M551 Sheridan
M551 Sheridan | |
---|---|
Type | Amphibious light tank[1] |
Place of origin | United States |
Service history | |
In service | 1969–1997 |
Wars | Vietnam War Operation Just Cause Persian Gulf War
|
Production history | |
Designer | M2 Browning machine gun with 1,000 rounds 1× .30 cal (7.62 mm) M73/M219 co-axial machine gun (later replaced by the M240C) with 3,000 rounds |
Engine | Detroit Diesel (General Motors) 6V53T, 6 cylinder, turbocharged diesel[3] 300 hp (220 kW) at 2800 rpm[3] |
Power/weight | 17.9 hp/ST (14.7 kW/t)[3] |
Transmission | XTG-250-1A |
Suspension | flat track, Torsion bar suspension |
Ground clearance | 19 in (48.3 cm)[3] |
Operational range | 350 mi (560 km) |
Maximum speed | Road: 43 mph (69 km/h) Swimming: 5.8 km/h (3.6 mph) |
The M551 "Sheridan" AR/AAV (Armored Reconnaissance/Airborne Assault Vehicle) was a light tank developed by the United States and named after General Philip Sheridan, of American Civil War fame. It was designed to be landed by parachute and to swim across rivers. It was armed with the technically advanced but troublesome M81/M81 Modified/M81E1 152 mm gun/launcher, which fired both conventional ammunition and the MGM-51 Shillelagh guided anti-tank missile.
The M551 Sheridan entered service with the
Based on its experiences in Vietnam, the Army realized the shortcomings of the Sheridan, and after the war in 1975 began to eliminate the vehicle from its units in 1979. A modest fleet of vehicles remained in the
A large number of Sheridans were retained in service at the National Training Center (NTC) at Fort Irwin, California and as Armor Officer Basic training at Armor Training Center, then located at Fort Knox, Kentucky. They worked as simulated Soviet armored opposition force (OPFOR) to train U.S. military units on simulated tank on tank armored combat to test on combat effectiveness in a desert environment. They were retired from the NTC in 2003.[5]
Development
In the immediate post-World War II era, the
In January 1959, the first concept studies were initiated for the armored reconnaissance/airborne assault vehicle that would replace both the M41 and
The AAI candidate had three crewmen, and weighed the closest to the 10-ton weight limit specified in the requirements. The Cadillac design was only slightly heavier, with four crew. The three-man turret of the Cadillac proposal was considered more effective than the two-man turret proposed by AAI. The weight limit was reset at 15 tons.[10] In June 1960, Cadillac Motor Car Division signed a contract to develop their concept further, which was designated as the AR/AAV XM551. In August 1961, the Secretary of the Army approved the name "Sheridan," after Major General Philip Sheridan.[11]
A test bed underwent operations at Cleveland Tank Plant in December 1961.[9] The decision to use the 152 mm caliber XM81 gun-launcher instead of a more conventional gun was driven by the desire to save weight. The XM81 weighed about half as much as the 105 mm caliber M68, and could fire both conventional and missile rounds. Testing of the XM81 began at Erie Army Depot in late 1961.[9]
By 1962, the Army realized that the MGM-51 Shillelagh missile system would not immediately be ready for the Sheridan, and so considered several alternative gun systems. These including conventional 76 mm, 90 mm and 105 mm options, as well as missile systems such as ENTAC and TOW. The Army ultimately decided to arm the Sheridan with just 152 mm conventional rounds until the Shillelagh was ready.[12]
The first of 12 pilots was delivered in June 1962. Pilots 1–3 comprised the first generation. With the second-generation pilots 4–6, the band track was replaced with single-pin, link type tracks.[13] An XM551 test bed turret with gun-launcher was mated to an M41 chassis, which began firing tests in August 1962 at Aberdeen Proving Ground.[14] The third generation of pilots, starting with pilot 7, eliminated the water jet propulsion.[15] Pilots 9–11 were delivered in 1964,[16] and pilot 12 was delivered in February 1965.[17]
In the 1960s the Army was also developing the
Production
In April 1965 the Army awarded a four-year $114.5 million contract to the
The Sheridan entered service in June 1967 with 1st Battalion, 63rd Armor Regiment at Fort Riley.[24] 2,426 Sheridans were planned.[25] In the end, 1,662 Sheridans were built between 1966 and November 1970. The total cost of the M551 program was $1.3 billion.[23] The M81 gun had problems with cracks developing near the breech after repeated firing, a problem that was later tracked to the "key" on the missiles that ran in a slot cut into the barrel.[23] Most field units were modified to help address the problem, but later the modified M81E1 was introduced with a shallower slot, along with a matching modification to the missile, that cured the problem.[23]
