ADA Units in Vietnam
Production of the M41 Walker Bulldog tank was undertaken by the Cadillac Car Division of the General Motors Corporation at the Cleveland Tank Plant and first production models were completed in 1951. The M41 was the first member of a whole family of vehicles sharing many common components. The family included the M42 self-propelled anti-aircraft gun or Duster as it is also known, which was in production from early 1952 to December 1959. Production of the M42 amounted to 3700 units.
The driver and radio operator are seated at the front of the vehicle with the other four crew members in the turret, which is in the center of the hull. The engine and transmission are in the rear. The M42 has torsion-bar suspension consisting of five dual rubber-tired road wheels with the idler at the front and the drive sprocket at the rear, and three track-return rollers. The first, second and fifth road wheel stations have a hydraulic shock absorber. The steel tracks have replaceable rubber pads.
The main armament consists of twin 40 mm cannon mounted in an open-topped turret. These have hydraulic elevation from -3 degrees to +85 degrees, and traverse through a full 360 degrees. Manual controls are also provided, and with these the guns can be depressed a further 2 degrees. Each barrel has a cyclic rate of fire of 120 rounds per minute. Maximum anti-aircraft range is 5,000 meters and maximum ground-to-ground range is 9,475 meters.
"Light air-defense guns, of calibres from 20 to 40 millimetres, were developed in the 1930s for protection against dive bombers and low-level attack. The most famous of these was a 40-millimetre gun sold by the Swedish firm of Bofors. Virtually an enlarged machine gun, this fired small exploding shells at a rate of about 120 rounds per minute--fast enough to provide a dense screen of fragments through which the aircraft would have to fly. Fire control was largely visual, though some guns were equipped with predictors and power control."
"The Duster's Bofors 40mm guns had been well tried by both sides in World War II. Loaded with four round clips, the guns could fire at a rate up to 240 rounds per minute to a theoretical extreme range of 9,200 meters. All 40mm ammunition was tracer, however, and the system was designed primarily for direct fire on pinpoint targets at ranges of approximately 2,000 meters, where the gunner could see the strike of the rounds. The two-round HEIT projectile used in Vietnam was point-detonating and designed to self-destruct at 3,500 meters.
Most of the 40mm ammunitions was stored in the ammunitions containers along the tops of the track guard either side of the turret. Three sighting devices are incorporated into the fire-control system:
M-55 Quad 50
Near LZ Betty, 1968
Known as the 'Whispering Death' - each M-55 Quad 50 consisted of four Browning M2 .50-caliber machine guns mounted in a power turret on a deuce and a half (2 1/2) or 5 ton truck. With an effective rate of fire of 1,000 to 1,500 rounds per minute, the Quad in action "could literally sick the life out of a hillside at ranges up to half a mile".
T-28-E1, the WWII predecessor to the Quad
Two .50 cal MG and a 37mm cannon
Courtesy of Patton Museum, Fort Knox, Kentucky
Both Dusters and Quads "served well in perimeter defenses, where gunners could establish clear fields of fire and alternate firing positions. It was there that the AN/MSS-3 (23-inch) and the newer AN/TVS-3 (30-inch) searchlights were most useful, too. At night the searchlights swept the perimeter in the infrared mode, so as to detect the enemy without disclosing their positions. Having found the enemy, gunners switched to visible light mode for target illumination and engagement. Quads and Dusters were quickly on target because the men routinely laid searchlight azimuth indicators parallel with the automatic weapons. The other major use of searchlights was to bounce light from clouds to improve vision for friendly patrols and nearby positions using starlight scopes."
Deployment of Dusters, Quad 50s and Searchlights
HAVE MERCY LIKE HELL I WILL
A Battery, 5th Battalion, 2nd Artillery, Lai Khe, 1969
"Once recovered from the National Guard, the old antiaircraft weapons went to Vietnam by the battalion. Starting in the fall of 1966, the U.S. Army deployed three battalions of Dusters to the Republic of Vietnam, each battalion consisting of a headquarters battery and four Duster batteries, and each augmented by one attached Quad-50 battery and an artillery searchlight battery."
