Heavy Expanded Mobility Tactical Truck

Ammunition Crew picking up the Ammunition for the Multiple Launching Rocket System (MLRS) on a Heavy Expanded Mobility Tactical Truck (HEMTT).

The Heavy Expanded Mobility Tactical Truck (HEMTT) series is a range of eight-wheel drive diesel-powered off-road capable trucks, used by the US military. Formally described as "Truck, Cargo: 10-Ton, 8x8", it has been nicknamed the "Dragon Wagon". HEMTT trucks first went into service with the U.S. Army in 1982, as a replacement for the M520 Goer.

A 10x10 variant of the HEMTT truck is used as prime mover in the Palletized load system (PLS). The vehicle is produced by the Oshkosh Corporation. In the civilian realm the truck's chassis is also used in the Oshkosh Striker as an airport crash tender.

The United States Marine Corps uses a similar vehicle, the Logistics Vehicle System (LVS), also manufactured by Oshkosh. An LVS differs in that it is actually an articulated vehicle, similar to a semi-trailer truck, using a modular system of a Front Power Unit attached to a Rear Body Unit, whereas HEMTTs are non-articulated, single unit vehicles.

The HEMTT's objective is to provide heavy transport capabilities for supply and re-supply of combat vehicles and weapons systems for the United States Army. It is distinguished by extreme mobility compared to standard 5-ton trucks, thanks to its large number of wheels and turbo-charged engine, combined with all-wheel drive and very large, low-pressure tires. Though far less publicized than the Humvee, it has been extremely important in transporting logistics behind quick-moving forces based on the M1 Abrams tank. Having proved itself as a key workhorse of the US heavy tactical wheeled vehicle fleet, about 13,000 HEMTT vehicles are in service today.

HEMTT trucks exist in several configurations:

  • M977 and M985 cargo trucks carry all types of equipment, including ammunition. A crane is mounted at the rear of the vehicle.
  • M978 tanker refuels tactical vehicles and helicopters in forward locations.
  • M983 tractor tows the trailer-mounted MIM-104 Patriot missile systems or the Interim Stryker Recovery System trailer.
  • M983 with 30 KW generator and a crane mounted behind the cab towed the MGM-31 Pershing Erector Launcher in CONUS (a MAN tractor was used in West Germany).
  • M984 recovery vehicle uses a lift-and-tow system to recover disabled vehicles in two-to-three minutes. It mounts a recovery winch, a crane and a large storage box.
  • M1120 HEMTT-LHS is an M977 HEMTT with a load handling system in place of a flat bed.

The cost of a 'plain' HEMTT (M977 or M985) begins at approximately $135,000.

The HEMTT A3 is a technology demonstrator with hybrid powerplant.

In the HEMTT A4, the latest in the series, the familiar Detroit Diesel engine has been replaced by the Caterpillar C15/17 inline six-cylinder diesel engine. All "CAT" engines are turbo charged and highly computerized. They are much more powerful than the previous Detroit Diesel engines, and more fuel efficient. Maintenance has also been simplified (at least when it comes to diagnostics) through the inclusion of OBD-II style technology.

Specifications (M977 A2)
Weight 38,800 lb (17,600 kg)
Length 33.4 ft (10.2 m)
Width 8 ft (2.4 m)
Height 9.3 ft (2.8 m)
Crew 2
Engine MTU Detroit Diesel 12.1 liter
445 hp (332 kW)
Transmission Allison 4500SP/5-speed automatic
Suspension Hendrickson w/equalizing beam
Ground clearance 24 in (610 mm)
Fuel capacity 155 US gal (587 l)
400 mi (644 km)
Speed 62 mph (100 km/h)


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