Jump to content
 







Main menu
   


Navigation  



Main page
Contents
Current events
Random article
About Wikipedia
Contact us
Donate
 




Contribute  



Help
Learn to edit
Community portal
Recent changes
Upload file
 








Search  

































Create account

Log in
 









Create account
 Log in
 




Pages for logged out editors learn more  



Contributions
Talk
 



















Contents

   



(Top)
 


1 Development  



1.1  Variants and upgrades  







2 Service  





3 Preserved vehicles on display  





4 See also  





5 References  





6 Sources  





7 External links  














M50 Ontos






العربية
Deutsch
Español
Français
Italiano
עברית

Norsk bokmål
Polski
Русский
Українська

 

Edit links
 









Article
Talk
 

















Read
Edit
View history
 








Tools
   


Actions  



Read
Edit
View history
 




General  



What links here
Related changes
Upload file
Special pages
Permanent link
Page information
Cite this page
Get shortened URL
Download QR code
Wikidata item
 




Print/export  



Download as PDF
Printable version
 




In other projects  



Wikimedia Commons
 
















Appearance
   

 






From Wikipedia, the free encyclopedia
 

(Redirected from Ontos tank)

Rifle, Multiple 106 mm, Self-propelled, M50 "Ontos"
Ontos M50A1, the 50-cal spotting rifles can be seen on the upper guns
TypeTank destroyer
Place of originUnited States
Service history
In service1956–69
Used byUnited States
WarsVietnam War
Dominican Civil War
1958 Lebanon Crisis
Production history
DesignerAllis-Chalmers
Designed1952
ManufacturerAllis-Chalmers
Produced1955–57
No. built297
VariantsM50A1
Specifications
Mass8,600 kg (19,000 lb)
Length3.83 m (12 ft 7 in)
Width2.59 m (8 ft 6 in)
Height2.13 m (7 ft 0 in)
Crew3 (driver, gunner and loader)

Sightsx6 .50 Single-Shot Spotting Rifles

Main
armament

6 × M40A1C recoilless rifles

Secondary
armament

1 × .30 (7.62 mm) M1919 Browning machine gun
EngineGM 6-cylinder inline 302 cu in (4.95 L) gasoline engine
145 hp (108 kW)

Operational
range

185 km (115 mi)
Maximum speed 48 km/h (30 mph)

Ontos, officially the Rifle, Multiple 106 mm, Self-propelled, M50, was an American light armored tracked anti-tank vehicle developed in the 1950s.

It mounted six 106 mm manually loaded M40 recoilless rifles as its main armament, which could be fired in rapid succession against single targets to increase the probability of a kill. Although the actual caliber of the main guns was 105 mm, it was designated 106 mm to prevent confusion with the ammunition for the 105 mm M27 recoilless rifle, which the M40 replaced.

It was produced in limited numbers for the U.S. Marines after the U.S. Army cancelled the project. The Marines consistently reported excellent results when they used the Ontos for direct fire support against infantry in numerous battles and operations during the Vietnam War. The American stock of Ontos was largely expended towards the end of the conflict and the Ontos was removed from service in 1969.

Development[edit]

The Ontos (Greek for "thing"[1]) project was created to be an air transportable tank destroyer capable of being lifted by the cargo aircraft of the 1950s. This limited the vehicle to a weight between 10 and 20 metric tons. The Ontos also had to use the six-cylinder engine then widely used in the Army's GMC trucks. Allis-Chalmers was awarded a contract on August 12, 1955, for 297 vehicles.

Allis-Chalmers' first vehicle, completed in 1952, was based on the running gear of the M56 Scorpion light anti-tank vehicle. The vehicle mounted a cast steel turret with two arms holding three rifles each. This early model could traverse the turret only about 15 degrees. A second prototype used a new suspension system, new tracks, and a newer turret with about 40 degrees traverse. The vehicle could carry only eighteen rounds for the main guns inside the vehicle due to limited space. Four of the recoilless rifles also had .50 BAT (12.7x77mm) M8C spotting rifles attached, each of which fired a tracer round with the same trajectory as the 106 mm round, and that gave off a flash and puff of white smoke on impact. The spotting rifles were used to line up the 105 mm recoilless rifles with the target. The Ontos also carried a single .30 caliber (7.62 mm) M1919A4 machine gun for anti-infantry use.

The vehicle was taken to the Aberdeen Proving Ground where single rifles had been tested earlier. When all six weapons were fired at once, the back blast from the firing knocked bricks out of a nearby building and knocked the rear windows out of several cars. The prototype and testing stage was completed by 1955, at which point the Army canceled its order.

As an anti-tank vehicle the Ontos had several problems, including a small ammunition load, a very high profile for such a small vehicle, and the need for the crew to exit the vehicle in order to reload the guns, exposing them to enemy fire. Although the Army canceled their order, the Marine Corps were desperate for any anti-tank vehicles they could get, and ordered 297. Production ran from 1955 through 1957. The Marine Corps accepted its first vehicle on 31 October 1956.

