Armor: Hummer Saved By A Chimney

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July 25, 2011: A group of American aeronautical engineers have developed an innovate design change for hummers that make these vehicles as resistant to the blast effect of roadside bombs, as an MRAP (Mine Resistant Ambush Protected) vehicle weighing more than twice as much. The solution was a chimney, made of lightweight, but very strong, material, that vents most of the bomb blast upward, sparing the crew. Five tests, using actual bombs, have proved the idea works. The new hummer also has a V shaped underbody, but still costs less than a third as much as an MRAP with the same carrying capacity. The Department of Defense wants to conduct more tests before building prototypes for testing in Afghanistan.

This new development gives hummers a new lease on life. Because of the roadside bomb danger, hummers have only been allowed to operate inside bases or in safe areas (that's actually most of Afghanistan, but not the areas where most American troops are operating, and fighting the Taliban.) All this is part of a decade long effort to make the hummer safe to use in the face of widespread use of roadside bombs.

Four years ago, the army responded to the roadside bomb threat by replacing the armored hummer (the M1114) with a new model (the M1151), that had removable armor. The M1151 also have some armor underneath, but otherwise looked exactly like the M1114. The armor in the M1114 was added at the end of the production process, and required special skills and tools to remove. The army planned to replace most of its 12,000 M1114s with M1151s, at the rate of over 600 a month.

The M1114 had been around since the 1990s. Originally designed for peacekeeping operations, it was meant for dangerous places like the Balkans. In 1998, only about 200 M1114s a year were being produced. The M1114 was based on a earlier armored hummer, that had served in the 1991 campaign in Kuwait. The M1114 is basically an armored car, with a crew of four and a payload of one ton (plus two tons that can be towed.) A 190 horsepower engine gives it a top speed of 80 kilometers an hour and a max range (on one tank, on roads) of 480 kilometers. All the armored protection (against 7.62mm machine-guns and rifles, bombs, landmines and nearby bursting shells of up to 155mm) has more than doubled the cost of the M1114 ($165,000 compared to $65,000 for an unarmored model.)

The problem with putting two tons of armor on a hummer is that it causes more wear and tear to the vehicle, and they burn more fuel as well. This is especially true for a vehicle that is used day after day, in hot and dusty conditions. The extra weight is also in places that the vehicle designers did not plan for. So the vehicles ride differently when armored. Drivers have to get used to it. The army wanted like to get rid of the armored hummers, and it has been working a new vehicle design to replace the hummer. That vehicle was designed to readily accept an armor kit, that the troops can install and remove as needed. But this hummer replacement project is stalled.

Meanwhile, a more robust (against bombs) hummer looks very attractive right now. There are several reasons for this. The cheapest MRAP costs more than three times as much as the "vented" hummer. Moreover, the hummer is much more maneuverable, and uses a lot less fuel, than an MRAP. Shrinking budgets has slowed the process to develop and build a hummer replacement. Keeping a lot of MRAPs in service is also very expensive. If the vented hummer survives further testing, it will save money and lives.