Zeppelin

A Zeppelin is a type of rigid airship pioneered by the German Count Ferdinand von Zeppelin in the early 20th century, based on designs he had outlined in 1874,^[1] designs he had detailed in 1893,^[2] and that were reviewed by committee in 1894,^[2] which he later patented in 1895.^[3] Due to 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 (DLG). DLG, the first commercial airline, served scheduled flights before World War I. After the outbreak of the war, the German military made extensive use of Zeppelins as bombers and scouts.

The German defeat halted the airship business temporarily, but under the guidance of Hugo Eckener, the successor of the deceased count, civilian zeppelins experienced a renaissance in the 1920s. They reached their zenith in the 1930s, when the airships LZ 127 Graf Zeppelin and LZ 129 Hindenburg operated regular transatlantic flights between Germany and both North America and Brazil. In fact, the Art Deco Spire of Empire State Building was designed originally to serve as a Dirigible Terminal for Zeppelins and other dirigibles to dock.^[4] The Hindenburg disaster in 1937, combined with political and economic issues, contributed to the demise of the Zeppelin.

Principal characteristics

A Zeppelin with the various main elements labelled.

The most important feature of Zeppelin's design is a rigid metal alloy skeleton, made of rings and longitudinal girders.^[5] The advantage of this concept is that they can be built much larger than non-rigid airships (which rely on a slight overpressure within the single gasbag to maintain their shape). This enables them to lift heavier loads and they can be equipped with more numerous and 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 competing firm of Schütte-Lanz Luftschiffbau, the design was changed to the familiar streamlined shape and cruciform fins used by almost all airships since. Within this outer envelope, several separate balloons, or "cells", contained the lighter-than-air gas hydrogen or helium. Non-rigid airships do not have multiple gas cells. Motive power was provided by several internal combustion engines, mounted in nacelles rigidly connected to the skeleton. Steering was made possible 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 is not the entire habitable space; they often carried crew or cargo internally for aerodynamic reasons.

History

The first generations

Ferdinand von Zeppelin.

Count Ferdinand von Zeppelin became interested in constructing a "Zeppelin balloon" after the Franco-Prussian War of 1870–1871, where he witnessed French use of them to transport mail during the early war.^[6] He had also encountered Union Army Balloon Corps employment in 1863, during the American Civil War, as a military observer with the Union Army.^[6] He first wrote of his dirigible interest in 1874^[7] and began to seriously pursue his project after his early retirement from the military in 1890 at the age of 52.^[7]

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,^[8] and detailed designs in 1893^[2] that were reviewed by committee in 1894,^[2] and that he patented in 31 August 1895,.^[9] with Theodor Kober producing the technical plans.^[3] In 1899, he started constructing his first guidable rigid airship, following his designs.

One unusual idea, which never saw service, was the ability to connect several independent airship elements like train wagons;^[3]^[10] in fact, the patent title called the design Lenkbarer Luftfahrzug (steerable air train).^[11]

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.^[10] In 1898 he founded the Gesellschaft zur Förderung der Luftschiffahrt (company 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 metres (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 ascent of LZ1 over the Bodensee in 1900.

The first Zeppelin flight occurred on 2 July 1900 over the Bodensee.^[12] It lasted only 18 minutes before LZ 1 was forced to land on the lake after the winding mechanism for the balancing weight broke. After it was placed back in the hangar an apparatus used to suspend it broke.^[12] Upon repair, rigid airship technology proved its potential in subsequent flights (the second and third flights were in 17 October 1900 and 24 October 1900)^[12] 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.^[12]^[13]

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.^[14] After both motors 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 traveled 4,398 kilometres (2,733 mi) in total 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.

Wreckage of LZ 4. The LZ 4 was destroyed when a storm broke the zeppelin from its mooring, causing it to crash into a tree and catch fire.

The army was also willing to buy LZ 4, but requested a demonstration of her ability to make a 24-hour trip.^[15] 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 to ruins. No one was seriously injured, though 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.

Prior to World War I

Monument near Bad Iburg commemorating the 1910 LZ 7 crash

Prior to 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 are LZ 8 Deutschland II (1911), LZ 11 Viktoria Luise (1912), LZ 17 Hansa (1912) and LZ 17 Sachsen (1913). Seven of these twenty-seven ships were destroyed in accidents, mostly while being transferred 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.^[16] The crew then let down a ladder to allow all to leave the ship.^[16] One crew member was slightly injured on leaving the ship.^[16]

Altogether, the several airships traveled approximately 200,000 kilometres (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 two of which people died: a storm pushed Navy Zeppelin LZ 14 "L 1" down into the North Sea, drowning 14, and LZ 18 "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 metres (490 to 520 ft) and volumes of 22,000-25,000 m³, enabling them to carry loads of around 9 tonnes (9,000 kg/20,000 lb). They were typically powered by three Maybach motors of around 400 to 550 horsepower (300 to 410 kW) each, reaching speeds up to about 80 kilometres per hour (50 mph).

