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"Gentiana acaulis, the stemless gentian,Lena Struwe (Editor), Victor A. Albert (Editor), Gentianaceae, Cambridge University Press, 2002; or trumpet gentian, is a species of flowering plant in the family Gentianaceae, native to central and southern Europe, from Spain east to the Balkans, growing especially in mountainous regions, such as the Alps and Pyrenees, at heights of . It is a perennial plant, growing up to a height of tall and forming a "mat" up to wide. The leaves, which can be lanceolate, elliptical or obovate, are evergreen, 2–3.5 cm long, in a basal rosette, forming clumps. The trumpet- shaped terminal flowers are blue with olive-green spotted longitudinal throats. They grow on a very short peduncle, 3–6 cm long. The flower stem is often without leaves, or has 1 or 2 pairs of leaves. It likes full sun, is fully hardy and flowers in late spring and summer. This plant, like others of its genus, is valued in cultivation for the unusually pure intense blue of its blooms. It has gained the Royal Horticultural Society's Award of Garden Merit. The Latin specific epithet acaulis means "short-stemmed". The closely related Gentiana clusii, often called by the same common name as this species, differs in its preference for limy (alkaline) soils. It also has shorter leaves and the flowers have no olive-green stripes. A depiction of a gentian flower can be seen on the obverse side of Austrian € 0.01 euro coins. File:Gentiana acaulis (34797333066).jpg GentianaAcaulisRannoch.jpg File:Gentiána.jpg File:Gentiana acaulis L ag1.jpgAn illustration of G. acaulis File:Gentiana acaulis (stemless gentian).jpgMacro photography of the flower References External links acaulis Alpine flora Flora of Europe Flora of the Alps Flora of the Pyrenees Plants described in 1753 Taxa named by Carl Linnaeus "
"A modern airship, Zeppelin NT D-LZZF in 2010 An airship or dirigible balloon is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air. Dirigible airships compared with related aerostats, from a turn-of-the-20th-century encyclopedia In early dirigibles the lifting gas used was hydrogen, due to its high lifting capacity and ready availability. Helium gas has almost the same lifting capacity and is not flammable, unlike hydrogen, but is rare and relatively expensive. Significant amounts were first discovered in the United States and for a while helium was only used for airships in that country. Most airships built since the 1960s have used helium, though some have used hot air.A few airships after World War II used hydrogen. The first British airship to use helium was the Chitty Bang Bang of 1967. The envelope of an airship may form the gasbag, or it may contain a number of gas-filled cells. An airship also has engines, crew, and optionally also payload accommodation, typically housed in one or more gondolas suspended below the envelope. The main types of airship are non- rigid, semi-rigid, and rigid. Non-rigid airships, often called "blimps", rely on internal pressure to maintain their shape. Semi-rigid airships maintain the envelope shape by internal pressure, but have some form of supporting structure, such as a fixed keel, attached to it. Rigid airships have an outer structural framework that maintains the shape and carries all structural loads, while the lifting gas is contained in one or more internal gasbags or cells.Mowthorpe, C. E. S. Battlebags, British Airships of the First World War, Phoenix Mill, United Kingdom. Alan Sutton Publishing, 1995, p. xx. Rigid airships were first flown by Count Zeppelin and the vast majority of rigid airships built were manufactured by the firm he founded, Luftschiffbau Zeppelin. As a result, rigid airships are often called zeppelins. Airships were the first aircraft capable of controlled powered flight, and were most commonly used before the 1940s; their use decreased as their capabilities were surpassed by those of aeroplanes. Their decline was accelerated by a series of high-profile accidents, including the 1930 crash and burning of the British R101 in France, the 1933 and 1935 storm-related crashes of the twin airborne aircraft carrier U.S. Navy helium-filled rigids, the and USS Macon respectively, and the 1937 burning of the German hydrogen-filled Hindenburg. From the 1960s, helium airships have been used where the ability to hover for a long time outweighs the need for speed and manoeuvrability, such as advertising, tourism, camera platforms, geological surveys and aerial observation. Terminology Ballon-Poisson, a navigable balloon designed by aeronaut Ferdinand Lagleize, ca. 1850 Airship During the pioneer years of aeronautics, terms such as "airship", "air-ship", "air ship" and "ship of the air" meant any kind of navigable or dirigible flying machine.US patent 467069 "Air-ship" referring to a compound aerostat/rotorcraft.Ezekiel Airship (1902) wright-brothers.orgaltereddimensions.net "airship,"- referring to an HTA aeroplane.The Bridgeport Herald, August 18, 1901 - "air ship" referring to Whitehead's aeroplane.Cooley Airship of 1910, also called the Cooley monoplane.- a heavier-than-air monoplane.Frater, A.; The Balloon Factory, Picador (2009), Page 163. - Wright brothers' "airship."George Griffith, The angel of the Revolution, 1893 - "air-ship," "vessel" referring to a VTOL compound rotorcraft (not clear from the reference if it might be an aerostat hybrid.) In 1919 Frederick Handley Page was reported as referring to "ships of the air," with smaller passenger types as "air yachts."Auckland Star, 24 February 1919 "Ships of the air," "Air yachts" - passenger landplanes large and small In the 1930s, large intercontinental flying boats were also sometimes referred to as "ships of the air" or "flying-ships".The Sydney Morning Herald, Monday 11 April 1938 -"ship of the airs," "flying-ship," referring to a large flying-boat.Smithsonian, America by air "Ships of the Air" referring to Pan Am's Boeing Clipper flying-boat fleet. Nowadays the term "airship" is used only for powered, dirigible balloons, with sub-types being classified as rigid, semi-rigid or non-rigid. Semi-rigid architecture is the more recent, following advances in deformable structures and the exigency of reducing weight and volume of the airships. They have a minimal structure that keeps the shape jointly with overpressure of the gas envelope.Liao, L., & Pasternak, I. (2009). A review of airship structural research and development. Progress in Aerospace Sciences, 45(4), 83–96.Tuckerman, L. B. (1926). Inertia factors of ellipsoids for use in airship design. Aerostat An aerostat is an aircraft that remains aloft using buoyancy or static lift, as opposed to the aerodyne, which obtains lift by moving through the air. Airships are a type of aerostat.Ege (1973). The term aerostat has also been used to indicate a tethered or moored balloon as opposed to a free-floating balloon. Aerostats today are capable of lifting a payload of to an altitude of more than above sea level. They can also stay in the air for extended periods of time, particularly when powered by an on-board generator or if the tether contains electrical conductors. Due to this capability, aerostats can be used as platforms for telecommunication services. For instance, Platform Wireless International Corporation announced in 2001 that it would use a tethered airborne payload to deliver cellular phone service to a region in Brazil. The European Union's ABSOLUTE project was also reportedly exploring the use of tethered aerostat stations to provide telecommunications during disaster response. Dirigible Airships were originally called dirigible balloons, from the French ballon dirigeable often shortened to dirigeable (meaning "steerable", from the French diriger – to direct, guide or steer). This was the name that inventor Henri Giffard gave to his machine that made its first flight on 24 September 1852. Blimp A blimp is a non-rigid aerostat. In British usage it refers to any non-rigid aerostat, including barrage balloons and other kite balloons, having a streamlined shape and stabilising tail fins.Wragg, D,; Historical Dictionary of Aviation, History Press (2008) Page 27. Zeppelin The term zeppelin originally referred to airships manufactured by the German Zeppelin Company, which built and operated the first rigid airships in the early years of the twentieth century. The initials LZ, for (German for "Zeppelin airship"), usually prefixed their craft's serial identifiers. Streamlined rigid (or semi-rigid) airships are often referred to as "Zeppelins", because of the fame that this company acquired due to the number of airships it produced.De Syon, G. (2001). Zeppelin!: Germany and the airship, 1900–1939. JHU Press.Hartcup, G. (1974). The achievement of the airship: a history of the development of rigid, semi-rigid, and non-rigid airships. David & Charles. Hybrid airship Hybrid airships fly with a positive aerostatic contribution, usually equal to the empty weight of the system, and the variable payload is sustained by propulsion or aerodynamic contribution.Buerge, B. T. (2009). The Suitability of Hybrid vs. Conventional Airships for Persistent Surveillance Missions. Unpublished report from Dr. Charles Perkins. Classification Airships are classified according to their method of construction into rigid, semi-rigid and non-rigid types. Rigid airships A rigid airship has a rigid framework covered by an outer skin or envelope. The interior contains one or more gasbags, cells or balloons to provide lift. Rigid airships are typically unpressurised and can be made to virtually any size. Most, but not all, of the German Zeppelin airships have been of this type. Semi-rigid airships A semi-rigid airship has some kind of supporting structure but the main envelope is held in shape by the internal pressure of the lifting gas. Typically the airship has an extended, usually articulated keel running along the bottom of the envelope to stop it kinking in the middle by distributing suspension loads into the envelope, while also allowing lower envelope pressures. Non-rigid airships Non- rigid airships are often called "blimps". Most, but not all, of the American Goodyear airships have been blimps. A non-rigid airship relies entirely on internal gas pressure to retain its shape during flight. Unlike the rigid design, the non-rigid airship's gas envelope has no compartments. It typically has smaller internal bags or "ballonets". At sea level, these are filled with air. As altitude is increased, the lifting gas expands and air from the ballonets is expelled through valves to maintain the hull's shape. To return to sea level, the process is reversed: air is forced back into the ballonets by scooping air from the engine exhaust and using auxiliary blowers. Construction U.S. Navy airships and balloons, 1931: in the background, ZR-3, in front of it, (l to r) J-3 or 4, K-1, ZMC-2, in front of them, "Caquot" observation balloon, and in foreground free balloons used for training. Envelope The envelope itself is the structure, including textiles that contain the buoyant gas. Internally two ballonets placed in the front part and in the rear part of the hull contains air. The problem of the exact determination of the pressure on an airship envelope is still problematic and has fascinated major scientists such as Theodor Von Karman.Von Karman, Theodor. "Calculation of pressure distribution on airship hulls." (1930). A few airships have been metal-clad, with rigid and nonrigid examples made. Each kind used a thin gastight metal envelope, rather than the usual rubber-coated fabric envelope. Only four metal-clad ships are known to have been built, and only two actually flew: Schwarz's first aluminum rigid airship of 1893 collapsed,Dooley, A.185-A.186 citing Robinson, pp.2–3 collapsed on inflation while his second flew;Dooley, A.193 (at Tempelhof, Berlin in 1897, landed but then collapsed) the nonrigid ZMC-2 built for the U.S. Navy flew from 1929 to 1941 when it was scrapped as too small for operational use on anti-submarine patrols;NAS Grosse Ile , NASGIVM. 