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U.S. Air Force Airmen from the 23rd Special Tactics Squadron drive a GMV-ST off a MC-130P Combat Shadow.

Thirty years ago the U.S. Army issued a specification for a new tactical vehicle and the concept for the High Mobility Multi-purpose Wheeled Vehicle (HMMWV) was born. The new tactical vehicle would enter service with the U.S. military in 1985 and would become as adaptable to its mission as the venerable jeep it replaced. The HMMWV has a low profile of 6 feet, a 7-foot-wide stance and is 15 feet in length. These proportions provide a low center of gravity making it a stable, road-hugging vehicle that is difficult to roll over. On one occasion while traversing the edge of an impact zone, the driver told me to tighten my seat belt and headed down a hillside, which I would not have tried on foot.

In the 1990s, the Special Forces missions established a need for a more robust version of the HMMWV. During the Gulf War, the Special Forces modified HUMMVs for extended desert missions. These modified Desert HMMWVs were often referred to as “Dum-Vees,” though this was never an official name. The modifications included a heavier suspension, more powerful engine, an open bed and back for storage of water and fuel and other mission-essential items.

Building A War Wagon

Further modifications of the vehicle included the placement of a cupola on the roof, which was used for mounting various weapons systems, including: M2 .50 machine guns, M240 7.62mm belt-fed machine guns, MK19/MK47 40mm grenade launchers, and M249 SAW 5.56mm machine guns. Some of these modifications were conducted by the original manufacturers, while other enhancements were performed by U.S. Army deports and third-party suppliers.

Used by the SF mounted teams, the basic deployment was four vehicles per ODA (operational detachment alpha, or “A” team), with a crew of three soldiers per vehicle. The “Desert Hummvee” greatly enhanced the capability of the mounted ODA, extending their mission endurance and flexibility. In the mid-90s the Special Forces began modifying the HMMWV M1025 model for their missions. These specially modified HMMWVs received the designation as GMV (Ground Mobility Vehicle) by the SF troops.

The need for improved payload and performance led AM General to provide a new ECV (expanded capacity vehicle), the model M1113. In 2003, the U.S. Special Operations Command would field more than 200 of the M1113 GMV, specially modified for special operations forces. In 2005, AM General began production of the M1165 variants, which incorporated the highest levels of armor protection including frag kits that can be installed or removed in the field. A Frag Kit is a vehicular armor developed by the U.S. Army Research Laboratory to defeat EFP (explosively formed projectiles), a type of IED.

Some of the modifications incorporated into the GMV include: 15-gallon auxiliary fuel tanks to achieve longer range, storage racks for ammo, an air compressor, electric winch, reinforcement of the rear floor, roll-over bars, rear bench seats, electronic-rack mounting for communications equipment, recovery strap kits, jacks, skid plates, spare tire carriers, side rails and an assortment of weapon mounts. Add-on armor provides 360-degree protection for the vehicle, additionally there is also a cupola for the gunner. In addition to the weapons systems, the GMV can be fitted with smoke grenade launchers positioned in the rear and front.

To Carry More, Farther
070410-A-9834L-006Special Forces use the GMV-S. Normally crewed by three soldiers with four GMVs per ODA.

Current efforts underway with the GMV family include a suspension upgrade that returns some of the pre-armor payload capacity and a significant standardization effort to consolidate the multiple configurations of the GMV into a single SOF GMV with a heavy and light configuration, based on the threat environment. An emerging requirement is the joint light tactical vehicle, which is a tactical replacement vehicle for the HMMWV.

To accomplish such an undertaking, SOCOM turned to the Letterkenny Army Depot in Pennsylvania to build a vehicle with unique capabilities above and beyond those provided by the Army-standard HMMWV. SOCOM needed more firepower and durability than the conventional HMMWV. SOCOM wanted increased lethality, survivability and sustainability. Working together with U.S. Special Operations Forces, the engineers and workers at Letterkenny have developed and modified special-purpose HMMWVs that are transformed into this new fighting platform called the Ground Mobility Vehicle. These Special Operations Forces teams include the Army Rangers, Special Forces Groups as well as Navy SEAL teams. Each team’s vehicles are tailored to meet various operational scenarios and tempo. It was estimated that private industry would have taken more than 20 months to turn this vehicle around. Letterkenny successfully accomplished the task of modifying a GMV from 10 weeks to three weeks. Eventually, their turnaround time was down to nine days from the time the vehicle came into the depot, until it was ready for delivery to the SOF unit.

