In 1848, Hugh Bell, an Englishman, built a cylindrical airship with convex pointed ends. It was 55 feet long and 21 feet in diameter. It had a keel-shaped framework of tubes to which the long narrow car was attached, and there was a screw propeller on each side, to be worked by hand, and a rudder to steer with. It failed to work.
In 1852, however, a new era opened for the airship. Henry Giffard, of Paris, the inventor of the world-famed injector for steam boilers, built an elliptical gas-bag with cigar-shaped ends, 144 feet long, and 40 feet in diameter, having a cubic content of 88,000 cubic feet. The car was suspended from a rod 66 feet long which hung from the net covering the gas-bag. It was equipped with a 3-horse-power steam engine which turned a two-bladed screw propeller 11 feet in diameter, at the rate of 110 revolutions per minute. Coke was used for fuel. The steering was done with a triangular rudder-sail. Upon trial on September 24, 1852, the airship proved a success, travelling at the rate of nearly 6 miles an hour.
The first Giffard dirigible.
Giffard built a second airship in 1855, of a much more elongated shape—235 feet long and 33 feet in diameter. He used the same engine which propelled his first ship. After a successful trial trip, when about to land, the gas-bag unaccountably turned up on end, allowing the net and car to slide off, and, rising slightly in the air, burst. Giffard and his companion escaped unhurt.
Giffard afterward built the large captive balloon for the London Exhibition in 1868, and the still larger one for the Paris Exposition in 1878. He designed a large airship to be fitted with two boilers and a powerful steam-engine, but became blind, and died in 1882.
The Haenlein airship inflated with coal gas and driven by a gas-engine.
In 1865, Paul Haenlein devised a cigar-shaped airship to be inflated with coal gas. It was to be propelled by a screw at the front to be driven by a gas-engine drawing its fuel from the gas in the body of the ship. An interior air-bag was to be expanded as the gas was consumed, to keep the shape intact. A second propeller revolving horizontally was intended to raise or lower the ship in the air.
It was not until 1872 that he finally secured the building of an airship, at Vienna, after his plans. It was 164 feet long, and 30 feet in diameter. The form of the gas-bag was that described by the keel of a ship rotated around the centre line of its deck as an axis. The engine was of the Lenoir type, with four horizontal cylinders, developing about 6 horse-power, and turned a propeller about 15 feet in diameter at the rate of 40 revolutions per minute. The low lifting power of the coal gas with which it was inflated caused it to float quite near the ground. With a consumption of 250 cubic feet of gas per hour, it travelled at a speed of ten miles an hour. The lack of funds seems to have prevented further experiments with an invention which was at least very promising.