   #copyright

Airship

2007 Schools Wikipedia Selection. Related subjects: Air & Sea transport

   USS Akron (ZRS-4) in flight, November 2, 1931
   Enlarge
   USS Akron (ZRS-4) in flight, November 2, 1931

   An airship or dirigible is a buoyant aircraft that can be steered and
   propelled through the air. Unlike aerodynamic craft (e.g. airplanes and
   helicopters) which stay aloft by moving an airfoil through the air in
   order to produce lift, aerostatic craft such as airships (and balloons)
   stay aloft primarily by means of a cavity (usually quite large) filled
   with a gas of lesser density than the surrounding atmosphere.

   Airships were the first aircraft to make controlled, powered flight.
   Their widest use took place from roughly 1900 through the 1930s.
   However, their use decreased over time as their capabilities were
   surpassed by those of airplanes. In addition they suffered a series of
   high profile accidents — most notably the burning of the Hindenburg.
   Today they are used in a variety of niche applications, particularly
   advertising.

Terminology

   In many countries, airships are also known as dirigibles from the
   French dirigeable, meaning "steerable." The first airships were called
   dirigible balloons. Over time, the word balloon was dropped from the
   phrase.

   The term zeppelin is a genericised trademark that originally referred
   to airships manufactured by the Zeppelin Company.

   In modern common usage, the terms zeppelin, dirigible and airship are
   used interchangeably for any type of rigid airship, with the terms
   blimp or airship alone used to describe non-rigid airships. In modern
   technical usage, however, airship is the term used for all aircraft of
   this type, with zeppelin referring only to aircraft of that
   manufacture, and blimp referring only to non-rigid airships.

   The term airship is sometimes informally used to mean any machine
   capable of atmospheric flight.

   In contrast to airships, balloons are buoyant aircraft that generally
   rely on wind currents for movement, though vertical movement can be
   controlled in both.

   There is often some confusion around the term aerostat with regard to
   airships. This confusion arises because aerostat has two different
   meanings. One meaning of aerostat refers to all craft that remain aloft
   using buoyancy. In this sense, airships are a type of aerostat. The
   other, more narrow and technical meaning of aerostat refers only to
   tethered balloons. In this second technical sense, airships are
   distinct from aerostats. This airship/aerostat confusion is often
   exacerbated by the fact that both airships and aerostats have roughly
   similar shapes and comparable tail fin configurations, although only
   airships have motors.

Types

   Several different kinds of US Navy airships and balloons, circa 1930
   Enlarge
   Several different kinds of US Navy airships and balloons, circa 1930
     * Rigid airships (for example, Zeppelins) had rigid frames containing
       multiple, non-pressurized gas cells or balloons to provide lift.
       Rigid airships did not depend on internal pressure to maintain
       their shape.
     * Non-rigid airships (blimps) use a pressure level in excess of the
       surrounding air pressure in order to retain their shape.
     * Semi-rigid airships, like blimps, require internal pressure to
       maintain their shape, but have extended, usually articulated keel
       frames running along the bottom of the envelope to distribute
       suspension loads into the envelope and allow lower envelope
       pressures.
     * Metal-clad airships had characteristics of both rigid and non-rigid
       airships, utilizing a very thin, airtight metal envelope, rather
       than the usual rubber-coated fabric envelope. Only two ships of
       this type, Schwarz's aluminium ship of 1897 and the ZMC-2, have
       been built to date.
     * Hybrid airship is a general term for an aircraft that combines
       characteristics of heavier-than-air (airplane or helicopter) and
       lighter than air technology. Examples include helicopter/airship
       hybrids intended for heavy lift applications and dynamic lift
       airships intended for long-range cruising. It should be noted that
       most airships, when fully loaded with cargo and fuel, are typically
       heavier than air, and thus must use their propulsion system and
       shape to generate aerodynamic lift, necessary to stay aloft;
       technically making them hybrid airships. However, the term "hybrid
       airship" refers to craft that obtain a significant portion of their
       lift from aerodynamic lift and often require substantial take-off
       rolls before becoming airborne.

