178. The high-altitude parachute flare, Fig. 67, is used primarily to illuminate seaplane landing areas at night, so that incoming seaplanes can alight on the water within the li-mits of marked channels. It is also used to locate island bases when low ceilings prevent proper visibilty from normal flying levels. The flare is fired from a mortar, which will be described under operational 179. The complete flare consists of a steel tube, closed at one end by a copper cup welded to it. The tube is 10.75 inches long and 2.5 inches in diameter. In the tube are the pyrotechnic candle, of 85,000 candlepower and one minute bruning time, a cloth parachute, and the expelling charge. The copper cup contains the propelling charge, a mixture of 25 grams of smokeless powder and black powder, and the primer and fuze assembly. The fuze assembly delays the ignition of the expelling charge until the flare reaches an altitude of 1,000 feet by the pressure of the propelling charge.

Figure 67. – High Altitude Parachute Flare and Mortar

Operation

179. The high-altitude parachute flare is fired from a special flare mortar, Fig. 67, design-ed for this use. The flare mortar is a steel tube which screws into a base plate, the steel tube serving as the mortar barrel. This barrel is 36 inches long and 2.8 inches in outside diameter. The steel base plate is 0.75 inch thick and one foot sqaure, having four holes drilled for attachment to a boat deck or to a concrete base on land. The base plate has a central stud, into which a hardened steel firing pin is press-fitted. This stud and pin may be removed with a socket wrench furnsihed with the flare mortar. The base plate is drilled with three vent holes to release air from the barrel and to allow the high-altitude parachute flare to drop freely down the barrel and against the firing pin. A special barrel wrench is clamped to the lower end of the barrel and used for removing the barrel from the base plate so that it may be cleaned. At the top end of the barrel, six inches from the muzzle, is a tranverse pair of holes to permit the insertion of a release pin, which is attached to a 30-foot lanyard. To fire a high-altitude flare from the mortar, take the following steps:

(a) Remove the closing cap from the upper end of the barrel, attach the 30-foot lanyard to the release pin, and insert the pin in the transverse holes.

(b) Remove the flare from its container and insert it carefully into the muzzle so that it rests on the release pin with the copper cup end down.

(c) The flare is fired by pulling the lanyard and release pin, which allows the flare to drop sharply down the barrel against the firing pin. The firing pin ignites the primer, which flas-hes into the propelling charge and ignites the fuze assembly. When the flare reaches, 1,000 feet altitude, the fuze ignites the expelling charge and the pyrotechnic candle. As the primer ignites the propelling charge, it also breaks the copper cup away from the flare housing. The cup fills the barrel to form a gas seal.

Packing

180. High-altitude parachute flares are packed in wood containers of 25 flares each. The flare mortar is packed in a wood case containing two mortars and the following accessor-ies: two barrel wrenchs, eight nuts, eight washers, four extra firing pins, two release pins, and two chains.

Storage

181. General rules for storage of pyrotechnic ammunition detailed in paragraphs 9 to 12, inclusive, apply to high-altitude parachute flares. The mortar must be cleaned by disas-sembly with the furnished tools after each use, and may be put into storage when not in use.

Safety Precautions

182. In operating the flare mortar with the high-altitude parachute flare, the following safety measures should be taken:

(a) A suitable barrier should be erected to shield the firing personnel.

(b) The tube of the mortar should be cleaned each time it is fired.

(c) The flare is subject to occasional misfire ot hangfire. In such cases it is necessary to wait at least three minutes before approaching the mortar. Then the barrel may be un-screwed from the base and cleaned. Misfires are sometimes caused by a defective primer of a weak impact of the primer on the firing pin. The weak impact may be caused by sluggishness in the fall of the flare down the barrel. In order to correct this, the barrel should be cleaned by swabbing with cloth dipped in acetone or other solvent. Misfires are also caused by chips of copper base cups from previous rounds, which remain in the bot-tom of the barrel and prevent the next round from striking the firing pin normally.