The gun was criticized for having too much recoil for the vehicle weight, the second and even third road wheels coming clear off the ground when the main gun fired.[26] In March 1967, a 105 mm howitzer XM103E7 and then a 76 mm gun was installed in the turret of an M551 at Rock Island Arsenal. Neither configuration was adopted.[27]
In January 1969 two squadrons (54 Sheridans) were deployed to the
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 problem had since then been resolved by a compressed-air system that forced hot ammunition residue from the breech, the Army told Congress. The Army said the Sheridan had performed well enough that it was planning to send hundreds more.[29] A Congressional report in July 1969 identified $1.2 billion wasted on the M60 and Sheridan. The report attributed several Vietnam War casualties to Sheridan design faults, and said that the tank had been wholly unready for combat there "without extensive and costly retrofits."[31]
The vehicle designed to mount the gun had a steel turret and aluminum hull. Although the hull could deflect heavy machine gun fire of up to 12.7 mm AP,[32] it was easily penetrated by rocket-propelled grenades (RPGs), which could destroy the vehicle if the spalling contacted the caseless main gun rounds. Like the M113 armored personnel carrier, it was vulnerable to mines.
Swimming capability was provided by a flotation screen, similar to that used by the World War II, amphibious
In the Vietnam War, firing the gun often adversely affected the delicate electronics, which were at the early stages of the transition to solid state devices, so the missile and its guidance system was omitted from vehicles deployed to South Vietnam. 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.
In 1971,
Service history
Vietnam War
The U.S. Army staff in Washington had been recommending since 1966 to the commander of U.S. forces in
In late 1968, General Abrams met with
First deployment
The first Sheridans arrived in South Vietnam in January 1969 and were accompanied by their factory representatives, instructors and evaluators as the new vehicles were issued to the 3rd Squadron, 4th Cavalry Regiment,[35] and the 1st Squadron of the 11th ACR.[34] By the end of 1970, there were more than 200 Sheridans in South Vietnam.[36] They stayed in the field until the last U.S. armored cavalry unit, the 1st Squadron, 1st Cavalry Regiment prepared for re-deployment back to the United States in April 1972.[37] 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.[38]
In 1969, armored cavalry units (minus the 11th ACR, which retained its M48 tank companies) began replacing their M48 Patton tanks, which were normally transferred to the
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. Despite vulnerability to rockets and mines, it was judged worthy of applying modifications and equipping all cavalry squadrons with the Sheridan.[39]
First combat/first losses
In addition to the problems presented by aluminum construction, the Sheridan had a defect that no other common armored vehicle possessed: it fired combustible-cased 152 mm main gun rounds. These rounds were "fixed", meaning that the projectile was firmly attached to the combustible-cased propellant charge, and if the projectile separated from the combustible-case during loading, which was not uncommon, the crewmen were instructed not to load the round. Sometimes, the combustible-cases and their charges remained on the turret floor due to the emergencies at the time, and additionally, all of the remaining serviceable 152 mm rounds were combustible-cased, and sleeved into a re-usable white nine-ply nylon
Performance
The Sheridan had several advantages: it did not get stuck in the mud as often as the 52-ton M48 did, nor did it throw its track off as often.
The reliability of the engine system and gun of the tank was, however, not fully up to the task. 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. An additional problem was that much of the carried machine-gun ammunition had to be stored outside the turret as the internal space was extremely limited.[44]
Although an average M48 crew could fire as many as seventeen 90 mm rounds during a "mad minute" (60 seconds with all guns firing-on command), the Sheridan was known to put out only two 152 mm rounds during the same time frame. The caseless rounds needed air vents to clear the gun tube and breech prior to loading another round, while the M48 breech block opened as the used case was ejected and closed as the new round was shoved in. The faster the loader, the faster the Patton's gun could be fired. For the Sheridan, the loader had to wait for the mechanism. After firing, the loader would have to wait, as the breech slowly opened rearward then turned downward. After another instrument indicated that all turret systems were still operational, the loader would gently push the 152 mm fixed round into the breech and watch the breech block slowly rotate upward, then forward into the breech, then again, wait for the lights.[45]
Over 200 Sheridans were shipped to Vietnam.