Variants and upgrades[edit]

Several variants were also studied. The Utility Vehicle, Tracked, Infantry, T55 was a light Armored personnel carrier (APC), but only two versions of the prototype were built. It proved impractical due to the limited room inside, carrying only five infantry and forcing the driver to lie prone. A "stretched" version known as the Utility Vehicle, Tracked, Infantry, T56 was also built, and while it held a complete eight-man team, their equipment had to be carried on the outside. Neither was considered very useful.

In 1960 there was a brief study made to replace the Ontos's 106 mm rifles with a new 105 mm design that included a revolver-style autoloader. This project was not accepted.

Another proposed upgrade was replacing the GMC engine with a newer Chrysler 361 cu in (5.92 L) V8 engine. This upgrade was implemented and the variant was named Rifle, Multiple 106 mm, Self-propelled, M50A1. However of the 297 vehicles initially accepted by the Marines, only 176 were converted between 1963 and 1965 to this standard.

Service[edit]

While the M50 was designed as a tank destroyer, during the Vietnam War most M50s did not engage enemy armor as the North Vietnamese Army deployed few tanks. The Ontos was therefore more widely used by the US Marines for direct fire support for the infantry in combat, a role that was never emphasized in training or doctrine. Its light armor was effective against small arms but vulnerable to mines and Rocket-propelled grenades. Consequently, many Ontos were deployed in static defense positions.

The relatively light weight of the M50 made it exceptionally mobile for the amount of firepower it carried. In one operation, the Ontos was the only tracked vehicle light enough to cross a pontoon bridge. In the Battle of Huế, Colonel Stanley S. Hughes felt the Ontos was the most effective of all Marine supporting arms. At ranges of 300 to 500 yards (270 to 460 m), its recoilless rifles could knock holes in or completely knock down walls. The appearance of an Ontos was sometimes enough to make the enemy break and run, and anecdotal accounts describe the enemy fleeing occupied buildings when an Ontos's spotting round entered a window. In Operation Desoto, the introduction of the large CH-53 Sea Stallion helicopter made possible moving a platoon 25 miles (40 km) south of Quảng Ngãi City carrying Ontos in slings underneath the aircraft.[2]

The Ontos units were deactivated in May 1969, and some of the vehicles were handed over to an Army light infantry brigade. They used them until they ran out of spare parts, and then removed the turrets and used them as fixed fortifications.[citation needed] Both these and the rest of the vehicles returned from Vietnam in 1970 and were cut up for scrap, with some of the chassis being sold off to be converted into construction vehicles. Some of the Ontos that were sold to construction companies were later acquired by collectors for restoration.

The Ontos did see use as an anti-tank weapon during the American involvement in the Dominican Civil War: on 29 April 1965 an M50 Ontos and an M48 Patton of the 6th MEU engaged and destroyed two rebel L/60L light tanks, each destroying one. In another instance, an Ontos destroyed an AMX-13.[3]

Preserved vehicles on display[edit]

M50 Ontos at the U.S. Army Armor & Cavalry Collection, Fort Benning (now Fort Moore), Georgia, in 2023

There are Ontos on display at the following US locations:

See also[edit]

Similar vehicles

References[edit]

  • ^ Sgt. T.D. Stephens (9 May 2006), Ontos-a mean thing feared by Viet Cong – via Newspaper clipping (Flickr)
  • ^ Roblin, Sebastien (22 June 2016). "In 1965, U.S. and Dominican Tanks Fought Brief, Violent Skirmishes". War is boring.
  • ^ Estes 2016, p. 47.
  • ^ Estes 2016, p. 36.
  • ^ "National Museum of Military Vehicles on Facebook". Facebook. Archived from the original on 2022-04-30.[user-generated source]
  • ^ "Restoration – Museum of the American G.I."
  • ^ "Two weeks out. Put it on your calendar! Come see us". Facebook. Indiana Military Museum. 9 July 2023. Retrieved 21 June 2024.
  • Sources[edit]

    External links[edit]


    Retrieved from "https://en.wikipedia.org/w/index.php?title=M50_Ontos&oldid=1230312196"

    Categories: 
    106 mm artillery
    Tank destroyers of the United States
    Cold War armored fighting vehicles of the United States
    Allis-Chalmers Manufacturing Company
    Military vehicles introduced in the 1950s
    Hidden categories: 
    Accuracy disputes from March 2022
    Articles with short description
    Short description is different from Wikidata
    All articles with unsourced statements
    Articles with unsourced statements from June 2022
    Articles with unsourced statements from April 2019
    All articles with vague or ambiguous time
    Vague or ambiguous time from April 2019
    Commons link is on Wikidata
    Articles with J9U identifiers
    Articles with LCCN identifiers
     



    This page was last edited on 22 June 2024, at 00:28 (UTC).

    Text is available under the Creative Commons Attribution-ShareAlike License 4.0; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.



    Privacy policy

    About Wikipedia

    Disclaimers

    Contact Wikipedia

    Code of Conduct

    Developers

    Statistics

    Cookie statement

    Mobile view



    Wikimedia Foundation
    Powered by MediaWiki