During World War I

Bombers and scouts

Zeppelins were used as bombers during World War I, without notable success. At the beginning of the conflict the German command had high hopes for the craft, as they appeared to have compelling advantages over contemporary aircraft — they were almost as fast, carried many more guns, and had a greater bomb load capacity and enormously greater range and endurance. However, their great weakness was their vulnerability to gunfire.

The German craft were operated by both the Army and Navy as two entirely separate divisions, at the beginning of the war the Army had nine craft (including three requisitioned from civilian ownership) and the Navy had four. All the craft were identified with the pre-war prefix LZ and a number, to avoid confusion between craft with the same number it is customary to use the prefix LZ for Naval craft and just L for Army craft (the Schütte-Lanz and Parseval types are sometimes identified with the respective prefixes SL and PL). Prior to the war the Army had lost three zeppelins to accidents and the Navy two, although both Naval losses occurred in 1913 and accounted for the majority of experienced personnel. There were major differences in doctrine. The Army emphasised bombing from a low level and close support to ground forces, while the Navy had trained for reconnaissance.

The first offensive use of Zeppelins was just two days after the invasion of Belgium. A single craft, the L. VI, flying from Cologne was damaged by gunfire while heading towards Paris and made a forced landing near Cologne. Two more Zeppelins were shot down in August and one was captured by the French, L. VIII was accidentally fired upon by German troops and then deliberately by French soldiers before crashing in Badonviller Forest, her crew attempted to set the craft afire but were driven off by French cavalry. Their use against well-defended targets in daytime raids was a mistake and the High Command lost all confidence in the Zeppelin, leaving it to the Naval Air Service to make any further use of the craft.

Patrols

The main use of the craft was in reconnaissance over the North Sea and the Baltic, where the endurance of the craft led German warships to a number of Allied vessels. Zeppelin patrolling had priority over any other airship activity.^[17] During the entire war around 1,200 scouting flights were made. During 1915 the German Navy had some 15 Zeppelins in commission and was able to have two or more patrolling continuously at any one time, almost regardless of weather.^[17] They kept the British ships from approaching Germany, spotted when and where the British were laying sea-mines, and later aided in the destruction of those mines.^[17] Zeppelins would sometimes land on the sea surface next to a minesweeper, bring aboard an officer and show him the lay of the mines.^[17] Before the widespread availability of incendiary ammunition made commerce raiding too risky, they would also land or hover close to a merchant ship suspected of carrying contraband, order all ship's hands to leave in boats, then inspect the ship, and either destroy it or take it back to Germany as prize.^[17]

Raids

The Naval Air Service also directed a number of strategic raids against Britain, leading the way in bombing techniques and also forcing the British to bolster their anti-aircraft defenses. The first airship raids were approved by the Kaiser in January 1915, although he demanded that no attacks be made on historic or government buildings or museums. The nighttime raids were intended to target only military sites, but after blackouts became widespread, many bombs fell randomly in East Anglia.

The first raid was on 19 January 1915, in which two Zeppelins dropped 24 Χ 50 kg high explosive bombs and ineffective 3 kg incendiaries on Great Yarmouth, Sheringham, King's Lynn and the surrounding villages. In all four people were killed, sixteen injured and monetary damage estimated at £7,740, although the public and media reaction were out of all proportion to the death toll. There were a further 19 raids in 1915, in which 37 tons of bombs were dropped, killing 181 people and injuring 455. British defenses were divided between the Royal Navy and the British Army at first, before the Army took full control in February 1916, and a variety of sub 4-inch (less than 102mm) caliber guns were converted to anti-aircraft use. Searchlights were introduced, initially manned by police, but their inexperience led to a number of illuminated clouds being mistaken for attacking airships. Aerial defenses against Zeppelins were haphazard and the lack of an interrupter gear in early fighters meant the basic technique of downing them was to drop bombs on them (a technique to resurface in World War II). The first man to bring down a Zeppelin in this way was R. A. J. Warneford of the RNAS, flying a Morane Parasol on 7 June 1915. Dropping six 9 kg bombs, he set fire to LZ 37 over Ghent and as a result won the Victoria Cross.

Plaque commemorating a World War I Zeppelin raid on 61 Farringdon Road, London.

