The car of a modern Balloon
A.A. Ballast bags filled with sand B. Instruments (such as a statoscope, which shows at any moment whether the balloon is rising or falling; and an altitude meter) C. Ring by which car is attached to balloon.
Semi-rigid Airship
But as airships were built larger, and greater speeds were obtained, it became necessary to strengthen the envelopes with some form of keel; and this led to a type which is known as the semi-rigid, and is developed successfully in France. The figure illustrates an airship of this build. Along the lower side of its envelope is placed a light, rigid framework or keel, and from this is suspended the car which contains engines and crew. A. Gas-containing envelope B. Strengthening keel C.C. Stabilising-planes D. Rudder E. Car carrying engines, propeller, and crew.
Hull of a Zeppelin during construction
Hull of a Zeppelin during construction. Craft of the semi-rigid type provide a link between small, non-rigid ships and the very large machine which is built with an entirely rigid framework, and has its example in the Zeppelin. The maker forms a skeleton hull of aluminium or some light metal alloy, a method that is shown in figure. The hull of a Zeppelin, slightly more than 500 feet in length, is sheathed with tightly stretched fabric; and within it are the gas-containers—a row of seventeen separate balloons, each in a compartment by itself, and containing a total of nearly 1,000,000 cubic feet of gas—which give these airships a lifting power of close upon 30 tons.
Early-type Airship
A typical craft, representing the first of those navigated with any certainty, is shown in Figure. A gas-containing envelope, made of a light, strong, varnished fabric, is kept taut by the pressure of the gas within; the car, constructed of wood or metal tubing, is suspended by ropes from the envelope, and contains engine and crew, with a two-bladed propeller revolving astern. Such a machine, in its control, had an elevating-plane and rudder, upon the same principle as those of the aeroplane. One of the difficulties to be overcome was the expansion and contraction of gas in the envelope owing to differences in altitude and temperature. When the craft ascended, its envelope completely inflated, the gas began to dilate owing to the outer air becoming less dense; and some had to be allowed to escape through automatic valves. Then, should the machine descend to a lower level, there was not sufficient gas in the envelope to keep it tightly stretched, and it tended to sag at the bow as it was driven through the air. A. Gas envelope B. Car suspended below envelope C. Motor, which drives propeller (D) through a shaft E. Small horizontal plane for rising or descending F. Fixed fin, or keel plane, to give stability G. Rudder.
Control platform of an Airship
A. Wheels operating elevating-planes and rudder B. Height recorder C. Speaking-tube to communicate with engineers.
A modern Balloon
Coal-gas superseded hot air in the filling of balloons, the latter being unsatisfactory, seeing that it cooled rapidly and allowed the balloon to descend; the only alternative being to do what some of the first aeronauts did, and burn a fire below the neck of their balloon even when in the air. But the dangers of this were great, seeing that the whole envelope might easily become ignited. With balloons filled with coal-gas long flights were possible, but they had always this disadvantage—the voyagers were at the mercy of the wind, and could not fly in any direction they might choose. If the wind blew from the north then they were driven south, the balloon being a bubble in the air, wafted by every gust. Aeronauts became disgusted with this inability to guide the flight of a balloon, and many quaint controls were tested; such, for example, as the use of a large pair of oars with which the balloonist, sitting in the car of his craft, rowed vigorously in the air.
An Experimental Airship
...it was followed in due course by the use of small steam engines and electric motors, which were made to turn propellers such as are used in aeroplanes. For such experimental craft, the rounded form of gas-container was abandoned and a cigar-shaped envelope adopted, pointed at both ends, which could be more easily driven through the air. An airship of a crude and early type is seen here. It was built by an experimenter named Gifford, and in 1852 it flew at the rate of seven miles an hour. A. Gas-containing envelope; B. Car suspended below envelope, which carried the aeronaut and a 3-horse-power steam engine; C. Two-bladed propeller driven by the engine; D. Rudder (in the form of a sail) by which the machine could be steered from side to side.
An Airship leaving its shed
An Airship leaving its shed A. The machine emerging stern first B. A sister craft in dock C. The launching crews D. Rails upon which the cars of the airship move, so as to prevent its swinging sideways in a gust E. Outlook station upon the roof of the shed F. Workshops; living quarters for the crews; plant for making hydrogen gas.
Aeroplanes attacking an airship from above
Airships, like aeroplanes, are being armed with guns and bombs; and their power of raising weights enables them to carry heavy weapons. Large and highly destructive bombs have been tested in the German airships, being released over the sea and aimed at targets in the form of rafts. Latest-type airships also carry guns in their cars; and the Zeppelins have a platform upon the tops of their hulls, reached by a ladder through the middle of the ship, from which a machine-gun can be fired upward. This is a very necessary precaution, and is intended to frustrate the attack of an aeroplane. It would be the aim of the latter, whenever possible, to manœuvre above its big enemy—as suggested in figure —and drop a bomb upon its hull. Hence the construction of the top platform of the airship, from which her gunners can direct a vigorous fire aloft.
The ascension of Montgolfier’s balloon
It was on June 5, 1783 that Stephen and Joseph Montgolfier, two French brothers, sent up the first balloon. You can just imagine the amazement it caused when it arose from the ground.