2006. while the 1929 nonrigid Slate Aircraft Corporation City of Glendale collapsed on its first flight attempt.National Air and Space Museum, Smithsonian Institution. 2008. Slate Aircraft Corporation City of Glendale Negatives, Accession number 2006-0039City of Glendale. Photo Album. Retrieved 3 September 2008. Lifting gas Thermal airships use a heated lifting gas, usually air, in a fashion similar to hot air balloons. The first to do so was flown in 1973 by the British company Cameron Balloons."Jane's All the World's Aircraft 1980–81", Pages 609–610 Gondola A gondola fitted with twin propellers Propulsion and control Small airships carry their engine(s) in their gondola. Where there were multiple engines on larger airships, these were placed in separate nacelles, termed power cars or engine cars. To allow asymmetric thrust to be applied for maneuvering, these power cars were mounted towards the sides of the envelope, away from the centre line gondola. This also raised them above the ground, reducing the risk of a propeller strike when landing. Widely spaced power cars were also termed wing cars, from the use of "wing" to mean being on the side of something, as in a theater, rather than the aerodynamic device. These engine cars carried a crew during flight who maintained the engines as needed, but who also worked the engine controls, throttle etc., mounted directly on the engine. Instructions were relayed to them from the pilot's station by a telegraph system, as on a ship. Environmental benefits The main advantage of airships with respect to any other vehicle is of environmental nature. They require less energy to remain in flight, if compared to any other air vehicle.Colozza, A., & Dolce, J. (2003). Initial feasibility assessment of a high altitude long endurance airship. A solar-powered airship would be estimated to only use 8 percent of the fuel required by jet aircraft. Furthermore, utilizing the jet stream could allow for a faster and more energy-efficient cargo transport alternative to maritime shipping. The International Air Transport Association has called for increasing the use of airships in an effort to tackle greenhouse gas emissions, claiming 80-90% reductions relative to conventional aircraft. This is one of the reasons why China has embraced their use recently. History Early pioneers Francesco Lana de Terzi's Aerial Ship design of 1670. Crossing of the English Channel by Blanchard in 1785. A model of the 1852 Giffard Airship at the London Science Museum. The navigable balloon developed by Henri Dupuy de Lôme in 1872. =17th–18th centuries= In 1670, the Jesuit Father Francesco Lana de Terzi, sometimes referred to as the "Father of Aeronautics", published a description of an "Aerial Ship" supported by four copper spheres from which the air was evacuated. Although the basic principle is sound, such a craft was unrealizable then and remains so to the present day, since external air pressure would cause the spheres to collapse unless their thickness was such as to make them too heavy to be buoyant. A hypothetical craft constructed using this principle is known as a Vacuum airship. A more practical dirigible airship was described by Lieutenant Jean Baptiste Marie Meusnier in a paper entitled "Mémoire sur l’équilibre des machines aérostatiques" (Memorandum on the equilibrium of aerostatic machines) presented to the French Academy on 3 December 1783. The 16 water-color drawings published the following year depict a streamlined envelope with internal ballonnets that could be used for regulating lift: this was attached to a long carriage that could be used as a boat if the vehicle was forced to land in water. The airship was designed to be driven by three propellers and steered with a sail-like aft rudder. 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 in a balloon equipped with flapping wings for propulsion and a birdlike tail for steering.Winter & Degner (1933), pp. 26–27. =19th century= The 19th century saw continued attempts to add methods of propulsion to balloons. The Australian William Bland sent designs for his "Atmotic Airship" to the Great Exhibition held in London in 1851, where a model was displayed. This was an elongated balloon with a steam engine driving twin propellers suspended underneath. The lift of the balloon was estimated as 5 tons and the car with the fuel as weighing 3.5 tons, giving a payload of 1.5 tons. Bland believed that the machine could be driven at and could fly from Sydney to London in less than a week. In 1852, Henri Giffard became the first person to make an engine-powered flight when he flew in a steam-powered airship.Winter & Degner (1933), p. 36. Airships would develop considerably over the next two decades. In 1863, Solomon Andrews flew his aereon design, an unpowered, controllable dirigible in Perth Amboy, New Jersey and offered the device to the U.S. Military during the Civil War.Glazer, Stephen D. "Rutgers in the Civil War," Journal of the Rutgers University Libraries Vol. 66 (2014), page 102 He flew a later design in 1866 around New York City and as far as Oyster Bay, New York. This concept used changes in lift to provide propulsive force, and did not need a powerplant. In 1872, the French naval architect Dupuy de Lome launched a large navigable balloon, which was driven by a large propeller turned by eight men.Brooks 1992 p. 19. It was developed during the Franco-Prussian war and was intended as an improvement to the balloons used for communications between Paris and the countryside during the siege of Paris, but was completed only after the end of the war. In 1872, Paul Haenlein flew an airship with an internal combustion engine running on the coal gas used to inflate the envelope, the first use of such an engine to power an aircraft.Winter & Degner (1933), p. 44.Bento S. Mattos, Short History of Brazilian Aeronautics (PDF), 44th AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada, 9–12 January 2006. 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. Dyer Airship 1874 Patent Drawing Page 1 In 1874, Micajah Clark Dyer filed U.S. Patent 154,654 "Apparatus for Navigating the Air". It is believed successful trial flights were made between 1872–1874, but detailed dates are not available. The apparatus used a combination of wings and paddle wheels for navigation and propulsion. More details can be found in the book about his life. In 1883, the first electric-powered flight was made by Gaston Tissandier, who fitted a Siemens electric motor to an airship. The first fully controllable free flight was made in 1884 by Charles Renard and Arthur Constantin Krebs in the French Army airship La France. La France made the first flight of an airship that landed where it took off; the long, airship covered in 23 minutes with the aid of an electric motor,Winter & Degner (1933), pp. 49–50. and a battery. It made seven flights in 1884 and 1885. In 1888, the design of the Campbell Air Ship, designed by Professor Peter C. Campbell, was submitted to aeronautic engineer Carl Edgar Myers for examination. After his approval it was built by the Novelty Air Ship Company. It was lost at sea in 1889 while being flown by Professor Hogan during an exhibition flight.Scientific American - 27 July 1889 From 1888 to 1897, Friedrich Wölfert built three airships powered by Daimler Motoren Gesellschaft-built petrol engines, the last of which caught fire in flight and killed both occupants in 1897.Brooks 1992 p. 20. The 1888 version used a single cylinder Daimler engine and flew from Canstatt to Kornwestheim.Mercedes-Benz Museum (Trip II): The beginning, gminsidenews.com, 2007.Member's Circular Letter February 2008, zeppelin-tourismus.de. Santos- Dumont No.6 rounding the Eiffel Tower in 1901. In 1897, an airship with an aluminum envelope was built by the Hungarian-Croatian engineer David Schwarz. It made its first flight at Tempelhof field in Berlin after Schwarz had died. His widow, Melanie Schwarz, was paid 15,000 marks by Count Ferdinand von Zeppelin to release the industrialist Carl Berg from his exclusive contract to supply Schwartz with aluminium.Brooks 1992 pp. 27–31. From 1897 to 1899, Konstantin Danilewsky, medical doctor and inventor from Kharkiv (now Ukraine, then Russian Empire), built four muscle-powered airships, of gas volume . About 200 ascents were made within a framework of experimental flight program, at two locations, with no significant incidents Bill Welker. Airships of Konstantin Danilewsky. Then-and-Now project, publication January 2018(2019) AirBike...1897. Ed. by A. B. Akimov and W. J. Welker. Sapphire Publications, US, 342 p. (Digital edition) Free download. Late 1800s work of Dr. Konstantin Dalilewsky to solve the problem of human flight presented for the first time in English. Including reproduction of the original Russian and German 1900 editions. Early 20th century LZ1, Count Zeppelin's first airship In July 1900, the Luftschiff Zeppelin LZ1 made its first flight. This led to the most successful airships of all time: the Zeppelins, named after Count von Zeppelin who began working on rigid airship designs in the 1890s, leading to the flawed LZ1 in 1900 and the more successful LZ2 in 1906. The Zeppelin airships had a framework composed of triangular lattice girders covered with fabric that contained separate gas cells. At first multiplane tail surfaces were used for control and stability: later designs had simpler cruciform tail surfaces. The engines and crew were accommodated in "gondolas" 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 engine compartments. Alberto Santos-Dumont was a wealthy Brazilian who lived in France and had a passion for flying. He designed 18 balloons and dirigibles before turning his attention to fixed- winged aircraft.Niccoli, R. The Book of Flight: From the flying machines of Leonardo da Vinci to the conquest of space, New