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. (12.7 mm) gun, allowing it to be fired with some level of protection. The driver has an unusual rotating hatch which has vision blocks when rotated forward. Included with the set was an extra layer of steel belly armor which was bolted onto the vehicle's bottom, although only covering from the front to half way to the end, possibly due to weight reasons.
A standard modification made during the mid-70s was the addition of the "Cereal Bowl" commander's cupola. 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. Nevertheless, the
In the early 1980s, the M551A1 was fitted with a visual modification kit to resemble
Panama
The Sheridan's only air drop in combat occurred during the
The Sheridan was praised for its performance in Panama. A U.S. after-action report noted the Sheridan's "extreme psychological effect on enemy forces", who were apparently deterred from firing at U.S. forces reinforced by tanks.[49]
Gulf War
In the early days of
Australian trials
During 1967 and 1968 the Australian Army trialed 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. 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. The main shortcoming revealed in the trials concerned the safety of the combustible case. The two Sheridans were returned to the U.S. Army in early 1969, and the Australian Army met its requirement by fitting turrets from Alvis Saladin armored cars to M113 armored personnel carriers.[54]
Replacement
In 1977, TRADOC commander General Donn A. Starry met with Army Chief of Staff General Edward C. Meyer to convince him that the service should retire the Sheridan. Starry had commanded the 11th ACR in Vietnam, and knew the vehicle's shortcomings. Starry's arguments prevailed over those of Army Material Command commander General John R. Guthrie, a Sheridan defender, and Meyer agreed the Sheridan would be retired. The Army decided on the M60A1 as the service's interim successor until the M3 Bradley was ready. At the time, 567 Sheridans existed in USAREUR, 535 in the continental U.S., and 41 in the Pacific. The Army began converting units in Europe in 1978, and in the rest of the service by 1980. The Army sustained 140 Sheridans in the 82nd Airborne Division and the National Guard. Some Sheridans were kept in pre-positioned reserve.[55]
Several attempts to improve or replace the Sheridan have been made over the years since it was introduced. In 1976,
From 1978 to 1980, under the joint Army–Marine Corps Advanced Antiarmor Vehicle Evaluation (ARMVAL),
In 1987, the Army tested a version of the
Design
Armament
Building a vehicle lighter than the T92 required an innovative solution for the main armament. A gun firing
The gun was ideal for infantry support. The large, low velocity gun could fire a large high explosive projectile or canister shot. In comparison, high-velocity anti-tank guns over-penetrated soft targets, while smaller caliber weapons could not carry as great a payload.
The M81E1 was not ideal in medium- and long-range tank engagements as its low velocity produced extended flight times, and made it difficult to lead moving targets. Therefore, the gun was also designed to fire
A number of existing vehicles already mounted only ATGMs, or alternately recoilless rifles like the M50 Ontos, but these typically had limited utility in the infantry support role, or in the case of Ontos could not be reloaded from within the vehicle. The XM551 appeared to offer a superior balance between anti-tank and infantry support.
Mobility
Tactical mobility
The Sheridan was powered by a large 300-hp (224 kW) Detroit Diesel 6V53T diesel engine, and a flat track (no support rollers).[66] The XM551 thus had an excellent power-to-weight ratio and mobility, able to run at speeds up to 72 km/h (45 mph). However, the vehicle proved to be very noisy and early Sheridans were unreliable under combat conditions.
The Sheridan could swim across a river that was about 46 m (50 yards) wide. Tanks in the Patton series (M46, M47, M48), as well as the M60 tank[67] could not perform these operations; they would have to crawl along the river bottoms using snorkels. Not by design, it was found that the swimming hardware acted to reduce the effectiveness of RPG hits, but it was rarely used in Vietnam.
Strategic mobility
The Sheridan can be rigged for low-velocity airdrop from
Variants
- XM551/M551 - The M551 was the basic production model, beginning production in 1967. 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. These were needed for stabilized turret operation.). The resulting additional space was filled with two separate boxes, one for 12.7×99mm NATO(.50 BMG) ammunition, and the missile stowage was redesigned to accept conventional rounds.
