Defense Media Network

Expeditionary Mobility

Across its portfolio spectrum, one key characteristic of United States Marine Corps land systems involves its expeditionary mobility. From light personnel carriers to heavy logistics transport vehicles, the emphasis on expeditionary mobility is a defining performance trait for Marine Corps platforms.

“The Marine Corps has a fairly unique perspective when they look at vehicle mobility,” offered Ben Garza, Marine Corps coordinator for Joint Center Ground Vehicles. “Based on its mission profiles, the Marine Corps looks at having the operational capability to support our expeditionary mission with all of our vehicle platforms.”

Outside the Marine Corps, few individuals have more personal knowledge and experience with the underlying mobility mandates than Henry Hodges, Jr., president of the Nevada Automotive Test Center (NATC).

Founded in 1957, the independent proving ground in western Nevada includes a 6,200-acre main ranch site and 1,200-square-mile operational area with more than 3,000 miles of measured test courses.

“What we try to do is measure and quantify the environment that supports the expeditionary role of the Marine Corps,” Hodges said. “And over the years – both on the commercial side and in support of the military – we have continued to measure, expand, and understand dirt. You have got to understand the soil and you have got to understand the conditions where these vehicles will operate. We put numbers to it and then give that data back to the Marine Corps, which uses the data as they see fit. But it is all focused on evaluating vehicles to the range of conditions in which they will be operating.

“And over the years that has allowed us to bring our knowledge – of the dirt and the terrain and the conditions and the roughness – and put those conditions in engineering terms that can be used by the Marine Corps,” he added.

Soft-Soil Mobility Analysis

Three elements of soft-soil mobility analysis are depicted in this cube graphic. Image courtesy of PEO LS

Hodges offered a historical image of “Twister,” an extremely high mobility platform developed by Lockheed Missiles and Space that has been identified by many as the most mobile vehicle ever built by the Army.

“The Twister was a high mobility twin engine – front-powered/rear-powered – vehicle with roll, pitch, and yaw articulation,” he explained. “And the reason that is significant relative to the Marine Corps is that their Logistics Vehicle System [LVS] purchased back in the 1980s represented the first application of a vehicle that had a center joint that allowed roll, pitch, and yaw, together with the associated mobility. Twister was really the precursor to that LVS platform.”

Over the past several decades, NATC representatives have traveled the globe and returned with specific information on conditions and terrain elements subsequently incorporated into the test venue.

“Whether it’s rice paddies, sand, or mountainous terrain, we want to be able to quantify how vehicles will perform in that broad range of conditions,” he said. “And we stay globally current because we also work for corporations and organizations involved in large international infrastructure projects. Obviously they will want to pick vehicles that will do their best for those big projects. And that entire process helps the Marine Corps as well, because we are able to explore some of those most severe conditions, which also helps the Marine Corps in their expeditionary role.”

“As an expeditionary force, the Marine Corps has to be very cognizant of those environmental extremes,” Garza echoed. “I’m not saying that our vehicles are deployed without support, but the expectation for all of our vehicles is that they will perform very well with great reliability and reduced life-cycle costs across those environmental extremes.”

Along with assured mobility, the engineering information is also used in modeling, simulation, and performance testing to help validate safety and survivability elements of the platform.

Garza and Hodges shifted from the testing and engineering foundation to explain how the NATC processes have been applied to the development of today’s Marine Corps land systems as well as how it is being applied to future initiatives.

“In ‘the old days,’ people might say that they want to be able to operate cross-country in rough terrain,” Hodges related. “Well, what does that mean? Are they talking about cross-country in Afghanistan? Iraq? Korea? All of those situations are different. So, in order to have a vehicle capable of worldwide expeditionary operations, you want to be able to quantify the information and bring it back to the Marine Corps so that they can do the necessary system evaluations to pave the way for an integrated vehicle design.”

“In order to really study worldwide operations accurately, you’ve got to pick some specific places,” he continued. “So, early on, and in concert with guidance received from the Marine Corps, we selected five operational areas as ‘representative’ of a very broad range of conditions.”

“In order to really study worldwide operations accurately, you’ve got to pick some specific places,” he continued. “So, early on, and in concert with guidance received from the Marine Corps, we selected five operational areas as ‘representative’ of a very broad range of conditions.”

Those five representative operational areas and related conditions include: Costa Rica (wet/hot, coastal plains to mountains, and limited infrastructure); Philippines (wet/hot, monsoons, jungles and mud, and limited infrastructure); Southwest Asia (dry/very hot, desert/sand, open spaces, varied infrastructure); Norway (very cold/snow, mountains with channelized access, and moderate infrastructure); and Korea (dry to wet, hot to cold, urban areas and mountains, and limited to moderate infrastructure).

“This is not because the Marine Corps is going to land in Costa Rica,” Hodges added. “But, in terms of South America, in an unclassified sort of way, it provides things like very interesting terrain, soil types, and heavy vegetation with grades. So, for each of these representative operational areas, specific missions were identified.”

Garza noted that the specific mission sets included things like non-combatant evacuation, humanitarian operations, raids and seizures, and full-on, force-on-force combat.

“What’s really important in that is that it allowed definition and measurement of everything from snow to jungle in engineering terms,” Hodges said. “Prior to this, we tended to ‘fight the Fulda Gap,’ worrying about the plains of Europe and how to operate in that environment. And that emphasis had established a certain set of criteria, in things like 60 to 70 percent on-road and 30 to 40 percent off-road. And a lot of vehicles were developed to those profiles.

“In the early 1990s, the Marine Corps recognized that their expeditionary roles would further limit their access to improved infrastructures. In many cases they would not have infrastructure to exploit for mobility. And, quite honestly, that 1990s shift in emphasis on mobility and infrastructure has put the Marine Corps in a good position in places like Afghanistan,” he added.