York, Friedman/Fairfax, 2002, p. 24. On 19 October 1901 he flew his airship Number 6, from the Parc Saint Cloud to and around the Eiffel Tower and back in under thirty minutes.Toland (1957), pp. 25–37. This feat earned him the Deutsch de la Meurthe prize of 100,000 francs. Many inventors were inspired by Santos-Dumont's small airships . Many airship pioneers, such as the American Thomas Scott Baldwin, financed their activities through passenger flights and public demonstration flights. Stanley Spencer built the first British airship with funds from advertising baby food on the sides of the envelope.Papers Past - Christchurch Star, 31 December 1903, WAYS OF AIRSHIPS (p. 2) 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.Toland (1957), pp. 49–51. An Astra-Torres airship In 1902 the Spanish engineer Leonardo Torres Quevedo published details of an innovative airship design in Spain and France. With a non-rigid body and internal bracing wires, it overcame the flaws of these types of aircraft as regards both rigid structure (zeppelin type) and flexibility, providing the airships with more stability during flight, and the capability of using heavier engines and a greater passenger load. In 1905, helped by Captain A. Kindelán, he built the airship "España" at the Guadalajara military base. Next year he patented his design without attracting official interest. In 1909 he patented an improved design that he offered to the French Astra company, who started mass-producing it in 1911 as the Astra-Torres airship. The distinctive three-lobed design was widely used during the Great War by the Entente powers. Other airship builders were also active before the war: from 1902 the French company Lebaudy Frères specialized in semirigid airships such as the Patrie and the République, designed by their engineer Henri Julliot, who later worked for the American company Goodrich; the German firm Schütte-Lanz built the wooden-framed SL series from 1911, introducing important technical innovations; another German firm Luft-Fahrzeug-Gesellschaft built the Parseval-Luftschiff (PL) series from 1909,Lueger 1920, pp.404–412, Luftschiff and Italian Enrico Forlanini's firm had built and flown the first two Forlanini airships.Ligugnana, Sandro On May 12, 1902, the inventor and Brazilian aeronaut Augusto Severo de Albuquerque Maranhao and his French mechanic, Georges Saché, died when they were flying over Paris in the airship called Pax. A marble plaque at number 81 of the Avenue du Maine in Paris, commemorates the location of Augusto Severo accident. The Catastrophe of the Balloon "Le Pax" is a 1902 short silent film recreation of the catastrophe, directed by Georges Méliès. In Britain, the Army built their first dirigible, the Nulli Secundus, in 1907. The Navy ordered the construction of an experimental rigid in 1908. Officially known as His Majesty's Airship No. 1 and nicknamed the Mayfly, it broke its back in 1911 before making a single flight. Work on a successor did not start until 1913. In 1910 Walter Wellman unsuccessfully attempted an aerial crossing of the Atlantic Ocean in the airship America. World War I Italian Military Airship, 1908 Schütte Lanz SL2 bombing Warsaw in 1914. The prospect of airships as bombers had been recognized in Europe well before the airships were up to the task. H. G. Wells' The War in the Air (1908) described the obliteration of entire fleets and cities by airship attack. The Italian forces became the first to use dirigibles for a military purpose during the Italo–Turkish War, the first bombing mission being flown on 10 March 1912.With the Dirigibles at TripoliFlight 30 March 1912 World War I marked the airship's real debut as a weapon. The Germans, French and Italians all used airships for scouting and tactical bombing roles early in the war, and all learned that the airship was too vulnerable for operations over the front. The decision to end operations in direct support of armies was made by all in 1917.Ventry & Koesnik (1982), p. 85.Robinson (1973), pp. 126–127. Many in the German military believed they had found the ideal weapon with which to counteract British naval superiority and strike at Britain itself, while more realistic airship advocates believed the zeppelin's value was as a long range scout/attack craft for naval operations. Raids on England began in January 1915 and peaked in 1916: following losses to the British defenses only a few raids were made in 1917–18, the last in August 1918.Robinson 1994, p. 360. Zeppelins proved to be terrifying but inaccurate weapons. Navigation, target selection and bomb-aiming proved to be difficult under the best of conditions, and the cloud cover that was frequently encountered by the airships reduced accuracy even further. The physical damage done by airships over the course of the war was insignificant, and the deaths that they caused amounted to a few hundred.Cole, Christopher and Cheesman, E. F. The Air Defence of Great Britain 1914–1918. London: Putnam, 1984. . p.449 Nevertheless, the raid caused a significant diversion of British resources to defense efforts. The airships were initially immune to attack by aircraft and anti-aircraft guns: as the pressure in their envelopes was only just higher than ambient air, holes had little effect. But following the introduction of a combination of incendiary and explosive ammunition in 1916, their flammable hydrogen lifting gas made them vulnerable to the defending aeroplanes. Several were shot down in flames by British defenders, and many others destroyed in accidents. New designs capable of reaching greater altitude were developed, but although this made them immune from attack it made their bombing accuracy even worse. Countermeasures by the British included sound detection equipment, searchlights and anti-aircraft artillery, followed by night fighters in 1915. One tactic used early in the war, when their limited range meant the airships had to fly from forward bases and the only zeppelin production facilities were in Friedrichshafen, was the bombing of airship sheds by the British Royal Naval Air Service. Later in the war, the development of the aircraft carrier led to the first successful carrier-based air strike in history: on the morning of 19 July 1918, seven Sopwith 2F.1 Camels were launched from and struck the airship base at Tønder, destroying zeppelins L 54 and L 60.Robinson (1994), pp. 340–341. View from a French dirigible approaching a ship in 1918. Wreckage of Zeppelin L31 or L32 shot down over England 23 Sept 1916. The British Army had abandoned airship development in favour of aeroplanes before the start of the war, but the Royal Navy had recognized the need for small airships to counteract the submarine and mine threat in coastal waters.Higham (1961), p. 111. Beginning in February 1915, they began to develop the SS (Sea Scout) class of blimp. These had a small envelope of and at first used aircraft fuselages without the wing and tail surfaces as control cars. Later, more advanced blimps with purpose-built gondolas were used. The NS class (North Sea) were the largest and most effective non-rigid airships in British service, with a gas capacity of , a crew of 10 and an endurance of 24 hours. Six bombs were carried, as well as three to five machine guns. British blimps were used for scouting, mine clearance, and convoy patrol duties. During the war, the British operated over 200 non-rigid airships.Mowthorpe, Ces, Battlebags, Stroud, Gloucs, Allan Sutton Publishing, 1995, p. xxiii. Several were sold to Russia, France, the United States, and Italy. 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. The Royal Navy continued development of rigid airships until the end of the war. Eight rigid airships had been completed by the armistice, (No. 9r, four 23 Class, two R23X Class and one R31 Class), although several more were in an advanced state of completion by the war's end.Patrick Abbott and Nick Walmsley, British Airships in Pictures: An Illustrated History, House of Lochar 1998, (pp.59–69) Both France and Italy continued to use airships throughout the war. France preferred the non-rigid type, whereas Italy flew 49 semi-rigid airships in both the scouting and bombing roles.Ventry & Koesnik (1982), p. 97. Aeroplanes had essentially replaced airships as bombers by the end of the war, and Germany's remaining zeppelins were destroyed by their crews, scrapped or handed over to the Allied powers as war reparations. The British rigid airship program, which had mainly been a reaction to the potential threat of the German airships, was wound down. The interwar period The Bodensee 1919 The Nordstern 1920 "Norge" airship in flight 1926 R-38/USN ZR-2, 24 August 1921. Britain, the United States and Germany built rigid airships between the two world wars. Italy and France made limited use of Zeppelins handed over as war reparations. Italy, the Soviet Union, the United States and Japan mainly operated semi-rigid airships. Under the terms of the Treaty of Versailles, Germany was not allowed to build airships of greater capacity than a million cubic feet. Two small passenger airships, LZ 120 Bodensee and its sister ship LZ 121 Nordstern, were built immediately after the war but were confiscated following the sabotage of the wartime Zeppelins that were to have been handed over as war reparations: Bodensee was given to Italy and Nordstern to France. On May 12, 1926, the Italian semi-rigid airship Norge was the first aircraft to fly over the North Pole. The British R33 and R34 were near-identical copies of the German L 33, which had come down almost intact in Yorkshire on 24 September 1916.Higham (1961), p. 138. Despite being almost three years out of date by the time they were launched in 1919, they became two of the most successful airships in British service. The creation of the Royal Air Force (RAF) in early 1918 created a hybrid British airship program. The RAF was not interested in airships while the Admiralty was, so a deal was made where the Admiralty would design any future military airships and the RAF would handle manpower, facilities and operations.Higham (1961), p. 176. On 2 July 1919, R34 began the first double crossing of the Atlantic by an aircraft. It landed at Mineola, Long Island on 6 July after 108 hours in the air; the return crossing began on 8 July and took 75 hours. This feat failed to generate enthusiasm for continued airship development, and the British airship program was rapidly wound down. During World War One, the U.S. Navy acquired its first airship, the DH-1, but it was destroyed while being inflated shortly after delivery to the Navy. After the war, the U.S. Navy contracted to buy the R 38, which was being built in Britain, but before it was handed over it was destroyed because of a structural failure during a test flight.Higham 1961, pp. 222–223. during construction, 1923 beside tender USS Patoka February 1931 America then started constructing the , designed by the Bureau of Aeronautics and based on