Count Ferdinand Von Zeppelin and his crew operated their first airship nearly onehundred years ago. Airships are big controllable balloons, also known as dirigibles. Thereare three classes of airships, rigid, nonrigid and semirigid. Rigid airships (zeppelins) useframework in the interior to keep their shape. Semirigid airships are a combination offramework and gas pressure to maintain their shape. Nonrigid airships (blimps) rely solelyon air pressure to keep their form. They are all propelled with engines, use rudders andelevator flaps for steering and have a gondola where passengers travel. The pride of thezeppelin works was a rigid airship which was one of the more than one hundred airshipsand she was the most efficient. She had returned a profit to her operators her first seasonof eighteen round trip Atlantic Crossings. Her name was the ?Hindenburg?. It was thelargest airship ever built, it was 245 meters(804 feet) long and a gas capacity of 190, 000,000 liters(6, 710, 000 cu. ft.). Its is Thursday, May 6, 1937, the Hindenburg was ten hours behind schedule.Winds over the Atlantic caused her to slow down. In the afternoon after a low flight overManhattan and Newark the Hindenburg reached Lakehurst. But the weather again causedmore delays for the airship. The captains set course for Asbury Park. When it reached theseaside it turned again southward and cruised along the shore waiting for weather that wasappropriate to land in. At 5:00pm the whistle sounded for the ground crew at the airstation. At 7:00pm the Hindenburg was ten minutes away from landing at Lakehurst.was 200 ft. up and her forward line where in the hands of the crew. A crew member,Navy Airshipman Vincent Sheridan noticed something wrong with the Hindenburg. The Hindenburg passed through the western boundary, gas was valved from therear of the ship. It seemed light due to runoff of rain water and drying of the fabric. Allthe people waiting for the ship to arrive including photographers and reporters were allglad the wait was over. Between 7:12 and 7:20 the Hindenburg moved eastwardweighting off slightly. Gas had been released from her nose to correct this imbalance andthe engines where placed on idle. As she was being brought down she still drifted forwardbecause of winds even though the propellers were still in reverse. The wind shiftedsuddenly southwest at about 8 knots. The rudders where turned so the nose went into thewind and the ground crew followed the ships every move trying to stay with it. Thespectators on the ground noticed the ships change in direction. The crew fastened thelines to what where called guy lines these made for stronger and better control. At 7:21PM the ship almost brought into the mooring mast, everything seemed fine. Then at7:23pm the stern of the ship caught fire and two very large explosions enveloped the ship.She burst into flames and dropped to the ground. Witnesses said it blew apart as if it hadbeen paper. They also stated that the fabric burned away in just a few second. Onewitness said he didn?t see any life on the ship from the minute. There had been thirty ormore ambulances prior to the disaster. People desperately tried to save the people afterthe ship hit ground. There where many notable people aboard this ship, people likemerchants, students and professional men. Experts said that the explosion was caused by the use of hydrogen and not astructural problem. Major General Oscar Westover, Chief of the Army Air Corps pointedout that the United States had begun using hydrogen in place of helium. Helium isproduced in large amounts in the United States. They also planned to build two helium
ships. In doing this they are trying to influence the Germans to discard hydrogen forhelium in their airships. Sabotage by anti-nazi citizens was also thought of, but later ruledout. Present day people are still asking about what actually happened to theHindenburg. The destruction if this ship affects the way people look at hydrogen and theuse of the gas as a power source. Hydrogen has taken the blame for the disaster since ithappened over sixty years ago. NASA has been conducting extensive research on theaccident. They analyzed original wreckage from the Hindenburg and talked to the fewremaining survivors. Observations of the Hindenburg disaster show evidence that doesn?tmatch what would have happened if it had been a hydrogen fire that caused the ship to godown. The Hindenburg did not explode, it burned very quickly in many differentdirections. It also stayed up in mid air after the fire had ignited, this means that if gas hadbeen burning it would have crashed much faster than it actually did. Pieces of the fabricthat had been used on the Hindenburg still burned as they fell some 200 feet from theburning ship and they did not go out, but continued to burn. This gives the idea that thefabric had to be highly flammable. Finally, the color of the flames on the Hindenburgwhere a bright orange, this again suggests that it was not gas. Hydrogen makes no visibleflame and could not be seen. When the ship was being constructed, the scent of garlic wasadded to the hydrogen so that a leak could easily be found. The method of landing the shipwas poorly chosen. Thunderstorms had been over Lakehurst that very day and lightingcould still be seen in the distance during the Hindenburg?s landing. Also when the lineshad been drooped and the ship was fastened to the ground and mad an electrical groundalmost immediately after a storm had just passed.
Addison Bain was the scientist who conducted all this research. He took twosamples of fabric from the ship and brought them to the NASA Materials Science
Laboratories. In the lab the first piece of fabric was subjected to flame, and it burnt up inseconds and still flammable after six decades. The second piece was shocked withelectricity duplicating what the weather was like on May 6, 1937. It only burnt a hole inthe fabric, but when it was mounted the same as the ship was the electric shocks ignitedthe fabric and it was gone in seconds. The fabric was found to be a ?cotton substrate with an aluminized cellulose acetatebutyrate dopant?. I myself am not to sure what this is but it states a fact that it was analuminum based fire. The brightness of the flames are similar to that of the space shuttle?srocket boosters which are an example of aluminum based combustion. It turns out that itwas in fact the flammability of the fabric and not a fire caused by the gas used to lift theship. There where files from the Zeppelin Archives in Friedrichshafen, Germany, theyconfirm what Bain found in his studies. There where several letters written and when theywhere translated into German proved what Bain uncovered. An electrical engineer wroteon June 28, 1937 that the actual cause of the fire was the extreme easy flammability of thecovering material brought on by electro magnetic impulses. In conclusion, since the destruction of the Hindenburg, airship use has been limitedto nonrigid type of craft. In 1938 all military blimps in the U.S. were placed under navyjurisdiction, with the Naval Airstation at Lakehurst as center of operations. DuringW.W.II, blimps where employed for patrol, scouting, convoy and antisubmarine work. Aprivate commercial firm in the U.S. developed several small nonrigid airship that havebeen use to provide aerial television views of sporting events and for advertising purposeswithout the fear of catching fire from the gas used nor the fabric used for the covering.
! |
Как писать рефераты Практические рекомендации по написанию студенческих рефератов. |
! | План реферата Краткий список разделов, отражающий структура и порядок работы над будующим рефератом. |
! | Введение реферата Вводная часть работы, в которой отражается цель и обозначается список задач. |
! | Заключение реферата В заключении подводятся итоги, описывается была ли достигнута поставленная цель, каковы результаты. |
! | Оформление рефератов Методические рекомендации по грамотному оформлению работы по ГОСТ. |
→ | Виды рефератов Какими бывают рефераты по своему назначению и структуре. |