Zeppelin Air Setup

[Florene Pothoven]

Thedefeat of Germany in 1918 temporarily slowed the airship business. Although DELAG established a scheduled daily service between Berlin, Munich, and Friedrichshafen in 1919, the airships built for that service eventually had to be surrendered under the terms of the Treaty of Versailles, which also prohibited Germany from building large airships. An exception was made to allow the construction of one airship for the United States Navy, the order for which saved the company from extinction.

In 1926, the restrictions on airship construction were lifted and, with the aid of donations from the public, work began on the construction of LZ 127 Graf Zeppelin. That revived the company's fortunes and, during the 1930s, the airships Graf Zeppelin, and the even larger LZ 129 Hindenburg operated regular transatlantic flights from Germany to North America and Brazil. The spire of the Empire State Building was originally designed to serve as a mooring mast for zeppelins and other airships, although it was found that high winds made that impossible and the plan was abandoned.[5] The Hindenburg disaster in 1937, along with political and economic developments in Germany, hastened the demise of airships.

The principal feature of the Zeppelin's design was a fabric-covered, rigid metal framework of transverse rings and longitudinal girders enclosing a number of individual gasbags. This allowed the craft to be much larger than non-rigid airships, which relied on the inflation of a single-pressure envelope to maintain their shape. The framework of most Zeppelins was made of duralumin, a combination of aluminium, copper, and two or three other metals, the exact composition of which was kept secret for years. Early Zeppelins used rubberized cotton for the gasbags, but most later craft used goldbeater's skin made from cattle gut.[6]

The first Zeppelins had long cylindrical hulls with tapered ends and complex multi-plane fins. During World War I, following the lead of the rival firm Schtte-Lanz Luftschiffbau, almost all later airships changed to the more familiar streamlined shape with cruciform tail fins.

Zeppelins were propelled by several internal combustion engines, mounted in gondolas or engine cars attached outside the structural framework. Some of these could provide reverse thrust for manoeuvring while mooring.

Early models had a fairly small externally-mounted gondola for passengers and crew beneath the frame. This space was never heated, because fire outside of the kitchen was considered too risky, and during trips across the North Atlantic or Siberia passengers were forced to bundle in blankets and furs to keep warm and were often miserably cold.

By the time of the Hindenburg several important changes had made traveling much more comfortable: the passenger space had been relocated to the interior of the framework, passenger rooms were insulated from the exterior by the dining area, and forced-warm air could be circulated from the water that cooled the forward engines. The new design did prevent passengers from enjoying the views from the windows of their berths, which had been a major attraction on the Graf Zeppelin. On both the older and newer vessels, the external viewing windows were often open during flight. The flight altitude was so low that no pressurization of the cabins was necessary. The Hindenburg did maintain a pressurized air-locked smoking room: no flame was allowed, but a single electric lighter was provided, which could not be removed from the room.[7]

Access to Zeppelins was achieved in a number of ways. The Graf Zeppelin's gondola was accessed while the vessel was on the ground, via gangways. The Hindenburg also had passenger gangways leading from the ground directly into its hull which could be withdrawn entirely, ground access to the gondola, and an exterior access hatch via its electrical room; this latter was intended for crew use only.

On some long-distance zeppelins, engines were powered by a special Blau gas produced by the Zeppelin facility in Friedrichshafen. The combustible Blau gas was formulated to make its weight near that of air, so that its storage and consumption had little effect on the zeppelin's buoyancy. Blau gas was used on the first zeppelin voyage to America, starting in 1929.[8]

Count Ferdinand von Zeppelin's interest in airship development began in 1874, when he was inspired by a lecture given by Heinrich von Stephan on the subject of "World Postal Services and Air Travel" to outline the basic principle of his later craft in a diary entry dated 25 March 1874.[9] It describes a large rigidly framed outer envelope containing several separate gasbags.[10] He had previously encountered Union Army balloons in 1863 when he visited the United States as a military observer during the American Civil War.[11]

