Airship envelope

“ The airship is, therefore, nothing else than a dirigible balloon, for the engines and other weights connected with the structure are supported in the air by an envelope or balloon, or a series of such chambers, according to design, filled with hydrogen or gas of some other nature. ”

“ Moreover, the direct longitudinal compression due to the rigging is applied to a point considerably above the axis of the ship. In a large non-rigid many of these difficulties can be overcome by distributing the weight into separate cars along the envelope itself.
We have seen that as an airship rises the gas contained in the envelope expands. If the envelope were hermetically sealed, the higher the ship rose the greater would become the internal pressure, until the envelope finally burst. To avoid this difficulty in a balloon, a valve is provided through which the gas can escape. ”

“ PARSEVAL AIRSHIP No. 4
This airship deserves special consideration for two reasons; firstly, on account of the active-service flying carried out by it during the first three years of the war, and, secondly, for its great value in training of the officers and men who later on became the captains and crews of rigid airships.
The Parseval envelope is of streamline shape which tapers to a point at the tail, and in this ship was of 300,000 cubic feet capacity. The system of rigging being patented, can only be described in very general terms. ”

“ This little airship made its first appearance in the spring of 1909. The envelope was fish-shaped and composed of gold-beater's skin, with a volume of 21,000 cubic feet. One ballonet was contained in the envelope which, at first, had three inflated fins to act as stabilizers. These proved unsatisfactory as they lacked rigidity, and were replaced after the first inflation by the ordinary type. Two 8 horse-power 3-cylinder Berliet engines were mounted in a long car driving a simple propeller, and at a later date were substituted by a R.E.P. engine which proved most unsatisfactory. ”

“ It is similar in design and in size to the Astra, but without the inflated stabilizers. Rounded slightly at the nose, the envelope tapers to a sharp-pointed stern.
The Lebaudy is the chief example of a French semi-rigid airship. The envelope is long and cylindrical, pointed at the nose and rounded at the stern, where it is fitted with stabilizing “fins.” The base of the envelope is fitted to a long keel, which ends at the rear in a rudder and fins. From this keel the car is suspended by strong cables, and beneath the car extends a conical structure of steel tubes, with points falling downward. ”

“ The only disadvantage of gold-beaters’ skin5 for the envelope of balloons and airships appears to be its very great expense. This, in the case of a large airship, is formidable. It should be mentioned, however, that it has sometimes been used for the separate gas compartments which, as will be seen, are a feature of the Zeppelin airship. ”

“ Impossible!” ejaculated the visitor, gaping at the picture.
“I don’t wonder at your surprise,” responded the managing editor, “but that’s exactly what they accomplished in their Ocean Flyer—the largest and highest-powered aircraft ever devised—a vessel capable of carrying six or seven passengers at a consistent velocity of two hundred miles and more per hour; an airship which can be easily operated at a height of eight or ten miles, where the driver of any other machine would either freeze to death or die from lack of oxygen.” ”

“ The arrangements made for handling airships on the ground and while landing, and also for moving them in the open, provide scope for great ingenuity. An airship when about to land is brought over the aerodrome and is "ballasted up" so that she becomes considerably lighter than the air which she displaces. ”

“ When all is ready to leave the masthead for flight, the pulling of a lever in the automatic coupling releases the ship. The latter then draws astern and upward, under the influence of the prevailing wind, until it is well clear of the landing station and can proceed on its course.
The design of this apparatus is such that the landing of an airship is as easy in a wind as in complete calm. With its help an airship can land in any speed of wind in which it is safe to fly. ”

“ OF THE NEW YORK HERALD.
“Three sets of follow or tandem planes project, with slight dihedral angles, for from eighty to forty feet on each side of the body of the craft, a wing width never before attained. Yet, in flight, the enormous craft is readily held aloft, with all its load, by wings that are no more than seven and one-half feet in chord—from front to trailing edge. Although it will be incomprehensible to many how such small lifting surface can elevate such a heavy structure, this becomes apparent when the airship is seen at rest. ”

“ A powerful engine driving a winch will be necessary to raise these heavy wires from the ground, although of course the lift of the airship will assist in this. Secondly, the lowering of passengers and cargo will not be easy as the ship will not be rigidly secured. This, however, can probably be managed when experiments have reached a further stage, and at present the system may be said to present distinct possibilities. ”

“ Owing to the clearness of the water in tropical regions, objects can be located at a great depth when viewed from the air, and it is imagined that an airship will be of great assistance in searching for likely places. Sponges and coral are also obtained by diving, and here the airship's co-operation will be of value. Small ships such as the S.S. Zero would be ideal craft for these and similar operations. ”

“ The earliest experiments undertaken by the Admiralty with craft lighter than air had been ambitious and unfortunate. It was always recognized by those who gave thought to aeronautics that for naval purposes the airship has some advantages over the aeroplane. It can remain longer in the air, so that its range of action is greater; it can easily carry wireless apparatus both for transmitting and for receiving; it can take up a stationary point of vantage where the (p. 172) aeroplane must needs keep moving; it can lift a greater weight ”

“ All of these facts Andy knew by heart and in the silence of the sunset hour he stood in awe before the sky king he was helping to create. In two more months the great doors would roll open, the huge mooring mast, with the Goliath in tow, would waddle out on the concrete runway, and the world’s greatest airship would be introduced to its public, some of whom would welcome it enthusiastically while others would gaze at it with questioning eyes, waiting for its trial flights to prove the claims of its builders. ”