Raids continued in 1916. After an accidental bombing of London in May (not the first, as the plaque to the right shows), in July the Kaiser allowed directed raids against urban centers.

There were 23 airship raids in 1916 in which 125 tons of ordnance were dropped, killing 293 people and injuring 691. Anti-aircraft defenses were becoming tougher and new Zeppelins were introduced which increased their operating altitude from 1,800 to 3,750 metres (5,900 to 12,000 ft). To avoid searchlights, they flew above the clouds whenever possible, lowering an observer through them to direct the bombing. The improved safety was counteracted by the extra strain on the airship crews and the British introduction in mid-1916 of synchronized-gun fighters. The first night-fighter victory came on 2 September 1916 when Lt. William Leefe Robinson, flying from Sutton's Farm, shot down one of a 16-strong raiding force over London, using incendiary ammunition. (The airship was not a Zeppelin but a wooden-framed Schütte-Lanz SL11). He too was awarded a Victoria Cross. Early in the morning of 24 September 1916, an airborne fighter and anti-aircraft guns caused the L.33 (Kapitänleutnant Bocker) to crash land at Little Wigborough near Colchester, Essex, on its first raid. A close inspection of its wrecked structure enabled the British to understand where their own rigid airship designs had been deficient. Furthermore, one 250 hp (190 kW) engine recovered from the wreck subsequently substituted for two (of four) 180 hp (130 kW) engines on a Vickers-built machine, the hitherto underpowered R.9.

Effective fighters marked the end of the Zeppelin threat. New Zeppelins came into service that could operate at 5,500 metres (18,000 ft) but exposed them to extremes of cold, and changeable winds that could, and did, scatter many Zeppelin raids. In 1917 and 1918 there were only 11 Zeppelin raids against England, the final one on 5 August 1918, resulted in the death of Korvettenkapitän Peter Strasser, commander of the German Naval Airship Department.

The British had started attacks by bombers (from the Royal Navy Air Service against the Zeppelin production lines and their sheds (Cologne and Dusseldorf) as early as September/October 1914. This was followed by the Cuxhaven Raid which included Zeppelins as its targets on Christmas Day 1914. In July 1918, the Tondern Raid by the RNAS destroyed two Zeppelins in their sheds.

Supply

In 1917, the German High Command made an attempt to dirigible-deliver much-needed supplies to Lettow-Vorbeck's East African Campaign in German East Africa. The L.59 Zeppelin travelled over 6,400 km (4,000 miles) in 95 hours, but in the end failed to deliver the supplies.^[18] The craft had been purpose-built, and had been intended to be broken apart and itself used as supplies on arrival. However, it never attempted the mission again, and was converted into a bomber.

Technological progress

Strategic issues aside, Zeppelin technology improved considerably as a result of the increasing demands of warfare. In late World War I the Zeppelin Company, having spawned several dependencies around Germany with shipyards closer to the fronts than Friedrichshafen, delivered airships of around 200 m (660 ft) in length (some even more) and with volumes of 56,000-69,000 m³. These dirigibles could carry loads of 40-50 tonnes and reach speeds up to 100 to 130 kilometres per hour (62 to 81 mph) using five or even six Maybach engines of around 260 hp (190 kW) each.

To avoid enemy defenses such as British aircraft guns and searchlights, Zeppelins became capable of much higher altitudes (up to 7,600 metres (25,000 ft)) and they also proved capable of long-range flights. For example, LZ 104 L.59, based in Yambol, Bulgaria, was sent to reinforce troops in German East Africa (today Tanzania) in November 1917. The ship did not arrive in time and had to return following reports of German defeat by British troops, but it had traveled 6,757 kilometres (4,199 mi) in 95 hours and thus had broken a long-distance flight record.

A considerable, frequently overlooked, contribution to these technological advancements originated from Zeppelin's only serious competitor, the Mannheim-based Schütte-Lanz airship construction company. While their dirigibles never became comparably successful, Professor Schütte's more scientific approach to airship design led to a number of important innovations copied, over time, by the Zeppelin company. These included, for example, the streamlined hull shape, the simple yet functional cruciform fins (replacing the more complicated box-like arrangements of older Zeppelins), individual direct-drive engine cars, anti-aircraft machine-gun positions,^[19] and gas ventilation shafts which removed excess hydrogen for safety.

End of the war

The German defeat in the war also marked the end of German military dirigibles, as the victorious Allies demanded a complete disarmament of German air forces and delivery of the remaining airships as war reparations. Specifically, the Treaty of Versailles contained the following articles dealing explicitly with dirigibles:

Article 198

The armed forces of Germany must not include any military or naval air forces. [...] No dirigible shall be kept.