Count Zeppelin began to seriously pursue his project after his early retirement from the army in 1890 at the age of 52. Convinced of the potential importance of aviation, he started working on various designs in 1891, and had completed detailed designs by 1893. An official committee reviewed his plans in 1894,[2] and he received a patent, granted on 31 August 1895,[12] with Theodor Kober producing the technical drawings.[3]

Count Zeppelin's attempts to secure government funding for his project proved unsuccessful, but a lecture given to the Union of German Engineers gained their support. Zeppelin also sought support from the industrialist Carl Berg, then engaged in construction work on the second airship design of David Schwarz. Berg was under contract not to supply aluminium to any other airship manufacturer, and subsequently made a payment to Schwarz's widow as compensation for breaking this agreement.[14] Schwarz's design differed fundamentally from Zeppelin's, crucially lacking the use of separate gasbags inside a rigid envelope.[15]

In 1898, Count Zeppelin founded the Gesellschaft zur Frderung der Luftschiffahrt[16] (Society for the Promotion of Airship Flight), contributing more than half of its 800,000 mark share-capital himself. Responsibility for the detail design was given to Kober, whose place was later taken by Ludwig Drr, and construction of the first airship began in 1899 in a floating assembly-hall or hangar in the Bay of Manzell near Friedrichshafen on Lake Constance (the Bodensee). The intention behind the floating hall was to facilitate the difficult task of bringing the airship out of the hall, as it could easily be aligned with the wind. The LZ 1 (LZ for Luftschiff Zeppelin, or "Zeppelin Airship") was 128 metres (420 ft) long with a hydrogen capacity of 11,000 m3 (400,000 cu ft), was driven by two 15 horsepower (11 kW) Daimler engines each driving a pair of propellers mounted either side of the envelope via bevel gears and a driveshaft, and was controlled in pitch by moving a weight between its two nacelles.[17]

The first flight took place over Lake Constance on 2 July 1900.[18] Damaged during landing, it was repaired and modified and proved its potential in two subsequent flights made on 17 and 24 October 1900,[18] bettering the 6 m/s ( 21.6 km/h (13.4 mph) ) velocity attained by the French airship La France. 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.[18][19]

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 made only a single flight on 17 January 1906.[20] After both engines failed it made a forced landing in the Allgu mountains, where a storm subsequently damaged the anchored ship beyond repair.

Incorporating all the usable parts of LZ 2, its successor LZ 3 became the first truly successful Zeppelin. This renewed the interest of the German military, but a condition of purchase of an airship was a 24-hour endurance trial.[21] This was beyond the capabilities of LZ 3, leading Zeppelin to construct his fourth design, the LZ 4, first flown on 20 June 1908. On 1 July it was flown over Switzerland to Zrich and then back to Lake Constance, covering 386 km (240 mi) and reaching an altitude of 795 m (2,608 ft). An attempt to complete the 24-hour trial flight ended when LZ 4 had to make a landing at Echterdingen near Stuttgart because of mechanical problems. During the stop, a storm tore the airship away from its moorings on the afternoon of 5 August 1908. It crashed into a tree, caught fire, and quickly burnt out. No one was seriously injured.

This accident would have finished Zeppelin's experiments, but his flights had generated huge public interest and a sense of national pride regarding his work, and spontaneous donations from the public began pouring in, eventually totalling over six million marks.[22] This enabled the Count to found the Luftschiffbau Zeppelin GmbH (Airship Construction Zeppelin Ltd.) and the Zeppelin Foundation.

In 1909, Count Zeppelin founded the world's first airline, the Deutsche Luftschiffahrts-Aktiengesellschaft (German Airship Travel Corporation), generally known as DELAG[26] to promote his airships, initially using LZ 6, which he had hoped to sell to the German Army. Notable aviation figures like Orville Wright offered critical perspectives on the Zeppelin; in a September 1909 New York Times interview,[27] Wright compared airships to steam engines nearing their developmental peak, while seeing airplanes as akin to gas engines with untapped potential for innovation.The airships did not provide a scheduled service between cities, but generally operated pleasure cruises, carrying twenty passengers. The airships were given names in addition to their production numbers. LZ 6 first flew on 25 August 1909 and was accidentally destroyed in Baden-Oos on 14 September 1910 by a fire in its hangar.[28]

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