Cadillac Gage Commando M706

 U.S.A. (1963)
Armoured Car – about 9000 built all combined V-100, 150 & 200.

Development of the M706

Terra-Space division of the Cadillac Gage company designed in 1960 4×4 amphibious armoured vehicle, expecting to fulfill the future needs of the army. The later required some sort of Jack-of-all-trades, a multi-purpose, 11-man APC, reconnaissance vehicle, convoy escort, command, patrol and a riot vehicle. By 1962, the patent was filed, and the projected vehicle named Commando. Development was fast as in 1963, the prototype undergone its first tests. The same year, the definitive production vehicle, the V-100, was tested thoroughly in Vietnam before the production was started in 1964. Total production figures are ellusive but at least 10 000 vehicles of the V-100, 150 and V-200 variants were delivered by CGC, then the Textron Marine & Land Systems company. The M706 is currently replaced by the M1117 since 1999, but still in service in many countries. Philippines are one of the most prolific user of the model.

Design

US Air Force Security Policemen aboard a V-100 (XM-706E2) during exercise Team Spirit ’81.

To kept the prices low, the vehicle used many existing components. The axles were similar to the M34 truck series while the engine was the same V8 Chrysler, 360-cubic-inch gasoline that powered the M113 armoured carriers. It had a 5-speed manual transmission. These allows a top speed of 62 mph (100 kph) over rough terrain. Its 4×4 independent sprung roadwheels had massive tires to reduce ground pressure. The CGC can also swim at 3 mph (4.8 kph). Protection was provided by the “Cadalaloy”, a custom 0.25 in hardness alloy steel, protecting against small arms fire (7.62 cal.). This protection was also given by the well-sloped monocoque welded hull, also protecting the crew from mine blasts. However the alloy was not espcially light, and the empty weight of the vehicle was 7 tons.

This take its toll on the rear axle, which frequently failed, and not designed to support this extra load. Access was allowed from the two side doors, and the turret cupola hatch. Vision was provided by height vision blocks (at first ten) with armoured glass, and the revolving turret which featured a peripherical vision with ten vision blocks, plus a periscope. For close-fire, six pistol ports were also provided on the upper sides. The hull featured also an internal modular arrangement with interchangeable components, aimed at the export market.

The CGC accepted a large array of weapons. The first military version V-100 was usually armed with the same revolving turret that equipped the M113, armed with a twin M37 browning cal.30 (7.62 mm). This was in standard, but some versions received an upper open supertructure and one to three Browning cal.50 (12.7 mm), the front one being protected by an armoured shield. Later on, the revolving turret was equipped with smoke dischargers and a M2 cal.50. Additional supports were sometimes welded for extra M60s. An export version accepted a M134 7.62mm Minigun. The V150 and V200 were more heavily armed and better used for recce and support. According to the Wall Street Journal in 1965, the base price tag for the M706 Commando was 24.500 $.

The V100

This was the main, early production version. Apart the facts given above, there were two basic versions, a turret one, and an open-top version, with added upper protections. The side door, at first, in single piece, was later produced in two-parts. In 1964, one of the XM 706 prototypes tested a 20 mm armed turret, which never made it before the reinforced and longer V-150. The vehicle impressed the ARVN (Allied south Vietnamese Army which became the first customer of the V-100, apart the ATAC (US Army Tank & Automotive Command).

A former V-100 from Viet-Nam, at Engineering School, Fort Leonard Wood, Missouri – Wikipedia, creative commons.

A 40 mm automatic grenade launcher and new turrets were also quickly developed since the AVRN complained about the lack of firepower of the twin cal.30. But the project failed to meet the US Army requirement and failed to materialized after US troops disengaged from VN in 1972-73. The USAF received the XM706E2, wiyh an open-top center parapet with with a single M2HB machine gun under mask assisted by a M60 or two. Some were still in service at Clark AFB in the Republic of the Philippines in 1988. In patrols, a crew of 12 was often seen, but it was systematic in ARVN forces.

The V200

The development was assumed by the Marine and Land Division of the Textron company. It was an elongated V-100 (in the middle section), partly based on U.S. Army’s 5 ton trucks components. It was built solely for export for the needs of the Singaporean army, or Singapore Armed Forces (SAF). Tey were modernized by ST Kinetics in the early 2000s and are still in service. Today singapore has 250 of these in service, plus 30 V-100 and 50 V-150.

Singapore Army V-200 Commando with 20mm cannon

The V150

This vehicle was based partly on the V-100, and the V-200. This hybrid was shorter but stronger and could accomodate much heavier turrets and armaments, and could be equipped with diesel or gasoline engines. Built for export, it was equipped with a large variety of armament configurations, including 12.7 mm and 20 mm armed turrets. Portugal had its V-150s modernized in the 1970s as the Chaimite, with a 90 mm Cockerill gun turret, known as the V-400 variant.

Saudi Arabian V-150, 1st gulf war, 1991.

2,968 LAV-150 vehicles were produced. The list of operators includes Bolivia (10), Bostwana (36), Cameroon (43), CHAD (9), Dom. Republic (8), Gabon (9), Guatemala (7), Haiti (6), Indonesia (200), Jamaica (13), Kuwait (20), Malaysia (184), Mexico (28), Philippines (165), Qatar (8), Saudi Arabia (1100), Singapore (280), Somalia (10), Sudan (100), Taiwan (300), Thailand (162), Turkey (125), USA (10), Venezuela (130), Vietnam (5).

Other Variants

The LAV-300 is a 6×6 version, partly based on the V-150.
The LAV-600 is developed from the LAV-300 with much heavier weapons, the most common being the 105 mm.
By 2013 Textron unveiled the Commando Select 90 mm Direct Fire, a new model aimed at export-market, armed with a CMI Defence Cockerill CSE 90LP weapons system and asked to perform a large range of misssions from conventional combat to counter-insurgency operations.

Active Service

The characteristic sloped hull of the CGC quckly earned the nicname “duck” or “the V” in Vietnam, which was its first active assignation. CGCs were massively deployed there, as available, for patrolling the DMZs and acting as military police vehicle, guarding AFBs (Air Force vehicles), and for other tasks. These were hard-pressed, especially at the time of the Têt offensive in 1969 when Viet-Minh commandos attacked several key points in Saigon and many other important cities. ARVN forces also actively used their vehicles after US troops disengaged from Vietnam in 1972-73.

US Air Force XM706 V-100, Tuy Hoa, 1968, Vietnam. Credits wikimedia commons

Many were captured by the NVA. After Vietnam, these vehicles saw limited use, and were affected to specific areas, like the Herlong Army Depot in California, and spent as targets. Other armies held their vehicles in service for longer periods, especially the Philippines. Many are still in operations. Outside these regular armies (Royal Thai Army, Republic of China Military Police, the Philippine Army, Marine Corps & Special Police Action Force, the Lebanese Armed Forces, the Army of Venezuela and the Jamaican Defence Force.), these vehicles has been used by many other operators for crowd control and anti-riot operations. SWAT teams also used some, as well as the LAPD. Later in 1991 gulf war, Saudi Arabia\’s guards V-150S took part in the battle of Khafji against Iraki forces.