Article 202

On the coming into force of the present Treaty, all military and naval aeronautical material [...] must be delivered to the Governments of the Principal Allied and Associated Powers. [...] In particular, this material will include all items under the following heads which are or have been in use or were designed for warlike purposes:

[...]

Dirigibles able to take the air, being manufactured, repaired or assembled.
Plant for the manufacture of hydrogen.
Dirigible sheds and shelters of every kind for aircraft.

Pending their delivery, dirigibles will, at the expense of Germany, be maintained inflated with hydrogen; the plant for the manufacture of hydrogen, as well as the sheds for dirigibles may at the discretion of the said Powers, be left to Germany until the time when the dirigibles are handed over. [...]

On 23 June 1919, a week before the treaty was signed, many war Zeppelin crews destroyed their airships in their halls in order to avoid delivery. In doing so, they followed the example of the German fleet which had been scuttled two days before in Scapa Flow. The remaining dirigibles were transferred to France, Italy, Britain, and Belgium in 1920.

A total of 84 Zeppelins were built during the war. Over 60 were lost, roughly evenly divided between accident and enemy action. 51 raids had been undertaken,^[20] in which 5,806 bombs were dropped, killing 557 people and injuring 1,358. It has been argued the raids were effective far beyond material damage in diverting and hampering wartime production, and diverting 12 fighter squadrons and over 10,000 personnel to air defenses.

After World War I

Renaissance

Count von Zeppelin had died in 1917, before the end of the war. Dr. Hugo Eckener, a man who had long before envisioned dirigibles as vessels of peace rather than warfare, took command of the Zeppelin business. With the Treaty of Versailles having knocked out their competitor Schütte-Lanz, specialist in military airships, the Zeppelin company and DELAG hoped to resume civilian flights quickly. In fact, despite considerable difficulties, they completed two small Zeppelins: LZ 120 Bodensee, which first flew in August 1919 and in the following two years actually transported some 4,000 passengers; and LZ 121 Nordstern, which was foreseen for a regular route to Stockholm.

However, in 1921, the Allied Powers demanded these two Zeppelins be delivered as war reparations, as compensation for the dirigibles destroyed by their crews in 1919. Further Zeppelin projects could not be realized, partly because of Allied interdiction. This temporarily halted German Zeppelin aviation.

However, Eckener and his co-workers refused to give up and kept looking for investors and a way to circumvent Allied restrictions. Their opportunity came in 1924. The United States had started to experiment with rigid airships, constructing one of their own, the ZR-1 USS Shenandoah (see below), and ordering another from the UK when the British R38 (ZR-2) was canceled. However, R38 (based on the Zeppelin L70, ordered as ZR-2) broke apart and exploded during a test flight above the Humber on 23 August 1921, killing 44 crewmen.

Under these circumstances, Eckener managed to acquire an order for the next American dirigible. Of course, Germany had to pay the costs for this airship itself, as they were calculated against the war reparation accounts, but for the Zeppelin company, this was secondary. So engineer Dr. Dürr designed LZ 126, and using all the expertise accumulated over the years, the company finally achieved its best Zeppelin so far, which took off for a first test flight on 27 August 1924.

ZR-3 USS Los Angeles over southern Manhattan.

The USS Los Angeles, a US Navy zeppelin built by the Zeppelin Company.

No insurance company was willing to issue a policy for the delivery to Lakehurst, which, of course, involved a transatlantic flight. Eckener, however, was so confident of the new ship that he was ready to risk the entire business capital, and on 12 October 0730 local time, the Zeppelin took off for the States under his command. His faith was not disappointed, and the ship completed her 8,050 kilometres (5,000 mi) voyage without any difficulties in 81 hours and two minutes. American crowds enthusiastically celebrated the arrival, and President Calvin Coolidge invited Dr. Eckener and his crew to the White House, calling the new Zeppelin an "angel of peace".

Under its new designation ZR-3 USS Los Angeles (the former LZ 126) became the most successful American airship. She operated reliably for eight years until being retired in 1932 for economic reasons and dismantled in August 1940.

Golden Age

With the delivery of LZ 126, the Zeppelin company had reasserted its lead in rigid airship construction, but it was not yet quite back in business. Acquiring the necessary funds for the next project proved a problem in the difficult economic situation of post-World-War-I Germany, and it took Eckener two years of lobbying and publicity work to secure the realization of LZ 127.

Another two years passed before 18 September 1928, when the new dirigible, christened Graf Zeppelin in honor of the Count, flew for the first time. With a total length of 236.6 metres (776 ft) and a volume of 105,000 m³, she was the largest dirigible yet.

