Dreaming of Air Ships— Henri Giffard
Henri Giffard’s dream of piloting an air ship hovered tantalizingly near, but ultimately it slipped beyond of his reach. Giffard was an accomplished inventor. He invented the water injector, a device for replenishing water in a steam boiler, which earned him millions when his invention became standard equipment on all steam engines. Giffard was fascinated by balloons from the time of his first ride in one at age 18, in 1843. This passion was widely shared; the basic technology of ballooning was 50 years old. But, Giffard was not interested to simply bob about like a cork in water, carried which ever way the wind was blowing.
Giffard set out to build an air ship that would allow him to navigate through the air at will, like a captain at the helm of one of the new steam-powered ships that had recently conquered travel across the oceans. The history of ballooning from this time is filled with fanciful designs for airships, many resembling 18th century sailing ships suspended in air. Working with two young engineers from the Ecole Centrale, Giffard set out methodically to solve the four problems of air travel outlined by the distinguished physicist Jules Jamin. He streamlined the gas bag, so that it could move more easily through the air. He designed and built a compact, highly efficient steam engine for power — highly risky considering that the gas bag was filled with flammable methane — and a propeller for propulsion. And finally, he attached a rudder for maneuverability.
Giffard launched his prototype airship from the Place d’Etoile in Paris on Friday, September 24, 1852, to great public acclaim. People called him the Fulton of air navigation, after Robert Fulton the inventor of the steamboat. The dream of air travel seemed within reach. Giffard confirmed that each of the airship’s systems functioned as intended, but overall performance fell short. He was able to steer and maneuver, but his ship lacked the speed necessary to travel against anything above a slight breeze. Top speed of the was limited to 2 to 3 metres per second in still air (about 6 miles per hour) by the 3-horsepower capacity of the engine. An engine with greater power was needed, and with the steam engine technology then available this meant that an airship capable of moving against the wind would have to be much larger. Giffard’s failed prototype was 44 metres long with a gas volume of 2,500 cubic metres. He estimated that a practicable ship would have to be 14 times this size, with a total length of 600 metres, and requiring nearly 100 times the volume of methane to lift it.
The cost of constructing such an airship was too great for Giffard to continue. He went on to construct several other balloons, but these were tethered in one spot and used only to give paying customers a taste of air travel. For the Paris Exposition of 1878, Giffard installed a huge hydrogen-filled balloon in the courtyard of the burned-out Tuileries Palace, near the Place de Concord, offering rides to a height of 500 metres above the city. At 25,000 cubic metres in volume, this was the largest balloon ever constructed, and 40 passengers could fit in its basket. Giffard died disappointed and despondent at the age of 57. He committed suicide after disease robbed him of his sight.
Demonstration of the first practical airship had to wait until 1901. That’s when Brazilian inventor Albert Santos-Dumont captured the Deutsch de la Meurthe prize by piloting his 33-metre long hydrogen-filled dirigible along a prescribed course that took it around the Eiffel Tower. Santos-Dumont’s accomplishment was made possible by the invention of the internal combustion engine, which is capable of producing about 10 times the power per unit weight as Giffard’s steam engine, and by improvements to the process of making hydrogen gas, which provides more buoyant lift per unit volume than methane. The availability of the lighter, more powerful internal combustion engine also opened the door to heavier-than-air aero plane technology. Santos-Dumont powered his dirigible with a 12-horsepower gasoline engine, and the Wright brothers demonstrated the feasibility of heavier-than-air flight using a 15-horsepower engine in 1903. Later in the first decade of the 20th century, German inventor Ferdinand von Zeppelin succeeded in building huge, lighter-than-air airships on the scale originally envisioned by Giffard, but the future belonged to the smaller and more practical airplane.
Henri Giffard is one of the 72 engineers and scientists named on the Eiffel Tower.