- "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. These were needed for stabilized turret operation.). The resulting additional space was filled with two separate boxes, one for
- M551A1 - Upgraded M551 with AN/VVG-1 laser rangefinder.
- M551A1 TTS - Tank Thermal Sight, fitted with the AN/VSG-2B thermal sight unit, similar to the unit used on the M60A3 MBT. This later became standard to all M551A1s.
- M551 NTC - .
- Armored Tracked Recovery Vehicle (ATRV) - Prototype.[70]
Table of variants
XM551 pilots 1–3[71] | M551[72] | M551A1 Sheridan (TTS)[3] | |
---|---|---|---|
Hull Length | 258 in (6.6 m) | 248 in (6.3 m) | |
Width | 110 in (2.8 m) | ||
Height | 108 in (2.7 m) | 116 in (2.9 m) | |
Ground Clearance | 19 in (48.3 cm) | ||
Top speed | 35 mph (56 km/h) | 43 mph (69 km/h) | |
Fording | Floats | ||
Max Grade | 60 percent | ||
Max Trench | 5 ft (1.5 m) | 8 ft (2.4 m) | |
Max Wall | 18 in (0.5 m) | 33 in (0.8 m) | |
Range | 300 mi (480 km) | 350 mi (560 km) | |
Power | 285 hp (213 kW) at 2800 rpm | 300 hp (220 kW) at 2800 rpm | |
Power-to-Weight Ratio | 17.1 hp/ST (14.1 kW/t) | 17.9 hp/ST (14.7 kW/t) | |
Torque | 435 lb⋅ft (590 N⋅m) at 1900 rpm | 615 lb⋅ft (830 N⋅m) at 2100 rpm | |
Weight, Combat Loaded | 33,247 lb (15,080 kg) | 33,460 lb (15,180 kg) | 33,600 lb (15,240 kg) |
Ground Pressure | 6.7 psi (46 kPa) | 6.8 psi (47 kPa) | 6.9 psi (48 kPa) |
Main Armament | M81E3 152 mm gun/launcher | M81E12 152 mm gun/launcher | M81E1 152 mm gun/launcher |
Coaxial weapon | XM121 .50 caliber (12.7 mm) spotting rifle, M73 7.62 mm machine gun |
M73 or M219 7.62 mm machine gun | M240 7.62 mm machine gun |
Elevation | +20° / -10° | +19.5° / -8° | |
Traverse Rate | 15 seconds/360° | 10 seconds/360° | |
Elevation Rate | 4°/second | ||
Main Gun Ammo | 20 rounds | 30 (including 10 missiles) | 29 (including 9 missiles) |
Firing rate | 4 rounds per minute | ||
Protection | 7039 aluminium alloy hull, Rolled homogeneous steel turret |
Display vehicles
- Airborne & Special Operations Museum, Fayetetteville, NC[73]
- American Armoured Foundation's Tank and Ordnance War Memorial Museum, Danville, VA. M551A1 deployed in Desert Shield/Storm. Markings: 3rd Battalion 73 Regiment, Co. B, 2nd platoon, attached to the 82nd Airborne Division.
- American Heritage Museum, Stow, Massachusetts has an M551 that is in operating condition.
- American Society of Military History and Museums, South El Monte, Ca. 2 non running exhibits and a running, ex-vismod unit.[74]
- Antioch, Illinois has a veterans monument displaying a M551A1 across the street from the police station.
- Camp Joseph T. Robinson, Arkansas National Guard Museum[75]
- Camp Perry, near Port Clinton, Ohio, has an M551 on display as part of a static display.
- Columbia, MO Outdoor display at American Legion Park, off East Broadway, 602 Legion Ln, Columbia, MO 65201, United States.
- First Division Museum at Cantigny,[76] an example of the M551A1 is on display in the tank park outside the museum in Wheaton, Illinois.
- Fort Bliss, static display at Sheridan Gate entrance.
- Fort Hunter Liggett on static display at the entrance.
- Fort Irwin/NTC, has one vehicle on display at the 11th Cavalry Regiment museum.
- 509th Parachute Infantry Regiment.
- Fort Knox, Kentucky. Static display at Wilson Road entrance.
- Fort Liberty, NC Outdoor exhibit at the 82d Airborne Division War Memorial Museum.
