The carton of the rocket head may be attached to the rocket body before introducing the parachute and light signals or the parachute and signals may be assembled and the rocket head then attached to the rocket body. In the event that the latter plan is adopted, a small wooden plug is temporarily forced into one end of the carton of the rocket head to act as a temporary bottom until the case is loaded, at which time it is removed and the rocket assembled.
The assembly of the parachute and signals with the exception of this one point is practically the same. The operation consists first of the introduction of the signal, which is shown in figure 60.
After the signal is placed in the carton, cotton batting is tamped into the case and around the signal light. A handful of bran or sawdust poured into the case fills up the space around the cotton batting and acts as an additional buffer to protect the parachute from the flame of the expelling charge, and also acts as a bed in which the parachute rests. Figure 61 shows this operation.
First the parachute is inspected for imperfections. This is done by the operator drawing the parachute quickly through the air by means of the strings, thus inflating it and giving it a test. The perfect parachutes are then rubbed thoroughly inside and out with powdered pumice stone.
This is necessary in order that the parachute shall open freely when expelled from the container.
The next operation is to tie the parachute strings to the tie cord and asbestos cord. The operator before tying the strings again inspects the parachute in a manner similar to that which has been described above. The tie cord and asbestos cord are tied to the parachute strings by a simple knot. The parachute is then ready for folding and the operator doing this work again inspects it in the same manner as above.
Fig. 60. - Placing signal light in rocket head.
The operator holds a parachute at its apex, and first runs his fingers as a comb downward through the strings, insuring against their being entangled. The seams of the various segments are drawn and accordion plaited, very much in the manner of an umbrella folded before being rolled.
The parachute is encircled by the hand, the folds are smoothed down into a cylindrical form, and the entire parachute is then folded double. The strings are caught up and coiled around three fingers of the hand and the coil placed against the side of the folded parachute. After the strings have been carefully arranged the coil is again folded over the strings, making a compact package, ready to be inserted into the case as shown in figure 63.
The parachute is now carefully folded in the manner described, care being taken to plait the folds of the parachute and to see that the strings are not tangled. The strings are coiled, set against the folded parachute, and the bundle is introduced into the rocket head. Figures 62 and 63 show the above operations.
Fig. 61. - Placing cotton twitting and sawdust around light in rocket head.
One method in use which seems to give satisfaction is shown in figures 64 and 65. In this operation a disk of strawboard forms a ring around the light just above the match, having an outside diameter the same as the inside diameter of the rocket head. The disk acts as an additional barrier to prevent the igniting flame from charring the parachute.
Fig. 62. - Plaiting folds of parachute.