Several 90mm and 20mm V-150s of Haitian Army seized by the U.S. military during Operation Uphold Democracy, 24 September 1994.

M46 links & resources

The CGC M706 on Wikipedia
On Global security
About the V-150

CGC M706 V100 Specifications

Dimensions (L-w-H) 18ft 7in x 7ft 5in x 8ft 4in in (5.69 x 2.26 x 2.54 m)
Total weight, battle ready 9.8 tons (21 800 lbs)
Crew 3+2 (Commander/radio, Driver, Assistant driver, Gunner, loader)
Propulsion V-504 V8 turbocharged diesel engine, 202 bhp, ptw ratio 18.75 bhp/ton
Maximum speed 60 mph (100 km/h) road, 3 mph water
Suspensions Independant, 4×4
Maximal range 400 miles (643 km)
Armament Main: twin M37 Browning cal.30 (0.3 in) MGs. See notes
Armor 0.25 in (6.35 mm)
Production (V100) estimated 5000

 

Cargo Carrier M29 Weasel

U.S.A. (1942)
Cargo Carrier – 15,892 Built

In 1942, the American Studebaker company based in South Bend, Indiana, famed for their luxury automobiles, answered a call for an armored vehicle capable of traversing deep Norwegian snow drifts for special forces operations. The vehicle became the M29 Weasel and went on to be a popular universal vehicle outside of its original intended use, akin to the British Universal Carrier. The M29 could traverse the hardest of terrains where wheeled vehicles could not go and saw service through the Second World War, the Korean War, the Vietnam War and saw use in the civilian sector.

An M29 named ‘Snookie’, date and location unknown. Photo: www.studebaker-weasel.com

Background

The idea for the Weasel came from the British Inventor Geoffrey Pyke, a man famed for his unorthodox methods. His most famous invention was Pykrete, a material that would’ve been used for the Habbakuk iceberg aircraft carrier. Pyke had long planned for Commando assaults on German power plants and industrial areas in Norway and also planned actions to interrupt the Nazi atomic weapons program in Operation Plough. Operation Plough is very much the origin of the Weasel. Pike called for a small, lightweight and fast vehicle, able to transport small teams of men across deep snow to take them deep into enemy territory.


The T15 Prototype in testing. Photo: www.studebaker-weasel.com

Design

The proposed design was designated T15, with the finalized design receiving T24. It was soon accepted and became the M29, a simple vehicle consisting of little more than a box on tracks. The Studebaker company would go on to build almost 16,000 M29s. Key elements of its design required that it be air-transportable, able to withstand the impact of a parachute drop, and able to carry enough supplies for a small commando team. It was powered by a 70 hp Studebaker Model 6-170 Champion 6-cylinder engine which propelled the vehicle to 36 mph (58 km/h), a speed it could sustain over most terrain types.

Suspension for the M29 consisted of rear mounted drive wheels (and transmission) with idlers in the front that were lower, giving the running gear the appearance of leaning forward. It featured four, two-wheeled bogies on each side, with two track return rollers. It had wide tracks from 15″ (380 mm) to 20″ (510 mm). This gave the Weasel a very low ground pressure of just 1.9 psi (Pounds Per Square Inch)a benefit in crossing soft ground. The tracks consisted of long metal plates connected by inner rubber bands, with a total of four bands per track, two on the outer edge and two in the center with a center guide horn. The bogie wheels ran on the center bands and. the outer face of the tracks featured two rubber blocks per link for grip on road surfaces.

A Weasel freeing a Willys Jeep from thick mud.

The M29 was operated by one driver and could carry three passengers. The driver was positioned in the front left with the engine compartment to his right and a row of three seats in the rear for the passengers. Though officially an unarmed vehicle, Browning M1919 .30 cal or .50 cal M2HB Machine Guns were often mounted for some form of offensive/defensive capability.

Variants

M29C Water Weasel

The M29C was the main variant of the Weasel. The M29 was already partly amphibious, able to traverse shallow and calm waters such as rivers and streams, but could not operate in rough, sea like waters. The M29C amended this issue, with the addition of buoyancy aids in the rear of the hull as well as two rudders. Removable pontoons were also added to the front and rear and.changes were made to the treads of the track links to allow it to propel itself in water, although it was very slow. This still didn’t make the M29 capable of seaborne amphibious landings, but allowed to be more stable in deeper or slightly rougher inland waters.

The M29C Water Weasel during testing.

M29/M29C Type A, B and C

These variants were all virtually unchanged from the standard M29/M29C, the only difference being that these were armed versions. The Type A featured a center-mounted 75mm M20 recoilless rifle. The Type B featured a rear-mounted 75mm Recoilless Rifle. The Type C featured a center-mounted 37mm Gun M3, the same gun used in the M3/M5 Stuart Light Tanks.

A Water Weasel armed with a 75mm Recoiless Rifle. Photo: TankPorn of Reddit

WW2 Service

The Norwegian mission that the M29 was designed for never took place. This did not mean that time had been wasted on the vehicle, as it soon found use in multiple roles, in multiple theaters, and by multiple countries.

An American Weasel in Normandy, 1944. Photo:WW2 in Color

The United States used the vehicle extensively during World War Two. It was used in Italy, the Western Front, and even in the Pacific. It saw action during the Normandy landings, St. Lo, and the Battle of the Bulge. It proved its usefulness at the engagements on the Ruhr and Rhine, where it was able to cross the thick, sticky river mud. In the Pacific, it was used by the United States Marine Corps (USMC) at Iwo Jima and Okinawa, where it proved capable of crossing loose sand, and the harsh tropical island terrain where the Marine Corps’ jeeps wouldn’t dare venture.

The use of the M29 Weasel as a universal vehicle soon became clear to the Americans. They used it regularly as a light troop carrier and cargo hauler, and also as a mobile command center, ambulance, and to lay telegraph wires. One of its major attributes was its ability to cross minefields, as its low-ground pressure was often not enough to trigger the anti-tank mines. The ground pressure was still more than enough to trigger anti personnel mines which could easily split a rubber track.

An M29C in an ambulance role on the Rhine.

Service in the Commonwealth

The British and Canadian armies also used the Weasel in World War Two. Supplementing a number of LVT Buffalos, M29C Water Weasels of the 79th Armored Division were used by Commando troops in the Walcheren Operation. The 79th also used a number of the standard M29s to clear mines and other defensive devices.The Canadians made use of the Weasel’s semi-amphibious nature in their engagements in the flooded estuaries of Antwerp in 1944, and would go on to serve them through the Netherlands and into Germany.

After WW2

The Weasel remained in service after the Second World War. In 1946, there was a plan for the US Army to use the Weasel to rescue the victims of the C-53 Skytrooper crash on the Gauli Glacier but the Swiss Air Force managed to rescue the victims first. With the US Army, they would go on to serve in the Korean War.