"M-55s and M-42s were old pieces of equipment that needed a lot of maintenance and required hard-to-get spare parts. The gasoline-powered Dusters were particularly susceptible to fires in the engine compartment. Thus, despite its cross country capability, it was not wise to use the Duster in extended search and destroy operations in heavy jungle terrain because of excessive wear on engines, transmissions and suspensions.
HAVE GUN WILL TRAVEL
C Battery, 5th Battalion, 2nd Artillery, Dong Tam, 1969
An Air Defense Vulcan test unit was deployed to Vietnam in late 1968. The unit, called the "Vulcan combat test team", consisted of a platoon of four XM-163 vehicles each mounting the Vulcan M16A1 six barreled gatling gun on a converted M113A1 chassis, plus one spare. (These were proper mods and not "in country" lash-ups of turrets and mini guns). The unit was attached to the 5/2nd Artillery operating out of Long Binh. Vehicles 1 & 2 had range only radar, whilst the remainder had dummy radars, presumably as they'd probably be used in a ground role (not Anti Aircraft). They were used mainly in the convoy escort role. Like all armored personnel carriers, however, the front of the Vulcan proved vulnerable to enemy RPGs.
The 1/44th Artillery battalion is now part of the AWE at Ft Hood, Texas, headquarters of the 4th Infantry Division. The 1/44th is now equipped with Bradley infantry fighting vehicles with Stinger missile pods mounted on them.
"Hawk means 'Homing All-the-Way Killer' and is a surprisingly long-lived US system which began development in 1952 and is still in use worldwide today. It was designed to be a low-level system for deployment with field armies. Although cumbersome and needing large numbers of men and vehicles, it was accepted because nothing else was remotely as good, and with a few modifications it has remained perfectly serviceable. The missile has a two-stage solid fuel motor, giving both an initial high acceleration rate and sustained thrust. The original launcher was a three-missile cluster on a trailer but fixed and mobile launchers with up to nine missiles are now in use. The Hawk is a radar homer which picks up signals from a radar which are reflected by the target, and steers itself to the interception."
Hawk anti-aircraft missile units served in Vietnam with the 97th ADA Gp, which consisted of the 6th Battalion 56th Arty ADA, and the 6th Battalion 71st Arty ADA. 6/56 with four line batteries, A, B, C and D and a headquarters battery (HHB), was located in the Long Binh and Bien Hoa area north of Saigon.
The 6/71 Arty ADA operated in Cam Ranh Bay and around Na Trang.
Order of Battle of ADA Units in Vietnam
"The 1st Battalion, 44th Artillery, with attached Battery G, 65th Artillery (M-55), and Battery G, 29th Artillery (Searchlight), supported the 3rd Marine Division in northern I Corps area. Based at Dong Ha and Da Nang, 1/44 operated from Phu Bai in the south to Con Thien in the north and Khe Sanh in the west.
"The 5th Battalion, 2nd Artillery, with attached Battery D, 71st Artillery (M-55), and Battery I, 29th Artillery; (Searchlight), was assigned to II Field Force Artillery at Long Binh [north of Saigon].
"The 4th Battalion, 60th Artillery, with attached Battery E, 41st Artillery (M-55), and Battery B, 29th Artillery (Searchlight), belonged to the 41st Artillery Group of I Field Force Artillery and operated out of Qui Nhon, An Khe and Tuy Hoa. A separate Quad unit, Battery G of the 55th Artillery, was assigned to the Americal Division at Chu Lai. Finally, Battery H of the 29th Artillery (Searchlight), supported operations of the 9th Infantry Division.
"Each of the Air Defense battalions had over a thousand men, but the units never fought as batteries, much less as battalions. Demands for fire support far outstripped availability of weapons, and individual fire units were quickly scattered throughout the battalions' areas of responsibility. Each Duster battery had two firing platoons, both of which could be employed independently, as could the six firing sections of each machine-gun battery. As a result, the war fought by the Air Defense gunners in Vietnam was overwhelmingly a sergeant's war, as detached platoons and firing sections found themselves under the operations control of other types of units. Normal missions for the automatic weapons included convoy security, perimeter defense, and fire support for maneuver operations."
"Automatic-weapons units began to stand down early in 1971 and had left Vietnam completely by mid-1972. By that time, the Quad and three Duster battalions sent to Vietnam had fired well over four million 40mm rounds and 10 million .50-caliber rounds in support of American, Vietnamese and Allied forces."