Eckener's initial concept was to use Graf Zeppelin for experimental and demonstration purposes to prepare the way for regular airship traveling, by carrying passengers and mail to cover the costs. In October 1928 the first long-range voyage brought her to Lakehurst, where Eckener and his crew were once more welcomed enthusiastically with confetti parades in New York and another invitation to the White House. Later Graf Zeppelin toured Germany and visited Italy, Palestine, and Spain. A second trip to the United States was aborted in France due to engine failure in May 1929.

In August 1929 LZ 127 departed for another daring enterprise: a circumnavigation of the globe. The growing popularity of the "giant of the air" made it easy for Eckener to find sponsors. One of these was the American press tycoon William Randolph Hearst, who requested the tour officially start in Lakehurst. As with the October 1928 flight to New York, Hearst had placed a reporter Grace Marguerite Hay Drummond-Hay on board who therefore became the first woman to circumnavigate the globe by air. From there, Graf Zeppelin flew to Friedrichshafen, then Tokyo, Los Angeles, and back to Lakehurst, in 21 days 5 hours and 31 minutes. Including the initial and final trips Friedrichshafen–Lakehurst and back, the dirigible traveled 49,618 kilometres (30,831 mi).

US Air Mail 1930 picturing Graf Zeppelin

airship LZ 127 "Graf Zeppelin"

In the following year, Graf Zeppelin undertook a number of trips around Europe, and following a successful tour to South America in May 1930, it was decided to open the first regular transatlantic airship line. Despite the beginning of the Great Depression and growing competition from fixed-wing aircraft, LZ 127 would transport an increasing volume of passengers and mail across the ocean every year until 1936. Besides, the ship pursued another spectacular venue in July 1931 with a research trip to the Arctic; this had already been a dream of Count von Zeppelin twenty years earlier, which could, however, not be realized at the time due to the outbreak of war.

Eckener intended to supplement the successful craft by another, similar Zeppelin, projected as LZ 128. However the disastrous accident of the British passenger airship R101 on 5 October 1930 led the Zeppelin company to reconsider the safety of hydrogen-filled vessels, and the design was abandoned in favor of a new project. LZ 129 would advance Zeppelin technology considerably, and was intended to be filled with inert helium.

Hindenburg, end of an era

Main article: LZ 129 Hindenburg

The Hindenburg on fire

Following 1933, the establishment of the Nazi dictatorship in Germany began to overshadow the Zeppelin business. The Nazis were not interested in Eckener's ideals of peacefully connecting people; they also knew very well dirigibles would be useless in combat and thus chose to focus on heavier-than-air technology.

On the other hand, they were eager to exploit the popularity of the airships for propaganda. As Eckener refused to cooperate, Hermann Göring, the Nazi Air minister, formed a new airline in 1935, the Deutsche Zeppelin-Reederei (DZR), which took over operation of airship flights. Zeppelins would now prominently display the Nazi swastika on their fins and occasionally tour Germany to indoctrinate the people with march music and Nazi propaganda speeches from the air.

On 4 March 1936, LZ 129 Hindenburg (quickly named after former President of Germany Paul von Hindenburg by Eckener in an attempt to preempt the Nazi Party from naming the ship after Hitler) made her first flight. The Hindenburg was the largest airship ever built. However, in the new political situation, Eckener had not obtained the helium to inflate it due to a military embargo; only the United States possessed the rare gas in usable quantities. So, in what ultimately proved a fatal decision, the Hindenburg was filled with flammable hydrogen. Apart from the propaganda missions, LZ 129 began to serve the transatlantic lines together with Graf Zeppelin.

On 6 May 1937, while landing in Lakehurst after a transatlantic flight, in front of thousands of spectators, the tail of the ship caught fire, and within seconds, the Hindenburg burst into flames, killing 35 of the 97 people on board and one member of the ground crew. The actual cause of the fire has not been definitively determined; it is likely that a combination of leaking hydrogen from a torn gas bag, the vibrations caused by a swift rotation for a quicker landing to have started static electricity in the duralumin alloy skeleton and a flammable outer coating similar to rocket fuel accounted for the fact that the fire spread from its starting point in the tail to engulf the entire airship so rapidly (34 seconds).

Whatever caused the disaster, the end of the dirigible era was due to politics and the upcoming war, not the wreck itself, though it surely led to some public misgivings. Despite everything, there remained a list of 400 people who still wanted to fly as Zeppelin passengers and had paid for the trip. In 1940 the money they had paid for the trip was refunded.

