The disc is fastened to the balloon or aeroplane and is left behind when the parachute falls, having done its work.
And now let us consider the tapes. As has already been remarked, a series of coiled cords cannot be relied upon to pull out straight without possibility of entanglement, but a tape, if folded to and fro like a Chinese cracker, will invariably do so. So packed tapes have been substituted for coiled corded rigging, with the certainty that they cannot be entangled in the fiercest air current.
And now we come to another interesting feature. The man is not suspended directly from the small disc to which the tapes are attached but by a non-spinning sling which contains a shock absorber. This latter consists of a number of strands of rubber and it is owing to its action that the aviator who trusts his life to the parachute suffers little or no shock; even when the instant opening of the parachute begins to arrest his fall. And not only does it save him from shock, but it also avoids the possibility of too great a stress coming suddenly upon the parachute or its rigging of tapes.
The aviator himself is attached to the parachute through the shock-absorber sling, by means of a harness which he wears constantly throughout his flight, so that in the event of trouble he only has to jump overboard and the parachute automatically does the rest. This harness consists of two light but
strong aluminium tubular rings through which he places his arms, combined with a series of straps which can be so adjusted that the stress of carrying him comes upon those parts of his body best adapted to bear it.
This improved parachute is the only one which is capable of being used instantly and without preparation for descent from an aeroplane flying at top speed. It is easy to see that it is one thing to drop from a stationary or nearly stationary balloon and quite another to dive from an aeroplane at one hundred miles per hour. The latter is equivalent to suddenly trusting oneself to a parachute during the strongest gale. It has been found, by experiment, however, that high speed is no bar to the use of this parachute since it only causes the parachute to open a little more quickly than usual, which means that it can be used with safety from an even lower height.
Under the worst conditions this wonderful parachute can be relied upon always to open and carry its load at a height of only one hundred feet, and its use is safe in all circumstances when dropped from two hundred feet above the ground. After it has once got into operation and taken charge of affairs, so to speak, the man descends at the rate of only fifteen feet per second, which is just about the same as dropping from a height of a little over three feet. In other words, he will arrive on the ground with no worse bump than you would get by jumping off the dining-room table.
But suppose that there were a wind blowing: would not the parachute come down in a slanting
direction and then drag the man along? Or may he not alight upon a tree or the roof of a house, only to be pulled off again and flung headlong? Quite true he might, were not proper provision made for such occurrences. Embodied in the harness is a lock which can be instantly undone, by a simple movement of a lever in the hand, and by its aid the man on touching earth or on alighting upon anything solid can release himself instantly, after which the parachute can sail away whither it will, but he will be safe and sound.
What Mr. Calthrop has accomplished by the invention of his "Guardian Angel" parachute may be summarised briefly by saying that he has reduced the minimum height from which a parachute could be dropped from two thousand to two hundred feet, and that he has made it possible to launch a parachute, with the certainty of safety, from any kind of aircraft flying at the slowest or highest speed of which they are capable.