Lifting gas

   In the early days of airships, the primary lifting gas was hydrogen.
   Until the 1950s, all airships, except for those in the United States,
   continued to use hydrogen because it offered greater lift and was
   cheaper than helium. The United States (until then the sole producer)
   was also unwilling to export helium because it was rare and was
   considered a strategic material. However, hydrogen is flammable when
   mixed with air, a quality that some think contributed to the Hindenburg
   disaster, as well as other rigid airship disasters. The buoyancy
   provided by hydrogen is actually only about 8% greater than that of
   helium . The issue therefore became one of safety versus cost.

   American airships have been filled with helium since the 1920s and
   modern passenger-carrying airships are often, by law, prohibited from
   being filled with hydrogen. Nonetheless, some small experimental ships
   still use hydrogen today.

   Some small ships, called thermal airships, are filled with hot air in a
   fashion similar to hot air balloons.

   Wikipedia maintains a list of lighter-than-air gases here. It is noted
   that the majority of such gases are either toxic, flammable, corrosive,
   or a combination of these, with the exception of helium, neon, and
   water (as steam), limiting use for airships. It is also noted there
   that both methane and ammonia have on occasion been used to provide
   lift for weather baloons, and an insulated airship containing steam has
   been investigated.

History

   The development of airships was necessarily preceded by the development
   of balloons. See balloon (aircraft) for details.

Pioneers

   Crossing of the English Channel by Blanchard in 1785.
   Enlarge
   Crossing of the English Channel by Blanchard in 1785.
   A model of the Giffard Airship at the London Science Museum.
   Enlarge
   A model of the Giffard Airship at the London Science Museum.
   The navigable balloon developed by Dupuy de Lome in 1872.
   Enlarge
   The navigable balloon developed by Dupuy de Lome in 1872.

   Airships were among the first aircraft to fly, with various designs
   flying throughout the 19th century. They were largely attempts to make
   relatively small balloons more steerable, and often contained features
   found on later airships. These early airships set many of the earliest
   aviation records.

   In 1784 Jean-Pierre Blanchard fitted a hand-powered propeller to a
   balloon, the first recorded means of propulsion carried aloft. In 1785,
   he crossed the English Channel with a balloon equipped with flapping
   wings for propulsion, and a bird-like tail for steerage.

   The first person to make an engine-powered flight was Henri Giffard
   who, in 1852, flew 27 km (17 miles) in a steam-powered airship.

   In 1872, the French naval architect Dupuy de Lome launched a large
   limited navigable balloon, which was driven by a large propeller and
   the power of eight people. It was developed during the Franco-Prussian
   war, as an improvement to the balloons used for communications between
   Paris and the countryside during the Siege of Paris by German forces,
   but was only completed after the end of the war.

   Charles F. Ritchel made a public demonstration flight in 1878 of his
   hand-powered one-man rigid airship and went on to build and sell five
   of his aircraft.

   Paul Haenlein flew an airship with an internal combustion engine on a
   tether in Vienna, the first use of such an engine to power an aircraft.

   In 1880, Karl Wölfert and Ernst Georg August Baumgarten attempted to
   fly a powered airship in free flight, but crashed.

   In the 1880's a Serb named Ogneslav Kostovic Stepanovic also designed
   and built an airship. However the craft was destroyed by fire before it
   flew.
   Santos-Dumont #6 rounding the Eiffel Tower in the process of winning
   the Deutsch Prize in 1901. Photo courtesy of the Smithsonian
   Institution (SI Neg. No. 85-3941)
   Enlarge
   Santos-Dumont #6 rounding the Eiffel Tower in the process of winning
   the Deutsch Prize in 1901. Photo courtesy of the Smithsonian
   Institution (SI Neg. No. 85-3941)

   In 1883, the first electric-powered flight was made by Gaston
   Tissandier who fitted a 1-1/2 horsepower Siemens electric motor to an
   airship. The first fully controllable free-flight was made in a French
   Army airship, La France, by Charles Renard and Arthur Krebs in 1884.
   The 170 foot long , 66,000 cubic foot airship covered 8 km (5 miles) in
   23 minutes with the aid of an 8-1/2 horsepower electric motor.

