ZEPPELIN
Zeppelin
A Zeppelin is a type of rigid airship pioneered by the German Count Ferdinand von Zeppelin in the early 20th century. It was based on designs he had outlined in 1874 and detailed in 1893. His plans were reviewed by committee in 1894 and patented in the United States on 14 March 1899. Given the outstanding success of the Zeppelin design, the term zeppelin in casual use came to refer to all rigid airships.
Zeppelins were operated by the Deutsche Luftschiffahrts-AG (DELAG). DELAG, the first commercial airline, served scheduled flights before World War I. After the outbreak of war, the German military made extensive use of Zeppelins as bombers and scouts.
The World War I defeat of Germany in 1918 halted the airship business temporarily. But under the guidance of Hugo Eckener, the deceased Count's successor, civilian zeppelins became popular in the 1920s. Their heyday was during the 1930s when the airships LZ 127 Graf Zeppelin and LZ 129 Hindenburg operated regular transatlantic flights from Germany to North America and Brazil. The Art Deco spire of the Empire State Building was originally designed to serve as a dirigible terminal for Zeppelins and other airships to dock. The Hindenburg disaster in 1937, along with political and economic issues, hastened the demise of the Zeppelin.
Principal characteristics
The most important feature of Zeppelin's design was a rigid metal alloy skeleton, made of rings and longitudinal girders. The advantage of this design was that the aircraft could be much larger than non-rigid airships (which relied on a slight overpressure within the single gasbag to maintain their shape). This enabled Zeppelins to lift heavier loads and be fitted with more and more powerful engines.
The basic form of the first Zeppelins was a long cylinder with tapered ends and complex multi-plane fins. During World War I, as a result of improvements by the rival firm Schütte-Lanz Luftschiffbau, the design was changed to the more familiar streamlined shape and cruciform fins used by almost all airships ever since. Within this outer envelope, several separate balloons, also known as "cells" or "gasbags", contained the lighter-than-air gas hydrogen or helium. For most rigid airships the gasbags were made of many sheets of goldbeater's skin from the intestines of cows. About 200,000 were needed for a typical World War I Zeppelin. The sheets were joined together and folded into impermeable layers. Non-rigid airships do not have multiple gas cells.
Forward thrust was provided by several internal combustion engines, mounted in nacelles (cowlings) connected to the skeleton. The R101 airship used diesel engines, which were then an untried technology for powering aircraft; they were unsuccessful. The Graf Zeppelin used spark-ignition engines, but fuelled with a natural gas called Blaugas, which was stored uncompressed. It was similar to propane and was named after its inventor rather than its colour (Blau is German for "blue"). The beauty of Blaugas for airships was that it weighed more or less the same as air and so as the fuel was used up, it did not affect the trim of the airship.
A current running Zeppelin flies in the skies of Monroeville, Pa. The rigid airship's codename is "Jenna". This Zeppelin is most known for its commercial use. Many local companies pay the commanders of "Jenna" for advertisement purposes.
A Zeppelin was steered by adjusting and selectively reversing engine thrust and by using rudder and elevator fins. The word for these combined control surfaces is empennage.
A comparatively small compartment for passengers and crew was built into the bottom of the frame, but in large Zeppelins this was not the entire habitable space; they often carried crew or cargo internally for aerodynamic reasons.
History
The first generations
Count Ferdinand von Zeppelin became interested in constructing a "Zeppelin balloon" after the Franco-Prussian War of 1870–1871, where he witnessed the French use balloons to transport mail during the early part of the war. He had also encountered Union Army balloons in 1863, during the American Civil War, where he was a military observer. He first wrote of his dirigible interest in 1874 and began to seriously pursue his project after his early retirement from the military in 1890 at the age of 52.
Convinced of the potential importance of aircraft designs, he started working on various designs shortly after leaving the military in 1891. He had already outlined an overall system in 1874, and detailed designs in 1893 that were reviewed by committee in 1894, and that he patented on 31 August 1895, with Theodor Kober producing the technical plans. After hearing about the rigid airship constructed by David Schwarz and witnessing its trial flight at the Tempelhof Airfield near Berlin on November 3rd 1897, he proceeded to buy the patent rights from the widow of the prematurely deceased Schwarz, in order to allow Berg to supply aluminum. However, Schwarz's design was "radically different from Zeppelin's" and in December 1897 Zeppelin admitted the Schwarz design could not be developed. Sean Dooley speculates on the indirect benefits Zeppelin gained from Carl Berg and Schwarz's work. In 1899, Zeppelin started constructing his first airship from his own designs.
One unusual idea, which never saw service, was the ability to connect several independent airship elements like train wagons; indeed, the patent title called the design Lenkbarer Luftfahrzug (steerable air train).
An expert committee to whom he had presented his plans in 1894 showed little interest, so the count was on his own in realizing his idea. In 1898 he founded the Gesellschaft zur Förderung der Luftschiffahrt (Society for the promotion of airship flight), contributing more than half of its 800,000 Mark share capital himself. He assigned the technical implementation to the engineer Theodor Kober and later to Ludwig Dürr.