the Zeppelin L 49.Swanborough, G. and Bowyers, P. M. United States Navy Aircraft Since 1912. London: Putnam, 1976 (2nd ed.) , p. 586 Assembled in Hangar No. 1 and first flown on 4 September 1923 at Lakehurst, New Jersey, it was the first airship to be inflated with the noble gas helium, which was then so scarce that the Shenandoah contained most of the world's supply. A second airship, , was built by the Zeppelin company as compensation for the airships that should have been handed over as war reparations according to the terms of the Versailles Treaty but had been sabotaged by their crews. This construction order saved the Zeppelin works from the threat of closure. The success of the Los Angeles, which was flown successfully for eight years, encouraged the U.S. Navy to invest in its own, larger airships. When the Los Angeles was delivered, the two airships had to share the limited supply of helium, and thus alternated operating and overhauls.Althoff, William F., USS Los Angeles, Washington DC, Brassey's, 2004, p. 48, In 1922 Sir Dennistoun Burney suggested a plan for a subsidised air service throughout the British Empire using airships (the Burney Scheme). Following the coming to power of Ramsay MacDonald's Labour government in 1924, the scheme was transformed into the Imperial Airship Scheme, under which two airships were built, one by a private company and the other by the Royal Airship Works under Air Ministry control. The two designs were radically different. The "capitalist" ship, the R100, was more conventional, while the "socialist" ship, the R101, had many innovative design features. Construction of both took longer than expected, and the airships did not fly until 1929. Neither airship was capable of the service intended, though the R100 did complete a proving flight to Canada and back in 1930.Countryman, Barry, R100 in Canada, Erin, Ontario, Boston Mills, 1982, On 5 October 1930, the R101, which had not been thoroughly tested after major modifications, crashed on its maiden voyage at Beauvais in France killing 48 of the 54 people aboard. Among the dead were the craft's chief designer and the Secretary of State for Air. The disaster put an end to further British airship development. The Locarno Treaties of 1925 lifted the restrictions on German airship construction, and the Zeppelin company started construction of the Graf Zeppelin (LZ 127), the largest airship that could be built in the company's existing shed, and intended to stimulate interest in passenger airships. The Graf Zeppelin burned blau gas, similar to propane, stored in large gas bags below the hydrogen cells, as fuel. Since its density was similar to that of air, it avoided the weight change as fuel was used, and thus the need to valve hydrogen. The Graf Zeppelin had an impressive safety record, flying over (including the first circumnavigation of the globe by airship) without a single passenger injury.Botting, Douglas, Dr. Eckener's Dream Machine. New York: Henry Hold, 2001. USS Macon over Lower Manhattan, 1933 The U.S. Navy experimented with the use of airships as airborne aircraft carriers, developing an idea pioneered by the British. The USS Los Angeles was used for initial experiments, and the and , the world's largest at the time, were used to test the principle in naval operations. Each carried four F9C Sparrowhawk fighters in its hangar, and could carry a fifth on the trapeze. The idea had mixed results. By the time the Navy started to develop a sound doctrine for using the ZRS-type airships, the last of the two built, USS Macon, had been lost. The seaplane had become more capable, and was considered a better investment.Smith (1965), pp. 171–174. Eventually, the U.S. Navy lost all three U.S.-built rigid airships to accidents. USS Shenandoah flew into a severe thunderstorm over Noble County, Ohio while on a poorly planned publicity flight on 3 September 1925. It broke into pieces, killing 14 of its crew. USS Akron was caught in a severe storm and flown into the surface of the sea off the shore of New Jersey on 3 April 1933. It carried no life boats and few life vests, so 73 of its crew of 76 died from drowning or hypothermia. USS Macon was lost after suffering a structural failure offshore near Point Sur Lighthouse on 12 February 1935. The failure caused a loss of gas, which was made much worse when the aircraft was driven over pressure height causing it to lose too much helium to maintain flight.Smith (1965), pp. 157–161. Only two of its crew of 83 died in the crash thanks to the inclusion of life jackets and inflatable rafts after the Akron disaster. The Empire State Building was completed in 1931 with a dirigible mast, in anticipation of passenger airship service. Various entrepreneurs experimented with commuting and shipping freight via airship. In the 1930s the German Zeppelins successfully competed with other means of transport. They could carry significantly more passengers than other contemporary aircraft while providing amenities similar to those on ocean liners, such as private cabins, observation decks, and dining rooms. Less importantly, the technology was potentially more energy-efficient than heavier-than-air designs. Zeppelins were also faster than ocean liners. On the other hand, operating airships was quite involved. Often the crew would outnumber passengers, and on the ground large teams were necessary to assist mooring and very large hangars were required at airports. The Hindenburg catches fire, 6 May 1937 By the mid-1930s only Germany still pursued airship development. The Zeppelin company continued to operate the Graf Zeppelin on passenger service between Frankfurt and Recife in Brazil, taking 68 hours. Even with the small Graf Zeppelin, the operation was almost profitable.Botting, Douglas, Dr. Eckener's Dream Machine. New York, Henry Hold, 2001, p. 235, In the mid-1930s work started to build an airship designed specifically to operate a passenger service across the Atlantic.Dick, Harold G., with Robinson, Douglas H., Graf Zeppelin & Hindenburg, Washington DC, Smithsonian Institution Press, 1985, p. 83, The Hindenburg (LZ 129) completed a successful 1936 season, carrying passengers between Lakehurst, New Jersey and Germany. The year 1937 started with the most spectacular and widely remembered airship accident. Approaching the Lakehurst mooring mast minutes before landing on 6 May 1937, the Hindenburg burst into flames and crashed. Of the 97 people aboard, 36 died: 13 passengers, 22 aircrew, and one American ground-crewman. The disaster happened before a large crowd, was filmed and a radio news reporter was recording the arrival. This was a disaster that theater goers could see and hear in newsreels. The Hindenburg disaster shattered public confidence in airships, and brought a definitive end to their "golden age". The day after the Hindenburg crashed, the Graf Zeppelin landed at the end of its flight from Brazil. This was the last international passenger airship flight. Hindenburgs sister ship, the Graf Zeppelin II (LZ 130), could not carry commercial passengers without helium, which the United States refused to sell to Germany. The Graf Zeppelin made several test flights and conducted some electronic espionage until 1939 when it was grounded due to the beginning of the war. The two Graf Zeppelins were scrapped in early 1940. Development of airships continued only in the United States, and to a smaller extent, the Soviet Union. The Soviet Union had several semi-rigid and non- rigid airships. The semi-rigid dirigible SSSR-V6 OSOAVIAKhIM was among the largest of these craft, and it set the longest endurance flight at the time of over 130 hours. It crashed into a mountain in 1938, killing 13 of the 19 people on board. While this was a severe blow to the Soviet airship program, they continued to operate non-rigid airships until 1950. World War II While Germany determined that airships were obsolete for military purposes in the coming war and concentrated on the development of aeroplanes, the United States pursued a program of military airship construction even though it had not developed a clear military doctrine for airship use. When the Japanese attacked Pearl Harbor on 7 December 1941, bringing the United States into World War II, the U.S. Navy had 10 nonrigid airships: *4 K-class: K-2, K-3, K-4 and K-5 designed as patrol ships, all built in 1938. *3 L-class: L-1, L-2 and L-3 as small training ships, produced in 1938. *1 G-class, built in 1936 for training. *2 TC-class that were older patrol airships designed for land forces, built in 1933. The U.S. Navy acquired both from the United States Army in 1938. Control car (gondola) of the Goodyear ZNPK (K-28) later operated by Goodyear as Puritan VI Only K- and TC-class airships were suitable for combat and they were quickly pressed into service against Japanese and German submarines, which were then sinking American shipping within visual range of the American coast. U.S. Navy command, remembering airship's anti-submarine success in World War I, immediately requested new modern antisubmarine airships and on 2 January 1942 formed the ZP-12 patrol unit based in Lakehurst from the four K airships. The ZP-32 patrol unit was formed from two TC and two L airships a month later, based at NAS Moffett Field in Sunnyvale, California. An airship training base was created there as well. The status of submarine- hunting Goodyear airships in the early days of World War II has created significant confusion. Although various accounts refer to airships Resolute and Volunteer as operating as "privateers" under a Letter of Marque, Congress never authorized a commission, nor did the President sign one.Theodore Richard, Reconsidering the Letter of Marque: Utilizing Private Security Providers Against Piracy (April 1, 2010). Public Contract Law Journal, Vol. 39, No. 3, pp. 411–464 at 429 n.121, Spring 2010. Available at SSRN A view of six helium-filled blimps being stored in one of the two massive hangars located at NAS Santa Ana, during World War II. 