US Navy HTT Snapshot
High Capacity Transport
In 2010, Navistar Defense set out to compete for the contract to build the US Navy’s Heavy Transport Truck (HTT). At the time, Navistar was not satisfied that there was an existing suspension that could meet the capacity demands and still offer suitable mobility in the environments in which the HTT would be tested. Navistar’s specific requirements included: High carrying capacity; safe high-speed operation; and reasonable off-road mobility.
Navistar decided to approach Raydan Manufacturing (now LSC) to develop the suspension for the Navy armored super heavy haul tractor after working together on a successful development project for the R-11 Air Force Refueller Program. Raydan had delivered 970 Air Link suspensions that incorporated a unique lift feature enabling the refuellers to be loaded onto the C130 Hercules aircraft. This history, combined with the HTT specification requiring an 84,000lb capacity, gave Navistar the confidence to move forward.
Rather than scaling the existing 75,000 lb. Air Link to meet the project requirements, the LSC/Raydan team developed an all-new design, modeled after a custom suspension originally created for Lockheed Martin’s ATS program. The ATS suspension was engineered to transport space-bound payloads from various construction sites around the US to the final integration centers. The new 84,000 lb. capacity would become the highest capacity Air Link available.
Due to tight time constraints, weekly progress meetings were held with both Navistar and Meritor – who were simultaneously developing a new family of hub-reduction axles for this truck. In less than ten weeks the initial design was completed. Eight weeks later, two prototypes were delivered to Navistar and a third prototype began undergoing rigorous testing on LSC’s own test rig. After completing the equivalent of 600,000 km (375,000 mi) without any failures, the suspension design was released for limited production. Raydan also sent staff to Navistar’s Garland assembly plant to assist in the first on-line installation of the suspension. The simplicity of the Air Link design allowed the 84,000 lb. suspension and axles, to be installed in the same amount of time as a regular 46,000 lb. suspension.
With the initial run of four trucks built, intensive testing was started on two units at NATC (Nevada Automotive Test Center). Following more than three months of stringent durability tests, the Navy was satisfied that these vehicles met their requirements and full production was authorized. Over the next few months, all 38 trucks were delivered and can now be found hauling heavy equipment wherever US Naval Construction Forces are needed.