Figure 133 shows an exposed longitudinal section of the rifle light with parachute.
Fig. 133. - Sectional view of parachute rifle light.
2. Wood plug. 8. Shell nail.
4. Time fuse.
6. Detonating-cap plate.
7. Detonating cap.
8. Protecting disk.
9. Protectlng-dlsk nail.
10. Expelling-charge holder.
11. Expelling charge.
12. Expelling-charge, muslin cover.
13. Expelling-charge, muslin prime.
14. Light case.
15. Bottom disk.
16. Bottom band.
17. Outer disk.
21. Quick-match prime.
22. Top disk.
23. Top-finishing band.
24. Tie cord.
26. Asbestos cord.
28. Packing wad.
29. Cork cap.
30. Identification cap.
31. Blank cartridge.
32. Protecting band for cartridge.
33. Cartridge tape.
34. Directions label.
35. Packing carton.
36. Tearing cord.
37. Directions label.
38. Shipping carton.
39. Identification label.
Fig. 135. - Sectional drawing of parachute rifle light.
Figure 134 shows the parachute with an illuminating star attached, suspended in the air.
Fig. 134. - Parachute functioning.
The shell consists of a tinned tube with lapped seams of an inside diameter of 1 3/4 inches and length of 5f inches. The shells are purchased from a tube manufacturer, and are shipped cut to length ready for assembly.
The wood plug which fits into the lower end of the shell is made of hardwood. It is 1 1/2 inches long, having a diameter of 1 3/4 inches for one-half of its length, the balance shouldered hav-hav- an increased diameter of 1 7/8 inches.A 3/16-inch hole is drilled through the center, in order to accommodate a time fuse, and a 5/8-inch hole is drilled in the large end to accommodate the detonating cap. This plug is manufactured and shipped to the plant ready for assembly.
Figure 136 shows the shell and wood plug. The plug is fitted into the shell and secured to it by four nails 3/8 inch long, which are driven through the shell at a distance 3/8 inch from the bottom of the tube. This operation is performed by a specially designed machine, the shell being turned by hand through an arc of 90° and a nail driven in at the conclusion of each turn.
Fig. 186. - Rifle-light shell and plug.
The shell and wood plug forming the case are painted on the outside by means of an air brush. The air brush consists of a spray-atomizing machine not unlike a "whitewash gun."
Fig. 137. - Machine used for nailing plug to shell.
Figure 138 shows a battery of shells which revolve on spindles, the whole being covered by a hood equipped with an exhaust fan. The operator atomizes the paint, directing the flow against the walls of the tubes, and rapidly gives them a light coating.
Fig. 138. - Shell-painting machine.
The time fuse is a tubular fuse purchased from the standard manufacturers, 3/16 of an inch in diameter by 1 1/4 inches long. This fuse is forced through the 3/16-inch hole drilled into the wood plug and is pushed up until the end protrudes into the 5/8-inch hole in the lower part of the plug. The fuse is now cut off flush with the top of the plug. This time fuse is necessary in order to delay the ignition of the prime and expelling charge until the light has reached the desired altitude.
This is a meal-powder and gum-water prime of similar specifications to those mentioned in preceding chapters. A blob of prime is placed over the end of the fuse which has been cut even with the top of the wood plug.
This consists of a steel disk 1 7/8 inches diameter of 16 metal gauge. There is a hole drawn in the center to hold the detonating cap, the head of which lies in the depression in such a manner that its surface is just beneath the top of the plate.
Before placing the protecting disk on top of the detonating-cap plate and attaching the whole firmly to the wood plug, a detonating cap is set in place, the head of the cap taking the position described above. These caps are 22 caliber rim-fire cartridge, loaded with a standard detonating mixture.
The protecting disk is cut from 24-gauge tin sheet and is 1 7/8 inches in diameter. This disk fits over the detonating-cap plate and is held in place by four small nails, which are driven through the protecting disk and detonating-cap plate into the bottom of the wood plug.
Figure 139 shows the machine used for driving home these nails. The protecting disk is placed over the detonating-cap plate for the purpose of preventing sparks or flames from issuing through the hole in the wood plug occupied by the time fuse, and thus showing the course taken by the rifle light during its flight.
Figure 140 shows first the plug on the extreme right with the fuse ready to be inserted in the hole in the center. Next to it on the left is the plug with the fuse cut off level with the top, then the plug with a blob of prime covering the end of the time fuse. The last two plugs show the detonating-cap plate and the protecting disk ready to be nailed together on the plug. In the foreground on the left is shown the detonating cap set in position; to the right the protecting disk.
Fig. 139. - Machine nailing plates to plugs.
Fig. 140. - Details of plug and igniter.
This consists of a felt disk 1 3/4 inches diameter by 1/2 inch thick, which has a half-inch hole in the center and a cotton disk glued to the bottom.
Figure 141 shows the expelling-charge holder on the right, in the center the loaded holder covered with a disk of cotton, and on the left the holder with the cotton disk painted with a daub of prime.
Fig. 140. - Details of plug and igniter.
The expelling-charge holder is loaded with 5F gunpowder, which fills the hole in the felt disk. In order to hold the charge of powder in place muslin disks are pasted on each side of the felt washer. One of these has a daub of prime in the center. When assembled this disk abutts the wood plug and the primed time fuse.
This is a carton, formed from a single sheet of two-ply Bird's hardward paper, cut 12 by 20 inches. It is rolled in a cylindrical form on a mandrel to a diameter of 1 1/2 inches, and a length of 12 inches. It is then cut in 2-inch lengths, the carton or light case being 1 1/2 inches in diameter and 2 inches long.
This is composed of two thicknesses of hardware paper, 1 5/8 inches in diameter, through the center of which is punched a hole 1/2 inch in diameter. This disk is glued in place and serves as a bottom to hold the light composition in the case.
Fig. 142. - Light case and cable.
Muslin cut in strips 8 inches long by 1 1/2 inches wide encircles the case with 1/2 inch projecting. The projecting part is pasted over the bottom disk, holding it securely in place.
Figure 142 shows the bottom band attached to the case.
A piece of 30-pound Kraft paper is cut circular in form 1 5/8 inches in diameter. It is pasted over the bottom disk and edge of the muslin band, completely covering the hole in the bottom disk.
This composition consists of -
It is mixed by weighing 6 pounds of saltpeter, 4 pounds of sulphur, and 1 pound of charcoal, and screening each ingredient separately through a 24-mesh sieve into a tub. The ingredients are mixed thoroughly by hand, then screened through a 16-mesh sieve. The amount used per light is about 10 per cent. of the total weight of the composition. This first-fire composition is pressed into the light case or carton until it occupies a space equivalent to approximately 1/10 of the volume of the case.