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 U.S. airships were produced by the Goodyear factory in Akron, Ohio. From 1942 till 1945, 154 airships were built for the U.S. Navy (133 K-class, 10 L-class, seven G-class, four M-class) and five L-class for civilian customers (serial numbers L-4 to L-8). The primary airship tasks were patrol and convoy escort near the American coastline. They also served as an organization centre for the convoys to direct ship movements, and were used in 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 U.S. air force (87%). During the war, some 532 ships without airship escort were sunk near the U.S. coast by enemy submarines. Only one ship, the tanker Persephone, of the 89,000 or so in convoys escorted by blimps was sunk by the enemy.Vaeth, J. Gordon, Blimps & U-Boats, Annapolis, MD, U.S. Naval Institute Press, 1992, pp. 20–21, Airships engaged submarines with depth charges and, less frequently, with other on- board weapons. They were excellent at driving submarines down, where their limited speed and range prevented them from attacking convoys. The weapons available to airships were so limited that until the advent of the homing torpedo they had little chance of sinking a submarine.Vaeth, J. Gordon, Blimps & U-Boats, Annapolis, MD, U.S. Naval Institute Press, 1992, Only one airship was ever destroyed by U-boat: on the night of 18/19 July 1943, the 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-74s 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, Aviation Machinist's Mate Second Class Isadore Stessel, died from a shark attack. The U-Boat, , was slightly damaged and the next day or so was attacked by aircraft, 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.U.S. Navy LTA history.U-134 history, Uboat.net. Fleet Airship Wing One operated from Lakehurst, New Jersey, Glynco, Georgia, Weeksville, North Carolina, South Weymouth NAS Massachusetts, Brunswick NAS and Bar Harbor Maine, Yarmouth, Nova Scotia, and Argentia, Newfoundland. K-class blimps of USN Blimp Squadron ZP-14 conducted antisubmarine warfare operations at the Strait of Gibraltar in 1944–45. Some Navy blimps saw action in the European war theater. In 1944–45, the U.S. Navy moved an entire squadron of eight Goodyear K class blimps (K-89, K-101, K-109, K-112, K-114, K-123, K-130, & K-134) with flight and maintenance crews from Weeksville Naval Air Station in North Carolina to Naval Air Station Port Lyautey, French Morocco. Their mission was to locate and destroy German U-boats in the relatively shallow waters around the Strait of Gibraltar where magnetic anomaly detection (MAD) was viable. PBY aircraft had been searching these waters but MAD required low altitude flying that was dangerous at night for these aircraft. The blimps were considered a perfect solution to establish a 24/7 MAD barrier (fence) at the Straits of Gibraltar with the PBYs flying the day shift and the blimps flying the night shift. The first two blimps (K-123 & K-130) left South Weymouth NAS on 28 May 1944 and flew to Argentia, Newfoundland, the Azores, and finally to Port Lyautey where they completed the first transatlantic crossing by nonrigid airships on 1 June 1944. The blimps of USN Blimp Squadron ZP-14 (Blimpron 14, aka The Africa Squadron) also conducted mine-spotting and mine-sweeping operations in key Mediterranean ports and various escorts including the convoy carrying United States President Franklin D. Roosevelt and British Prime Minister Winston Churchill to the Yalta Conference in 1945. Airships from the ZP-12 unit took part in the sinking of the last U-Boat before German capitulation, sinking the U-881 on 6 May 1945 together with destroyers Atherton and Mobery. Other airships patrolled the Caribbean, Fleet Airship Wing Two, Headquartered at NAS Richmond, Florida, covered the Gulf of Mexico from Richmond and Key West, Florida, Houma, Louisiana, as well as Hitchcock and Brownsville, Texas. FAW 2 also patrolled the northern Caribbean from San Julian, the Isle of Pines (now called Isla de la Juventud) and Guantánamo Bay, Cuba as well as Vernam Field, Jamaica. Navy blimps of Fleet Airship Wing Five, (ZP-51) operated from bases in Trinidad, British Guiana and Paramaribo, Suriname. Fleet Airship Wing Four operated along the coast of Brazil. Two squadrons, VP-41 and VP-42 flew from bases at Amapá, Igarapé-Açu, São Luís Fortaleza, Fernando de Noronha, Recife, Maceió, Ipitanga (near Salvador, Bahia), Caravelas, Vitória and the hangar built for the Graf Zeppelin at Santa Cruz, Rio de Janeiro. Fleet Airship Wing Three operated squadrons, ZP-32 from Moffett Field, ZP-31 at NAS Santa Ana, and ZP-33 at NAS Tillamook, Oregon. Auxiliary fields were at Del Mar, Lompoc, Watsonville and Eureka, California, North Bend and Astoria, Oregon, as well as Shelton and Quillayute in Washington. From 2 January 1942 until the end of war airship operations in the Atlantic, the blimps of the Atlantic fleet made 37,554 flights and flew 378,237 hours. Of the over 70,000 ships in convoys protected by blimps, only one was sunk by a submarine while under blimp escort. The Soviet Union flew 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 flights with 300 metric tons of cargo until 1945. On 1 February 1945, the Soviets constructed a second airship, a Pobeda-class (Victory-class) unit (used for mine-sweeping and wreckage clearing in the Black Sea) that crashed on 21 January 1947. Another W-class - W-12bis Patriot - was commissioned in 1947 and was mostly used until the mid 1950s for crew training, parades and propaganda. Postwar period One of the Goodyear Tire and Rubber Company's blimp fleet, being replaced by Zeppelin NT semirigids Although airships are no longer used for major cargo and passenger transport, they are still used for other purposes such as advertising, sightseeing, surveillance, research and advocacy. In the 1980s, Per Lindstrand and his team introduced the GA-42 airship, the first airship to use fly-by- wire flight control, which considerably reduced the pilot's workload. The world's largest thermal airship () was constructed by the Per Lindstrand company for French botanists in 1993. The AS-300 carried an underslung raft, which was positioned by the airship on top of tree canopies in the rain forest, allowing the botanists to carry out their treetop research without significant damage to the rainforest. When research was finished at a given location, the airship returned to pick up and relocate the raft.Thermal Airships , Lindstrand Technologies. In June 1987, the U.S. Navy awarded a US$168.9 million contract to Westinghouse Electric and Airship Industries of the UK to find out whether an airship could be used as an airborne platform to detect the threat of sea-skimming missiles, such as the Exocet.. At 2.5 million cubic feet, the Westinghouse/Airship Industries Sentinel 5000 (Redesignated YEZ-2A by the U. S. Navy) prototype design was to have been the largest blimp ever constructed.. Additional funding for the Naval Airship Program was killed in 1995 and development was discontinued. The CA-80 airship, which was produced in 2000 by Shanghai Vantage Airship Manufacture Co., Ltd., had a successful trial flight in September 2001. This was designed for advertisement and propagation, air-photo, scientific test, tour and surveillance duties. It was certified as a grade-A Hi-Tech introduction program (No. 20000186) in Shanghai. The CAAC authority granted a type design approval and certificate of airworthiness for the airship.. In the 1990s the Zeppelin company returned to the airship business. Their new model, designated the Zeppelin NT, made its maiden flight on 18 September 1997. there were four NT aircraft flying, a fifth was completed in March 2009 and an expanded NT-14 (14,000 cubic meters of helium, capable of carrying 19 passengers) was under construction. One was sold to a Japanese company, and was planned to be flown to Japan in the summer of 2004. Due to delays getting permission from the Russian government, the company decided to transport the airship to Japan by sea. One of the four NT craft is in South Africa carrying diamond detection equipment from De Beers, an application at which the very stable low vibration NT platform excels. The project included design adaptations for high temperature operation and desert climate, as well as a separate mooring mast and a very heavy mooring truck. NT-4 belonged to Airship Ventures of Moffett Field, Mountain View in the San Francisco Bay Area, and provided sight-seeing tours. Blimps are used for advertising and as TV camera platforms at major sporting events. The most iconic of these are the Goodyear Blimps. Goodyear operates three blimps in the United States, and The Lightship Group, now The AirSign Airship Group, operates up to 19 advertising blimps around the world. Airship Management Services owns and operates three Skyship 600 blimps. Two operate as advertising and security ships in North America and the Caribbean. Airship Ventures operated a Zeppelin NT for advertising, passenger service and special mission projects. They were the only airship operator in the U.S. authorized to fly commercial passengers, until closing their doors in 2012. Skycruise Switzerland AG owns and operates two Skyship 600 blimps. One operates regularly over Switzerland used on sightseeing tours. The Spirit of Dubai approaches its motorized mooring mast The Switzerland-based Skyship 600 has also played other roles over the years. For example, it was flown over Athens during the 2004 Summer Olympics as a security measure. In November 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 world's largest man-made islands created as a residential complex. Los Angeles-based Worldwide Aeros Corp. produces FAA Type Certified Aeros 40D Sky Dragon airships.. In May 2006, the U.S. Navy began to fly airships again after a hiatus of nearly 44 years. The program uses a single American Blimp Company A-170 nonrigid airship, with designation MZ-3A. Operations focus on crew training and research, and the platform integrator is Northrop Grumman. The program is directed by the Naval Air Systems Command and is being carried out at NAES Lakehurst, the original centre of U.S. Navy lighter-than-air operations in previous decades. In November 2006 the U.S. Army bought an A380+ airship from American Blimp Corporation through a Systems level contract with Northrop Grumman and Booz Allen Hamilton. The airship started flight tests in late 2007, with a primary goal of carrying of payload to an altitude of under remote control and autonomous waypoint navigation. The program will also demonstrate carrying of payload to The platform could be used for Multi- Intelligence collections. In 2008, the CA-150 airship was launched by Vantage Airship. This is an improved modification of model CA-120 and completed manufacturing in 2008. With larger volume and increased passenger capacity, it is the largest manned nonrigid airship in China at present.. An airship was prominently featured in the James Bond film A View to a Kill, released in 1985. The Skyship 500 had the livery of Zorin Industries.. In late June 2014 the Electronic Frontier Foundation flew the GEFA-FLUG AS 105 GD/4 blimp AE Bates (owned by, and in conjunction with, Greenpeace) over the NSA's Bluffdale Utah Data Center in protest. =Postwar projects= Hybrid designs such as the Heli-Stat airship/helicopter, the Aereon aerostatic/aerodynamic craft, and the CycloCrane (a hybrid aerostatic/rotorcraft), struggled to take flight. The Cyclocrane was also interesting in that the airship's envelope rotated along its longitudinal axis. In 2005, a short-lived project of the U.S. Defense Advanced Research Projects Agency (DARPA) was Walrus HULA, which explored the potential for using airships as long-distance, heavy lift craft."Contractors for Walrus Program announced" , press release, Defense Advanced Research Projects Agency, 26 August 