"Mounted Combat In Vietnam." Department of the Army publication, 1989. Zaloga, Steven J., M551 Sheridan, US Airmobile Tanks 1941–2001.
The T92 was already in the prototype stage and could not be easily refitted for this role, so the design of an entirely new system started as the XM551. In the 1960s the Army was also developing the MBT-70 main battle tank with West Germany.
In 1960, with the deactivation of its last (M103) heavy tank battalion, and the fielding of the new M60 series tank, the U.S.
Partly because of this policy, the new M551 could not be classified as a light tank, and was officially classified as an "Armored Reconnaissance/Airborne Assault Vehicle". In April 1965 the Army awarded a four-year $114.5 million contract to the Cadillac Gage division of the General Motors (GM) for the production of the M109 howitzer and the XM551 General Sheridan.
The XM551 had been a limited run pre-production model produced in 1965. * "Two Box" M551 - With the obvious shortcomings of the Shillelagh missile, all but two of the guidance and fire control components of the missile system were removed (the power supply and rate sensor were retained.
At the time of the M551's acceptance into service production in 1966, the United States Army no longer used the heavy, medium, and light tank classifications.
Stratton criticized Army officials for the program's high costs, and accused officials of concealing cost figures to cover up for their own "bumbling ineptness." A GAO report leaked in May revealed the Army had fast-tracked the program to avoid budgetary scrutiny, despite indications by May 1966 that the tank's caseless ammunition was prone to cooking off.
The expensive missile was fired in anger only in the Persian Gulf War's Operation Desert Storm, despite a production run of 88,000 units. ==Production== Production started on 29 July 1966, and it entered service in June 1967 with 1st Battalion, 63rd Armor Regiment at Fort Riley.
In the end, 1,662 M551s were built between 1966 and 2 November 1970.
Army staff in Washington had been recommending since 1966 to the commander of U.S.
It was armed with the technically advanced but troublesome M81/M81 Modified/M81E1 152mm gun/launcher, which fired both conventional ammunition and the MGM-51 Shillelagh guided anti-tank missile. The M551 Sheridan entered service with the United States Army in 1967.
The expensive missile was fired in anger only in the Persian Gulf War's Operation Desert Storm, despite a production run of 88,000 units. ==Production== Production started on 29 July 1966, and it entered service in June 1967 with 1st Battalion, 63rd Armor Regiment at Fort Riley.
The AGS lost out against the wheeled General Dynamics Land Systems Stryker M1128 Mobile Gun System. ===Australian trials=== During 1967 and 1968 the Australian Army trialled two Sheridans to determine if the type met a requirement for light armored fighting vehicles to serve with the Royal Australian Armoured Corps newly formed cavalry regiments.
On landing, they go to their tank, release the lines, and drive it away. ==Variants== XM551/M551 - The M551 was the basic production model, beginning production in 1967.
By 1968, the new, or soon to be, U.S.
cavalry squadrons for the vehicle, the affected squadrons expressed their concerns that the new aluminum tanks were not only highly vulnerable to mines and anti-tank rocket fire, but they would not be as capable of "jungle busting" as the M48A3 medium tanks. In late 1968, General Abrams met with Colonel George S.
The AGS lost out against the wheeled General Dynamics Land Systems Stryker M1128 Mobile Gun System. ===Australian trials=== During 1967 and 1968 the Australian Army trialled two Sheridans to determine if the type met a requirement for light armored fighting vehicles to serve with the Royal Australian Armoured Corps newly formed cavalry regiments.
The main trials took place in the tropical Innisfail area of north Queensland between January and June 1968.
Commander, Military Assistance Command Vietnam, at the time, the M551 was rushed into combat service in Vietnam in January 1969.
In April and August 1969, M551s were deployed to units in Europe and South Korea, respectively.
In March 1969, after the Army invoked secrecy in declining to disclose program costs, a Government Accountability Office (GAO) official said development costs had reached $1.3 billion.
In 1969, armored cavalry units (minus the 11th ACR, which retained its M48 tank companies) began replacing their M48 Patton tanks, which in turn were normally transferred to the South Vietnamese military.
This was largely due to the high casualty rate of both Sheridans and their crews as mines and rocket-propelled grenades (RPGs) that would only damage an M48 Patton tank, would destroy the Sheridan and kill or wound most, if not all, of its crew. A 1969 evaluation of the vehicles found that the M551 was employed in reconnaissance, night patrol and road clearing, accumulating 39,455 road miles and 520 combat missions, with a ready rate of 81.3 percent.
