| M398: Dimensions | |||
| Weight | 16,000lbs 7,300kg |
Height | 116" 295cm |
| Length | 263" 668cm |
Width | 94" 240cm |
| Tread | 70" 180cm |
Wheelbase | 154" 394cm |
| Ground clearance | 11" 28cm |
||
| M398: Armament | ||||
| Type | Mount | Ammunition | Elevation | Traverse |
| Guided Artillery Missile M4 | Helical launcher at rear | 1 missile | 30° (15° left and right; manual) |
+70° to +5° |
| Aiming equipment | ||||
| Panoramic telescope M12A7 for operator | ||||
| M398: Armor |
| None |
| M398: Automotive | |||||
| Engine | Reo Motors OA-331 or Continental COA-331; 6 cylinder, 4 cycle, inline gasoline | ||||
| Horsepower | 127@3,400rpm | Torque | 248lb-ft@1,400rpm | Fuel capacity | 50gal 190L |
| Transmission | Spicer Model 3053A synchromesh, 5 speeds forward, 1 reverse | ||||
| Steering | Ross TA-66 cam and twin lever; steering wheel | ||||
| Brakes | Air over hydraulic | ||||
| M398: Suspension | ||
| Type | Road wheels | Shock absorbers |
| Semi-elliptic leaf spring | 3/side | On front wheels |
| M398: Performance | |
| Turning radius | 36' 11m |
The M398 was used as an assembly platform for the guided artillery missile M4 Lacrosse, and also transported the assembled missile and supported it during laying and firing. It was based on the 2½-ton 6x6 truck chassis M45, and consisted of a work platform, launcher rail and tube assembly, sighting and laying equipment, storage compartments, and hydraulic and electrical systems. It could travel at 20mph (32kph) on gravel or Belgian block roads, 15mph (24kph) on radial washboard and typical cross-country roads, and 5mph (8kph) on 6" (15cm) washboard roads.
The guided artillery missile M4 was used to provide general support in precision and area fire against targets such as pillboxes, blockhouses, enemy troops, materiel, installations, or supply lines. The missile was initially a Navy project, but was assigned to the Army on 31 August 1950 after the Joint Chiefs of Staff enacted a policy in late 1949 decreeing that ground-launched, short-range, surface-to-surface guided missiles supporting or extending conventional artillery capabilities would be an Army Ordnance responsibility. The missile was radio controlled by a forward observer using a ground station located away from the launcher, using the control equipment to acquire the missile's tracking signal and adjust its path to the target. The missile could be armed with a 540lb (245kg) T34 shaped charge or a 10 kiloton W-40 nuclear device. Four hundred W-40s were produced for the Lacrosse from September 1959 to May 1962. An improved MOD I guidance system that would have decreased the possibility for enemy jamming of the radio signal was cancelled on 18 August 1959 due to lack of funding, leading to the US Marine Corps backing away from employing the missile. The first missiles were delivered on 1 July 1959, and the type was redesignated as MGM-18A in June 1963. Difficulties with the guidance equipment, intensive maintenance, and subpar reliability led to the Lacrosse being declared obsolete in February 1964.
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References
- TM 9-500 C3 Data Sheets for Ordnance Type Materiel. Washington, DC: Headquarters, Department of the Army, 12 October 1966.
- TM 9-2320-209-10 C11 Operator's Manual for Truck, 2½ Ton, 6x6 Gasoline Engine Models: M185, M185A1, M34, M35, M36, M36C, M47, M49, M342, V18A/MTQ, M17A/MTQ, M49, M49C, M50, M48, M275, M567, M292, M109, M109A1, M108, M60; Mutifuel Engine Models: Truck, Van, Expansible: M292A1, M292A2, M292A5 (Body Only). Washington, DC: Headquarters, Department of the Army, 15 May 1980.
- TM 9-2320-209-20 C3 Organizational Maintenance Manual 2½ Ton, 6x6, Chassis, Truck: M44, M44A1, M44A2, M45, M45A1, M45A2, M45C, M46, M46A1, M46C, M57, M58, M58A1; Instrument Repair Shop, Truck MTD: M185, M185A1, M185A2, M185A3; Truck, Cargo: M34, M35, M35A1, M35A2, M36, M36A2, M36C; Truck, Dump: M47, M59, M342; Truck, Maintenance: Earth Boring Machine and Pole Setter, V-18/MTQ; Truck, Maintenance: Telephone Construction and Maintenance, V-17A/MTQ; Truck, Tank: Fuel Servicing, 1,200-gal., M49, M49A1C, M49A2C, M49C; Truck, Tank: Water, 1,0000-gal., M50, M50A1, M50A2; Truck, Tractor: M48, M275, M275A1, M275A2; Truck, Van, Expansible, M292, M292A1, M292A2; Truck, Van: Missile Firing Data Computer, XM472; Truck, Van: Shop, M109, M109A1, M109A2, M109A3, M109C, M109D, XM567; Truck, Wrecker: Crane, M108; Truck, Wrecker: Light, M60. Washington, DC: Headquarters, Department of the Army, 7 April 1965.
- Parsch, Andreas. "Martin MGM-18 Lacrosse." Designation-Systems.Net. 26 January 2002. Accessed 8 October 2024 <http://www.designation-systems.net/dusrm/m-18.html>.
- "Lacrosse." Redstone Arsenal Historical Information. Accessed 8 October 2024 <https://history.redstone.army.mil/miss-lacrosse.html>.
- "MGM-18 Lacrosse." GlobalSecurity.org. 12 June 2017. Accessed 8 October 2024 <https://www.globalsecurity.org/military/systems/munitions/mgm-18.htm>.
- Sublette, Carey. "List of All U.S. Nuclear Weapons." The Nuclear Weapon Archive: A Guide to Nuclear Weapons. 30 March 2023. Accessed 8 October 2024 <https://nuclearweaponarchive.org/Usa/Weapons/Allbombs.html>.
Last updated 8 Oct 2024.
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