   In 1888, Wölfert flew a Daimler-built petrol engine powered airship at
   Seelburg.

   In 1896, a rigid airship created by Croatian engineer David Schwarz
   made its first flight at Tempelhof field in Berlin. After Schwarz's
   death, his wife, Melanie Schwarz, was paid 15,000 Marks by Count
   Ferdinand von Zeppelin for information about the airship.

   In 1901, Alberto Santos-Dumont, in his airship "Number 6", a small
   blimp, won the Deutsch de la Meurthe prize of 100,000 francs for flying
   from the Parc Saint Cloud to the Eiffel Tower and back in under thirty
   minutes. Many inventors were inspired by Santos-Dumont's small airships
   and a veritable airship craze began world-wide. Many airship pioneers,
   such as the American Thomas Scott Baldwin financed their activities
   through passenger flights and public demonstration flights. Others,
   such as Walter Wellman and Melvin Vaniman set their sights on loftier
   goals, attempting two polar flights in 1907 and 1909, and two
   trans-atlantic flights in 1910 and 1912.

   The beginning of the "Golden Age of Airships" was also marked with the
   launch of the Luftschiff Zeppelin LZ1 in July of 1900 which would lead
   to the most successful airships of all time. These Zeppelins were named
   after the Count von Zeppelin. Von Zeppelin began experimenting with
   rigid airship designs in the 1890's leading to some patents and the LZ1
   (1900) and the LZ2 (1906). At the beginning of World War I the Zeppelin
   airships had a cylindrical aluminium alloy frame and a fabric-covered
   hull containing separate gas cells. Multi-plane tail fins were used for
   control and stability, and two engine/crew cars hung beneath the hull
   driving propellers attached to the sides of the frame by means of long
   drive shafts. Additionally there was a passenger compartment (later a
   bomb bay) located halfway between the two cars.

First World War

   Construction of the USS Shenandoah (ZR-1), 1923
   Enlarge
   Construction of the USS Shenandoah (ZR-1), 1923

   The prospect of using airships as bomb carriers had been recognised in
   Europe well before the airships themselves were up to the task. H. G.
   Wells described the obliteration of entire fleets and cities by airship
   attack in The War in the Air (1908), and scores of less famous British
   writers declared in print that the airship had altered the face of
   world affairs forever. On 5 March 1912, Italian forces became the first
   to use dirigibles for a military purpose during reconnaissance west of
   Tripoli behind Turkish lines. It was World War I, however, that marked
   the airship's real debut as a weapon.

   Count Zeppelin and others in the German military believed they had
   found the ideal weapon with which to counteract British Naval
   superiority and strike at Britain itself. More realistic airship
   advocates believed the Zeppelin was a valuable long range scout/attack
   craft for naval operations. Raids began by the end of 1914, reached a
   first peak in 1915, and then were discontinued after 1917. Zeppelins
   proved to be terrifying but inaccurate weapons. Navigation, target
   selection and bomb-aiming proved to be difficult under the best of
   conditions. The darkness, high altitudes and clouds that were
   frequently encountered by zeppelin missions reduced accuracy even
   further. The physical damage done by the zeppelins over the course of
   the war was trivial, and the deaths that they caused (though visible)
   amounted to a few hundred at most. The zeppelins also proved to be
   vulnerable to attack by aircraft and antiaircraft guns, especially
   those armed with incendiary bullets. Several were shot down in flames
   by British defenders, and others crashed 'en route'. In retrospect,
   advocates of the naval scouting role of the airship proved to be
   correct, and the land bombing campaign proved to be disastrous in terms
   of morale, men and material. Many pioneers of the German airship
   service died bravely, but needlessly in these propaganda missions. They
   also drew unwanted attention to the construction sheds which were
   bombed by the British Royal Naval Air Service.
   The USS Akron over Manhattan circa 1932
   Enlarge
   The USS Akron over Manhattan circa 1932

