Airships :: essays research papers

Airships INDEX PROLOGUE 2 TYPES OF AIRSHIP 2 RIGID AIRSHIP 2 NONRIGID AIRSHIP 3 HISTORY OF RIGID AIRSPS 3 HISTORY OF NONRIGID AIRSHIPS 4 AIRSHIPS TODAY 5 HINDENBURG 6 HINDENBURG DISASTER 7 PROLOGUE An airship is a type of lighter-than-air aircraft with propulsion and steering systems, it is used to carry passengers and cargo. It obtains its buoyancy from the presence of a lighter-than-air gas such as hydrogen or helium. The first airship was developed by the French, called a ballon dirigible, it could be steered and could also be flown against the wind. TYPES OF AIRSHIP Two basic types of airship have been developed: the rigid airship, the shape of which is fixed by its internal structure; and the nonrigid blimp, which depends on the pressure created by a series of air diaphragms inside its gas space to maintain the shape of its fabric hull. Inventors sought to combine the best features of these models in a semirigid type, but it met with only limited success. Today only the nonrigid airship is used. Rigid Airship The rigid airship's structure resembled a cage that enclosed a series of balloons called gas cells. These cells were tailored to fit the cylindrical space and were secured in place by a netting that transmitted the lifting force of their gas to the structure. Each gas cell had two or more valves, which operated automatically to relieve pressure when the gas expanded with altitude, the valves could also be operated manually so that the pilot could release gas whenever desired. Also on board was a ballast system that used water as ballast. On the ground this ballast served to make the airship heavier than air. When part of it was released, the airship ascended to a cruising altitude where the engines supplied propulsion, and further ballast could be released to gain more altitude. As fuel was consumed, the airship became lighter and tended to climb. This was countered in hydrogen-inflated airships by simply releasing gas into the atmosphere. The method was uneconomical, however, with helium-inflated airships, and they were therefore equipped with ballast generators, apparatuses that condensed moisture out of the engines' exhaust gases to compensate for fuel that was consumed. But this ballast-generating equipment was expensive, complex, heavy, and difficult to maintain and was thus one of the most serious disadvantages of airships filled with the safer but more expensive helium. Nonrigid Airship In contrast to the rigid airship, the nonrigid blimp has no internal structure to maintain the shape of its hull envelope, which is made of two or three plies of cotton, nylon, or dacron impregnated with rubber for gas tightness. Inside the gas space of the hull are two or more air diaphragms called ballonets that