Warplanes: <b>December 5, 2003</b>

December 5, 2003

The "air conditioned suit" of legend, and science fiction, has become a reality. After three years of work, the U.S. Army has put into service the "Air Warrior Microclimate Cooling System." It's a vest full of tiny tubes that carry cooled water (with some non-toxic antifreeze added). Worn under the flak jacket, it keeps the trunk of the wearer cool, thus greatly reducing the "heat load" and potential for heat stroke or heat fatigue among pilots in smaller (un-air-conditioned) helicopters or door gunners of larger choppers.

Helicopter crews, especially the crew chiefs who man a machine-gun mounted on an open door, have always had a problem with the weather. Few military helicopters have air conditioning, even for the pilots, and the crew chief on the UH-60 Blackhawk has to stay on his feet, and alert, for up to three hours at a time. In tropical areas, be they Vietnam four decades ago, or Iraq today, that can be a real chore. The crew chief wears a fire-resistant jumpsuit, flak jacket and helmet. Flying low to the ground, the heat is often over 100 degrees. Often there's not much breeze, for the chopper frequently hovers or moves slowly (under fifty kilometers an hour.) So the crew chief has to fight the heat while staying alert to any potential threats below. When the helicopter lands, the crew chief has to help with loading or unloading personnel or cargo, and maybe run around the chopper to check for any damage.

The cooling vest can only be used in vehicles, because the entire unit consists of the vest, a 13 pound cooling unit and an umbilical cord that attached to the vest. The cooling unit is plugged into the choppers electrical system. The current vests cost about $7,000 each and the army plans to equip the crews of over 9,000 helicopters with the vests by 2010.

Designing the equipment was not as difficult as was making it rugged, reliable and inexpensive. The first units are being tested in Iraq, although they won't get a real workout until next Spring. It's often quite cool in Iraq during the Winter, although there can still be days where the temperature gets up to a hundred degrees. Such equipment is nothing new for aircrew. During World War II, there was a similar problem for door gunners in heavy bombers (B-17s and B-24s). Operating at 20,000 feet or higher, it was the cold that was a killer. So the Army Air Force developed electrically heated clothing to keep the gunners in operation, and prevent frost bite. The first flak jackets were also designed for aircrews. Too heavy for ground troops, the weight was no problem if you were sitting down (as most of the bomber crews were) or even standing (like the door gunners, who could sit down for most of the flight, standing only when enemy fighters were in the area.)

Ultimately, the Army wants to develop cooling vests for infantry, but first the unit has to be made lighter, and much better batteries have to be developed. Current prototypes of the infantry vest weigh five pounds, but are waiting for a light and long lasting battery. The vests are finding their way into mechanized units, with the army ordering 200 vests for operators of the M-9A combat bulldozer. The operators of these machines spend hours working in an un-air-conditioned armored vehicle, which in Iraq can mean interior temperatures way over 100 degrees. But many other armored vehicles have no air conditioning, and then there are those troops who stand in a turret manning a machine-gun, or even for hummer crews, while patrolling a very hot area. Ironically, Iraqis have assumed American troops must have had cooling vests, to be able to run around last Summer wearing a helmet and flak jacket. This Summer, some American troops will be wearing the vests.

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