2005."US CBO Gives OK to HULA Airships for Airlift", Defense Industry Daily, 21 October 2005. The primary goal of the research program was to determine the feasibility of building an airship capable of carrying of payload a distance of and land on an unimproved location without the use of external ballast or ground equipment (such as 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. Congress removed funding for Walrus HULA in 2006. Modern airships Military airships In 2010, the U.S. Army awarded a $517 million (£350.6 million) contract to Northrop Grumman and partner Hybrid Air Vehicles to develop a Long Endurance Multi-Intelligence Vehicle (LEMV) system, in the form of three HAV 304s."The Difference Engine: Not all hot air"", The Economist, July 29th 2010"Photo Release — Northrop Grumman Awarded $517 Million Agreement for US Army Airship With Unblinking Eye" , Northrup Grumman, June 14, 2010, access date July 29, 2010 The project was cancelled in February 2012 due to it being behind schedule and over budget; also the forthcoming U.S. withdrawal from Afghanistan where it was intended to be deployed.InsideDefense.com - February 13, 2013: Army Deflates LEMV Airship; Cost And Schedule Cited Following this the Hybrid Air Vehicles HAV 304 Airlander 10 was repurchased by Hybrid Air Vehicles then modified and reassembled in Bedford, UK, and renamed the Airlander 10. It is currently being tested in readiness for its UK flight test programme. , a French company, manufactures and operates airships and aerostats. For 2 years, A-NSE has been testing its airships for the French Army. Airships and aerostats are operated to provide intelligence, surveillance, and reconnaissance (ISR) support. Their airships include many innovative features such as water ballast take-off and landing systems, variable geometry envelopes and thrust–vectoring systems.A-N400 (A-NSE company) The U.S. government has funded two major projects in the high altitude arena. The Composite Hull High Altitude Powered Platform (CHHAPP) is sponsored by U.S. Army Space and Missile Defense Command. This aircraft is also sometimes called HiSentinel High-Altitude Airship. This prototype ship made a five-hour test flight in September 2005. The second project, the high- altitude airship (HAA), is sponsored by DARPA. In 2005, DARPA awarded a contract for nearly $150 million to Lockheed Martin for prototype development. First flight of the HAA was planned for 2008 but suffered programmatic and funding delays. The HAA project evolved into the High Altitude Long Endurance- Demonstrator (HALE-D). The U.S. Army and Lockheed Martin launched the first- of-its kind HALE-D on July 27, 2011. After attaining an altitude of , due to an anomaly, the company decided to abort the mission. The airship made a controlled descent in an unpopulated area of southwest Pennsylvania. On 31 January 2006 Lockheed Martin made the first flight of their secretly built hybrid airship designated the P-791. The design is very similar to the SkyCat, unsuccessfully promoted for many years by the British company Advanced Technologies Group (ATG). Dirigibles have been used in the War in Afghanistan for reconnaissance purposes, as they allow for constant monitoring of a specific area through cameras mounted on the airships. Passenger transport 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 semirigids. 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. 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 2008, Airship Ventures Inc. began operations from Moffett Federal Airfield near Mountain View, California and until November 2012 offered tours of the San Francisco Bay Area for up to 12 passengers. Exploration In November 2005, De Beers, a diamond mining company, launched an airship exploration program over the remote Kalahari desert. A Zeppelin NT, equipped with a Bell Geospace gravity gradiometer, was used to find potential diamond mines by scanning the local geography for low-density rock formations, known as 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. Thermal airships Thermal airship (manufacturer GEFA- FLUG/Germany) 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 inflated with hot air instead of helium to provide the lifting force. A small gondola, carrying the pilot and passengers, a small engine, and the burners to provide the hot air are suspended below the envelope, beneath an opening through which the burners protrude. Hot-air airships typically cost less to buy and maintain than modern helium-based blimps, and can be quickly deflated after flights. This makes them easy to carry in trailers or trucks and inexpensive to store. They are usually very slow moving, with a typical top speed of 25–30 km/h (15–20 mph, 6.7–8.9 m/s). 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. Unmanned remotes Remote-controlled (RC) airships, a type of unmanned aerial system (UAS), are sometimes used for commercial purposes such as advertising and aerial video and photography as well as recreational purposes. They are particularly common as an advertising mechanism at indoor stadiums. While RC airships are sometimes flown outdoors, doing so for commercial purposes is illegal in the US.FAA Docket FAA-2006-25714 , Federal Aviation Authority. Commercial use of an unmanned airship must be certified under part 121. Current design projects The largest airship, the LZ 129 Hindenburg at 245 meters length and 41 meters diameter, dwarfs the size of the largest historic and modern passenger and cargo aeroplanes. Today, with large, fast, and more cost-efficient fixed-wing aircraft and helicopters, 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 possible 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 generally require only small and flexible craft, and have thus generally been better fitted for cheaper (non-passenger) blimps. Heavy lifting It has periodically been suggested that airships could be employed for cargo transport, especially delivering extremely heavy loads to areas with poor infrastructure over great distances. This has also been called roadless trucking."Roadless trucking" , Dynalifter. Also, airships could be used for heavy lifting over short distances (e.g. on construction sites); this is described as heavy-lift, short-haul."Boeing and SkyHook International to Build JHL-40 Heavy-Lift Rotorcraft", press release, 8 July 2008. In both cases, the airships are heavy haulers. 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, CargoLifter AG built the world's largest self-supporting hall, measuring long, wide and high about south of Berlin. In May 2002, the project was stopped for financial reasons; the company had to file bankruptcy. The enormous CargoLifter hangar was later converted to house the Tropical Islands Resort. Although no rigid airships are currently used for heavy lifting, hybrid airships are being developed for such purposes. AEREON 26, tested in 1971, was described in John McPhee's The Deltoid Pumpkin Seed. An impediment to the large-scale development of airships as heavy haulers has been figuring out how they can be used in a cost-efficient way. In order to have a significant economic advantage over ocean transport, cargo airships must be able to deliver their payload faster than ocean carriers but more cheaply than airplanes. William Crowder, a fellow at the Logistics Management Institute, has calculated that cargo airships are only economical when they can transport 500 to 1,000 tons, approximately the same as a super-jumbo aircraft. The large initial investment required to build such a large airship has been a hindrance to production, especially given the risk inherent in a new technology. The chief commercial officer of the company hoping to sell the LMH-1, a cargo airship currently being developed by Lockheed Martin, believes that airships can be economical in hard-to-reach locations such as mining operations in northern Canada that currently require ice roads. Metal-clad airships A metal-clad airship has a very thin metal envelope, rather than the usual fabric. The shell may be either internally braced or monocoque as in the ZMC-2, which flew many times in the 1920s, the only example ever to do so. The shell may be gas-tight as in a non-rigid blimp, or the design may employ internal gas bags as in a rigid airship. Compared to a fabric envelope the metal cladding is expected to be more durable. Hybrid airships A hybrid airship is a general term for an aircraft that combines characteristics of heavier-than-air (aeroplane 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. Most airships, when fully loaded with cargo and fuel, are usually ballasted to be heavier than air, and thus must use their propulsion system and shape to create aerodynamic lift, necessary to stay aloft. All airships can be operated to be slightly heavier than air at periods during flight (descent). Accordingly, the term "hybrid airship" refers to craft that obtain a significant portion of their lift from aerodynamic lift or other kinetic means. For example, the Aeroscraft is a buoyancy assisted air vehicle that generates lift through a combination of aerodynamics, thrust vectoring and gas buoyancy generation and management, and for much of the time will fly heavier than air. Aeroscraft is Worldwide Aeros Corporation's continuation of DARPA's now cancelled Walrus HULA (Hybrid Ultra Large Aircraft) project. The Patroller P3 hybrid airship developed by Advanced Hybrid Aircraft Ltd, BC, Canada, is a relatively small (85,000 feet3 = 2,400 m3) buoyant craft, manned by the crew of 5 and with the endurance of up to 72 hours. The flight-tests with the 40% RC scale model proved that such a craft can be launched and landed without a large team of strong ground- handlers.Vollrath, Jurgen. From the Hindenburg airship to the Goodyear Blimp – and now Hybrid Aircraft. Exponential Technology Counsel, Episode 39, 2016 Design features a special “winglet” for aerodynamic lift control.Blake, Bruce. Patroller 3 hybrid aircraft. Onboard System specifications. AHA Ltd web- publication. January, 2017 Airships in space exploration Artist's rendering of a NASA manned floating outpost on Venus Airships have been proposed as a potential cheap alternative to surface rocket launches for achieving Earth orbit. JP Aerospace have proposed the Airship to Orbit project, which intends to float a multi-stage airship up to mesospheric altitudes of 55 km (180,000 ft) and then use ion propulsion to accelerate to orbital speed. At these heights, air resistance would not be a significant problem for achieving such speeds. The company has not yet built any of the three stages. NASA have proposed the High Altitude Venus Operational Concept, which comprises a series of five missions including manned missions to the atmosphere of Venus in airships. Pressures on the surface of the planet are too high for human habitation, but at a specific altitude the pressure is equal to that found on Earth and this makes Venus a potential