High Mobility Multipurpose Wheeled Vehicle

The High Mobility Multipurpose Wheeled Vehicle (HMMWV or Humvee) is a military 4WD motor vehicle created by AM General. It has largely supplanted the roles formerly served by the M151 1/4 ton MUTT, the M561 "Gama Goat", their M718A1 and M792 ambulance versions, the CUCV, and other light trucks with the United States military, as well as being used by a number of other countries and organizations.

Features
The HMMWV uses independent suspensions for high ground clearance, and has an axially delivered central tire inflation system. The vehicle also has disk brakes on all 4 wheels, and 4-wheel double-wishbone suspension. The brake disks are not mounted at the wheels as on conventional automobiles, but near the differentials to protect the brake lines.

There are at least 17 variants of the HMMWV in service with the United States armed forces. HMMWVs serve as cargo/troop carriers, automatic weapons platforms, ambulances (four litter patients or eight ambulatory patients), M220 TOW missile carriers, M119 howitzer prime movers, M-1097 Avenger Pedestal Mounted Stinger platforms, MRQ-12 direct air support vehicles, S250 shelter carriers, and other roles. The HMMWV is capable of fording 2.5 ft (76 cm) normally, or 5 ft (1.5 m) with the deep-water fording kits installed.

Optional equipment includes a winch (maximum load capacity 6000 lb (2700 kg)) and supplemental armor. The M1025 and M1043/M1044 armament carriers provide mounting and firing capabilities for the MK19 grenade launcher, the M2 heavy machine gun, the M240G/B machine gun and M249 SAW. The newly introduced M1114 "up-armored" HMMWV also features a similar weapons mount. In addition, some M1114 and M1116 up-armored and M1117 Armored Security Vehicle models feature a Common Remotely Operated Weapon System (CROWS), which allows the gunner to operate from inside the vehicle, and/or the Boomerang anti-sniper detection system. Recent improvements have also led to the development of the M1151 model, which is quickly relegating the previous models obsolete. By replacing the M1114, M1116, and earlier armored HMMVW types with a single model, the U.S. Army hopes to lower maintenance costs.

History
In the 1970s, the United States Army concluded that the militarized civilian trucks in use no longer satisfied their requirements. In 1977, Lamborghini developed the Cheetah model in attempt to meet the Army contract specifications. In 1979, the Army drafted final specifications for a High Mobility Multipurpose Wheeled Vehicle, or HMMWV. In July of that year, AM General (a subsidiary of American Motors Corporation) began preliminary design work, and less than a year later, the first prototype, the M998, was in testing.

In June 1981, the Army awarded AM General a contract for development of several more prototype vehicles to be delivered to the U.S. government for another series of tests, and the company was later awarded the initial production contract for 55,000 HMMWVs to be delivered in 1985. HMMWVs first saw combat in Operation Just Cause, the US invasion of Panama in 1989.

The HMMWV has become the vehicular backbone of U.S. forces around the world. Over 10,000 were employed by coalition forces during Operation Iraqi Freedom, the 2003 invasion of Iraq.
Usage in combat

The HMMWV was designed primarily for personnel and light cargo transport behind front lines. Like the previous Jeep, the basic HMMWV has no armor or protection against nuclear, biological, and chemical threats. Nevertheless, losses were relatively low in conventional operations, such as Desert Storm. Vehicles and crews suffered considerable damage and losses during the Battle of Mogadishu due to the nature of the urban engagement, however, the chassis survivability allowed the majority of those crews to return to safety, though the HMMWV was never designed to offer protection against intense small arms fire, much less machine guns and rocket propelled grenades. However, with the rise of asymmetric warfare and low intensity conflicts, the HMMWV has been pressed into service in urban combat roles for which it was not originally intended.

After Somalia, the military recognized a need for a more protected HMMWV and AM General developed the M1114, an armored HMMWV to withstand small arms fire. The M1114 has been in limited production since 1996, seeing limited use in the Balkans before deployment to the Middle East. This design is superior to the M998 with a larger, more powerful turbocharged engine, air conditioning, and a strengthened suspension system. More importantly, it boasts a fully armored passenger area protected by hardened steel and bullet-resistant glass. With the increase in direct attacks and guerrilla warfare in Iraq, AM General has diverted the majority of its manufacturing power to producing these vehicles.