On 15 February 1969, just one month after the Sheridan's arrival in South Vietnam, an M551 from the 3/4th Cavalry detonated a 25-pound pressure-triggered land mine, which ruptured its hull and ignited the 152mm shells, resulting in a secondary explosion that destroyed the tank.
In late 1969, nine Sheridans from the 4th Squadron, 12th Cavalry Regiment were fording a river near the DMZ, when three of the M551s detonated mines, completely destroying them.
Of 74 M551 sent to Vietnam in February 1969, by May there were recorded 16 serious mechanical faults, 41 failed shots, 140 defective ammunitions and 25 burned engines; the turret itself had 125 electric faults, several recoil system faults and instances of blown up guns.
In January 1969 the Minister for the Army announced that Australia would not purchase any Sheridans as the tanks did not meet the Army's requirements.
Army in early 1969, and the Australian Army met its requirement by fitting turrets from Alvis Saladin armoured cars to M113 armored personnel carriers. ==Design== ===Armament=== Building a vehicle lighter than the T92 required an innovative solution for the main armament.
In the end, 1,662 M551s were built between 1966 and 2 November 1970.
By the end of 1970, there were more than 200 Sheridans in South Vietnam, and they stayed in the field until the last U.S.
Sheridan losses were heavy during normal operations, largely due to land mines and anti-armor weapons, but were especially heavy after the start of the Cambodian Campaign on 1 May 1970 in which, among other cavalry squadrons, the 11th ACR was thrown into the fight.
On March 1971, five Sheridans from the 11th ACR were lost in one day to RPG fire; all five vehicles burst into flames and were totally destroyed.
Army's final offensive of the war, operation Dewey Canyon II, when the Cavalry's remaining Sheridan squadrons met near disaster on the Laos border during the early months of 1971, in particular the 1/1st Cavalry. ====Combat field modifications==== A common field-modification was to mount a large steel shield, known as an "ACAV set" (Armored Cavalry Assault Vehicle), around the commander's 50-cal.
armored cavalry unit, the 1st Squadron, 1st Cavalry Regiment prepared for re-deployment back to the United States on 10 April 1972.
By the end of its combat debut in 1972, the Sheridan had seen extensive action in the Vietnam War, being assigned to nearly all armored cavalry squadrons involved in that conflict.
This mod came about due to the "broken rib" effect that occurred when the Sheridan fired conventional rounds; the recoil would pitch the commander against the armor plating, resulting in cracked ribs. ===Post-Vietnam War service=== The Army began to phase out the Sheridan in 1978, although at the time there was no real replacement.
Their units were later upgraded to the M551A1 TTS model, including a thermal sighting system for the commander and gunner. In the early 1980s, the M551A1 was fitted with a visual modification kit to resemble Warsaw Pact vehicles from Soviet BMP-1, ZSU-23, T-55 to T-80s, at the National Training Center at Fort Irwin, California.
Presidio Press: 1986. Sorley, Lewis.
The four M551s transported by the C-5 were secretly deployed to Panama in November 1989, where they were attached to TF Bayonet (193rd Infantry Brigade), and attached down further to TF Gator.
"Mounted Combat In Vietnam." Department of the Army publication, 1989. Zaloga, Steven J., M551 Sheridan, US Airmobile Tanks 1941–2001.
The Low Altitude Parachute Extraction System (LAPES) is a somewhat risky maneuver that allows accurate delivery onto a field when landing is not possible, and the practice was stopped in the late 1990s.
Now retired from service, it saw extensive combat in the Vietnam War, and limited service in Operation Just Cause in Panama, and the Persian Gulf War in Kuwait. The Sheridan was retired without replacement officially in 1996.
Nevertheless, the 82d Airborne Division was able to keep them until 1996.
The Army sought replacement in the United Defense M8 Armored Gun System, but the program was canceled in 1997 by the Pentagon before it could enter production.
United Defense again pitted their AGS against other vehicles in the Mobile Gun System program of the 2000s.
They were finally retired from the NTC in 2003. ==Development== In the immediate post-World War II era, the U.S.
The OPFOR Sheridans no longer fulfill that role, having been retired at the end of 2003 and subsequently scrapped or made available as "hard targets" or, in a few cases, as museum pieces.
All text is taken from Wikipedia. Text is available under the Creative Commons Attribution-ShareAlike License .
Page generated on 2021-08-05