FMC XR311 (G.I. Hotrod) Multi-Purpose / Multi-Role 4x4 Vehicle
Though not adopted for service into the American Army, the XR311 helped to pave the way for like-minded special forces Fast Attack Vehicles to come.
Authored By Staff Writer; Content ©www.MilitaryFactory.com
In 1969, the FMC Corporation undertook in-house development of a new multi-purpose four-wheeled military vehicle designed to handle several battlefield-minded roles. The United States Army's interest in its capabilities peaked when it committed to a procurement order of ten prototype examples under the designation of "XR311". The vehicle was considered in a few differing configurations - Anti-Tank Guided Missile (ATGM) carrier, fast reconnaissance and escort/security. The missile carrier was procured in four examples (these armed with the TOW missile launcher), the reconnaissance model in three (with 1 x 12.7mm heavy machine gun) and the escort/security model in three (with 3 x 7.62mm machine guns and additional chassis armor). A standard operating crew was three personnel while power was delivered from a V8 gasoline-fueled engine of 187 horsepower @ 4,000rpm fitted to a rear compartment. This was coupled to a 3-speed Chrysler TorqueFlite A727 series automatic transmission. The vehicle weighed in at 6,300lbs and featured a road speed topping 80 miles per hour with a 0-60 time of 12 seconds. Operating ranges were limited to 300 miles while the chassis was capable of crossing 20-inch-high vertical obstacles and fording depths up to 30 inches. A pair of prototypes were made ready for evaluation in 1970.
For its military-minded service, the vehicle was completed with full-time 4x4 wheel drive with the forward axle being steerable (under power-assist). A light steel sheet metal armor skin was used to cover the steel tube roll cage within. A skid plate mounted under the chassis allowed the vehicle to traverse extremely rocky/uneven terrain with some security from becoming stuck in place. Each rubber-tired road wheel was independently suspended for improved cross-country mobility. Dimensionally, the XR311 was given a running length of 4.3 meters, width of 2 meters and height to hull roof of 1.6 meters. The entire vehicle was coated in a non-reflecting black matte finish.
Externally, the vehicle was of a conventional arrangement with the driver seated behind a steering column in the usual way. A twin-panel windscreen protected the frontal view while the sides, rear and top of the cabin were optionally left open. The roll bar assembly ran behind the cabin and across center. The six-shot TOW missile launcher was fitted overhead on the center beam. Stowage boxes were situated to either side of the engine installation at rear and additional tow launcher tubes could be fixed on mountings over the front wheel fenders. All pertinent systems gauges were installed along a contained dash area near the steering column. The gear stick control was between the two frontal seats while there proved a small area behind the seats for additional crew or storage (the passenger front seat was noticeably larger in size for two possible occupants. The engine compartment was well-ventilated through slits across the top and grating along the back facing.
While tested by the United States Army (through the 2nd Armored Division into 1974), the XR311 was never ordered for serial production, leaving the few completed units in existence (the US Army eventually committed to the 4x4 HUMVEE series
in 1984). One XR311 example sits at the indoor display of the Russell Military Museum in northern Illinois - this version fitted with the multi-shot TOW missile system and over-fender TOW launchers. While not formally adopted, US Army interest in the XR311 inevitably led to other like-minded special fast wheeled developments such as the Chenoweth Desert Patrol Vehicle (DPV).
The XR311 eventually became known under the nickname of "G.I. Hotrod" for rather obvious reasons.