Modifications
In response to the vulnerability of HMMWVs operating in Iraq, "Up-Armor" kits were designed and installed on M998 HMMWVs. These kits, of which there are several types and iterations, include armored doors with bullet-resistant glass, side and rear armor plates, and a ballistic windshield which offer greater protection from ballistic threats and simple IEDs.

Although some of these kits were available prior to the 2003 invasion of Iraq, they were not provided in great numbers to American forces in Iraq prior to the invasion. As a result of this, American soldiers and Marines often improvised extra armor with scrap materials, known as "hillbilly armor" or "farmer armor" to improve the safety of the HMMWV. While this may have made the vehicle somewhat safer from a ballistic attack, it also increased the weight and raised the center of gravity of the vehicle, reducing its acceleration, handling, braking, reliability, and service life due to its overstressed suspension and drivetrain.

In December 2004, Secretary of Defense Donald Rumsfeld came under criticism from U.S. soldiers and their families for not providing better-equipped HMMWVs. Rumsfeld pointed out that, prior to the war, armor kits were produced only in small numbers per year. As the role of American forces in Iraq changed from fighting the Iraqi Army to suppressing the guerrilla insurgency, more armor kits were being manufactured, though perhaps not as fast as production facilities were capable of bringing them online. Even more advanced kits were also being developed. However, while these kits are much more effective against all types of attacks, they weigh between 1,500 to 2,200 lb and have some of the same drawbacks as the improvised armor. Unlike similar-size civilian cargo and tow trucks, which typically have dual rear wheels to reduce sway, the HMMWV has single rear wheels due to its independent rear suspension coupled with the body design.

The armor on most up-armored HMMWVs holds up well against lateral attacks, when the blast is distributed in all different directions, but offers little protection from a mine blast below the truck, such as buried IEDs and land mines. Explosively formed penetrators (EFPs) can also defeat the armor kits, causing casualties.

The armor kits fielded include the Armor Survivability Kit (ASK), the FRAG 5, FRAG 6, as well as upgrade kits to the M1151. The ASK was the first fielded, in October 2003, adding about 1,000 lb to the weight of the vehicle. Armor Holdings fielded an even lighter kit, adding only 750 lb to the vehicle's weight. The Marine Armor Kit (MAK), fielded in January 2005, offers more protection than the M1114, but also increases weight. The FRAG 5, the latest fielded armor kit, offers the greatest protection but may still be inadequate to stop EFP attacks. The FRAG 6 kit, designed to do just that, is still in development, however its increased protection comes at a hefty price. Over 1,000 lb is added to the vehicle over the FRAG 5 kit, and the width of the vehicle is increased by 2 ft. In addition, the doors may require a mechanical assist device to open and close.
Another drawback of the up-armored HMMWVs occurs during an accident or attack, when the heavily armored doors tend to jam shut, trapping the troops inside. As a result, HMMWVs are being fitted with hooks on their doors, so that another vehicle can rip the door off, freeing the troops inside. In addition, Vehicle Emergency Escape (VEE) windows, developed by BAE Systems are currently being fielded for use on the M1114 uparmored HMMWV, with 1,000 kits ordered.

The soldier manning the crew-served weapon on top of the vehicle is extremely vulnerable; however, many HMMWVs have been fitted with basic gun shields, as was the case with M113 APCs after they were first deployed in Vietnam. The U.S. military is currently evaluating a new form of protection, developed by BAE Systems as well as systems designed by the Army, which are already in theater. The new gunner's seat is protected by 1.5 to 2 feet (45.72 - 60.96 cm) high steel plates with bullet-proof glass windows. Additionally, some HMMWVs use CROWS, which slaves the machine gun to controls in the back seat to allow remote operation. The Boomerang anti-sniper system is also being fielded by some HMMWVs in Iraq to immediately give troops the location of insurgents firing on them.

Alternatives
Other countries in Europe and South Africa employ a number of different light armored vehicles, both tracked and wheeled, and some even built in the U.S. by Cadillac Gage, that are designed more specifically for low intensity combat situations, and are more resistant to small arms; some trucks even have high v-hull bottoms to deflect mine blasts.