Construction of the first Zeppelin began in 1899 in a floating assembly hall on Lake Constance in the Bay of Manzell, Friedrichshafen. This location was intended to facilitate the difficult launching procedure, as the hall could easily be aligned with the wind. The prototype airship LZ 1 (LZ for Luftschiff Zeppelin, or "Airship Zeppelin") had a length of 128 meters (420 ft), was driven by two 14.2 horsepower (10.6 kW) Daimler engines and was controlled in pitch by moving a weight between its two nacelles.
The first Zeppelin flight occurred on 2 July 1900 over Lake Constance (the Bodensee). It lasted only 18 minutes before LZ 1 was forced to land on the lake after the winding mechanism for the balancing weight failed. After it was placed back in the hangar an apparatus used to suspend it broke. Upon repair, rigid airship technology proved its potential in subsequent flights (the second and third flights were on 17 October 1900 and 24 October 1900) beating the 6 m/s velocity record of the French airship La France by 3 m/s. Despite this performance, the shareholders declined to invest more money, and so the company was liquidated, with Count von Zeppelin purchasing the ship and equipment. The Count wished to continue experimenting, but he eventually dismantled the ship in 1901.
It was largely due to support by aviation enthusiasts that von Zeppelin's idea got a second (and third) chance and would be developed into a reasonably reliable technology. Only then could the airships be profitably used for civilian aviation and sold to the military.
Donations, the profits of a special lottery, some public funding, a mortgage of Count von Zeppelin's wife's estate and a 100,000 Mark contribution by Count von Zeppelin himself allowed the construction of LZ 2, which took off for the only time on 17 January 1906.
After both engines failed, it made a forced landing in the Allgäu mountains, where the anchored ship was subsequently damaged beyond repair by a storm.
Incorporating all usable parts of LZ 2, the successor LZ 3 became the first truly successful Zeppelin, which by 1908 had travelled a total of 4,398 kilometers (2,733 mi) in the course of 45 flights. The technology then interested the German military, who bought LZ 3 and redesignated it Z 1. She served as a school ship until 1913, when she was decommissioned as obsolescent.
The army was also willing to buy LZ 4, but requested a demonstration of her ability to make a 24-hour trip. While attempting to fulfill this requirement, the crew of LZ 4 had to make an intermediate landing in Echterdingen near Stuttgart. During the stop, a storm tore the airship away from its anchorage in the afternoon of 5 August 1908. She crashed into a tree, caught fire, and quickly burnt out. No one was seriously injured, although two technicians repairing the engines escaped only by making a hazardous jump. This accident would have certainly knocked out the Zeppelin project economically had not one of the spectators in the crowd spontaneously initiated a collection of donations, yielding an impressive total of 6,096,555 Mark. This enabled the Count to found the Luftschiffbau Zeppelin GmbH (Airship Construction Zeppelin Ltd.) and a Zeppelin Foundation.
Before World War I
Before World War I, a total of 21 Zeppelin airships (LZ 5 to LZ 25) were manufactured. In 1909 LZ 6 became the first Zeppelin used for commercial passenger transport. The world's first airline, the newly founded DELAG, bought seven Zeppelins by 1914. The airships were given names in addition to their production numbers, four of which were LZ 8 Deutschland II (1911), LZ 11 Viktoria Luise (1912), LZ 17 Hansa (1912) and LZ 17 Sachsen (1913). Seven of the twenty-seven were destroyed in accidents, mostly while being moved into their halls. There were no casualties. One of them was LZ 7 Deutschland which made its maiden voyage on 19 June 1910. On 28 June it began a pleasure trip to make Zeppelins more popular. Among those aboard were 19 journalists, two of whom were reporters of well known British newspapers. LZ 7 crashed in bad weather at Mount Limberg near Bad Iburg in Lower Saxony, its hull getting stuck in trees. The crew then let down a ladder to allow all the passengers to leave the ship. One crew member was slightly injured on leaving the craft.
All together, the several airships traveled approximately 200,000 kilometers (120,000 mi) and transported about 40,000 passengers.
The German Army and Navy purchased 14 Zeppelins, who labeled their aircraft Z 1/2/... and L 1/2/..., respectively. During the war, the Army changed their scheme twice: following Z XII, they switched to using LZ numbers, later adding 30 to obscure the total production. When World War I broke out, the military also took over the three remaining DELAG ships. By this time, it had already decommissioned three other Zeppelins (LZ 3 "Z 1" included). Five more had been lost in accidents, in which two people had died; a storm forced Navy Zeppelin LZ 14 or "L 1" down into the North Sea, drowning 14; LZ 18 or "L 2" burst into flames following an engine explosion, killing the entire crew.
By 1914, state-of-the-art Zeppelins had lengths of 150 to 160 meters (490 to 520 ft) and volumes of 22,000–25,000 m3, enabling them to carry loads of around 9 tones (9,000 kg; 20,000 lb). They were typically powered by three Maybach engines of around 400 to 550 horsepower (300 to 410 kW) each, reaching speeds of up to 80 kilometers per hour (50 mph).
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