M50 Ontos
Rifle, Multiple 106 mm, Self-propelled, M50 "Ontos" | |
---|---|
1958 Lebanon Crisis | |
Production history | |
Designer | Allis-Chalmers |
Designed | 1952 |
Manufacturer | Allis-Chalmers |
Produced | 1955–57 |
No. built | 297 |
Variants | M50A1 |
Specifications | |
Mass | 8,600 kg (19,000 lb) |
Length | 3.83 m (12 ft 7 in) |
Width | 2.59 m (8 ft 6 in) |
Height | 2.13 m (7 ft 0 in) |
Crew | 3 (driver, gunner and loader) |
Sights | x6 .50 Single-Shot Spotting Rifles |
Main armament | 6 × M40A1C recoilless rifles |
Secondary armament | 1 × .30 (7.62 mm) M1919 Browning machine gun |
Engine | GM 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
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
Development
The Ontos (Greek for "thing"
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
Several variants were also studied. The Utility Vehicle, Tracked, Infantry, T55 was a light
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
While the M50 was designed as a tank destroyer, during the
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
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
Preserved vehicles on display
There are Ontos on display at the following US locations:
- The Patton Museum of Cavalry & Armor in Fort Knox, Kentucky[4] (no longer on display, may have moved with the Armor school to Fort Benning).[citation needed]
- The Rock Island Arsenal Museum in Rock Island, Illinois.[citation needed]
- Camp Atterbury, Edinburgh, Indiana.[citation needed]
- The American Military Museum, in El Monte, California has an M50 that is missing its six recoilless rifles.[citation needed]The Aberdeen Proving Ground's Museum in Aberdeen, Maryland has a T165E2, the 19th prototype, though it is not currently on display. The vehicle is currently[when?] undergoing a cosmetic restoration.[citation needed]
- Fred Ropkey, owner of the Ropkey Armor Museum in Crawfordsville, Indiana owns the first prototype T165, a later model Ontos, and a parts machine.[citation needed]
- The National Museum of the Marine Corps in Quantico, Virginia has completed the restoration of an M50A1 Ontos.
- The Museum of The Marine in Jacksonville, North Carolina has an operational M50A1 Ontos which is not on public display.[citation needed]
- There is an M50A1 Ontos on outside display at the Navy Facility at China Lake, California.[citation needed]
- The Marine Corps Air Ground Combat Center Twentynine Palms, California has an M50A1 Ontos on outside display.[citation needed]
- The Military Vehicle Technology Foundation in Portola Valley, California has a T165E1 prototype with the original GM 302ci engine which is currently undergoing a complete operational restoration, and a second prototype T165E2 Ontos.[citation needed]
- The Ft. Sill, Oklahoma.[citation needed]
- The Marine Corps Mechanized Museum, Camp Pendleton, displays a M50A1 Ontos that took part in the Battle of Hue.[5]
- There is an M50 Ontos on display inside of the National Museum of Military Vehicles in the Vietnam exhibit, near Dubois, Wyoming[6]
- Russell Military Museum in Zion, Illinois.
- The Museum of the American GI in College Station, Texas has one undergoing restoration.[7]
See also
- List of artillery
- List of self-propelled anti-tank guns
- List of artillery of the United States
- G-numbers(SNL G288)
- Similar vehicles
References
- ^ Standard Catalog of U.S. Military Vehicles – 2nd Edition p. 376
- ^ 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.
- user-generated source]
- ^ "Restoration – Museum of the American G.I."
Sources
- Estes, Kenneth W (2016). M50 Ontos and M56 Scorpion 1956–70: US Tank Destroyers of the Vietnam War. New Vanguard 240. ISBN 9781472814739.
- Kutta, Timothy J., "ONTOS: The USMC's Most Famous Anti-Tank Weapon", Modern War magazine, no. #14 November/December 2014, Bakersfield, California: Strategy & Tactics Press (Decision Games), pp. 72–75
- McNab, Chris (2003). Military Vehicles. Hoo, Kent, UK: Grange Books. p. 56. ISBN 1-84013-539-5.