In 2007, the Marine Corps announced an intention to replace all HMMWVs in Iraq with MRAP (Mine Resistant Ambush Protected) armored trucks because of high loss rates, and has issued contracts for the purchase of several thousand of these vehicles, which include the International MaxxPro, the BAE OMC RG-31, the BAE RG-33 and Caiman, and the Force Protection Cougar, which have been deployed with the Army and Marines primarily for mine clearing duties. Heavier models of Infantry Mobility Vehicles (IMV) can also be used for patrol vehicles. Unfortunately, some MRAP vehicles have been known to become stuck or roll over much more readily due to their high center of gravity and overall larger size compared to the HMMWV.
Another weakness for the hummvee has proven to be its size, which has limited its deployment in Afghanistan because it is too large for many forms of air transport. This size also limits the ability for the vehicle to be manhandled out of situations. Additionally, troops in Bosnia found the vehicle's wide track to be a liability, since two Humvees could not pass each other on narrow mountain roads. One vehicle had to drive with two wheels on the unpaved berm, exposing it to land mine danger.

Replacement
The HMMWV replacement process, now being undertaken by the U.S. military, is an effort to replace the current AM General HMMWV. The HMMWV has evolved several times since its introduction, and is now used in tactical roles for which it was never originally intended. The U.S. military is currently pursuing several initiatives to replace it, both in the short and long terms. The short term replacement efforts utilize Commercial off-the-shelf vehicles as part of the Mine Resistant Ambush Protected (MRAP) program. Long term efforts include the Joint Light Tactical Vehicle and Future Tactical Truck Systems programs, which are currently focused on building requirements for the HMMWV replacement and technology research and evaluation. Various prototype vehicles such as the MillenWorks Light Utility Vehicle, International FTTS and the ULTRA AP have been constructed as part of these efforts.

Versions
Major HMMWV versions
M56 Coyote Smoke Generator Carrier
M707 HMMWV
M966 HMMWV TOW Armored
M996 Mini-Ambulance, Armored
M997 Maxi-Ambulance, Armored
M998 Cargo/Troop
M998 HMMWV Avenger
M1025 Armament Carrier, Armored
M1026 Armament Carrier, Armored W/W
M1035 Soft-Top Ambulance
M1036 TOW Armored W/W
M1037 S-250 Shelter Carrier
M1038 Cargo/Troop Carrier W/W
M1042 S-250 Shelter Carrier W/W
M1043 Armament Carrier, Up-Armored
M1044 Armament Carrier, Up-Armored W/W
M1045 TOW Up-Armored Armor
M1046 TOW Up-Armored Armor W/W
M1069 Tractor for M119 105-mm Gun
M1097 Heavy
M1097 Heavy HMMWV Avenger
M1109 Up-Armored Armament Carrier
HLONS

Expanded capacity
M1113 The M1113 has been selected by the Army as its A2 chassis for HMMWV purchases. Currently, the ECV is used for special operations vehicles and communications shelter carriers.
During 1995, production of the M1114 based on the improved ECV chassis began. The M1114 meets Army requirements for a scout, military police, and explosive ordnance disposal vehicle with improved ballistic protection levels. The M1114 provides protection against 7.62 mm armor-piercing projectiles, 155 mm artillery air bursts and 12 lb. anti-tank mine blasts. The U.S. Air Force has a number of vehicles under the designation M1116, specifically designed to meet the requirements of the Air Force. The M1116 features an expanded cargo area, armored housing for the turret gunner and increased interior heating and air conditioning system. The M1114 and M1116 receive armor at O'Gara-Hess & Eisenhardt Armoring Company of Fairfield, Ohio.

M1114 Up-Armored Armament Carrier
M1116 Up-Armored HMMWV
M1123 Heavy
M1121 TOW Armored
M1145 Up-Armored HMMWV
M1151 Up-Armored Capable HMMWV
M1152 Up-Armored Capable HMMWV
Packhorse - Attachment to convert an M1097 to tractor version for semi-trailers.
Scorpion - Version fitted with 2B9 Vasilek 82 mm automatic mortar. This is a heavy chassis Humvee equipped with a 2B9 Vasilyek 82 mm automatic mortar and intended to provide more protection for US troops in combat zones. This was developed in 2004 by engineers at the US Army's Picatinny Arsenal. The mortar itself can fire on single shots or on automatic using 4 round clips. Range for direct fire is 1,000m and indirect fire is 4,000m. It is also intended to provide another means of destroying roadside bombs but at a safer standoff range.
Composite HMMWV - A prototype developed by TPI Composites of Rhode Island and AM General. The purpose of the concept vehicle is to reduce the vehicle's weight so that it may more easily carry an up armor kit. TPI's all-composite HMMWV saves approximately 900 pounds when compared to a current steel and aluminum HMMWV.