but neither they nor the United States Air Force could hold ground. While U.S. forces could deliver massive casualties, Giap was quite prepared to fight an attritional strategy, aimed at U.S. opinion. COL (ret.) Harry Summers, a U.S. Army historian and strategist, is said to have said to a North Vietnamese counterpart during talks, "We never lost a battle." The DRV colonel said "true, but irrelevant."

Military aircraft are inherently dangerous, especially at low altitude where helicopters often operated. Most jet aircraft have the gliding performance of a brick when they lose power. A helicopter that loses power, but maintains the integrity of its rotors, is at a few thousand feet of altitude, and has a competent pilot, can "autorotate" to a landing, the airflow of the fall spinning the rotors and generating lift. At low altitude, there is no time to generate that lift. Jet fighters do have ejection seats to blast pilots clear of an impending crash, where helicopter crews have neither ejection seats nor parachutes.

8,000 went down during the war, killing 3,000 in combat operations and another 2,200 in accidents. (Most of the casualties were passengers; 700 pilots were killed.)

Medical support

Immense improvements over even Korean War field medicine, of M*A*S*H fame, were a great morale factor. They involved several key factors:

1. Rapid helicopter evacuation, with more advanced medical technicians, from the battlefield
2. Mobile trauma hospitals a short distance from the battlefield
3. Improved medical understanding of trauma management, especially aggressive prevention of shock and related respiratory conditions, rather than treating those often-lethal complications once they had developed.

"Dust Off" medical evacuation UH-1 Huey helicopters. promptly removed the wounded from the battlefield, and to an advanced trauma hospital system. Medevac runs had the highest priority, and were unusually dangerous. Two medevac pilots won the Congressional Medal of Honor for their heroism. It took on average 100 minutes to rush a casualty to the nearest field hospital. 390,000 American and ARVN casualties were medevaced. Thanks to quick hospitalization and aggressive prevention of traumatic shock and the acute respiratory distress syndrome, 82% of the seriously wounded who arrived at hospitals survived, a sharp improvement over previous wars due to helicopters, as well as significant advances in trauma management.