Armored Personnel Carrier, Equipment Carrier XM474
A UNIVERSAL CHASSIS BASED UPON THE M113 SERIES
Early in the development program, it was obvious that a successful armored personnel carrier would provide the basis for an entire family of vehicles. Such a family would utilize many of the same components greatly simplifying logistical support. Although the T149 was dropped along with the Dart missile, another antiaircraft weapon was under development which would make use of the M113 type chassis.
This was the 37mm gun T250, a six barrel Gatling type gun being developed both as a towed weapon, Vigilante A, and as a self-propelled gun, Vigilante B. A modified version of the T113E1/E2 armored personnel carrier was proposed as the prime mover for the Vigilante A. Designated as the high speed, full-tracked, tractor T122, it retained the suspension, tracks, and power train of the personnel carrier.
The driver and the engine compartment in the front hull were protected by aluminum alloy armor as were the two fuel cells located in the open top rear compartment. These cells were installed in the rear corners of the compartment on each side of the fifth wheel support. The contents of the rear compartment could be protected by the installation of an armor blanket on three aluminum bows. This blanket consisted of 12 ply, unbonded nylon, bar laminate, armor cloth.
FMC received a contract on 9 June 1958 to build a prototype and two pilot tractors. The prototype was accepted for test in July 1959 and the first pilot was scheduled for completion in March 1960. However, fonds were not available for the second pilot. With the termination of the Vigilante weapon system, the T122 project also was canceled.
The self-propelled Vigilante В was installed on a low silhouette armored vehicle based upon the same components as the personnel carrier. Designated as the self-propelled gun chassis T249, it was slightly longer than the other vehicles with the ground contact length increased from 105 inches to 110% inches. Additional details of the T249 appear in the section on antiaircraft vehicles.
During the initial development of the Pershing guided missile system, it was intended to use two types of tracked vehicles to transport the missile and its support equipment. The missile equipment carrier XM474 and was based upon components from the T113 series of vehicles developed by FMC. The servicing equipment carrier was designated as the XM476 and it was based upon the T116 amphibious cargo carrier. This was the vehicle standardized later as the M116 Husky.
It was developed and manufactured by the Pacific Car and Foundry Company. Prototypes were constructed of both the XM474 and the XM476, but further analysis indicated that the XM474 could meet all of the ground transportation requirements of the Pershing system. As a result, the XM476 program was terminated. Further development resulted in changes to the XM474. To meet air transport requirements, the vehicle was reduced in width from 102 inches to 100 inches and it was lengthened, increasing the ground contact length to 111 inches. The first modified design concept was designated as the XM474E1, but the final, lengthened, version became the XM474E2 (U.S. Army).
Four of the XM474E2s, equipped with bolt-in kits were required to transport the complete Pershing system. This included the missile itself on the transporter-erector-launcher, the communications hut, the fire control hut, the reentry unit with the warhead, and the personnel and miscellaneous hardware required to launch the missile.
The XM474E2 was a low silhouette, unarmored, vehicle assembled by welding 5083 aluminum alloy with the same suspension, tracks, and power train components as the M113 armored personnel carrier. As on the M113, the driver rode in the left front with the engine and transmission on the right. Without the missile system components, the XM474E2 weighed about 11,900 pounds. The vehicle had a maximum fording depth of 42 inches, but it could be made amphibious by the installation of a kit.
The Pershing missile system was deployed initially using the XM474E2. However its primary theater of operation was in Europe. Here, the excellent road system did not require the use of transporters with good cross-country performance. As a result by 1967, the Pershing system was being deployed using five 5 ton 8x8 trucks.