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| BRITISH EXPLOSIVE ORDNANCE |
| Part 1 - Chapter 20 |
| Aircraft Pyrotechnics |
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Smoke Float No. 3 Mk I (Obsolescent) |
| Data |
| Fuzing | Pull-percussion igniter |
| Color markings | Upper half of body is yellow; lower half green, with red band ½ in. from bottom |
| Over-all lenght | 10.1 in. |
| Body diameter | 6.7 in. by 4.95 in. (rectangular) |
| Duration of burning | 40 sec. |
| Color of smoke | Red |
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Description: The float consists of a thin metal body at the upper end of which six smoke-emission holes, covered by a fabric seal, are loacted. A wire gauze washer, held in place by an upper and lower liner, divides the body into two portions, the upper por-tion comprising buoyancy chamber, and the lower portion housing a number of large and small smoke pellets disposed around a pull-percusssion igniter. The large smoke pellets are arranged in tiers. The pellets in the upper tier are each contained in a primed cambric cylinder. Below the wire gauze washer, a primed cambric washer rests on the upper ends of the primed pellets, and strips of primed cambric cross over the igniter. The igniter, which is secured to the body, includes a splitheaded clutch which is movable lengthwise in the ingiter body. A whipcord becket is secured to the head of the clutch and threaded through a rubber disc. The upper end of the clutch is sprung over one end of a striker, which is spring-loaded when the clutch is pulled out. Opposite the free end of the striker is a perussion cap, and an anvil housed in an ignited plug screwed into the igniter body. A length of safety fuse, enclosed in a tube, terminates in a capsule filled with igniter composition. |
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When the float is to be used, proceed as follows: Remove the adhesive tapes secur-ing the covers and remove both cobers. Press in the center of the press-cap to release the cap, and then remove the cap. Pull the whipcord becket and the clutch out of the float, and immediately throw the smoke overboard to leeward. |
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Functioning: When the clutch is pulled out, the striker is released and fires the per-cussion cap. The flash from the cap ignites the safety fuse, which fires the igniter com-position in the capsule after a delay of not less than eight seconds. The flash from the igniter composition is cenveyed by the primed cambric strips and the primed cambric washer to the pellets in the upper tier. The smoke produced raises the pressure in the buoyancy chamber until the pressure bursts the fabric seal, and the smoke escape to the atmosphere through the smoke-emission holes. |
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Remarks: This smoke float is intended for use from an emergency dinghy after a for-ced landing has been made, to assist search planes. |
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Figure 98 - Smoke Float No. 3 Mk I |
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