French M29C in Vietnam.

In 1947, the French Army used the M29 in the First Vietnam war, where the 1er Régiment Étrangers de Cavalerie were equipped with the M29C variant. They armed them with multiple types of weapons, from the Chatellerault M1924/29 and Browning M1919 machine guns to 57mm recoilless rifles. The M29 would remain in service with French mountain troops and Gendarmerie as late as 1970.

Civilian Use

With a large surplus supply, the United States sold off large quantities of the M29 to various countries, including Sweden, France and Norway. Many Weasels served in scientific arctic expeditions, but their most famous use in civilian hands was at the 1960 Olympic Winter Games at Squaw Valley, California, USA.

The Automotive Company, Consolidated, sought to update the Weasel in 1960. They designed the ‘Sno T’rrain,” which was two Weasel chassis coupled together with fully enclosed canopies.

Today, there is a large community of Weasel collectors and restorers. As such, there are many running examples in private collections world wide.

Cargo Carrier M29 Weasel

Dimensions (L-W-H) 10′ 6” in x 5′ x 4′ 3”
(3.20 x 1.5 x 1.80 m)
Total weight 1.8 tons
Crew 1 driver, 3 passengers
Propulsion Studebaker Model 6-170 Champion 6-cylinder, 70hp
Speed (road) 36 mph (58 km/h)
For information about abbreviations check the Lexical Index

Links, Resources & Further Reading

The M29 on Military Factory
www.m29cweasel.com
www.studebaker-weasel.com

M551 Sheridan

U.S.A. (1965)
Light Tank – 1662 built

The Missile-Firing tank

The Sheridan was one of these developments tailored to explore a tactical theory and put it to the test. At the time the perpetual chase between armour and weaponry seen lost in favour or the new ammunition, and the tactical possibilities introduced by lighter missiles met US Army Ordnance specifications for a new light tank. The previous M41 was too heavy, had a short range and inadequate weaponry already, so lighter models like the T71 and T92 were tested. None were amphibious however, and after reports about the new Soviet PT-76, the XM551 was built and tested. To meet all conflicting requirements the new design showed a combination of an aluminium hull with a steel turret, to keep the weight down while providing buoyancy and the required level of protection. The vehicle had yet another remarkable feature with a 152 mm gun capable of firing the MGM-51 Shillelagh AT missile.

Development History

The task of the designers of the XM551 was daunting. Providing an amphibious tank (none were built since the specialized World War 2 LVT families and DUKW and SEEP) light enough to be airlifted seemed only possible with a small model build from light alloys, but at the same time, mobility and range were to be greatly enhanced and moreover the armament needed to be enough to knock-out a 1960s main battle tank. This squaring of the circle resulted in the Sheridan. Since a “normal” gun powerful enough for the task would have needed a long barrel, large turret, and hull, the solution was to use missiles instead, which provided their own velocity and could be launched from a simple tube. At the end the solution was so unusual it was called an “Armoured Reconnaissance/Airborne Assault Vehicle” but not a light tank.

XM551 Pilot

Design

Obviously the protection seemed to be sacrificed on this model. The aluminium hull and the steel turret could only hold against 0.5 inches fire (heavy MG) but remains vulnerable to grenade, ATGMs and mines. The hull was compartmented into lateral flotations screens, with a front “surfboard” made of wooden hinged folded layers. It could be deployed into a frontal sloping vertical surface, with canvas to cover the flanks, maintained by poles at the rear, sides, and high as the turret top. The system was directly taken from World War 2 DD tanks. The front “bow” comprised a plastic window for the driver which provided a mediocre visibility was later eliminated. The driver steered the tank blind, guided by the Commander towering above his cupola. In all, the tank was only 15.2 tons which was light enough to be airlifted by “heavy duty” helicopters like the Boeing Ch-47 Chinook and the Ch-58 Sea Stallion and most air transporters. There was sufficient buoyancy to allow the tank to swim at at 5.8 km/h (3.6 mph), rather than just sink like most MBTs to cross deep rivers. Therefore it was amphibious and NBC-proof, like the Soviet PT-76. This swimming characteristics, lightweight hull allowing air transportation combined with a top speed in excess of 70 kph gave an excellent strategic and tactical mobility, at least on the paper.

CH-54B carrying an M551 Sheridan tank.

The aluminium hull was entirely welded, with some cast elements at the front and rear. Armour thickness ranged from approx. 8 mm to 13 mm at the front. The Detroit Diesel (General Motors) 6V53T, 6 cylinder, turbocharged diesel gave indeed an output of 300 hp (220 kW), and a favourable power/weight ratio of 19.7 hp/tonne. The driver train reused standard roadwheels and tracks (five doubled rubber-clad roadwheels per side, suspended by torsion bars) but there were no return rollers and the drive sprocket and idler were both specific to this model. The crew of 4 comprised the driver, located in the center, with his own hatch and three vision blocks, and two headlights/blackout lamps protected by armoured covers. The commander, gunner and loader were all located in the center fighting compartment, in a rather cramped turret. The latter was relatively flat and was given extremely sloped sides to maximize the effective thickness of the armour. The commander cupola was located on the right hand side, and was given a cal.50 HMG ring mount. The loader’s hatch was located at his left. There were also two banks of height electrically fired smoke dischargers on each side.

XM-551 Pilot #12 at Fort Knox, Kentucky.  Mid 1960’s

The armament was remarkable as a lightweight solution which could deliver a potentially killer blow. The M81E1 Rifled cannon was a short barrel, able to fire either missiles or tailored ammunitions for fire support. Due to the unfavourable velocity ratio, only traditional HE rounds were fired, for infantry support, while the AP capability was entirely provided by the new Shillelagh missile system. The latter was developed in 1958 by Sperry and Ford Aeronautics (Later Martin Marietta) as the XM13, produced in 1964 as the MGM-51. It was 152 mm in diameter with the winglets folded, and 290 mm wingspan unfolded, with a solid-fuel rocket and a 15 pdr shaped-charge (6.8 kgs) warhead. Guided by infra-red signals it could fly at 1,060 feet (320 m) per second. This was sufficient to defeat 150 mm of RHA plate at a 60º angle at the range varying from 2000 to 3000 m depending of the models A, B or C. 88 194 of these were produced until 1971. It was also deployed by the M60A2 “Starship” and the first prototype of the MBT-70. This weapon was completed by a roof-mounted cal.50 M2 (1000 rounds) and a coaxial M73 LMG with 3000 rounds.

 

Production & Variants

Production started on 29 July 1966, and the Sheridan entered service in June 1967. In all 1,662 M551s were built between 1966 and November 2, 1970 for a total cost of $1.3 billion for the entire program. However problems with the M81 gun quickly showed, as cracks developed near the breech after intensive firing, later linked to the Shillelagh “key” running in a slot cut into the barrel. The modified M81E1 introduced a shallower slot and matching modification to the missile. Still, the gun was criticized for having too much recoil for the vehicle’s weight and frail construction. The blast was enough to lift-off the second and even third road wheels. Experimental 76 mm guns were also tried but never adopted.

