By Scott R. Gourley

A recent paper prepared by the Congressional Budget Office (CBO) helped highlight several critical aspects of the U.S. Army’s tactical wheeled vehicle fleet. Titled “Replacing and Repairing Equipment Used in Iraq and Afghanistan: The Army’s Reset Program,” the September 2007 paper stated: “With so many trucks being left in the theater, returning units must rely on equipment supplied from excess stocks or left behind by deploying units. In some cases, as with HMMWVs [Humvees], FMTVs [family of medium tactical vehicles] and heavy expanded-mobility tactical trucks [HEMTTs], there is no surplus—indeed, the Army does not have enough of those types of trucks to equip all of its units.”

Elaborating on that shortage, the CBO paper noted: “Even in the absence of constraints arising from operations in Iraq, the Army would need almost 30,000 additional FMTVs and almost 3,000 more HEMTTs to fully equip its forces.” Fortunately, in the case of HEMTTs, the Army will soon begin receiving the initial quantities of new HEMTT A4 platforms, enhanced capability systems that will significantly expand warfighter capabilities on the battlefields of today and tomorrow.

According to Mike Ivy, director, Army Tactical Vehicle Programs, Defense Business, Oshkosh Truck Corporation, the HEMTT A4 is a product improvement to the HEMTT A2. Ivy explained that the new A4 design includes enhancements like a new drivetrain, upgraded suspension system, a new “ready-to-armor” cab, electrical system improvements and installation of a J1939 data bus.

“It’s all based off the same HEMTT platform that has been in service since the early 1980s,” Ivy said. “But it’s a product-improved truck. So it’s not a program ‘new start’ or anything like that. And it will give the Army a significantly improved capability for the coming years.”

The vehicles will enter the Army’s wheeled fleet through a combination of new production vehicles and remanufactured former A2 models that will be taken down to the frame rails and sent back through the new vehicle production line.

Characterizing the HEMTT A2 now in the field as “the workhorse of Army tactical logistics,” Ivy acknowledged that “the A2 is in theater today with an add-on armor kit. And with the add-on armor it has attendant issues on things like suspension and the horsepower necessary to drive the truck, and so on.”

With the A4 systems, the horsepower will be increased through the installation of a new 500 hp Caterpillar C-15 engine (peaks at 515 hp to provide 70 hp more than HEMTT A2). Another drivetrain enhancement involves the Allison 4500 SP/five-speed automatic transmission, rated for 600 hp and offering 1,750-pound torque, gross input, to handle more power.

“The Allison-Caterpillar lash-up in the drivetrain is going to be a significant improvement over today’s vehicle,” Ivy said. “That will compensate for the addition of the armor weight. We’re [also] making suspension changes to account for the addition of armor weight. We’re installing climate control in the cab—that’s something that has to be done in an ‘after market’ fashion on the old A2—and we’re going to do that on the factory floor now, which will make the armor installation a much easier and quicker process.

“So we’re doing a number of things that will address—I wouldn’t call them problems—but they are issues with the A2, as the A2 has been armored and really run hard in theater today,” Ivy added.

According to Ivy, HEMTT A4 origins date back approximately two years, to an Army contract that directed Oshkosh Truck Corporation to product-improve the HEMTT A2. Following an analysis-of-alternatives process, the Army then put the company under contract to design the truck to integrate the new C-15 engine, a greater cooling package and a ready-to-armor cab.

“That began about two years ago, based primarily on customer initiative to modernize the HEMTT A2,” Ivy observed. “The HEMTT … A2 is fundamentally the same truck that we began building 25 years ago.”

After more than 45,000 miles of testing on the HEMTT A4 prototype design, Oshkosh received its initial HEMTT A4 production contract in October 2007. In March Oshkosh received a contract modification to the current FHTV contract, ordering the manufacture of 1,084 HEMMTs in the A4 configuration. This contract modification raises the total of HEMTT A4s to 1,745, with production to begin in July.

“We’re not on contract yet to do any ‘recap,’” Ivy said. “That’s in a contract that should come this summer.”

While declining to offer specifics, Ivy also acknowledged some level of international interest in the A4 platforms.

In addition to the enhancements of the new design—reliability, maintainability, survivability and capability—Ivy noted that part of the future planning by the government and industry team also involves various ways to enhance situational awareness for the HEMTT A4 crews.

“We are installing in one of our prototype trucks, located at Aberdeen Proving Ground, Md., a number of installation kits for the suite of C4ISR [command, control, communications, computers, intelligence, surveillance and reconnaissance] systems that soldiers expect to see in vehicles today,” Ivy said. “That includes things like the Movement Tracking System, GPS, Battle Command System—the whole suite of systems that gives the soldier increased situational awareness. Although there is nothing inherent in the A4 for the Future Combat System-equipped brigade, it could easily be adapted to that, given the right installation kits.” The integration of the installation kits by Oshkosh will allow the Army to test a range of potential C4ISR capabilities for the new platforms.

“One thing that really sets the A4 apart from other trucks in the Army fleet—and it doesn’t matter whether you are talking light, medium or heavy—is the fact that the HEMTT A4 will be the first LTAS [long-term armor strategy]-compliant truck that the Army has fielded,” Ivy noted. “By that, I mean that it is the first truck made to receive B-kit armor. And that’s a big deal. The cab will be made with the appurtenances to receive B-kit armor. We are under contract to design that armor. We’ve done that and it has been tested at Aberdeen—very successfully,” he said.

Ivy noted that Plasan Sasa played a large role in the design of the B-kit armor and that DRS Technologies Inc. will serve as the major vendor/supplier for that armor.
“We will be the first truck platform in the Army that will come with the A-kit/B-kit configuration on the crew cab,” he added. “And we’re very excited about that.”

In addition to offering significant survivability improvements over today’s add-on armor, Ivy summarized that additional warfighter benefits will be derived through emerging commonality in the heavy truck fleet.

“We’re also currently improving the palletized load system (PLS) truck,” he said. “And the PLS and the HEMTT, going forward, are going to share some significant features, such as the Cat C-15 engine, commonality in transmission—there will be some modification, but the core transmission will be the same—and, significantly, the cabs will be the same on both of those trucks. So they will have the same B-kit armor for both trucks. That’s a change from today. If you look at the HEMTT A2 cab and today’s PLS cab, they look the same—but dimensionally they are not. So you don’t put the same armor on both those cabs. But when the Army buys PLS A1, they will have a common cab with HEMTT A4, which will reduce the logistics burden and simplify the training in how to install armor and operate vehicles.