Branch-Dedicated Variants
The SOCOM Ground Mobility Vehicle program modifies the basic High Mobility Multi-purpose Wheeled Vehicle (HMMWV) into one of several GMV variants: GMV-R (Ranger) and GMV-S SOF for the U.S. Army Special Operations Command; GMV-N (Navy) for the Naval Special Warfare Command; GMV-M (USMC) for the Marine Special Operations Command. The Air Force Special Operations Command (AFSOC) operates three variants of the GMV: a training vehicle (GMV-T), one for the 24th STS (JSOC) based at Pope AFB (GMV-SD) and the GMV-ST (Special Tactics) for Hurlburt Field, with special mounts for ATC equipment and radios.
The workhorse GMV of the U.S. special operations forces is the 1-1/2 ton, 4×4, M1165, vehicle. This tactical vehicle is designed for use over all types of roads, as well as cross-country terrain, in all weather conditions. The vehicle has four driving wheels powered by a 6.5 liter V8, turbo charged, liquid cooled diesel engine that develops 190 horsepower at 3,400 rpm. It has four-wheel hydraulic disc brakes and a mechanical parking brake; as well as power steering. It is equipped with a pintle hook for towing; tie downs and lifting eyes are provided for air, rail, or sea shipment.

Take the Fight to the Enemy
7-marsoc-gun-truck-take-aim-at-taliban-oef-usmc-photoU.S. Marines on patrol with an up-armored MARSOC GMV-M take aim on Taliban fighters in a Helmand Province village in Afghanistan.

The M1165 is an expanded capacity vehicle capable of transporting four man crew, weapons, and mission essential equipment. The M1165 is equipped with a reinforced frame, cross-members, lifting shackles, heavy-duty variable rate rear springs, shock absorbers, reinforced control arms, military 37×12.5 low-profile run-flat radial tires, and a transfer case and differential with a modified gear ratio to accommodate higher payloads. The suspension system is an independent coil spring-type system.

The GMV is constructed on a steel frame with boxed frame rails and five cross members constructed from high-grade alloy steel. Once the substructure is assembled, E-coating is applied to provide additional corrosion protection. The aluminum body reduces weight and provides resistance to corrosion. Aluminum body panels are riveted and bonded together with technologically-advanced adhesives to provide additional strength. The body is designed to flex to accommodate off-road stresses.

Nimble and Strong
Fully-loaded M1165 utility trucks can scale road grades as steep as 60 percent and negotiate side slopes of up to 40 percent. The GMV is capable of traversing hard bottom water crossings up to 30 inches without a deep water fording kit and up to 60 inches with the kit installed. The engine is equipped for deep water fording, having a specially sealed dipstick, dipstick tube, and vented CDR valve. With 16 inches of ground clearance, that makes the GMV an exceptional off-road vehicle.

The GMV is a light tactical vehicle specifically designed to provide a combination of mobility and payload to provide the tactical flexibility required by SOF units. The addition of field installable armor allows the operators to trade payload for protection to meet their ever-changing mission requirements. Other upgrades include: frag kits (armor protection), fire suppression systems, and a high-output 30,000 BTU A/C unit. The armor is available in two kits, an ‘A’ kit and a ‘B’ kit, which, when combined, provide mine and ballistic protection.

The GMV is designed with an open rear, where the cabin would normally be enclosed. This flat bed area is used to store all the fuel, ammunition, rations and other supplies. The GMV has a cruising range of up to 275 miles, which is well suited for Special Forces ODAs who often need to operate far behind enemy lines, on their own, with only occasional re-supply from the air. Special Forces ODAs as well as other SOF units undergo extensive training in driving and maintaining the vehicle, with an emphasis on off-road handling and in-field repairs. The new series of GMVs will serve the SOF teams well as they continue to prosecute America’s war on terrorism.

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