FMC XR311 The XR311 was a prototype military vehicle of US origin , given the nickname G . I . Hotrod . Development . Development of the XR311 commenced as a private venture in 1969 with the first of two prototypes being completed in 1970 . As a result of the trials of these 2 prototypes the US Army purchased 10 improved or second generation models in 1971 . Of these 10 vehicles , 4 had TOW missile installation for use in the anti - tank role , 3 had an M2HB machine - gun for use in the reconnaissance role and 3 had 7 . 62mm M60 machine gun s and the crew armor kit for use in the escort / security role . These trials were completed in 1972 . They were then tested by the 2nd Armored Division . In 1974 they were also tested in the 2nd Armored Reconnaissance Scout Vehicle competition along with a number of vehicles including the original FMC Technologies and Lockheed Martin designs . It has been stated that an XR311 with TOW missile installation costs around $ 50 , 000 . The XR311 has been designed to carry out a wide variety of roles including anti - tank , recce , convoy escort , command and control , medivac , military police , mortar carrier , internal security and forward air defense communications vehicle . Variants . There are 2 models of the XR311 : Reconnaissance : Fitted with a ring - mounted . 50cal M2HB machine guns with a 360 degree traverse Convoy Escort / Security Vehicle : This can be provided with a pintle - mount 5 . 56mm / 7 . 62 mmCal GPMG ' s , XM174 automatic grenade launchers and various other similar weapons . These weapons can also be mounted on the reconnaissance model on the ring mount . The following kits are available for the basic vehicle : Crew compartment armor kit , consisting of a high - hardness steel doors , side body panels , toe panel , firewall , bullet - proof windshield and bullet - proof side windows . Armored radiator , Armored fuel tank , Top and door kit ( water - proof fabric with plastic windows and hinged doors ) Various communications installations , High output alternators , 100 and 180 Amp , Litter - carrying kit , Jump seat for two additional passengers . , Explosion resistant reticulated foam fuel - tank filler , Radial ply tires or bullet - proof foam - filled tires , Extreme climate kits for winterization or desert temperatures , Tool kit and portable fire extinguisher . Overview . The XR311 is built around a tubular - steel frame safety roll - cage which protects the passenger compartment if the vehicle turns over . This cage is covered by a heavy - gauge sheet metal . An electrical winch with a capacity of can be mounted at the front of the vehicle if required , and the windshield can be removed . The passenger compartment is in the center of the vehicle with the driver on the left and two passenger seats to his right . There is space for of cargo behind the passenger seats . The engine and transmission are at the rear of the hull and there is a load - carrying space above this which can take a maximum load of . A full length skid pan protects the hull and allows the vehicle to slide over obstacles . The transmission is a Chrysler A - 727 fully automatic with a torque converter , there are 3F and 1R gears - the XR311 is in 4 x 4 drive all the time . Limited - slip clutches , in front and rear , and inter - axle differentials automatically distribute more torque to those wheels with the most grip . The independent suspension is of a double ' A ' design with a torsion - bar spring and hydraulic telescopic shock absorber at each station . A stabilizer bar is provided for the rear suspension . The steering is power - assisted and the tubeless tires have a high - pressure tube inner tire which provides a built - in spare for each tube as well as eliminating rim leaks during high speed cornering . The tires are self - cleaning and disc brakes are fitted on all four wheels . The electrical system is 24V DC and two batteries with a capacity of 45 Amp / Hr are provided . The alternator is of the integral rectifier and regulator type . The XR311 is proved with a heavy duty towing pintle as well as a trailer wiring harness receptacle . It is air - transportable and can be air - dropped .