The signal light consists of the following:
2. Bottom disk.
3. Muslin disk.
5. First fire.
7. Top disk.
8. Muslin wrapper.
9. Wet prime.
10. Ignition match and tie string.
11. Parachute tie string.
Fig. 47. - Briquette.
Pig. 48. - Wrapped briquette.
Fig. 49. - Wrapped briquette showing quick match and knot socket.
The case consists of a cylindrical paper carton made of Kraft paper, 200-pound stock, basis 40 inches by 48 inches. This paper is cut into strips 7 inches wide by 16 inches long. One short edge of the sheet is feathered and given a coat of paste similar to that used in rolling the rocket body or carton, and it is then rolled by hand over a mandrel, producing a cylinder of 1 1/4 inches inside diameter and 7 inches in length. This cylinder is cut in half, thus making the dimensions of the signal-light carton 1 1/4 inches inside diameter and 3 1/2 inches in length.
This disk measures 1 1/4 inches in diameter and has a hole 3/4-inch in diameter in the center. The disk is cut from 30-pound strawboard, and before being forced into the carton the latter is given a coating of glue on the inside close to the bottom, so that the disk will beeome firmly attached thereto. The disk is inserted in the top of the case and driven into position at the bottom by means of a rammer where it comes in contact with the glue.
This is cut 1 5/8 inches in diameter from unbleached muslin and is placed on top of the bottom disk.
A piece of 6-ply quick match, 7/8 inch long, is dropped on top of the muslin disk. The function of this match is to facilitate the ignition of the first fire.
Different formulas are used by different manufacturers for this first fire. The first fire is a quick-burning composition which takes its ignition from the match and ignites the illuminating composition. A mixture of 50 per cent. of the illuminating composition with 50 per cent. of meal powder slightly dampened with wood alcohol is a characteristic composition. Another formula consists of -
Sulphur (flour) ..................
This first-fire composition is introduced into the case, occupying a depth of approximately 1/8 inch.
A variety of formulas are used for the compounding of the white signal light. The basis of these is the use of barium nitrate and some finely divided metallic powder which will burn with an intense illumination. As the composition contains salts that tend on burning to produce a yellow flame, the presence of the barium nitrate which.imparts a green color to the flame tones down the yellow and gives the metallic powder an opportunity to burn with a bright white light scarcely masked, if at all, by the burning of the other materials. Two characteristic formulas are given as follows -
A. Barium nitrate......................
B. Barium nitrate..........................
Irrespective of the formulas, the component parts are mixed in much the same manner, namely, hand mixing in an open trough and repeated screening through a sieve to insure a homogeneous mixture.
Figures 50, 51, and 52 show the operation of introducing the charge into the signal-light case, the packing or driving home of this charge by means of a suitable rammer, driven in by a hand mallet, and the insertion of the top disk.
This top disk is the same as the bottom disk with the exception that there is no hole in the center. After the disk is set in place on top of the composition charge, glue is wiped around the inside of the carton, holding the top disk firmly. The composition weighs approximately 4 1/2 ounces and should burn at least 25 seconds, giving a white light of intensity ranging from 9,000 to 12,000 candlepower.
The case is inverted and a blob of prime is placed in the hole in the bottom disk against the composition.
The wrapper is a piece of unbleached muslin cut 6 by 6 1/2 inches. Wet paste is applied to the cloth and the case is now rolled in this wrapper, which protrudes 1 1/2inches at either end, as shown in figure 53.
Fig. 50. - Filling light case.
The case is now set into a form as shown in figure 54, with the end containing the perforated disk up, a blob of prime having been previously put over the hole in the disk.
The match is an 8-ply quick match cut to a length of 6 inches. This match is folded in the center and the double fold is again folded, forming an L, the short leg of which is inserted into .the case to rest on the blob of prime and is tied firmly in place as shown in figure 54.
The parachute cord, at the end of which has been tied a knot, is now introduced into the case which is again reversed.
Fig. 51. - Ramming charge into light case.
Figure 55 shows the introduction of the cord and knot well into the muslin socket and the tying of the muslin socket around the cord above the knot by means of a stout hemp tie string, the operator making a half hitch to insure safety. On making this assembly the parachute string is given a stout pull, the case being held firmly in the hand, to insure a secure attachment.
Fig. 52. - Capping light case.
Fig. 53. - Light case with muslin wrapping.