   Meanwhile the Royal Navy had recognised the need for small airships to
   counteract the submarine threat in coastal waters, and beginning in
   February 1915, began to deploy the SS (Sea Scout) class of blimp. These
   had a small envelope of 60-70,000 cu feet and at first utilised
   standard single engined planes (BE2c, Maurice Farman, Armstrong FK)
   shorn of wing and tail surfaces as an economy measure. Eventually more
   advanced blimps with purpose built cars, such as the C (Coastal), C*
   (Coastal Star), NS (North Sea), SSP (Sea Scout Pusher), SSZ (Sea Scout
   Zero), SSE (Sea Scout Experimental) and SST (Sea Scout Twin) classes
   were developed. The NS class, after initial teething problems proved to
   be the largest and finest airships in British service. They had a gas
   capacity of 360,000 cu feet, a crew of 10 and an endurance of 24 hours.
   Six 230 lb bombs were carried, as well as 3-5 machine guns. British
   blimps were used for scouting, mine clearance, and submarine attack
   duties. During the war, the British built over 225 non-rigid airships,
   of which several were sold to Russia, France, the US and Italy.
   Britain, in turn, purchased one M-type semi-rigid from Italy whose
   delivery was delayed until 1918. Eight rigid airships had been
   completed by the armistice, although several more were in an advanced
   state of completion by the war's end. The large number of trained
   crews, low attrition rate and constant experimentation in handling
   techniques meant that at the war's end Britain was the world leader in
   non-rigid airship technology.

   Airplanes had essentially replaced airships as bombers by the end of
   the war, and Germany's remaining zeppelins were scuttled by their
   crews, scrapped or handed over to the Allied powers as spoils of war.
   The British rigid airship program, meanwhile, had been largely a
   reaction to the potential threat of the German one and was largely,
   though not entirely, based on imitations of the German ships.
   U.S. Navy Zeppelin ZRS-5 "USS Macon" over Moffett Field in 1933
   Enlarge
   U.S. Navy Zeppelin ZRS-5 "USS Macon" over Moffett Field in 1933

Inter-war period

   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 September
   24, 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 July 2, 1919 R34 began the first
   double crossing of the Atlantic by an aircraft. It landed at Mineola,
   Long Island on July 6, 1919 after 108 hours in the air. The return
   crossing commenced on July 8 because of concerns about mooring the ship
   in the open, and took 75 hours. Impressed, British leaders began to
   contemplate a fleet of airships that would link Britain to its
   far-flung colonies, but unfortunately post-war economic conditions lead
   to most airships being scrapped and trained personnel dispersed, until
   the R-100 and R-101 commenced construction in 1929.

   Another example was the first American-built rigid dirigible USS
   Shenandoah, which flew in 1923, while the Los Angeles was under
   construction. The ship was christened on August 20 in Lakehurst, New
   Jersey and was the first to be inflated with the noble gas helium,
   which was still so rare at the time that the Shenandoah contained most
   of the world's reserves. So, when the Los Angeles was delivered, it was
   at first filled with the helium borrowed from ZR-1.

   The Zeppelin works were saved by the purchase of what became the USS
   Los Angeles by the United States Navy, paid for with "war reparations"
   money, owed according to the Versailles Treaty. The success of the Los
   Angeles encouraged the United States Navy to invest in larger airships
   of its own. Germany, meanwhile, was building the Graf Zeppelin, the
   first of what was intended to be a new class of passenger airships.
   Interestingly, the Graf Zeppelin burned unpressurised blau gas, similar
   to propane, as fuel. Since its density was similar to that of air, it
   avoided the weight change when fuel was used.

   Initially airships met with great success and compiled an impressive
   safety record. The Graf Zeppelin, for example, flew over one million
   miles (including the first circumnavigation of the globe by air)
   without a single passenger injury. The expansion of airship fleets and
   the growing (sometimes excessive) self-confidence of airship designers
   gradually made the limits of the type clear, and initial successes gave
   way to a series of tragic rigid airship accidents.

