HMMWV (Humvee®)
The High Mobility Multipurpose Wheeled Vehicle (HMMWV), commonly known as the Humvee, is a four-wheel drive military automobile produced by AM General. It has largely supplanted the roles formerly served by smallerjeeps such as the M151 1⁄4-short-ton (230 kg) MUTT, the M561 "Gama Goat", their M718A1 and M792 ambulance versions, the CUCV, and other light trucks. Primarily used by the United States military, it is also used by numerous other countries and organizations and even in civilian adaptations. The Humvee's widespread use in the Persian Gulf War helped inspire the civilian Hummer automotive marque.
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Wherever you see American troops around the world, you see HMMWVs (Humvees) in action. Even around the U.S., in natural disasters such as floods, hurricanes and tornadoes, you'll see HMMWVs when the National Guard is at work.
Although the HMMWV has been in production since 1985, its design is still as revolutionary today as it was when engineers began initial concepts in 1979. The final design met military requirements to replace numerous types of aged vehicles and to keep up with swift moving tanks. The Army wanted durability, mobility and reliability. The unique geometry of the truck provides these qualities. No other light tactical vehicle in the world approaches the HMMWV's capabilities or cost effectiveness.
That doesn't mean today's HMMWVs are the same as those first produced. The HMMWV is a dynamic vehicle with changes and improvements continually added. For instance, thorough corrosion resistance has been added and most components have been upgraded, including the move to a larger 6.5-litre diesel engine. From day one, system developers have continually found new users for the flexible HMMWV. Initially introduced with a 1½-ton payload capacity, increased payload requirements to carry various systems have led to Expanded Capacity Vehicles with payloads up to 5,100 lbs. and gross vehicle weight rating (GVW) up to 12,100 lbs.
As we move well into the 21st century, the workhorse HMMWV is being called on to carry new sophisticated communications and weapons systems. The ongoing story of this rugged truck will continue to unfold as new users are found and new missions require its use.
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FEATURES & Design
Its 15 configurations (cargo/troop carriers, weapons carriers, ambulances and shelter carriers) share a common engine, chassis and transmission, with 44 interchangeable parts that are used in more than one position. That means fewer training hours are necessary for the mechanics who will maintain it. Its simplified supply, maintenance and logistics system — essentially one set of common parts for 15 configurations — means lower life-cycle costs which saves tax dollars.
HMMWVs are maintainable, reliable and survivable. They meet all of these requirements while incorporating new standards of reliability for combat vehicles. They score high on Reliability, Availability, Maintainability and Durability (RAM-D) requirements and specifications. During initial production tests, the new vehicle proved to be nearly twice as durable as the Army required.
High ground clearance is a prerequisite for superior mobility. The 16-inch ground clearance of the HMMWV is an engineering feat considering that the vehicle stands only 72 inches high. Full-time four-wheel drive, independent suspension, steep approach and departure angles, 60 percent slope-climbing, 40 percent side slope and 60-inch water-fording capabilities combine with the high ground clearance to make the HMMWV an exceptional off-road vehicle.
The M998 A0 series has a curb weight of approximately 5,200 lbs., a payload of 2,500 lbs. (GVW 7,700 lbs.), and a 6.2 liter V-8 diesel engine with a three-speed automatic transmission. The current comparable model, the M1097A2, weighs only 700 lbs. more but can carry almost twice the payload at 4,400 lbs. (GVW 10,300 lbs). It has a 6.5-liter V-8 diesel with a four-speed automatic transmission. The current production Expanded Capacity Vehicle (ECV) model M1113 has a payload of 5,100 lbs. That is over 2 ½ tons, or very nearly the M1113's own weight of 6,400 lbs. The M1113 has a turbocharged 6.5-liter V-8 diesel. The up-armored variant M1114 is produced by AM General with the armor package installed by O'Gara Hess and Eisenhart.
Design
The HMMWV has a low profile (six feet tall), a wide stance (seven feet wide) and is 15 feet long. These proportions contribute to a stable, road-hugging truck that is very difficult to roll over. This contrasts to the old M151 Jeeps that were considered unstable.
The HMMWV 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.
The AM General-designed geared hub assembly in the power train doubles the torque to each wheel in the hub of the wheel. This also helps achieve 16 inches of ground clearance, far more than any other vehicle in its class. The use of a double A-arm independent suspension front and rear, coil springs and hydraulic double-acting shock absorbers gives the HMMWV unsurpassed mobility. Four-wheel disc brakes are mounted inboard against the sides of the differentials both of which are located up, between the frame rails, protecting them from impact and debris. Torque-biasing differentials allow the vehicle to continue to move forward as long as any one wheel has traction.
This unique configuration of components along with military 37 x 12.5 radial tires with low-profile runflat devices allows the HMMWV to go places that no other wheeled vehicle in U.S. or foreign military service could go. Some HMMWVs are equipped with an optional central tire inflation system (CTIS). This enables the operator to adjust tire pressure from the driver's seat "on the move" to adapt to changing terrain conditions for greater off-road mobility.
The M1097A2 series features a 6.5-liter Optimizer 6500 diesel engine built by AM General's subsidiary, General Engine Products. It is coupled to a four-speed automatic transmission and full-time four-wheel drive transfer case to provide the HMMWV with exceptional performance. (See specifications) The vehicle can reach speeds of more than 70 mph.
The truck utilizes a 12/24-volt electrical system and has a 25-gallon fuel tank. It has power-assisted hydraulic disc brakes and power steering.
The vehicle has either a 1 + 1 or 2 + 2 seating, depending on the model, on each side of the drive train, which is elevated, allowing the differentials to be raised. This, along with the geared hubs, contributes to high ground clearance. The location of the crew on each side of the drive train also allows for a low center of gravity.
At A Glance
| Type | Unarmored: Light Utility Vehicle Armored: Light Armored Car |
|---|---|
| Place of origin |  United States of America |
| Service history | |
| In service | 1984–present |
| Production history | |
| Manufacturer | AM General |
| Unit cost | Unarmored: $65,000 Armored: $140,000 |
| Produced | 1984–present |
| Specifications | |
| Weight | 5,200–5,900 lb (2,359–2,676 kg) curb weight |
| Length | 15 ft (4.57 m), wheelbase 10 ft 10 in (3.30 m) |
| Width | 7 ft 1 in (2.16 m) |
| Height | 6 ft (1.83 m), reducible to 4 ft 6 in (1.37 m) |
| Main armament | see text |
| Engine | 8 Cyl. Diesel 6.2 L (380 cu in) or 6.5 L (400 cu in) V8 turbo diesel 6.5 L V8 turbo diesel: 190 hp (142 kW) @ 3,400 rpm / 380 lbf·ft (515 N·m) @ 1,700 rpm |
| Transmission | 3-speed automatic |
| Suspension | Independent 4x4 |
| Fuel capacity | 25 U.S. gal (95 L) |
| Speed | 55 mph (89 km/h) at max gross weight Over 70 mph (113 km/h) top speed |