Graf Zeppelin completed more flights, though not for overseas commercial flights to the U.S., and was retired one month after the Hindenburg wreck and turned into a museum. Dr. Eckener kept trying to obtain helium gas for Hindenburg's sister ship, Graf Zeppelin II, but due to political bias against the airship's commercial use by the Nazi leadership, coupled with inability to obtain helium gas in sufficient quantities due to an embargo by the United States, his efforts were in vain. The intended new flagship Zeppelin was completed in 1938 and, inflated with hydrogen, made some test flights (the first on 14 September), but never carried passengers. Another project, LZ 131, designed to be even larger than Hindenburg and Graf Zeppelin II, never progressed beyond the production of some single skeleton rings.

The career of Graf Zeppelin II was not over. She was assigned to the Luftwaffe and performed about 30 test flights prior to the start of World War II. Most of those test flights were carried out near the Polish border, first in the Sudeten mountains region of Silesia and later in the Baltic Sea region. During one flight LZ 130 crossed the Polish border near Hel Peninsula, where she was intercepted by a Polish Lublin R-XIII from Puck naval airbase and forced to leave Polish airspace. During this time, LZ 130 was used as an electronic scouting vehicle and was equipped with various telemetric equipment. From May to August 1939, she performed flights near the coastline of Great Britain in an attempt to determine whether the 100-meter towers erected from Portsmouth to Scapa Flow were used for aircraft radio localization. Tests included photography, radio wave interception, magnetic analysis and radio frequency analysis but were unable to detect operational British Chain Home radar due to the searching in the wrong frequency range - the frequencies searched were too high, an assumption based on the Germans' own radar systems. The (incorrect) conclusion was the British towers were not connected to radar operations, but formed a network of naval radio communication and rescue.

After the German invasion of Poland started the Second World War on 1 September, the Luftwaffe ordered LZ 127 and LZ 130 moved to a large Zeppelin hangar in Frankfurt, where the skeleton of LZ 131 was also located. In March 1940 Göring ordered the destruction of the remaining vessels and the aluminium fed into the Nazi war industry. In May a fire broke out in the Zeppelin facility, which destroyed most of the remaining parts. The rest of the parts and materials were soon scrapped, with almost no trace of the German "giants of the air" remaining by the end of the year.

Non-German rigid airships

Main article: Airship

U.S. Navy Zeppelin ZRS-5 "USS Macon" over Moffett Field in 1933

Airships using the Zeppelin construction method are sometimes referred to as zeppelins even if they had no connection to the Zeppelin business. Several airships of this kind were built in the USA and Britain in the 1920s and 1930s, mostly imitating original Zeppelin design derived from crashed or captured German World War I airships.

The British R33 and R34, for example, were near identical copies of the German L-33, which crashed virtually intact in Yorkshire on 24 September 1916. Despite being almost three years out of date by the time they were launched in 1919, these sister ships were two of the most successful in British service. On 2 July 1919, R34 began the first return crossing of the Atlantic by aircraft. She landed at Mineola, Long Island on 6 July 1919 after 108 hours in the air. The return crossing commenced on 8 July because of concerns about mooring the ship in the open, and took 75 hours. Impressed, Britain began to contemplate a fleet of airships as links to far-flung colonies, but unfortunately post-war economic conditions lead to most airships being scrapped and trained personnel dispersed, until R-100 and R-101 commenced construction in 1929.

Another example was the first American-built rigid dirigible ZR-1 USS Shenandoah, which flew in 1923, while USS Los Angeles (ZR-3) was under construction. The ship was christened on 20 August in Lakehurst, New Jersey and was the first to be inflated with helium, which was still so rare at the time that Shenandoah contained most of the world's reserves. When Los Angeles was delivered, she was at first filled with helium borrowed from ZR-1. Other airships were the USS Akron (ZRS-4) and the USS Macon (ZRS-5).

Recent developments

Economically, it was surprising that even in the 1930s, Zeppelins could compete with other means of transatlantic transport. Their advantage was the ability to carry significantly more passengers than other contemporary aircraft, while providing conveniences like the luxury of ship voyages. Less importantly, the technology was potentially more energy-efficient than heavier-than-air designs. On the other hand, operating the giants was quite involved, especially in terms of personnel. Often the crew would outnumber passengers on board, and on the ground large teams were necessary to assist starting and landing. Also, to accommodate Zeppelins like Hindenburg (which was more than five times as long as the height of the Statue of Liberty without the pedestal), very large hangars were required at airports.