The M551 in Action

Vietnam War

In June 1967, the first batch of Sheridans entered service with 1st Battalion, 63rd Armor Regiment at Fort Riley. At that time, the concept was ready to be battle tested in Vietnam although there was no immediate use for the cavalry unit. This came in late 1968 when General Creighton Abrams met with Colonel George S. Patton IV and his 11th Armored Cavalry Regiment (11th ACR Blackhorse) as despatched in Vietnam (and remained the only cavalry unit in service here). These tanks were evaluated by the 3rd Squadron, 4th Cavalry, and the 1st Squadron, 11th ACR from January 1969 to the fall of 1970. These suffered badly from mines and RPGs, always fatal contrary to the M48 “Patton”. Sheridans there assumed reconnaissance, night patrol and road clearing duties and totalled 39,455 road miles and 520 combat missions with a combat readiness of 81.3%. Reports were enough to decide to equip all other cavalry squadrons with this tank. However it was also detected that the caseless 152 mm main gun rounds used were easy to ignite when the tank was hit by a mine.

Sheridan M-551 and crew members of the 3rd Squadron, 4th Cavalry, Vietnam. Circa 1969

This was demonstrated in late 1969 when three out of the nine Sheridans of the 4th Squadron, 12th Cavalry detonated on mines when crossing a river near the DMZ, being total losses. On march 1971, five (11th ACR) were lost in a row by a Vietcong ambush operating RPGs. In all these cases, the Sheridan just “melted” due to the heat intensity and aluminium nature, gaining a sinister reputation. However their mobility was excellent in mud and in general all terrains. They were found very effective in infantry support, bursting M657 HE shell or the M625 canister round which launched a devastating bunch of flechette rounds, despite their slow reloading time. Their low ammunition stock was compensated by their combination with combination with ACAVs (M113s) that carried extra rounds.

MGM-51 Shillelagh Anti-tank miisile fired from M551 Sheridan light tank.

By May 1970, the 11th Armored Cavalry Regiment entered Cambodia. Most vehicles has been modified with a large steel shield (“ACAV set”) to protect the commander when firing the 12.7 mm HMG buttoned-up in his open cupola. The driver was given a modified rotating hatch and an extra layer of bolted steel was applied to the belly to protect against mines, but mostly protecting the front part of the belly due to weight issues. The 11th Cav. also participated in Operation Dewey Canyon II in support to ARVN Lam San 719 Operation, taking heavy losses in the process.

A C-130 delivering an M551 Sheridan tank using LAPES (Low Altitude Parachute Extraction System).

The 1980s

The Army began to retire the Sheridan in 1978. But due to the lack of suitable replacement some units like the 82d Airborne Division retained them until the 1990s (1996 for the 82 AD). Another task was found to keep them active: Doing the bad guys in training, modified to resemble mock T-72 and T-80s. These vehicles were active at the National Training Center at Fort Irwin, California in the 1980s. They were retired at the end of 2003, and either scrapped, ended as targets, given to collections or dumped into the sea. During the invasion of Panama (Operation Just Cause) in 1989, fourteen M551s were deployed, among which four were transported by C-5 Galaxys and ten air-dropped by C-130s (two Sheridans destroyed upon landing). They were attached to TF Bayonet (193rd Infantry Brigade) part of TF Gator, taking part on the attack on the Commandancia and later provided support to JSOC elements inside Panama City. Height fought at Torrijos-Tocumen Airport. Their performance received mixed reviews.

First Gulf War (1990s)

Fifty-one Sheridans were deployed by the 82nd Airborne Division during Operations Desert Shield and Desert Storm. Their role was limited to reconnaissance and possibly six or fewer Shillelagh missiles were fired on anti-tank guns or T-55s in operation, the only operational use of these ordnance among 88,000 missiles produced. These were deactivated after the war. Attempts to provide them a standard NATO 105 mm failed. In fact replacement came with the M1128 Mobile Gun System variant of the Stryker. So the Sheridan was perhaps the last of American light tanks. 

M551 Sheridan Links & Resources

The M551 Sheridan on Wikipedia

M551 Sheridan Specifications

Dimensions (L-W-H) 20’6″ x 9’2″ x 9’6″ ft.in
(6.29m x 2.81m x 2.94m)
Total weight, battle ready 15.2 tons (34 000 lbs)
Crew 4 (Commander, Driver, Loader, Gunner)
Propulsion Detroit 6V53T 6 cyl. supercharged diesel 300 hp (220 kW).
Top speed 43 mph (76 km/h) road, 3.6 mph water
Suspensions Torsion bars
Range 348 miles (560 km)
Armament Main: 152 mm (5.98 in) gun M81E1, 9 missiles, 20 roundsSec: 1 cal.50 M2 (12.7 mm)+ 1 cal.30 (7.62 mm) M73
Armor Aluminium & steel – Max 0.3 in (8 mm)
Production (all combined) 1662

M41 “Walker Bulldog”

Development History

On November, 7, 1950, the US Ordnance Committee Minutes (OCM) published the #33476 item. This was a new classification between the heavy (120 mm gun), medium (90 mm), and light tank (76 mm), according to their main armament. At the same time, a replacement for the late WW2 standard light tank, the M24 Chaffee, was started in 1947 with researches on the T37 to fit a more efficient armament to deal with armour. Added to this was chosen to to make the new model air-transportable for fast deployment into enemy territory, since reconnaissance was still the main duty for light tanks. Work on a longer barrel was accompanied by a more efficient rangefinder, which was deemed in 1949 too ambitious for such tank class and downgraded on the next T41 prototype. This was the final production prototype, and Cadillac’s Cleveland Tank Plant (which already had experience producing the former M5 and M24 light tanks) was chosen for the first batch in 1952.

Design

Compared to M24 Chaffee, the M41 was a much bigger tank, a direct consequence of the main gun’s breech block length. The turret was enlarged, with a turret ring 2 inches (50 cm) wider, imposing a longer hull, (16.06 vs 19.9 fts or 5.03 m vs. 5.9 m), wider (10.5 vs 9.10 fts or 3.2 vs 3 m), but slightly lower (8.9 vs 9.1 fts or 2.77 vs 2.71 m). But it was also 5 tons heavier. Armour still relied on welded RHA sloped plates, with storage sponson boxes for tooling, with vertical openings. The armor was similar to the M24 Chaffee at 1.5 in (38 cm) at the thickest (the glacis plate and turret mantlet). To keep mobility high, the AOS 895-3 6-cylinder gasoline engine was now rated to a comfortable 500 hp (vs. 110 hp on the M24), which provided a favourable 21.5 hp/ton (vs 16 hp/ton). Top speed gain 10 mph as a result of the engine improvement, well served by a modern wheeltrain relying on torsion bars on solid single pin track, chevron lever blocks, with five double roadwheels, heavenly spaced but further apart from one to another. The drive sprockets and idler position were shifted, the former been relocated at the rear. The upper tracks were still supported by three return rollers. The two former roadwheels pairs were suspended by shock dampers.