   The "catastrophist theory" of airship development owes much to the
   sensationalist press of the 1920s and 1930s and ignores successful
   ships such as Graf Zeppelin, R100 and Los Angeles. The worst disasters
   — R-101, USS Shenandoah, USS Akron and Hindenburg were all partially
   the result of political interference in normal airship construction and
   flight procedures.
   Rescuers scramble across the wreckage of British R-38/USN ZR-2, August
   24, 1921
   Enlarge
   Rescuers scramble across the wreckage of British R-38/USN ZR-2, August
   24, 1921

   The U.S. Navy toyed with the idea of using airships as "flying aircraft
   carriers." With wide oceans protecting the homeland, the idea of fleets
   of airships capable of rapidly crossing them (and the country) to
   deliver squadrons of fighters to attack approaching enemies had a
   certain appeal. This was a radical idea, however, and probably did not
   gain too much support in the Navy's traditional hierarchy. They did,
   though, build the USS Akron and USS Macon to test the principle. Each
   airship carried four fighters inside, and could carry a fifth on the
   "landing hangar." Perhaps the ease with which a fragile airship could
   be destroyed accidentally was the final justification for not pursuing
   this idea further.

   The USS Los Angeles flew successfully for 8 years, but eventually the
   U.S. Navy lost all three of its American-built rigid airships to
   accidents. USS Shenandoah, on a poorly planned publicity flight, flew
   into a severe thunderstorm over Noble County, Ohio, on 3 September 1925
   and broke into pieces, killing 14 of her crew. USS Akron was caught by
   a microburst and driven down into the surface of the sea off the shore
   of New Jersey on April 3, 1933. The USS Akron carried no life boats and
   few life vests. As a result, 73 of her 76-men crew died from drowning
   or hypothermia. USS Macon broke up after suffering a structural failure
   in its upper fin off the shore of Point Sur in California on 12
   February 1935. Only 2 of her 83-man crew died in the crash thanks to
   the inclusion of life jackets and inflatable rafts after the Akron
   disaster.

   Britain suffered its own airship tragedy in 1930 when R-101, a ship far
   advanced for its time but rushed to completion and sent on a trip to
   India before she was ready, crashed in France with the loss of 48 out
   of 54 aboard on 5 October. Because of the bad publicity surrounding the
   crash, the Air Ministry grounded the competing R100 in 1930 and sold it
   for scrap in 1931. This was despite the fact that the
   differently-designed R100 had completed a successful transatlantic
   maiden flight.
   The Hindenburg — moments after catching fire, May 6, 1937
   Enlarge
   The Hindenburg — moments after catching fire, May 6, 1937

   The most spectacular and widely remembered airship accident, however,
   is the burning of the Hindenburg on 6 May 1937, which caused public
   faith in airships to evaporate in favour of faster, more cost-efficient
   (albeit less energy-efficient) airplanes. Of the 97 people on board,
   there were 36 deaths: 13 passengers, 22 aircrew, and one American
   ground-crewman. (Much controversy persists as to the cause(s) of the
   accident. See Hindenburg for a discussion of this topic.)

   Most probably the airplane became the transport of choice also because
   it is less sensitive to wind. Aside from the problems of maneuvering
   and docking in high winds, the trip times for an upwind versus a
   downwind trip of an airship can differ greatly, and even crabbing at an
   angle to a crosswind eats up ground speed. Those differences make
   scheduling difficult.

Second World War

   While Germany determined that airships were obsolete for military
   purposes in the coming war and concentrated on the development of
   airplanes, the United States pursued a program of military airship
   construction even though it had not developed a clear military doctrine
   for airship use. At the Japanese attack on Pearl Harbour on 7 December
   1941 that brought the United States into World War II, it had 10
   non-rigid airships:
     * 4 K-class: K-2, K-3, K-4 and K-5 designed as a patrol ships built
       from 1938.
     * 3 L-class: L-1, L-2 and L-3 as small training ships, produced from
       1938.
     * 1 G-class built in 1936 for training.
     * 2 TC-class that were older patrol ships designed for land forces,
       built in 1933. The US Navy acquired them from Army in 1938.

   Only K and TC class airships could be used for combat purposes and they
   were quickly pressed into service against Japanese and German
   submarines which at that time were sinking US shipping in visual range
   of US coast. US Navy command, remembering the airship anti-submarine
   success from WWI, immediately requested new modern anti-submarine
   airships and on 2 January 1942 formed the ZP-12 patrol unit based in
   Lakehurst from the 4 K airships. The ZP-32 patrol unit was formed from
   two TC and two L airships a month later, based at US Navy (Moffet
   Field) in Sunnyvale in California. An airship training base was created
   there as well.