- Fort Moore, static display on Tower Branch of U.S. Army Airborne School across from Maneuver Center of Excellence.
- Fort Richardson, Camp Denali on static display.
- Gowen Field, Idaho Army National Guard
- Hardwood Range,[77] an example is on static display at the visitor center at Hardwood Air-to-Ground Weapons Range in Finley, Wisconsin.
- Ike Skelton Missouri National Guard Training Facility, Jefferson City Missouri. Ike Skelton Training Facility has a M551 in their outside museum.
- Louisiana National Guard Training Center Pineville in Pineville, LA static display outside of the post museum.
- Leon Davenport Building in Blairsville, GA has an M551 on display outside.
- Mott's Military Museum in Groveport, Ohio has an M551 on display outside with other various vehicles.
- The Museum of American Armor, Old Bethpage, NY on static display.
- Museum of Missouri Military History, on static display outside the museum.
- The Ontario Regiment Museum, in Oshawa, has two Sheridan tanks on display. One is in not operating condition and the other has been restored with its original 11th Cavalry markings.
- Sullenberger Aviation Museum
- Vietnam Veterans of America, in Baltimore, MD has an M551A1 on display outside of the building at 6401 Beckley St.
- Watervliet Arsenal
- Yad La-Shiryon Israel
- Yuma Proving Ground in Yuma, AZ. On static display outside range control.
See also
- List of "M" series military vehicles
- List of vehicles of the U.S. Armed Forces
- M60A2, which used a similar 152 mm gun-launcher
- M3 Bradley, a modern AFV that sometimes covers the same roles
References
- Notes
- ISBN 978-1-101-00226-1. Retrieved 20 January 2011.
- ^ Defense Industry Bulletin (May 1965), p. 25
- ^ a b c d e f g h i j k l Hunnicutt 1995, p. 309.
- ^ Hunnicutt 1995.
- ^ a b Byron Hartshorn. "The Strange Second Life of the M551 Sheridan Light Tank". Retrieved 16 February 2015.
- ^ Hunnicutt 1995, p. 53.
- ^ Hunnicutt 1995, p. 75.
- ^ a b Hunnicutt 1995, p. 76.
- ^ a b c Hunnicutt 1995, p. 78.
- ^ Hunnicutt 1995, p. 76-77.
- ^ Hunnicutt 1995, p. 77-78.
- ^ Hunnicutt 1995, p. 79-82.
- ^ Hunnicutt 1995, p. 88.
- ^ Hunnicutt 1995, p. 82.
- ^ Hunnicutt 1995, p. 90.
- ^ Hunnicutt 1995, p. 92.
- ^ Hunnicutt 1995, p. 97.
- ISBN 0-89141-304-9.
- ISBN 0-89141-230-1.
- ^ Middleton, Drew (20 June 1962). "NATO Ponders How to Overcome East Bloc's Tank Superiority". The New York Times. Retrieved 13 August 2018.
- ^ Hunnicutt 1995, p. 7.
- ^ "Contract Awards". The New York Times. Associated Press. 13 April 1965. Retrieved 15 August 2018.
- ^ a b c d Hunnicutt 1995, p. 101.
- ^ a b Zaloga 2009, p. 26.
- ^ Zaloga 2009, p. 25-26.
- ^ "The M41 Walker Bulldog Light Reconnaissance Tank - YTread". youtuberead.com. Retrieved 2023-04-05.
- ^ Hunnicutt 1995, p. 109.
- ^ Starry p. 143
- ^ a b Sheehan, Neil (15 May 1969). "Army Accused of Rushing Work On Tanks to Avoid Budget Scrutiny". The New York Times. Retrieved 14 August 2018.
- ^ "Army Is accused of Hiding 'Ineptness' in Tank Program". The New York Times. UPI. 14 March 1969. Retrieved 14 August 2018.
- ^ "U.S. Tank Systems Attacked In House". The New York Times. 10 July 1969. Retrieved 14 August 2018.
- ^ Zaloga 2009.
- ISBN 0 7106-0849-7.
- ^ a b c d e Starry 1978, p. 143.
- ^ "3d Squadron, 4th Cavalry". Archived from the original on May 7, 2013. Retrieved July 30, 2013.
{{cite web}}
: CS1 maint: bot: original URL status unknown (link) - ^ Starry 1978, p. 144.