The much longer 75 mm gun had indeed a far greater punch than the M24 Chaffee, but it was already barely sufficient against modern tanks of the 1960s, like the T-54/55. The gun had a T-shaped muzzle brake and efficient fume extractor. There were 57 rounds in store, eleven ready AP/HE in the turret and the others stored mostly into the right front hull (replacing the co-driver). It was coaxial with a cal. 0.30 Browning M1919A4 machine gun in the mantlet, while a fixed pintle mount for a heavy cal.50 M2HB (12.7 mm) machine gun took place in front of the commander cupola. The latter was placed on the right hand side, behind the gunner’s location, and counted six vision blocks, a rotatable cupola, and a hatch periscope with magnification. The gunner’s had a direct vision telescope coaxial to the gun and a roof sight with magnification, protected behind an armoured shutter. The gunner’s hatch located at the turret’s left hand side was a simple piece, and a small periscope was located at the front. The turret traverse was electrical, with a manual backup.

1951 M41 outside the Veterans of Foreign Wars, V.F.W Post 803, 911 N State St, Clairton, PA, USA

At the rear of the turret bustle top was located a mushroom-shaped fume extractor. Inside the bustle were located the radios. On the bustle back was fixed a large storage bin, to add balance to the main gun. The turret sides counted fasteners for canvas and additional storage, including fuel jerrycans. The turret front counted handles for an easier access and the mantlet was usually covered by a tarpaulin to prevent rain and snow infiltration inside the crew compartment. The driver’s hatch was located at the left hand side, with a single piece which opened laterally. The driver could see through four vision blocks, three facing the front arc, and one the right-rear, plus a removable hatch periscope. The gun lock was used for transportation. Unlike the Sherman tank the gun lock was at the rear and offset to the left side of the tank, not in the middle like on most tanks. This was to enable the driver to get out of his hatch. If the gun lock at the rear of the tank was in the middle the rear turret bustle would block the hatch. Notice no front hull machine gun was added to the front of the M41 Walker Bulldog. This was to enable additional ammunition to be stored in the front right hand side of the tank. The crew had to rely on the coaxial cal.30 (7.62 mm) Browning M1919A4 machine gun next to the main gun in the turret for self defence and the exterior turret mounted Cal.50 M2 (12.7 mm) machine gun. The Cal.50 machine gun could be disconnected from its turret mounting. A large caliber machine gun tripod was often attached to the rear of the turret bustle box for use by the crew on the ground behind cover.

Former US Army M41 at Ulbeek in Belgium.
Same, rear view.

Production

The production at Cadillac started in 1951, replacing gradually the M24 Chaffee. At the same time, the initial surname “Little Bulldog” was replaced by “Walker Bulldog” to honor the memory of a tank General killed in a jeep accident in Korea in 1950. The production will last until 1967, when replacement by the M551 Sheridan became effective. Until then, and its first deployment in Korea, many modifications occurred, later turned into production variants. The M41A1 was the first production variant, in 1954. The electric traverse system was replaced by an hydraulic traverse, the extra room allowed to increase the ammunition storage from 57 to 65 rounds. The M41A2 appeared in 1956, with an engine upgrade, the fuel injected Continental AOS 895-3 replacing the ancient carburettor fuel system. The M41A3 were upgraded M41/M41A1 to the new fuel injection system. The M42 Duster was the anti-aircraft variant, with a twin Bofors 40 mm guns turret replacing the turret.

ARVN (South Vietnamese) M47 at the Battle of Saigon. May, 1968

Exports

The M41 was largely distributed among allied nations inside NATO, namely Austria (42 used from 1960 to 1979), Belgium (135 used from 1958 to 1974), Denmark (53 M41DK used from 1953 to 1998), Spain (), and West Germany. West German tanks were apparently upgraded in the late 1970s with a new Cummin engine s ATV-903TR of 465 hp diesel engine and upgraded main gun (firing AFPDS ammo) as well as the Spanish tanks. The last Danish tanks were retired in 1998. They had been upgraded as the M41 DK-1 which included a complete overhaul: New engine, thermal sights for the gunner and commander, complete NBC protection lining and anti-SPG side skirts. Spain also operated 180 M41s in the 1960-70s, in a modernized version. Exports comprised also nations of the middle East, like Jordan and Lebanon. In the latter country, 20 M41A3 were passed onto the Army of Free Lebanon, Lebanese Arab Army, Tigers Militia, Kataeb Regulatory Forces, and Lebanese Forces). In Africa, Somalia, Tunisia, and South Africa also used it. In Asia-Pacific, New Zealand acquired 10 tanks. The South Vietnamese forces received ex-US Army tanks, 30 were captured later by the NVA. The Philippines (7), Japan (147), and Thailand (200) also used the type (now all retired). Taiwan still operates some 675 M41A3/M41D in service today. The M41D is the local upgrade developed for the Marine Corps and Army, comprising a new gun, modern FCS, thermal sights and new computerized targeting systems, a Detroit Diesel 8V-71T diesel engine, side skirts and reactive armor. Taiwan also developed the experimental Type 64 with a new 520 hp diesel engine and coaxial GMPG machine gun.

Danish M41DK Light Tanks.

South American nations also purchased the M41, namely Chile (60 M41A3, now retired), the Dominican Republic (12 M41B now retired), Guatemala (12 ex-Danish DK), and Uruguay (22 M41UR and 24 M41B). The M41UR was developed for export in Denmark and comprised a 90 mm Cockerill cannon and a Scania DS-14 diesel engine. Brazil was also a proficient user of the type (300 tanks), and developed local upgrades, the M41B and M41C. The first one comprised a new FCS, new Belgian Cockerill 90 mm main gun, a DS14 Scania diesel, Groton electric generator, smoke grenade launchers, and armoured side skirts. The M41B was a much thorough modernization with a computerized FCS, new night sights and radio, by the Sao Paulo based Bernardini Company. They are all retired now or have been exported. NIMDA systems of Israel also developed an export package comprising a modernized FCS, new diesel engine and new cooling system.

Taiwanese M41D.

Issues

The M41 was a real improvement over the M24 Chaffee, it was even more mobile and agile, well-armed to deal against lighter armor than MBTs and ww2-era tanks, with an accurate and fully stabilized main gun. It was simple to operate, maintain, with an engine which can be quickly replaced on the field. However it was also found cramped, noisy (a real problem in reconnaissance missions) with an engine of high consumption with limited range. Later foreign upgrades included systematic replacement of the powerplant for a sober Scania or Cummins diesel engine and extended fuel capacity. The M41 was also too heavy for air transport. Prospects of parachute-dropping were abandoned, airlifting by helicopter impossible even for the twin-rotor Chinook, and deployment eventually was confined to heavy duty global transporters like those used in Vietnam. In 1952 work began on lighter designs like the T71 and T92, also abandoned. The M41 was not amphibious or treated NBC, but this was not seen as a problem given the fact others contemporary MBTs were not either. The M551 Sheridan tried to respond to these limitations with a NBC, amphibious aluminium alloy hull which solved the weight issue as well as an innovative missile cannon system to compensate for the firepower issue. However this model had troubles of its own. Foreign upgrades addressed many of the issues listed above which allowed to keep it in service until recently or up to this day.