   In the years 1942–44, approximately 1,400 airship pilots and 3,000
   support crew members were trained in the military airship crew training
   program and the airship military personnel grew from 430 to 12,400. The
   US airships were produced by the Goodyear factory in Akron, Ohio. From
   1942 till 1945, 154 airships were built for the US Navy (133 K-class,
   ten L-class, seven G-class, four M-class) and five L-class for civilian
   customers (serial number L-4 to L-8).

   The primary airship tasks were patrol and convoy escort near the US
   coastline. They also served as an organisation centre for the convoys
   to direct ship movements, and were used during naval search and rescue
   operations. Rarer duties of the airships included aerophoto
   reconnaissance, naval mine-laying and mine-sweeping, parachute unit
   transport and deployment, cargo and personnel transportation. They were
   deemed quite successful in their duties with the highest combat
   readiness factor in the entire US air force (87%).

   During the war some 532 ships were sunk near the coast by submarines.
   However, not a single ship of the 89,000 or so in convoys escorted by
   blimps was sunk by enemy fire. Airships engaged submarines with depth
   charges and, less frequently, with other on-board weapons. They could
   match the slow speed of the submarine and bomb it until its
   destruction. Additionally, submerged submarines had no means of
   detecting an airship approaching.

   Only one airship was ever destroyed by U-boat: on the night of 18/ 19
   July 1943 a K-class airship (K-74) from ZP-21 division was patrolling
   the coastline near Florida. Using radar, the airship located a surfaced
   German submarine. The K-74 made her attack run but the U-boat opened
   fire first. K-74's depth charges did not release as she crossed the
   U-boat and the K-74 received serious damage, losing gas pressure and an
   engine but landing in the water without loss of life. The crew was
   rescued by patrol boats in the morning, but one crewman, Isadore
   Stessel, died from a shark attack. The U-Boat, U-134, had been damaged
   but not significantly. It was attacked by aircraft in the next day or
   so sustaining damage that forced it to return to base — it was finally
   sunk on 24 August 1943 by a British Vickers Wellington near Vigo, Spain

   Some US airships saw action in the European war theatre. The ZP-14 unit
   operating in the Mediterranean area from June 1944 completely denied
   the use of the Gibraltar Straits to Axis submarines. Airships from the
   ZP-12 unit took part in the sinking of the last U-Boat before German
   capitulation, sinking U-881 on 6 May 1945 together with destroyers
   Atherton and Mobery.

   The Soviet Union used a single airship during the war. The W-12, built
   in 1939, entered service in 1942 for paratrooper training and equipment
   transport. It made 1432 runs with 300 metric tons of cargo until 1945.
   On 1 February 1945 the Soviets constructed a second airship, a
   Pobieda-class (Victory-class) unit (used for mine-sweeping and wreckage
   clearing in the Black Sea) which later crashed on 21 January 1947.
   Another W-class — W-12bis Patriot was commissioned in 1947 and was
   mostly used for crew training, parades and propaganda.

Continued use

   Zeppelin NT airship
   Enlarge
   Zeppelin NT airship

   Although airships are no longer used for passenger transportation, they
   continued to be used for other purposes such as advertising and
   sightseeing. In particular, the U.S. Navy as above.

   In recent years, the Zeppelin company has reentered the airship
   business. Their new model, designated the Zeppelin NT made its maiden
   flight on September 18, 1997. There are currently three NT aircraft
   flying. One has been sold to a Japanese company, and was planned to be
   flown to Japan in the summer of 2004. However, due to delays getting
   permission from the Russian government, the company decided to
   transport the airship to Japan by ship.
   One of The Goodyear Tire & Rubber Company's blimp fleet.
   Enlarge
   One of The Goodyear Tire & Rubber Company's blimp fleet.

