NEW AIRFIELD CRASH TRUCK GIVEN SPECTACULAR TRYOUT Fog and Foam Making Make Quick Work of Gasoline Soaked Plane Fires On July 12, 1943 at LaGuardia Airport, New York, a very spectacular demonstration was given of one of the new Air Corps crash trucks for handling airplane crash fires. This new truck, which is built by the Mack Manufacturing Corporation, was developed under the direction of W.W. Dean of the Fire Prevention Section, Corps of Engineers and Colonel Kuldell of the Office of the Chief of Engineers. This unit employs high pressure fog and foam through two deck turrets, tow hand fog guns, and a hand applicator nozzle. Its normal crew includes two men in asbestos suits for executing rescue operations under the protection of the high capacity fog guns, and three or more additional men to operate hand lines. Mack Class 155 prototype Two tests were conducted at the demonstration. The first test consisted of extinguishing fire in a makeshift plane, with strips of corrugated iron as wings. The plane and area around it were drenched with 300 gallons of gasoline. It took but forty-seven seconds to bring the fire under control, and possibly a half minute longer to wipe out small remaining bits of fire within the fuselage and on the ground. In this operation 500 gallons of water were used. Both deck guns and three hand lines, one with applicator, were employed. Pump pressure was 600 pounds per square inch.
The second test included the extinguishing of a fire in the same plane, but in this case only fog was employed, at 600 pounds nozzle pressure. Two hundred twenty-five gallons of gasoline were sprayed over the fuselage and on the ground and it required twenty-one seconds to bring the fire under control. In this operation 300 gallons of water were used. During July the prototype traveled to Dow Field, LaGuardia Field and the Washing DC National Airport were it was demonstrated to military personnel and government representatives. Crash truck starting operation on plane enveloped by fire from 300 gallons of gasoline. The specifications of the crash trucks are as follows. Mack Model L, Type 19, 4x2 chassis fire apparatus type, six cylinder, with 200 horsepower at 2500 R.P.M. An all steel cab with seating positions for driver and two passengers is part of the standard equipment. The pump is a 4-stage centrifugal Hale pump modified for this special service. Modifications consisting of locking the stages in series making this pump strictly a high pressure low volume pump are included. Operating pressure is 600 pounds per square inch, and maximum pressure, 700 pounds per square inch. Maximum water delivery is 350 gallons per minute. The pump is provided with one heavy duty 3 inch discharge valve on each side of the apparatus. In addition, 2 ½ inch lines to two revolving high pressure deluge guns located on top deck of apparatus are included. A 3 1/2 inch suction line is provided from the water tank to the pump, and provision is also made to attach hydrant 2 ½ inch line to the suction side of the pump. The pump is controlled from the driver's seat by the use of a hand lever and roding arrangement to the pump transmission. The truck carries a 1,000 gallon water tank made of heavy gauge steel, baffled to five divisions of the tank. Provision on the tank for bucket filling or hose line filling through top opening in the tank is included. The unit is furnished with two modified McIntyre deluge guns. These guns are furnished with with revolving type turret heads mounted on a twenty-six high monitor. The gun nozzles are specially designed for high pressure water fog application or for foam developing use. Nozzles are adjustable for water deliveries from approximately 189 gallons per minute with pump pressure of 600 pounds per square inch.
McIntyre Turret Nozzle The truck is also equipped with two Meyers fire guns with adjustable spray nozzle tips. The diameters of the tips furnished are 3/16, 7/32 and ¼. Each of these guns is attached to 100 feet of 3//4 inch high pressure hose. Hose and guns are mounted in baskets located on top of apparatus. In addition to the two high pressure lines, an additional 100 foot ¾ inch diameter high pressure line is equipped with a Rockwood applicator for development of fog protection wall around the firemen or extinguishing fire in enclosed areas.
**************************************************** Fortunately for the Army the Mack Class 155 prototype never entered production. During field testing it was discovered the truck did not perform well as it lacked off road capability, the midship mounted pump prevented pump and roll operations and the attack lines, mounted on the top deck of the truck would be hard to reach by firefighters. In addition, parts for the Mack Model L were not carried in the supply system requiring repair parts to be procured and shipped to the disable vehicle.