An AVRN (South Vietnam) M41 during a training operation. Circa 1964

The M41 in Action

By 1953, the M41 was fist deployed in Korea, in first numbers. Known as the T41, it was deployed apparently without proper gunnery training and a troublesome rangefinder. These issues were addressed later. However it performed much better, as intended, than the M24 facing North Korean and Chinese T34/85s. In 1961, 160 were passed onto Japan Ground Self-Defense Force in addition to the local Type 61. The main theatre of operation for the M41 was Viet-Nam. At first, it replaced the few M24 Chaffee inherited from the French in 1964. The M41A3 was first used by units of the ARVN in january 1965, followed-up by American vehicles with the UD deployment in 1965-66. The ARVN used the model intensively until the end of the war, and appreciated the type as more adapted to their smaller stature, as well as handling and reliability. A massive combined ARVN (1st Armor Brigade)/US (airborne and cavalry units) assault on Lam Son in Laos (Operation Lam Son 719) on February 1971 saw the M41s massively engaged, with a deep penetration and disrupted as intended the NVA supply lines in the area. This saw a tank battle, with 17 M41s knocking out 22 NVA tanks (6 T-54s and 16 PT-76s) for the loss of 5 M41s. In 1973, the ARVN still deployed about 200 M41s.

M41A3 Walker Bulldog Specifications

Dimensions (L-W-H) 26’9″ (19’1″ without gun) x 10’3″ x 10’1″ ft.in
(8.21m (5.81m) x 3.13m x 3.07m)
Total weight, battle ready 23.5 tons
Crew 4 (Commander, Driver, Loader, Gunner)
Propulsion Continental AOS 895-3 6-cyl. gas. 500 hp (373 kW)
Top speed 45 mph (72 kph) on road
Suspensions Torsion bars
Range 100 miles (161 km)
Armament 75 mm (3 in) gun M32, 70 rounds
cal.50 M2 (12.7 mm)
cal.30 (7.62 mm) Browning M1919A4
Armor Hull armour 25 mm front and sides. 19 mm rear
Turret Armour 25 mm all-round.
Gun mantle 38 mm
Production 5500

M42 Duster

From Dust to Dust…

Immortalized in the Vietnam War for its tremendous firepower, the Duster was one of the US Marines and Army great friend in the Jungle, cleaning up and effectively turning to dust any threat lurking into the green. It was of course not its main vocation, but turned it to be so at a time most planes flew above the sound barrier. At the origin it was conceived to replace the ww2 era M19 Gun Motor Carriage, based on the M24 Chaffee, that operated a twin 40 mm arrangement in a rear-mounted turret. It was decided in 1950 to transplant the system on the M41 Light tank chassis instead, keeping the same turret. This new vehicle turned into the M42 of which 3,700 were cranked-up until 1956, largely exported, and enjoying a long and very active carrier (1988 for the US Army), barely over now worldwide.

Design

Construction called for all welded steel (RHA). Most of the components came from the M41 to keep the cost down, and the compartimentation was unchanged, with the driver located at the front, central fighting compartment with the M42 turret seated on the original turret ring location, albeit larger, and rear engine compartment. The turret was open to allow maximal visibility, but the armament was shielded, protecting the front against retaliatory strafing attacks. However only the pointers and gunners had some protection, the loader remained exposed. The Armament consisted of fully automatic twin 40 mm M2A1 Bofors, which had a rate of fire of 2 ×120 rounds per minute (rpm). In addition, for close defence, a 8mm (0.30 in) Browning M1919A4 or a 7.62mm M60 machine gun could be installed on a side pintle located at the right hand side of the turret. To maximize effectiveness, it was thought these vehicles could be assisted by a single M42 converted as radar fire control system, but the project was dropped because of cost issues.

M42 Turret details, showing internal arrangements and the external ammo storage bins.

For propulsion, the M42 relied on a 500 hp, six-cylinder, Continental (or Lycoming ), air-cooled gasoline engine, which was also common with the M41 and well-proven. Thanks to this and a an overall weight of 24.8 t (loaded), the power-to-weight ratio was 22.2 hp/t which gave a top speed of 45 mph (72 kph) on flat. Its only problem was the lack of range: Only 100 miles (170 km). The engine was coupled to a cross-drive, 2-speed Allison transmission. The drivetrain comprised six double rubberized roadwheels, as the front pair served as track tensioners/idlers. Drive sprockets were located at the rear so the transmission tunnel was quite short. Suspensions called for torsion bars, and shock dampers were given to the first two roadwheel pairs. Rigid dust side skirts were installed, which can be lifted up but were often removed.

The M42 in Service

Production was undergone by the tank division of the General Motors Corporation, Cleveland Tank Plant. The first rolled of the line in 1952 and were in service in 1953. The production was altered in 1956 (M42A1) when a new Lycoming AOSI-895-5 engine (500 hp) was procured and the same range of upgrade as for the M41. Production eventually stopped in December 1959, as it was concluded that new SAM systems like the HAWK more effective against jets and condemned the SPAAGs. So the lifespan of service in the US Army was quite short, as it was decided to gradually retire all M42 from front line units and passed them to the National Guard until 1963, the only exception being the 4th Bn, 517th Air Defense Artillery Regiment which operated in the Panama Canal Zone in the 1970s.

Reborn in Viet-Nâm

As the second Indochina war escalated, it was discovered that the new HAWK system performed poorly in low altitude defense. Therefore the Army recalled M42A1s back into active service, organized into air defense artillery (ADA) battalions, a process which started in November 1966 when the first three battalions arrived in VN. Crews were trained at the 1st. Advanced Individual Training Brigade (Air Defense) at Fort Bliss, Texas. Each comprised a headquarters battery, four Duster batteries, one attached Quad-50 battery, and one artillery searchlight battery. But the threat posed by NV aircraft weakened to the point units found themselves underemployed, therefore increasingly called for ground support missions. In that area they soon excelled, gaining an enviable reputation against massed infantry attacks. In addition M42s were also used for point security, convoy escort or perimeter defense.

M42 Duster at a MACV compound, Têt. February, 1968.

Late Cold War

In the 1970s, it was generally accepted that SPAAGs were complementary to SAMs systems, the first providing an extra bubble of protection against aircraft and helicopters that escaped the longer missile range. However after Vietnam it was nevertheless decided to give these vehicles back to the National Guard, maintained until 1988 as corps level ADA assets.