   Blimps continue to be used for advertising and as TV camera platforms
   at major sporting events. The most iconic of these is the Goodyear
   blimps. Goodyear operates 3 blimps in the United States. In addition,
   the Lightship group operates up to 19 advertising blimps around the
   world.

   In addition, Airship Management Services, Inc. operates 3 Skyship 600
   blimps. Two operate as advertising and security ships in the North
   America and the Caribbean and one operates under the name SkyCruizer
   providing sightseeing tours in Switzerland.

   The Switzerland-based Skyship 600 has also played other roles over the
   years. For example, it was also flown over Athens during the 2004
   Summer Olympics as a security measure. In November of 2006, it carried
   advertising calling it " The Spirit of Dubai" as it began a publicity
   tour from London to Dubai, UAE on behalf of The Palm Islands, the
   worlds largest man-made islands created as a residential complex.
   The Spirit of Dubai approaches its motorised mooring mast.
   Enlarge
   The Spirit of Dubai approaches its motorised mooring mast.

   In May of 2006, press reports indicate that the US Navy is starting to
   fly airships again after a hiatus of nearly 44 years. At present, the
   program utilizes a single American Blimp Company A-170 non-rigid
   airship. Operations will focus on crew training and research. The
   program is under the direction of the Naval Air Systems Command and is
   being carried out at NAES Lakehurst, the original centre of US Navy
   lighter-than-air operations in previous decades.

   Several companies, such as Cameron Balloons in Bristol, United Kingdom,
   build hot-air airships. These combine the structures of both hot-air
   balloons and small airships. The envelope is the normal 'cigar' shape,
   complete with tail fins, but is not inflated by helium, but by hot air
   (as in a balloon), which provides the lifting force. A small gondola,
   carrying the pilot (and sometimes between 1 and 3 passengers), a small
   engine and the burners to provide the hot air is suspended below the
   envelope, below an opening through which the burners protrude.

   Hot-air airships cost less to buy and maintain than modern Helium-based
   blimps, and they can be quickly deflated after flights. This makes them
   easy to carry in trailers or trucks and inexpensive to store. Such
   craft are usually very slow moving, with a typical top speed of 15-20
   mph. They are mainly used for advertising, but at least one has been
   used in rainforests for wildlife observation, as they can be easily
   transported to remote areas.

Present-day research

   The gondola and engines of a contemporary airship.
   Enlarge
   The gondola and engines of a contemporary airship.

   There are two primary focuses of current research on airships: 1) high
   altitude, long duration, sensor and/or communications platforms and 2)
   long distance transport of very large payloads.

   The US government is funding two major projects in the high altitude
   arena. The first is sponsored by U.S. Army Space and Missile Defense
   Command and is called the Composite Hull High Altitude Powered Platform
   (CHHAPP). This aircraft is also sometimes referred to as the HiSentinel
   High-Altitude Airship. This prototype ship made a 5 hour test flight in
   September 2005. The second project is being sponsored by the US Defense
   Advanced Research Projects Agency (DARPA) and is called the
   high-altitude airship (HAA). In 2005, DARPA awarded a contract for
   nearly $150 million to Lockheed-Martin for prototype development. First
   flight of the HAA is planned for 2008.

   There are also three private companies funding working on high altitude
   airships. Sanswire is developing high altitude airships they call "
   Stratellites" and Techsphere is developing a high altitude version of
   their spherically shaped airships. JP Aerospace has discussed its
   long-range plans that include not only high altitude communications and
   sensor applications but also an " orbital airship" capable of lifting
   cargo into low earth orbit with a marginal transportation cost of $1
   per short ton per mile of altitude.

   On January 31, 2006 Lockheed-Martin made the first flight of their
   secretly built hybrid-airship designated the P-791 at the company's
   flight test facility on the Palmdale Air Force Plant 42. The P-791
   aircraft is very similar in design to the SkyCat design unsuccessfully
   promoted for many years by the now financially troubled British company
   Advanced Technology Group. Although Lockheed-Martin is developing a
   design for the DARPA WALRUS project (see below), the company claimed
   that the P-791 is unrelated to WALRUS. Nonetheless, the design
   represents an approach that may well be applicable to WALRUS. Some
   believe that Lockheed-Martin had used the secret P-791 program as a way
   to get a "head-start" on the other WALRUS competitor, Aeros.