“ The single-wire system is at the same time the simplest and most obvious method which suggests itself, and means that the ship is secured by a wire cable attached to a suitable point in the ship and led to some fixed point on the ground. It has been found that an airship secured in this way requires constant attention, and that steering is always necessary to render her steady in the air. Considerable improvement is obtained if a dragging weight is added to the wire, as it tends to check to a considerable extent lateral motion of the bow of the ship. ”

“ Hitherto43 airships, when not in flight, have been housed in enormous hangars, involving heavy cost of installation and their landing has required the services of hundreds of men—an operation that will probably seem laughable in its crudity to the next generation. The airship of the future will probably never go into a hangar at all except for occasional overhauling, as an ordinary ship goes into drydock. ”

“ Lift is directly proportional to purity.
AIRSHIP DESIGN
The design of airships has been developed under three distinct types, the Rigid, the Semi-Rigid, and the Non-Rigid.
The rigid, of which the German Zeppelin is the leading example, consists of a framework, or hull composed of aluminium, wood, or other materials from which are suspended the cars, machinery and other weights, and which of itself is sufficiently strong to support its own weight. Enclosed within this structure are a number of gas chambers or bags filled with hydrogen, which provide the necessary buoyancy. ”

“ As if the occupants of the airship had heard the words of the aged inventor, they headed their craft toward earth. The combined aeroplane and dirigible balloon, a most wonderful traveler of the air, swung around, and then, with the deflection rudders slanted downward, came on with a rush. When near the landing place, just at the side of the house, the motor was stopped, and the gas, with a hissing noise, rushed into the red aluminum container. This immediately made the ship more buoyant and it landed almost as gently as a feather. ”

“ Experience in the war has proved that for military purposes the large rigid, capable of long hours of endurances and the small non-rigid made thoroughly reliable, are the most valuable types for future development. The larger non-rigids, with the possible exception of the North Sea, do not appear to be likely to fulfil any very useful function.
Airship design introduces so many problems which are not met with in the ordinary theory of structures, that a whole volume could easily be devoted to the subject, and even then much valuable information would have to be omitted from lack of space. ”

“ The aeroplane is eminently adapted for certain purposes, and the greatest bigot in favour of the airship can hardly dispute the claims of this machine to remain predominant for short-distance travel, where high speed is essential and the load to be carried is light. For long distance voyages over the oceans or broken or unpopulated country, where large loads are to be carried, the airship should be found to be the more suitable. ”

“ Just as the curve of a clam shell helps it to mount upward, so the curve of the elevating or depressing rudder on an airship helps it to go up or down. If the rudder is inclined upward the aeroplane shoots toward the clouds. When the rudder is parallel to the plane of the earth's surface, the airship flies in a straight line. When the rudder is tilted downward, down goes the craft. ”

“ But, Alan—boys!—think of the sum you are offered: twelve times the actual cost, if the new owners are given immediate possession, and providing you agree not to dispose of another similar machine within a period of one year. You can build another airship just like the Flyer within two or three months at the longest, and you are at liberty to use it yourselves as you may please. ”

“ Owing to its ceiling, rate of climb and speed, which we take to be from 70 to 80 miles per hour in the airship of the future, the airship may be regarded as comparatively safe against attack from the ordinary type of seaplane. The chief danger to be apprehended is attack from small scouting seaplanes, possessing great speed and the power to climb to a great height, or from aeroplanes launched from the decks of ships. ”

“ According to this plan, although both names stand for an aerial vessel88 capable of travelling in the sky by its own motion, an airship is a machine supported in the air by reason of its buoyancy, while a flying machine is kept aloft only by virtue of its onward movement.
In other words, part of the construction of an airship consists of a bag or balloon, filled with gas or hot air, which causes the whole to rise and maintain its position in the air. ”

“ France must be credited with at least eighteen airships of various types—England had only seven—Russia had probably not more than three airships available—Belgium had one airship Austria had not less than three, not more than five airships available—Germany had twenty three airships of the rigid, semi-rigid, and non-rigid type. ”

“ The general idea of the airship was that of the familiar aeroplane, but in addition to the sustaining surfaces of the planes, there was an aluminum, cigar-shaped tank, holding a new and very powerful gas, which would serve to keep the ship afloat even when not in motion.
Two sets of planes, one above the other, were used, bringing the airship into the biplane class. There were also two large propellers, one in front and the other at the rear. These were carefully made, of different layers of wood "built up" as they are called, to make them stronger. ”

“ He brought the unconscious man into the cabin, and then, quickly returning to the platform, he detached the piece of scarf from the propeller blade. Next he started the motor, and also turned on the gas tank, so that the airship, in a few minutes, could float in space without motion. ”

“ On the other hand, the airship, being provided with engines to propel it through the air, and with rudders and elevators to control it for direction and height, can be steered in whatever direction is desired, and voyages can be made from one place to another--always provided that the force of the wind is not sufficiently strong to overcome the power of the engines. ”

“ Why the United States Government, to increase interest in airship navigation, and construction, especially for army purposes, has offered a prize of twenty thousand dollars for the first flight from the Atlantic to the Pacific, or from New York to San Francisco, by an airship carrying at least three persons. Only two landings are allowed during the flight, to take on gasolene, or make repairs. ”

“ There is a strong probability that the airship, rather than the airplane, may prove to be the great aerial liner of to-morrow. The large airship of the Zeppelin type, traveling at greater speed than the fastest express train, and carrying a large number of passengers and a heavy cargo, is apt before long to become the deadly rival of the steamship. A voyage across the Atlantic in such an airship would be far shorter, safer and pleasanter than in the finest of the ocean vessels. ”