Flakpanzer M42 in training, Altenkirchen-Hachenburg (Oberwesterwald), West Germany. September, 1958

M42 Duster Specifications

Dimensions 5.82 x3.23 x2.85 m (19.1 x10.7 x9.4 ft)
Total weight, battle ready 24.8 tons
Crew 4-6 (driver, Cdr, gunners, pointers, loader)
Propulsion 6-cyl AC gasoline 500 hp (375 kW) p/w 22.2 hp/t
Suspension Torsion bar & shocks absorbers
Speed (road) 72 km/h (45 mph)
Range 160 km (100 mi)
Armament 2x 40mm M2A1 336 rds, 0.8mm (0.3 in) M1919A4 or M60.
Armor 9 to 25 mm front (0.35-1 in)
Total production 3,700 in 1952-1959

Daimler Armored Car

Daimler’s Great Brother of the Dingo

The Daimler Dingo was arguably the most successful British reconnaissance armored car of World War Two, to the point of being copied by the Italians. However, the company that built it, Birmingham Small Arms design was already working on a parallel project. This was a scaled-up version, better armed with the turret developed for the Mark VII Light Tank. It was mass-produced from 1941 to the end of the war, declined into three versions and served well until the late 1960s in India.

A British radio operator stands in his Armored Daimler Command Car to relay a message to headquarters. Circa 1942

Development of the Daimler AC

This model incorporated many advanced design concepts for the time and was considered as one of the best British AFVs of the Second World War. Its use was considered complementary to the lighter Dingo with reconnaissance units, mostly to bring fire support in cases of bad encounters. The hull was strongly related to the Dingo, entirely welded with some bolted elements. Prototypes were ready in 1939 but problems with the complex transmission and amplified by the added weight of the vehicle delayed it entering service well until mid-1941. In total, 2,694 such armored cars would be built by Daimler. Most were sold after a long service in the British inventory (1960). They saw action with other countries afterward.

Daimler Mark I
Daimler Mark I

Design

Daimler Mark 2
Daimler Mark II

The hull was made of welded steel. The sides were sloped in order to better deflect bullets (16 mm thick at the front, 6 mm elsewhere). There was a small cabin-like compartment for the driver at the front, complete with two side sight slits and a front armored shutter. The commander and gunner took place inside the cramped turret, just large enough to allow the recoil of the light 2-pounder gun (40 mm), the standard British antitank gun of the time. The turret roof had a large opening hatch, folding to the rear. There were some additional storage racks and fittings on the hull for jerrycans, toolboxes, and spades. The rounds were small but muzzle velocity was excellent and at least did the job well until 1942. Later in the war in Europe, the Littlejohn adaptor was tried to add some muzzle velocity and hitting power against German tanks. Other than the main gun, there was a coaxial 0.3 in Besa machine gun, left to the gun, and also a roof provision for a pintle mount for a light AA Bren machine gun. 52 2-pdr shells and 2500 rounds for the Besa LMG were carried inside.  The Daimler 27 4.1 liter 6-cylinder petrol engine gave 95 hp (71 kW) for a power to weight ratio of 12.5 hp/tonne.  The rear 95 hp engine was connected to a Wilson preselector gearbox through a fluid flywheel and then by prop shafts to each wheel. The four wheel steering was similar to early models of the Dingo, but following early experience with the scout car, and added weight, entirely rethought. The Daimler also featured a fully independent suspension and four-wheel drive. The epicyclic gearing in the wheel hubs enabled a very low ratio in bottom gear. It was credited with managing 1:2 inclines. The rugged nature of the terrain combined with this mechanical reliability made it ideal for reconnaissance and escort work. This was compounded by large, well-spaced roadwheels that gave it excellent ground clearance. Spare side roadwheels also acted as additional armor, although blocking the lower slope escape hatches in case the vehicle was toppled over.

Side view of a Daimler Mk.II
Side view of a Daimler Mark II

Variants

  • Mark I – The first version
  • Mark I CS – Close support version with 76 mm (3 in) gun
  • Mark II – Improved turret with modified gun mount, better radiator, driver escape hatch incorporated into the roof, WP Grenade container fitted to the turret and smoke generator container modified.
  • Turretless regimental command version – This version was known as SOD (“Sawn-Off Daimler”).

Service History

British troops hitch a ride on a Mk. II Daimler Scout Car in the North African desert. Circa 1943

Just like the Dingo, the Daimler AC was extensively used in North Africa, notably with the 11th Hussars and Derbyshire Yeomanry. Others saw action in Europe. Late war reconnaissance squadrons in NW Europe generally comprised two Daimler Armoured Cars and two Dingo scout cars. Some received a Littlejohn adaptor for their 2 pounder gun. This device worked on the squeeze bore principle to increase the gun’s theoretical armor penetration. A few served in the Asiatic theater, like the 16th Light Cavalry British Indian Army armored car regiment (part of Fourteenth Army troops) in the reconquest of Burma. Postwar use was extensive, as Daimlers were used by the territorial units of the British Army until the 1960s, well outlasting the Coventry Armored Car. The 11th Hussars, B Squadron, deployed them in Northern Ireland as late as January 1960. Also postwar, the 63th Cavalry Indian Army regiment used this model for one of its squadrons, later reformed as an independent reconnaissance squadron and, later updated to the integral squadron. Some formed the mounts of the President’s Bodyguard. They served in the defense of Chushul at heights above 14,000 ft during the 1962 Indo-China War. Post-war service of the Daimler AC also included the Korean War, Vietnam War, 1948 Arab–Israeli War, Indo-Pakistani War, Ceylonese insurrection of 1971 and Sri Lankan civil war. This vehicle was used post war by no less than eleven countries, Australia, Belgium, Canada, India, Israel, Malaysia, New Zealand, Qatar, Sri Lanka, United Kingdom, and Poland.

Daimler AC Specifications

Dimensions 4 x 2.46 x 2.26 m (13’1” x 8’1” x 7’95”)
Total weight, battle ready 7.6 tons
Crew 3 (driver, gunner, loader)
Propulsion Daimler 27 4.1 litre, 6-cylinder petrol, 95 hp (71 kW), 12.5 hp/ton
Suspension 4×4 independent coil springs
Speed (road) 80 km/h (50 mph)
Range 320 km (200 mi)
Armament 2-pdr (40 mm) gun, 0.303 in (7.7 mm) AA LMG
Armor 12 mm sides to 30 mm front (0.24-0.35 in)
Total production 2693 in 1941-1945

M113 APC (Armored Personnel Carrier)

A combined arms operation in Vietnam. M113s clear the way through heavy bush while infantry follows. Circa 1967
A combined arms operation in Vietnam. M113s clear the way through heavy bush while infantry follows. Circa 1967

The M113 APC

The M113 is a fully tracked APC (Armored Personnel Carrier) that was developed by Ford Machinery Company (FMC). The vehicle was first fielded by the United States Army’s mechanized infantry units in Vietnam in April 1962. The M113 was the most widely used armored vehicle of the U.S. Army in the Vietnam War, earning the nickname ‘Green Dragon’ by the Viet Cong as it was used to break through heavy thickets in the midst of the jungle to attack and overrun enemy positions. It was largely known as an “APC” or an “ACAV” (armored cavalry assault vehicle) by the allied forces. The M113 introduced new aluminum armor that made the vehicle much lighter than earlier vehicles; it was thick enough to protect the crew and passengers against small arms fire but light enough that the vehicle was air transportable and moderately amphibious. In the U.S. Army, the M113 series have long been replaced as front-line combat vehicles by the M2 and M3 Bradley’s , but large numbers are still used in support roles such as armored ambulance, mortar carrier, engineer vehicle, and command vehicle. The army’s heavy brigade combat teams are equipped with around 6,000 M113s and 4,000 Bradley’s.