Today, with large, fast, and more cost-efficient fixed-wing aircraft, it is unknown whether huge airships can operate profitably in regular passenger transport though, as energy costs rise, attention is once again returning to these lighter than air vessels as a viable alternative. At the very least, the idea of comparatively slow, "majestic" cruising at relatively low altitudes and in comfortable atmosphere certainly has retained some appeal. There have been some niches for airships in and after World War II, such as long-duration observations, antisubmarine patrol, platforms for TV camera crews, and advertising; these, however, generally require only small and flexible craft, and have thus generally been better fitted for cheaper blimps.

Heavy lifting

It has periodically been suggested Zeppelins could be employed for cargo transport, especially delivering extremely heavy loads to areas with poor infrastructure. One recent enterprise of this sort was the Cargolifter project, in which a hybrid (thus not entirely Zeppelin-type) airship even larger than Hindenburg was projected. Around 2000, this idea was realized, when the CargoLifter AG constructed the world's largest cantilever shop hall measuring 360 metres (1,200 ft) long, 210 metres (690 ft) wide and 107 metres (350 ft) high about 60 kilometres (37 mi) south of Berlin. In May 2002, the project was stopped for financial reasons; the company had to file bankruptcy. Although no rigid airships are currently used for heavy lifting, hybrid airships are being developed for such purposes. John McPhee's The Deltoid Pumpkin Seed is the story of one company attempting this.

Passenger transport

A small company in Germany is currently examining the possibility of building a cruise airship, for now known as the Zeppelin ET (for Euro Tour); it will be able to carry passengers on week-long cruises at comfort levels and prices comparable to those of luxury sea cruises of similar duration. However, although this airship bears the name "Zeppelin", it is not a rigid but a semi-rigid airship (even though "zeppelin" has come to be almost a synonym for rigid airship). The project is still in its early stages and nothing practical has resulted as of 2004.

A Zeppelin NT airship.

In the 1990s, the successor of the original Zeppelin company in Friedrichshafen, the Zeppelin Luftschifftechnik GmbH, reengaged in airship construction. The first experimental craft (later christened Friedrichshafen) of the type Zeppelin NT flew in September 1997. Though larger than common blimps, the Neue Technologie (new technology) Zeppelins are much smaller than their giant ancestors and not actually Zeppelin-types in the classical sense; they are sophisticated semi-rigids. Apart from the greater payload, their main advantages compared to blimps are higher speed and excellent maneuverability. Meanwhile, several Zeppelin NT have been produced and operated profitably in joyrides, research flights and similar applications.

In June 2004, a Zeppelin NT was sold for the first time to a Japanese company, Nippon Airship Corporation, for tourism and advertising mainly around Tokyo. It was also given a role at the 2005 Expo in Aichi. The aircraft began a flight from Friedrichshafen to Japan, stopping at Geneva, Paris, Rotterdam, Munich, Berlin, Stockholm and other European cities to carry passengers on short legs of the flight. However, Russian authorities denied overflight permission so the airship had to be dismantled and shipped to Japan rather than following the historic Graf Zeppelin flight from Germany to Japan.

In 2007, Airship Ventures Inc. began operations from Moffett Federal Airfield near Mountain View, California and currently offers tours of the San Francisco Bay Area for up to 12 passengers.

Use in exploration

In November 2005, De Beers, the diamond mining company, launched an airship exploration program over the remote Kalahari desert. A Zeppelin, loaded with high-tech equipment, is used to find potential diamond mines by scanning the local geography for low-density rock formations — so-called kimberlite pipes. On 21 September 2007, the airship was severely damaged by a whirlwind while in Botswana. One crew member, who was on watch aboard the moored craft, was slightly injured but released after overnight observation in hospital.

Cultural influences

The history of Zeppelins is of particular interest to stamp collectors. Many nations issued high-denomination Zeppelin stamps, intended for franking of Zeppelin mail. Among the rarest of Zeppelin covers are those carried during the fateful flight of the Hindenburg. An airship museum is planned to open in Suffolk, England.

