Hummer - HMMWV

2001 Victorian 4WD Show: This Hummer is an ex-USAF LHD model, complete with revolving roof hatch and webbing "seat".

- 4wd.sofcom.com/Mil/Mil.html

It sits in the courtyard of Holden Special Vehicle's (HSV) Clayton factory. It must be the most unusual HSV project of all time. It does have four wheels and under the hood is a V8 but that is the end of any resemblance to the hot V8 Holdens with their deep gloss paint, mag' wheels, body kits and wings that are parked nearbye.

Apart from the matt military paint which is faded by the sun, it could be a (big) bush-cocky's ute. At the back is a wide, flat tray. Wooden strakes would hold a good few bales of straw, or a whole flock of nervous sheep on board. It has been well used and many drivers have tested its limits. The cab is best described as basic. Each door is a crude metal frame covered with fabric and secured by the flimsiest of rubber catches. The driver and passenger sit many feet apart and there would be room for four abreast if it were not for the engine and transmission cover bulging between them.

It is an M998A2 High Mobility Multi-purpose Wheeled Vehicle, HMMVW or Hummer. This one has been brought to Australia as part of AM General Corporation's "expression of interest" in the Australian Army's project Mulgara. That project called for 350 to 500 light survey vehicles to be acquired from about the year 2000 and on. Can you call the Hummer light? AMG selected HSV to do the local engineering for the submission. The particular vehicle is fitted with a 6.2L V8 diesel and 3-speed automatic gearbox but the later model with a 6.5L engine and a 4-speed transmission was to be used for any final tender.

Engineer Brad Dunstan leaves the office and goes out to play, sorry, goes out to work. The Hummer makes light work of the factory car park and service road, then it descends a short grassy slope and eases down a 2 foot high brick wall. The chassis just touches the top of the wall as the front wheels reach the low point. The rear wheels follow with no drama. Then it drives back up the brick wall. This is impressive, really impressive to anyone who has contemplated how easily a step that a human can climb defeats almost any wheeled vehicle. There is no denying that 37x12.5R16 tyres and portal axles with hub-reduction gearing make for good ground clearance.

Next there is a grass slope. It must be 30 degrees although it looks like 45 as the Hummer noses down it. It has been raining and the first attempt to climb back up the grass, from a standing start mind you, does not quite succeed. The second attempt, with a bit more welly, is successful. The automatic transmission and the torque-biasing differential certainly make it easy for the driver. After that the 30 degree side-slope is an anti-climax.

The Hummer is big - 6' (1.83m) tall, 7' 2" (2.18m) wide, and 15' 10" (4.84m) long. The wheel track is a shade under 6' - 71.6" or 50% greater than the old MB Jeep; no way is it going to fall over! Suspension is independent with double wishbones and coil springs at each corner. There is reduction gearing in the hubs which allows the half shafts to be raised so that there is 15" (0.39m) of ground clearance on the centre-line. The transmission is also cleanly tucked up between and above the chassis rails. Braking is by in-board mounted discs. The chassis is steel and the bodywork is aluminium except for the composite bonnet (hood).

A central tyre inflation system (CTIS) allows the tyre pressure to be varied on the move (it is running at 15psi). The air line is carried down the centre of the non-rotating stub axle and there is a seal and air hose to the tyre valve on the outside of the wheel, another advantage of portal axles with hub reduction gearing. A similar arrangement is used by some Unimogs. All in all it is a typical piece of "money no object" military engineering.

The Hummer is the absolute antithesis of the Jeep, the Land Rover, the European style of military four wheel drive. Where the latter are small, minimal and nimble, the Hummer is large, substantial with all eventualities covered; it is hard to imagine it on a narrow Austrian mountain track or squeezing down narrow lanes between shelled buildings in a combat zone.

Verdict: not bad. The preconception was that it would be big and flabby. It is big but it is not flabby - © L. A11ison

• See the Civilian RHD model, Hummer specifications, Scale Models and Broken Arrow (movie) pages
• Military vehicles page