Development

The M113 was developed by Ford Machinery Company (FMC), which had produced the earlier M59 and M75 Armored Personnel Carriers. The M113 bears a very strong resemblance to both of these earlier vehicles. The M75 was too heavy and expensive to be useful; its weight prevented amphibious capability, and being transported by air. The lightened M59 addressed both of these problems, but ended up with too little armor, and was unreliable as a result of efforts to reduce its cost.

The army was looking for a vehicle that combined the best features of both designs, the “airborne armored multi-purpose vehicle family” (AAM-PVF). of all-purpose, all-terrain armored fighting vehicles FMC had been working with Kaiser Aluminum and Chemical Company in the late 1950s to develop suitable aluminum armor. It was known that use of this armor could produce a vehicle that provided the protection of the M75, and the light weight and mobility of the M59.

Food Machinery Corp. responded with two proposals; two versions of the aluminum T113—a thicker and a thinner armored one—along with the similar but mostly steel T117. The thicker-armored version of the T113, effectively the prototype of the M113, was chosen because it weighed less than its steel competitor, while offering the same level of protection. An improved T113 design, the T113E1, was adopted by the U.S. Army in 1960 as the “M113”. A diesel prototype, T113E2, was put into production in 1964 as the “M113A1”, and quickly supplanted the gasoline-engined M113.

The M113 was developed to provide a survivable and reliable light tracked vehicle able to be air-lifted and air-dropped, by C-130 and C-141 transport planes. The original concept was that the vehicle would be used solely for transportation, bringing the troops forward under armor and then having them dismount for combat; the M113 would then retreat to the rear. Entering service with the U.S. Army in 1960, the M113 required only two crewmen, a driver and a commander, and carried 11 passengers inside the vehicle. Its main armament was a single .50-caliber (12.7 mm) M2 Browning MG (machine gun) operated by the commander.

On 30 March 1962, the first batch of 32 M113s arrived in Vietnam, and were sent to two Army of the Republic of Vietnam (ARVN) mechanized rifle companies, each equipped with 15 of the APCs. On 11 June 1962, the two mechanized units were fielded for the first time. During the Battle of Ap Bac in January 1963, at least fourteen of the exposed .50 caliber gunners aboard the M113s were killed in action, necessitating modifications to improve crew survivability. Soon, makeshift shields formed from metal salvaged from the hulls of sunken ships were fitted to the carriers, which afforded better protection. But, finding that this material could be penetrated by small arms fire, subsequent shields were constructed from scrapped armored vehicles.

The ARVN 80th Ordnance Unit in South Vietnam developed the shield idea further and commenced engineering general issue gun shields for the M113. These shields became the predecessor to the standardized armored cavalry assault vehicle (or ACAV) variant and were issued to all ARVN mechanized units during the early 1960s. The ARVNs had modified the M113s to function as “amphibious light tanks” and not as battle taxis as U.S. designers had intended. Instead of an armored personnel carrier, the ARVN used the carried infantry as extra “dismountable soldiers” in “an over-sized tank crew”. These “ACAV” sets were eventually adapted to U.S. Army M113s with the arrival of the army’s conventional forces in 1965. The vehicles continued to operate in the role of a light tank and reconnaissance vehicle, and not as designed in theater. Still, the M113 could carry 11 infantrymen inside, with two crewmen operating it. The U.S. Army, after berating the Vietnamese for flouting battle doctrine, came out with their own ACAV version. This more or less standardized ACAV kit included shields and a circular turret for the .50-caliber M2 machine gun in the track commander (TC) position, two M60 machine guns with shields for the left and right rear positions, and “belly armor”—steel armor bolted from the front bottom extending 1/2 to 2/3 of the way towards the bottom rear of the M113. The two rear machine gunners could fire their weapons while standing inside the rectangular open cargo hatch. This transformed the M113 into a fighting vehicle, but the vehicle still suffered from its lightly armored configuration, having never been designed for such a role.

 

 

Design

Armament

The basic M113 armored personnel carrier can be fitted with a number of weapon systems. The most common weapon fit is a single .50 caliber M2 machine gun. However, the mount can also be fitted with a 40 mm Mk. 19 automatic grenade launcher. A number of anti-tank weapons could be fitted to the standard variant: the U.S. Army developed kits that allowed the M47 Dragon and BGM-71 TOW anti-tank missile systems to be mounted. In the case of the M47, the system mated to the existing machine gun mount, without having to remove the machine gun. This allowed the commander to use both weapons. A large array of turrets and fixed mounts are available to mount high explosive cannon ranging from 20 mm to 105 mm on to the M113 series, making them function as assault guns and fire support; while in many cases still having room inside to carry dismounted infantry or cavalry scouts.

Armor

The M113 is built of 5083 aircraft-quality aluminum alloy, which gives it some of the same strength as steel at a slightly reduced weight, as the greater thickness allows structural stiffness. The M113A3 was designed to provide protection against 7.62mm threat, and this proved not to be enough when tested in combat.

In comparison, modern APCs like the Stryker have an all-around 7.62mm armor-piercing protection, plus 14.5 mm protection on the front, sides, and rear. Also protection against antipersonnel mines through the vehicle floor is installed.

Mobility

Its weight allows the use of a relatively small engine to power the vehicle, a Detroit 6V53 V6 two-stroke diesel engine of 318 cubic inches (5,210 cc) with an Allison TX-100-1 three-speed automatic transmission. This allows the vehicle to carry a large payload cross-country and to be transported by fixed- and rotary-wing aircraft. Original production M113s can swim without deploying flotation curtains, using only a front-mounted trim vane; they are propelled in the water by their tracks.

 

An M113 armored personnel carrier, foreground, M1A1 Abrams main battle tanks and other equipment of the 3rd Armored Division move out on a mission during Operation Desert Storm. February 15, 1991

Specifications:

Type: APC (Armored Personnel Carrier)

Weight: 12.3 tonnes

Length: 16 ft tall (4.86 m)

Width: 8 ft 9 in (2.68 m)

Height: 8 ft 2 in (2.5 m)

Crew: 2

Passengers: 11

Armor: Aluminum, 12-38 mm (0.47-1.50 in)

Main Armament: M2 Browning MG

Engine: Detroit Diesel 6V53T, 6-cylinder diesel engine

Operational Range: 300 mi (480 km)

Speed: 42 mph (67.6 km/h), 3.6 mph (5.8 km/h) swimming