Facts About Dirigible
The term dirigible is used to describe any lighter than air aircraft that has an engine to propel it and which can be steered. The first dirigible flight was made in Paris, France, in 1852. Henri Giffard flew a cigar shaped balloon propelled by a small steam engine connected to a large propeller. A crude rudder permitted limited directional control.
There are several kinds of dirigibles. The no rigid dirigible, frequently called a blimp, uses the internal gas pressures to inflate and maintain its shape. Steel cables inside the rubberized envelope help support the control car and engines. In the semi rigid modification, a structural keel is added to the bottom of the gasbag to reduce the stress and strain.
The rigid dirigible has a lightweight metal framework which is usually covered by a metalized fabric. Several individual gas cells or balloonets are located within the frame work. The framework also supports the gondola, storage areas and engine mounts. Vertical and horizontal stabilizers with moveable control surfaces are located at the rear of the craft. Count Ferdinand von Zeppelin of Germany built and flew the first practical rigid dirigible in 1900. The name Zeppelin became almost synonymous with any rigid type airship.
All airships depend upon the buoyancy of a light gas. Hydrogen, a highly flammable gas, was used in foreign dirigibles because of its availability. Fire was a major cause of dirigible losses.
The delicate balance between the lift force of the gas and the weight of the airship is primarily maintained through the dropping of ballast and valving of gas. The power plants and horizontal control surfaces are used to aid in climbing and descending flight.
Germany used many rigid dirigibles in World War I. Zeppelins were used by the German navy to patrol water surfaces and or bombing raids.
Great interest was shown by several countries after World War I in commercial and military dirigibles. The Graf Zeppelin was designed to provide in flight comfort comparable to a steamship. It was 236 meters ling, 30.5 meters in diameter. Fully loaded it weighs 258,000 pounds.
Image source: en.wikipedia.org