- ^ Starry 1978.
- ^ a b Starry 1978, p. 143-145.
- ^ Washer evaluation 1969 Archived 2011-07-14 at the Wayback Machine
- ^ ISBN 0-89141-171-2.
- ^ Starry 1978, p. 144-145.
- ^ a b Nolan 1986.
- ^ ARMY CONCEPT TEAM IN VIETNAM APO SAN FRANCISCO 96384. Optimum Mix of Armored Vehicles for Use in Stability operations Volume 1. 31 MAR 1971
- ^ Pignato, Nicola, 'History of armoured vehicles', 1976, F.lli Fabbri editions, Bologna, p. 630
- ^ Stanton 2003, p. 277.
- ^ Doyle 2008, p. 31.
- ^ a b Hunnicutt 1995, p. 280.
- ^ Doyle 2008, p. 44, 46.
- ^ a b Zaloga 2009, p. 40-42.
- ^ a b c d e Zaloga 2009, p. 43.
- ^ Zaloga 2009, p. 39.
- ^ Doyle 2008, p. 4.
- ^ Hunnicutt 1995, p. 282.
- ^ "Paul D Handel, Sheridan Tropical Trials in Australia". Anzacsteel.hobbyvista.com. Retrieved 2014-04-10.
- ^ Zaloga 2009, p. 35-38.
- ^ Zaloga 2009, p. 45.
- ^ Hunnicutt 1995, p. 160.
- ISBN 0-85045-541-3.
- ^ Zaloga 2009, p. 44-45.
- JSTOR 43988110. Retrieved 23 January 2022.
- ^ Arenstein, Seth (4 March 1996). "AGS killed as Army budget rises". Defense Daily. Archived from the original on 13 April 2017. Retrieved 12 April 2017.
- JSTOR 43985396. Retrieved 23 January 2022.
- ^ The Army Is Ditching All of Its Stryker Mobile Gun Systems. Military.com. 12 May 2021.
- JSTOR 26416303. Retrieved 26 February 2022.
- ^ "Sheridan Tank Weapons Demonstration (1969)". Special Operations History Foundation. Retrieved 30 April 2013.[permanent dead link]
- ^ Hunnicutt "Abrams" (1990) p. 23
- ISBN 0-89141-230-1.
- ^ "Gary's Combat Vehicle Reference Guide". Inetres.com. Retrieved 2014-04-10.
- ^ "4 x M551 Sheridan Light Tanks LVAD C-5B Paradrop". YouTube. 2007-11-24. Archived from the original on 2021-12-11. Retrieved 2014-04-10.
- ^ Hunnicutt 1995, p. 134.
- ^ Hunnicutt 1995, p. 307.
- ^ Hunnicutt 1995, p. 308.
- ^ "Airborne & Special Operations Museum - Fayetteville, NC". Asomf.org. 1940-08-16. Archived from the original on 2014-03-05. Retrieved 2014-04-10.
- ^ GNP (2011-10-19). "tankland.com". tankland.com. Retrieved 2014-04-10.
- ^ "arngmuseum.com". arngmuseum.com. Retrieved 2014-04-10.
- ^ "First Division Museum at Cantigny". Firstdivisionmuseum.org. Archived from the original on 2012-07-03. Retrieved 2012-10-25.
- ^ "Wisconsin Air National Guard: Hardwood Air-toGround Weapons Range, Finley, Wisconsin" (PDF). Volkfield.ang.af.mil. Archived (PDF) from the original on 2022-10-09. Retrieved 2012-10-25.
- Bibliography
- Doyle, David (2008). M551 Sheridan. Squadron Signal Publications. ISBN 978-0-89747-582-2.
- Hunnicutt, R.P. Abrams, A History of the American Main Battle Tank. Vol. 2. Presidio Press 1990.
- ISBN 978-1-62654-154-2.
- ISBN 978-0-89141-247-2.
- ISBN 978-025322-002-8.
- Stanton, Shelby L. (2003). Vietnam Order of Battle: A Complete Illustrated Reference to U.S. Army Combat and Support Forces in Vietnam 1961-1973. Stackpole Books. ISBN 978-0-81170-071-9.
- ISBN 978-1-83931-084-3. Archived(PDF) from the original on 2022-10-09. Retrieved 16 March 2022.
- ISBN 978-1-84603-391-9.