Zeppelins have been an inspiration to music, cinematography and literature. In 1934, the calypsonian, Attila the Hun recorded "Graf Zeppelin", commemorating the airship's visit to Trinidad while on its way from Rio de Janeiro to Chicago for the World Fair. In cinematography, Zeppelins have been depicted several times, including Zeppelin (UK, 1971) about a German-English soldier (Michael York) and a German scientist (Elke Sommer) participating in a German Zeppelin mission in World War I; Darling Lili (US, 1970); The Hindenburg (US, 1975) a disaster film of the ill-fated last trip of LZ 129; and a short appearance in the films The Assassination Bureau (UK 1968), A View To A Kill (UK, 1985), Indiana Jones and the Last Crusade (US, 1989), The Rocketeer (US, 1991), Sky Captain and the World of Tomorrow (US, 2004), A Very Long Engagement (France, 2004) and Flyboys (USA, 2007). Zeppelins have also served as an inspiration to the Crimson Skies computer/video game series, in which the airship is re-imagined as an integral segment of international commerce. Also in Max Brooks' novel, World War Z (An Oral History of the Zombie War), the United States uses advanced command and control Zeppelins (as a flying command post) to oversee military operation in white zones (i.e., areas that have not been completely pacified). Airships also make appearances in some fantasy worlds, usually in the form of a small regular ship lifted to the air by a huge balloon. In the Real-Time Strategy game Command and Conquer: Red Alert 2, the Soviet Union invades the United States with enormous Zeppelin bombers (called Kirov Airships) making up most of their air force. In the RPG-Series Final Fantasy, there is some kind of airship in every game. In the MMORPG World Of Warcraft, you can take Zeppelin transports from and to certain cities, usually for long distances such as crossing an ocean or an entire continent. Zeppelins are also heavily portrayed as vicious weapons of war in the steampunk anime Steamboy in which they are equipped from anything from steam powered manipulators to high capacity bomb chutes.

The band Led Zeppelin received their name after The Who drummer, Keith Moon, joked that the band would go down like a "lead zeppelin". The name was changed to Led Zeppelin so Americans would say it correctly.

Zeppelins are commonly used as a moving headquarters for villains in common culture. Examples include Timesplitters, A View to a Kill, His Dark Materials, and Patria.

The steampunk genre of science fiction has adopted the zeppelin as something of a mascot. They are representative of general steampunk themes with their grand scale, Victorian aesthetics, and failure to be put into common use. They are often portrayed either as massive and imposing transports or powerful flying gunships (standing up to much more fire than a real zeppelin). (See the Captain Bastable trilogy: The Warlord of the Air, The Land Leviathan, and The Steel Tsar by Michael Moorcock).

Notes

↑ Eckener 1938. pages 155-157
↑ ^2.0 ^2.1 ^2.2 ^2.3 Dooley A.187
↑ ^3.0 ^3.1 ^3.2 Dooley A.190
↑ "ESB in the News" (July 2000).
↑ "Airships". Military. GlobalSecurity.org. Retrieved on 2007-02-20.
↑ ^6.0 ^6.1 de Syon (2001), p.15
↑ ^7.0 ^7.1 Dooley A.183
↑ Eckener 1938. pages 155–157
↑ de Syon (2001), p.18
↑ ^10.0 ^10.1 de Syon (2001), p.16
↑ Zeppelin's 1895 German patent number 98580 was titled: Lenkbarer Luftfahrzug mit mehreren hintereinander angeordeneten Tragkörpern.Dooley A.233 which translates as "steerable airship train with linearly connected lifting bodies"
↑ ^12.0 ^12.1 ^12.2 ^12.3 Dooley A.197-A.198
↑ de Syon (2001), p.25
↑ de Syon (2001), p.26
↑ de Syon (2001), p.35
↑ ^16.0 ^16.1 ^16.2 editors of German Wikipedia
↑ ^17.0 ^17.1 ^17.2 ^17.3 ^17.4 Lehmann Chapter VI
↑ First World War — Willmott, H.P.; Dorling Kindersley, 2003, Page 192
↑ University of Constance. Gefahren und Strapazen der Luftschiffeinsätze, upper platform with machine-gun placement and gunners
↑ The figures given total 54. While A. Whitehouse in The Zeppelin Fighters (1966) gives figures of 5,907 bombs dropped, 528 people killed, 1,156 wounded in 208(!) raids.

References

Guillaume de Syon (2001). Zeppelin!: Germany and the Airship, 1900–1939. Johns Hopkins University Press. ISBN 0801867347. (General information)
Dooley, Sean C., The Development of Material-Adapted Structural Form - Part II: Appendices. THÈSE NO 2986 (2004), École Polytechnique Fédérale de Lausanne
Eckener, Hugo. 1938. Count Zeppelin: The Man and His Work, translated by Leigh Fanell, London -- Massie Publishing Company, Ltd. -- (ASIN: B00085KPWK) (online extract pages 155-157, 210-211)
Lehmann, Ernst A.; Mingos, Howard. The Zeppelins. The Development of the Airship, with the Story of the Zepplins Air Raids in the World War. Chapter VI THE NORTH SEA PATROL -- THE ZEPPELINS AT JUTLAND (online chapter)
editors of German wikipedia, LZ 7