| Airship |
Index for Airship |
Shopping Airship |
Information AboutAirship |
|
An airship 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 Balloon s) stay aloft primarily by means of a cavity (usually quite large) filled with a gas of lesser Density than the surrounding atmosphere. 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 of its rarity and the fact it was considered a strategic material. However, hydrogen is flammable when mixed with air, a quality that, among other factors, contributed to the Hindenburg Disaster . The buoyancy provided by hydrogen is actually only about 10% 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. Other small experimental ships (i.e. Thermal Airship s) are filled with hot air in a fashion similar to Hot Air Balloon s. Terminology Airships are also known as dirigibles from the French ''dirigeable'', meaning "steerable." 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 a machine capable of atmospheric flight. In contrast to airships, Balloon s 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''. Types airships and balloons, circa 1930]]
History The development of airships was necessarily preceded by the development of balloons. See Balloon (aircraft) for details. Airship Pioneers by Blanchard in 1785.]] 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.]] 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. 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 Croatia n 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 Zeppelin for information about the airship. In 1901 , 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 Zeppelin s were named after the pioneer Count Ferdinand 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 WW1 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. Airships in the First World War , 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 Tracer Bullet s. 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 .
circa 1932]] 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. over Moffett Field in 1933 ]] Airships in the 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 un-pressurised ''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 1 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 - R101, USS ''Shenandoah'' , USS ''Akron'' and ''Hindenburg'' were all partially the result of political interference in normal airship construction and flight procedures. 1921 ]] Although the USS ''Los Angeles'' flew successfully for 8 years, the U.S. Navy eventually 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 '' R101 '', 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. '' — 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. What is generally not remembered is that of the 97 people on board, 62 got out alive. There were 36 dead: 13 passengers, 22 aircrew, and one American groundcrewman. Most probably the airplane became the transport of choice also because it is less sensitive to wind. Aside from the problems of manoeuvering 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. Airships in the 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 Japan ese Attack On Pearl Harbor on 7 December 1941 that brought the United States into World War II, it had 10 non-rigid airships:
Only K and TC class airships could be used for combat purposes and they were quickly pressed into service against Japanese and German Submarine s 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 2 TC and 2 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 1942-1944, approximately 1400 airship pilots and 3000 support crew members were trained in the military airship crew training program and the airship military personnel grew from 430 to 12400. 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, 10 L-class, 7 G-class, 4 M-class) and 5 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 center 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%). They were extremely successful in their primary goal of anti-submarine warfare as the below numbers illustrate: During the war some 532 ships were sunk near the coast by submarines.
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 Charge s, and less frequently, with other on-board weapons. They were very successful since 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 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. Due to the failure of the depth charge release mechanism, the airship was unable to release the bombs during the bombing run and the German returned fire. The (K-74) received serious damage and was forced to make a water landing. The crew was rescued by patrol boats in the morning, but one crewman died from a Shark attack. The U-Boat responsible was sunk a few hours later. Some US airships saw action in the European war theater. 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 Ton s of cargo until 1945. On 1 February 1945 the Soviets constructed a second airship, a Pobieda-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 's Blimp fleet.]] Although airships abandoned carrying passengers, they continued to be used for other purposes. In particular, the US 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 Japan ese 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. An airship was flown over Athens during the 2004 Summer Olympics as part of security anti-terrorism measures. Blimp s continue to be used for advertising and as TV camera platforms at major sporting events. Several companies, such as Cameron Balloons in Bristol , UK, 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. The advantages with the hot-air airship are that is costs less to buy and maintain than a standard modern Blimp and it can be quickly deflated at the end of a flight, meaning it is easily transported on a trailer or truck, without the need for expensive storage arrangements. Such craft usually are very slow moving, with a typical top speed of 15-20 mph. They are used mainly for advertising, but several have been used in Rainforest s for wildlife observation, because they could easily be transported into remote areas. Present-day research 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 " Stratellite s" 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. The largest project focused on long distance and heavy lift is the WALRUS HULA {Link without Title} sponsored by the US Department of Defense {Link without Title} The primary goal of the research program is 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. The future of the project is in question. In late March of 2006, the 2007 Budget request from DARPA calls for the termination of work on WALRUS after completion of the current Phase I contracts. 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, the company claims 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 has used the secret P-791 program as a way to get a "head-start" on the other WALRUS competitor. 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. Proposed designs There are several proposed long-range/large-payload designs. All of these designs are still on the "drawing board". 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 1970's. The Cyclocrane was a hybrid aerostatic/rotorcraft in which the entire airship envelope rotated along its longitudinal axis. Cargolifter was a very large semi-rigid airship to be built in Germany 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 Island ". Fiction See Also: Airships in culture Fictionalized representations of airships have appeared in a number of media, including books and films. See also
References
External links General
Associations
Historical
Manufacturers and commercial operators
Experiments, prototypes and one-offs
Designs under development
Proposed designs
|