That mobility recognition in the early- to mid-1990s also supported a need to quantify those values on a worldwide basis. Moreover, it coincided with Marine Corps efforts to transition from their aging 5-ton logistics platforms to a newer model vehicle design.

The service’s search for a “better 5-ton” included a look at expected operational terrains, recognition of the realities of a third-world roadway infrastructure, the need to navigate beach or littoral operational entry points, and the ability to perform in urban terrain environments. When combined with mobility and reliability issues from Desert Storm, the resulting Marine Corps Medium Tactical Vehicle Replacement (MTVR) requirements literally flipped the historical operational profile to reflect 30 percent on-road and 70 percent off-road operations.

Sand Mountain State Park

Comparative analysis of soft-soil mobility between the AAVP7, the MPC-TD, and the M1A1 Abrams tank, conducted at Sand Mountain State Park, Nev. Image courtesy of PEO LS

“They needed that mobility and capability,” Hodges said. “And this is the time frame when certain definitions were identified and established.”

From an engineering perspective, the specific definitions encompassed figures for root mean square (RMS). At a “top level” view, it meant that the cross-country terrain RMS of 0.6 to 2 inches RMS for the historical Eurocentric mission profile was now reflected for MTVR as 1.5 to 4.8 inches.

“This was kind of a turning point,” Hodges observed. “It meant that as an expeditionary force the Marine Corps looked at the terrain roughness and the severity of conditions associated with that requirement [and] they realized that their operational terrain would be considerably rougher than previously specified.”

Applying those operational terrain differences to specific platform requirements eventually led to the acquisition and fielding of MTVR by the Marine Corps and the Family of Medium Tactical Vehicles (FMTV) by the Army.

“Similarly, there is a significant difference between the Palletized Loading System [PLS] for the Army and the Logistics Vehicle System-Replacement [LVS-R] for the Marine Corps,” Hodges noted.

He added that most recently, the Army and Marine Corps worked closely to reach operational consensus on the JLTV.

“The Marine Corps had previously established levels of roughness and, in discussions with the Army and recognition of how JLTV would be used in the future, joint service agreement was reached,” Hodges said. “As a result, the JLTV now has terrain conditions, roughnesses, and severity that match what the Marine Corps identified and defined starting back in the mid-1990s with the MTVR.”

From a developmental standpoint, the identification and definition of terrain leads to determination regarding overall system performance and capability. Specifically, once mission terrain profiles and environmental extremes are specified, requirements planners can identify how fast they want to cross that terrain; how much they need to carry; the reliability required; and system survivability mandates.

“When you integrate all those elements it effectively defines how much wheel travel you need to have, how big the tires have to be, how much traction you need, how big the motor has to be, and other on-board capabilities that might be required.”

“When you integrate all those elements it effectively defines how much wheel travel you need to have, how big the tires have to be, how much traction you need, how big the motor has to be, and other on-board capabilities that might be required,” Hodges asserted. “So by having the terrain measurement and then being able to sit down and work up your operational mode summary, you can define all those elements of an integrated design. And not only do you understand what the vehicle needs to be successful, but as the missions change going forward, you understand what you need to do to update or optimize that vehicle.”

In terms of hardware, the Marine Corps mobility requirements process has also been fed by lessons learned through two decades of NATC Advanced Concept Technology Demonstration (ACTD) platforms for the MTVR, LVS-R, Combat Tactical Vehicle Technology Demonstrator (CTVTD), and Marine Personnel Carrier Technology Demonstrator (MPCTD). Each of the ACTDs built off previous efforts and incorporated additional capabilities onto the platforms.

“The MTVR was the first ACTD ‘out of the box’ in the early 1990s,” Hodges said. “And it allowed the Marine Corps to bring a number of major technologies to the forefront. Those included things like geared reduction hubs, 1600R20 tires, and big motors. At the time, many people were saying that if you put a big motor in there you would kill yourself in terms of fuel economy. But as it turned out, a compliant suspension, with big tires, with a properly sized motor – in terms of payload delivered – has more than a 30 percent improvement over a solid-axle truck with a 250-horsepower Cummins installed. That’s comparing the 5-ton to the MTVR.”

He added, “The point is that the Marine Corps has been able to break down some of those vehicle design and performance paradigms to be very successful.” As Hodges noted above, the same processes that feed new requirements development also allow planners to optimize the update/reset/ recapitalization of existing vehicle platforms. An excellent example can be found in the new Marine Corps HMMWV Sustainment Modification Initiative (HSMI). The initiative is designed to help identify options for extending the viability of remaining HMMWV fleet elements that will not be replaced by JLTV.

“As the HMMWV has gotten so much heavier – in both the Marine Corps and the Army – it gets stuck a lot,” Hodges said. “The M1165s and similar HMMWVs will get stuck at their current weights, whereas future vehicles, like JLTV, will not be getting stuck.”

In support of HSMI, NATC has developed four different concept vehicle designs, each incorporating different enhancements in the areas of increased wheel travel and damper technology, larger tires with central tire inflation system, and upgraded power train. The designs also reflect a modular approach that would facilitate further cost-effective upgrades of the platforms with future new technologies.

Although focusing on wheeled vehicle performance, Hodges acknowledged that the issues were representative of a similar story regarding Marine Corps tracked vehicles.

“Mobility has always been key for the Marine Corps because of its expeditionary role,” he concluded. “And because of that, the Marine Corps has invested in quantifying and making those measurements to ensure that those vehicles can be deployed and will successfully perform worldwide.”

This article first appeared in the Marine Corps Outlook 2013-2014 Edition.


Scott Gourley is a former U.S. Army officer and the author of more than 1,500...