   A privately funded effort to build a heavy-lift aerostatic/aerodynamic
   hybrid craft, called the Dynalifter, is being carried out by Ohio
   Airships. The company has stated that they expect to begin test flight
   of the Dynalifter in Spring of 2006.

   21st Century Airships Inc. is a research and development company for
   airship technologies. Projects have included the development of a
   spherical shaped airship, as well as airships for high altitude,
   environmental research, surveillance and military applications, heavy
   lift and sightseeing. The company's airships have set numerous world
   records.

Proposed designs and application

   There are several proposed long-range/large-payload designs. All of
   these designs are still on the "drawing board".

   The proposed Aeroscraft is Aeros Corporation's continuation of the now
   cancelled WALRUS project (see below.) This proposed craft is a hybrid
   airship that, while cruising, obtains two thirds of its lift from
   helium and the remaining third aerodynamic lift. Jets would be used
   during take-off and landing.

   There is a case for the airship or zeppelin as a medium to long
   distance air 'cruise ship' using helium as a lifting agent. An airship
   engine need not be a turbojet and could use less expensive fuel or even
   use biodiesel.

   The disadvantage would be an increased journey time and the inability
   to overfly large mountain ranges. The Rocky Mountains, Alps and
   Himalayas, remain as major obstacles to economic airship navigation. As
   against this, airship ports would be relatively quiet and might even
   make use of seaport harbours.

   The longer journey times derive from the fact that airships are by
   definition slower than heavier-than-air-craft, the Hindenburg's top
   speed having been 135 km/h (84 mph), the current airship " Spirit of
   Dubai" (a Skyship 600) can achieve only 50-80 km/h (30-50 mph), and the
   Zeppelin NT up to 125 km/h (78 mph). This compares to a Boeing 737's
   cruising speed of just over 900 km/h (560 mph), or normal intercity
   rail speeds of in excess of 150 km/h (100 mph).

   Unless new technology permits greater speeds, anyone using airships
   over aeroplanes would need to accept journey durations at least seven
   times longer, significantly reducing the ability for air travel to
   "make the world smaller". It is unknown as to whether ecological
   concerns could drive this motivation sufficiently, or indeed whether
   the economies could accept such added impracticalities of travel ( 75
   hours for a transatlantic crossing having been normal in the early age
   of airships).

   Airship passengers could have spacious decks inside the hull to give
   ample room for sitting, sleeping and recreation. There would be ample
   room for restaurants and similar facilities. The potential exists for a
   market in more leisurely journeys, such as cruises over scenic terrain.

Noteworthy historic prototypes and experiments

   The Heli-Stat was an airship / helicopter hybrid built in New Jersey in
   1986.

   The Aereon was a hybrid aerostatic/aerodynamic craft built in the
   1970s.

   The Cyclocrane was a hybrid aerostatic/rotorcraft in which the entire
   airship envelope rotated along its longitudinal axis.

   CL160 was a very large semi-rigid airship to be built in Germany by the
   start-up Cargolifter, but funding ran out in 2002 after a massive
   hangar was built. The hangar, built just outside Berlin, has since been
   converted into a resort called " Tropical Islands".

   In 2005, there was a short-lived project focused on long distance and
   heavy lift was the WALRUS HULA sponsored by the US Department of
   Defense The primary goal of the research program was to determine the
   feasibility of building an airship capable of carrying 500 short tons
   (450 metric tons) of payload a distance of 12,000 miles (20,000 km) and
   land on an unimproved location without the use of external ballast or
   ground equipment (e.g. masts.) In 2005, two contractors,
   Lockheed-Martin and US Aeros Airships were each awarded approximately
   $3 million to do feasibility studies of designs for WALRUS. In late
   March of 2006, DARPA announced the termination of work on WALRUS after
   completion of the current Phase I contracts.

Fiction

   Fictionalized representations of airships have appeared in a number of
   media, including books and films.

   Retrieved from " http://en.wikipedia.org/wiki/Airship"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