target for human colonization. Hypothetically, there could be an airship lifted by a vacuum—that is, by material that can contain nothing at all inside but withstand the atmospheric pressure from the outside. It is, at this point, science fiction, although NASA has posited that some kind of vacuum airship could eventually be used to explore the surface of Mars.The Age of the Airship May Be Dawning Again Comparison with heavier-than-air aircraft The advantage of airships over aeroplanes is that static lift sufficient for flight is generated by the lifting gas and requires no engine power. This was an immense advantage before the middle of World War I and remained an advantage for long-distance or long-duration operations until World War II. Modern concepts for high-altitude airships include photovoltaic cells to reduce the need to land to refuel, thus they can remain in the air until consumables expire. This similarly reduces or eliminates the need to consider variable fuel weight in buoyancy calculations. The disadvantages are that an airship has a very large reference area and comparatively large drag coefficient, thus a larger drag force compared to that of aeroplanes and even helicopters. Given the large frontal area and wetted surface of an airship, a practical limit is reached around . Thus airships are used where speed is not critical. The lift capability of an airship is equal to the buoyant force minus the weight of the airship. This assumes standard air-temperature and pressure conditions. Corrections are usually made for water vapor and impurity of lifting gas, as well as percentage of inflation of the gas cells at liftoff.Ausrotas, R. A., "Basic Relationships for LTA Technical Analysis," MIT Flight Transportation Library, 1975 Based on specific lift (lifting force per unit volume of gas), the greatest static lift is provided by hydrogen (11.15 N/m3 or 71 lbf/1000 cu ft) with helium (10.37 N/m3 or 66 lbf/1000 cu ft) a close second.Layton, D. M., Basic Aerostatics - A Tutorial, 1985 In addition to static lift, an airship can obtain a certain amount of dynamic lift from its engines. Dynamic lift in past airships has been about 10% of the static lift. Dynamic lift allows an airship to "take off heavy" from a runway similar to fixed-wing and rotary-wing aircraft. This requires additional weight in engines, fuel, and landing gear, negating some of the static lift capacity. The altitude at which an airship can fly largely depends on how much lifting gas it can lose due to expansion before stasis is reached. The ultimate altitude record for a rigid airship was set in 1917 by the L-55 under the command of Hans-Kurt Flemming when he forced the airship to attempting to cross France after the "Silent Raid" on London. The L-55 lost lift during the descent to lower altitudes over Germany and crashed due to loss of lift.Robinson (1994), p. 294. While such waste of gas was necessary for the survival of airships in the later years of World War I, it was impractical for commercial operations, or operations of helium-filled military airships. The highest flight made by a hydrogen-filled passenger airship was on the Graf Zeppelin's around-the-world flight."Honors to Dr. Hugo Eckener: The First Airship Flight Around the World", National Geographic, Vol. LVII, No. 6, June 1930, p. 679. The greatest disadvantage of the airship is size, which is essential to increasing performance. As size increases, the problems of ground handling increase geometrically.Brooks 1992 pp. 7–8 As the German Navy changed from the P class of 1915 with a volume of over to the larger Q class of 1916, the R class of 1917, and finally the W class of 1918, at almost ground handling problems reduced the number of days the Zeppelins were able to make patrol flights. This availability declined from 34% in 1915, to 24.3% in 1916 and finally 17.5% in 1918.Robinson (1994), p. 373. So long as the power-to- weight ratios of aircraft engines remained low and specific fuel consumption high, the airship had an edge for long-range or -duration operations. As those figures changed, the balance shifted rapidly in the aeroplane's favour. By mid-1917, the airship could no longer survive in a combat situation where the threat was aeroplanes. By the late 1930s, the airship barely had an advantage over the aeroplane on intercontinental over-water flights, and that advantage had vanished by the end of World War II. This is in face-to-face tactical situations. Currently, a high-altitude airship project is planned to survey hundreds of kilometres as their operation radius, often much farther than the normal engagement range of a military aeroplane. For example, a radar mounted on a vessel platform high has radio horizon at range, while a radar at altitude has radio horizon at range. This is significantly important for detecting low-flying cruise missiles or fighter-bombers. Safety The most commonly used lifting gas, helium, is inert and therefore presents no fire risk.Stwertka, Albert, Guide to the Elements: Revised Edition. New York; Oxford University Press, 1998, p. 24. A series of vulnerability tests were done by the UK Defence Evaluation and Research Agency DERA on a Skyship 600. Since the internal gas pressure was maintained at only 1–2% above the surrounding air pressure, the vehicle proved highly tolerant to physical damage or to attack by small-arms fire or missiles. Several hundred high- velocity bullets were fired through the hull, and even two hours later the vehicle would have been able to return to base. Ordnance passed through the envelope without causing critical helium loss. In all instances of light armament fire evaluated under both test and live conditions, the airship was able to complete its mission and return to base.High Safety Level (page 5) and Structural Vulnerability Tests (page 7). World Skycat. Retrieved 25 April 2008. See also *Airborne aircraft carrier *Aircruise *Airship hangar *Barrage balloon *Evolutionary Air and Space Global Laser Engagement *High- altitude platform station *Hyperion, fictional airship type. *List of airship accidents *List of British airships *List of current airships in the United States *List of Zeppelins *Mystery airship *Stratellite *SVAM CA-80 *Worldwide Aeros Corp *Zeppelin mail Notes References Citations Bibliography *Althoff, William F., USS Los Angeles: The Navy's Venerable Airship and Aviation Technology, 2003, *Ausrotas, R. A., "Basic Relationships for LTA Technical Analysis," Proceedings of the Interagency Workshop on Lighter-Than-Air Vehicles, Massachusetts Institute of Technology Flight Transportation Library, 1975 *Archbold, Rich and Ken Marshall, Hindenburg, an Illustrated History, 1994 *Bailey, D. B., and Rappoport, H. K., Maritime Patrol Airship Study, Naval Air Development Center, 1980 *Botting, Douglas, Dr. Eckener's Dream Machine. New York Henry Hold and Company, 2001, Burgess, Charles P., Airship Design, (1927) 2004 *Cross, Wilbur, Disaster at the Pole, 2002 *Dick, Harold G., with Robinson, Douglas H., Graf Zeppelin & Hindenburg, Washington, D.C., Smithsonian Institution Press, 1985, ISBN Ege, L.; Balloons and Airships, Blandford (1973). *Frederick, Arthur, et al., Airship saga: The history of airships seen through the eyes of the men who designed, built, and flew them, 1982, *Griehl, Manfred and Joachim Dressel, Zeppelin! The German Airship Story, 1990, *Higham, Robin, The British Rigid Airship, 1908–1931: A study in weapons policy, London, G. T. Foulis, 1961, *Keirns, Aaron J, "America's Forgotten Airship Disaster: The Crash of the USS Shenandoah", Howard, Little River Publishing, 1998, . *Khoury, Gabriel Alexander (Editor), Airship Technology (Cambridge Aerospace Series), 2004, McKee, Alexander, Ice crash, 1980, Morgala, Andrzej, Sterowce w II Wojnie Światowej (Airships in the Second World War), Lotnictwo, 1992 *Mowthorpe, Ces, Battlebags: British Airships of the First World War, 1995 Robinson, Douglas H., Giants in the Sky, University of Washington Press, 1973, *Robinson, Douglas H., The Zeppelin in Combat: A history of the German Naval Airship Division, 1912–1918, Atglen, PA, Shiffer Publications, 1994, *Smith, Richard K. The Airships Akron & Macon: flying aircraft carriers of the United States Navy, Annapolis MD, US Naval Institute Press, 1965, *Shock, James R., Smith, David R., The Goodyear Airships, Bloomington, Illinois, Airship International Press, 2002, *Sprigg, C., The Airship: Its design, history, operation and future, London 1931, Samson Low, Marston and Company. Toland, John, Ships in the Sky, New York, Henry Hold; London, Muller, 1957, *Vaeth, J. Gordon, Blimps & U-Boats, Annapolis, Maryland, US Naval Institute Press, 1992, *Ventry, Lord; Kolesnik, Eugene, Jane's Pocket Book 7: Airship Development, 1976 *Ventry, Lord; Koesnik, Eugene M., Airship Saga, Poole, Dorset, Blandford Press, 1982, p. 97 *Winter, Lumen; Degner, Glenn, Minute Epics of Flight, New York, Grosset & Dunlap, 1933. *US War Department, Airship Aerodynamics: Technical Manual, (1941) 2003, External links * Aeronautics Gases "
"The Bachem Ba 349 Natter (Usually mis-translated as "Viper" or "Adder". However, the corresponding German terms (Viper and Otter) always refer to venomous snakes. Natter traditionally denotes a non-venomous snake, especially the common grass-snake of Europe (Natrix natrix). Technically, the literal English translation of Natter would be "colubrid"; no corresponding vernacular term exists in English, since rather than distinguishing "adders" from non- venomous snakes, German developed a venomous and a non-venomous variant of its equivalent of "adder".) was a World War II German point-defence rocket-powered interceptor, which was to be used in a very similar way to a manned surface- to-air missile. After a vertical take-off, which eliminated the need for airfields, most of the flight to the Allied bombers was to be controlled by an autopilot. The primary role of the relatively untrained pilot was to aim the aircraft at its target bomber and fire its armament of rockets. The pilot and the fuselage containing the rocket-motor would then land using separate parachutes, while the nose section was disposable. The first manned vertical take-off flight, on 1 March 1945, ended in the death of the test pilot, Lothar Sieber. Development In 1943 Luftwaffe air superiority was being challenged by the Allies over the Reich and radical innovations were required to overcome the crisis. Surface-to-air missiles appeared to be a promising approach to counter the Allied strategic bombing offensive; a variety of projects were started, but invariably problems with the guidance and homing systems prevented any of these from attaining operational status.Dryden 1945, pp. 1–11. Providing the missile with a pilot, who could operate a weapon during the brief terminal approach phase, offered a solution. Submissions for a simple target defence interceptor were requested by the Luftwaffe in early 1944 under the umbrella of the , literally "Fighter Emergency Program".Proctor 1945Pabst 1984, p. 166. A number of simple designs were proposed, including the Heinkel P.1077 Julia, in which the pilot lay prone (on his stomach), to reduce the frontal area. The Julia was the front-runner for the contract. The initial plan was to launch the aircraft vertically, but this concept was later changed to a conventional horizontal take-off from a tricycle-wheeled trolley, similar to that used by the first eight prototypes of the Arado Ar 234 jet reconnaissance bomber.Bachem 1944b Bachem's proposal Erich Bachem's BP-20 ("Natter") was a development from a design he had worked on at Fieseler, the Fi 166 concept, but considerably more radical than the other submissions.Green 1970, p. 65. It was built using glued and nailed wooden parts with an armour- plated bulkhead and bulletproof glass windshield at the front of the cockpit. The initial plan was to power the machine with a Walter HWK 109-509A-2 rocket motor; however, only the 109-509A-1, as used in the Me 163, was available.Gooden 2006, pp. 124–127. It had a sea level thrust variable between at "idle" to at full power, with the Natter's intended quartet of rear flank- mount Schmidding SG34 solid fuel rocket boosters used in its vertical launch to provide an additional thrust for 10 seconds before they burned out and were jettisoned. The experimental prototypes slid up a -tall vertical steel launch tower for a maximum sliding length of in three guideways, one for each wing tip and one for the lower tip of the ventral tail fin. By the time the aircraft left the tower it was hoped that it would have achieved sufficient speed to allow its aerodynamic surfaces to provide stable flight.Reyle 1998, pp. 70–73.Bachem-Werk 1944, pp. 183–185. Under operational conditions, once the Natter had left the launcher, it would be guided to the proximity of the Allied bombers by an autopilot with the possibility of an added beam guidance similar to that used in some V-2 rocket launches. Only then would the pilot take control, aim and fire the armament, which was originally proposed to be a salvo of nineteen 55mm R4M rockets.Bachem 1944a Later, 28 R4Ms or a number of the larger, 73mm Henschel Hs 297 Föhn rockets were suggested,Köster 1944.Christopher, John. The Race for Hitler's X-Planes (The Mill, Gloucestershire: History Press, 2013), p.153. with either variety of unguided rocket fired from the Natter's nose-mounted cellular launch tubes. The Natter was intended to fly up and over the bombers, by which time its Walter motor would probably be out of propellant. Following its one-time attack with its rockets, the pilot would dive his Natter, now effectively a glider, to an altitude of around , flatten out, release the nose of the aircraft and a small braking parachute from the rear fuselage. The fuselage would decelerate and the pilot would be ejected forwards by his own inertia and land by means of a personal parachute.Christopher, p.153. In an early proposal in August 1944, the Natter design had a concrete nose; it was suggested that the machine might ram a bomber, but this proposal was subsequently withdrawn in later Project Natter outlines. Bachem stated clearly in the initial proposal that the Natter was not a suicide weapon and much effort went into designing safety features for the pilot. However, owing to the potential dangers for the pilot inherent in the operation of this precarious aircraft, the Natter is sometimes listed as a suicide craft.German Suicidal Aircraft The design had one decisive advantage over its competitors – it eliminated the necessity to land an unpowered gliding machine at an airbase, which, as the history of the Me 163 rocket aircraft had clearly demonstrated, made an aircraft extremely vulnerable to attack by Allied fighters. Modifications Heinrich Himmler became interested in Bachem's design. The Reichsführer-SS granted Bachem an interview and fully supported the project. In the middle of September 1944 the Technical Office of the Waffen-SS made an order for Bachem to develop and manufacture the Natter at his Waldsee factory.Grieger 1990, p. 26. In December 1944 the project came largely under the control of the SS and Hans Kammler.Felkin 1945 This decision is said to have been the only time the SS significantly interfered with aircraft design and air fighting strategy.Speer 2001, p. 215. Early-on in the project, the Reichsluftfahrtministerium (RLM) undertook an engineering assessment of the Natter, which it reported on 28 October 1944.Magerstädt 1944 The Natter was designed to be built by unskilled labor with poor-quality tools and inexpensive material. Various stringent economies were imposed on an already frugal design. The Natter had no landing gear, which saved weight, expense, and construction time. Consequently, one of the most unusual features of the machine was the escape of the pilot and recovery of the machine. The proposed sequence of these events was as follows: After the attack, the Natter might dive to a lower altitude and flatten out into level flight. The pilot would then proceed with a well-practised escape sequence. He would open the cockpit canopy latch, which would allow the canopy to flick backwards on its hinge in the airstream. Next, the pilot would undo his seat belt and remove his feet from the rudder pedal stirrups. By squeezing a lever mounted on the control column, he would release a lock at the base of the column, which would allow him to tilt the column forwards where it could engage in and undo a safety latch for the nose release mechanism. He would then lean a little further forward and pull a lever hinged near the floor at the front of the cockpit, freeing the nose section, which self-jettisoned as a result of the reduced aerodynamic pressure at the front of the fuselage. As the nose section separated, it was intended to briefly pull on two cables that released a small ribbon parachute stored on the starboard side of the rear fuselage. The parachute subsequently opened and decelerated the Natter. The pilot would be ejected from the cockpit by his own inertia and as soon as he was clear of the fuselage, he would open his personal parachute and descend to the ground.Gooden 2006, pp. 101–102. A parachute was to eject the valuable Walter rocket motor from the rear, which would decelerate the aircraft and eject the pilot with inertia, but associated problems were still not fully resolved prior to the war's end. Professor Wilhelm Fuchs reportedly calculated the Natter's aerodynamics at the Technische Hochschule, Aachen using a large analog computer. Wind tunnel testing on a wooden model, scaled to 40% of full size, was performed at the Deutsche Versuchsanstalt für Luftfahrt (DVL), the Institute for Aerodynamics at Berlin-Adlershof in September 1944 at speeds up to 504 km/h. Results from these tests were reported in January 1945 to the Bachem-Werk.Wacke 1945, p. 218. Further model tests were carried out at the Luftfahrtforschungsanstalt Hermann Göring (LFA) facility in Völkenrode- Braunschweig, at speeds close to Mach 1.Millikan 1945, p. 14. In March the Bachem-Werk simply received a statement that satisfactory flying qualities should be expected with speeds up to 1,100 km/h.Bratt 1945 Testing Construction of the first experimental prototype Natter, Versuchsmuster 1, was completed on 4 October 1944. V1 was subsequently referred to as Baumuster1 (BM1) and later still the "B" was dropped and the machine became known as the M1. Most subsequent prototypes were known by 'M' codes, as the later prototypes of the Heinkel He 162 were. Manned glider flights began on 3 November 1944. The first glider M1 was towed to around 3,000 m by a Heinkel He 111 bomber with a cable (Tragschlepp mode) at Neuburg an der Donau. The pilot was Erich Klöckner, who made all four documented Tragschlepp ("towed") flights. After carrying out the test programme of the M1, he bailed out and the machine crashed into the ground.Klöckner 1944 It was found that the towing cable, and in the case of the M3, the undercarriage interfered with the flight characteristics of the gliders and consequently the results were difficult to interpret. To clear any lingering doubts about the Natter in the glider mode, Hans Zübert made a daring free flight in the M8 on 14 February, and showed that the Natter was indeed a very good flying machine.Zübert 1945 The vertical take-off trials were conducted on high ground called the Ochsenkopf at the Truppenübungsplatz (military training area) Heuberg near Stetten am kalten Markt, Württemberg. The first successful unmanned vertical take-off from the experimental launch tower occurred on 22 December 1944. The test machine, the M16, was powered only by the Schmidding solid boosters,Christopher, p.154. as were all the early vertical launch trials. Up to and including 1 March 1945, 16 prototypes had been used, eight in glider trials and eight in VTO trials.Gooden 2006, pp. 114–115. Manned test flight By January 1945 Bachem was under pressure from the authorities in Berlin to carry out a manned flight by the end of February.de Bok 1978, pp. 104–109. On 25 February, M22 was in the experimental launch tower. It was as complete an operational machine as possible with the Walter HWK 109-509 A1 motor installed for the first time. A dummy pilot was in the cockpit. Lift-off from the tower was perfect. The engineers and ground crew watched as the M22 ascended under the combined power of the four Schmidding boosters and the Walter motor, an estimated total thrust of . The nose separated as programmed and the dummy pilot descended safely under its personal parachute. The remainder of the fuselage came down under its two large salvage parachutes, but when it hit the ground the Walter liquid-propellant rocket motor's residual hypergolic propellants (T-Stoff oxidizer and C-Stoff fuel) exploded and the machine was destroyed.Lommel 1998, p. 92. Despite Bachem's concerns that the test programme had been significantly cut short, a young volunteer Luftwaffe test pilot, Lothar Sieber, climbed into the cockpit of the fully fuelled M23 on 1 March. The aircraft was equipped with an FM transmitter for the purpose of transmitting flight data from various monitoring sensors in the machine.Wilde 1945 A hard wire intercom appears to have been provided between Sieber and the engineers in the launch bunker using a system similar to that used in the manned glider flights. Around 1100 am, the M23 was ready for take-off. Low stratus clouds lay over the Ocksenkopf. The Walter liquid-fueled rocket motor built up to full thrust and Sieber pushed the button to ignite the four solid boosters. Initially, it rose vertically. at an altitude of about , the Natter suddenly pitched up into an inverted curve at about 30° to the vertical. At about the cockpit canopy was seen to fly off. The Natter continued to climb at high speed at an angle of 15° from the horizontal and disappeared into the clouds. The Walter motor stalled about 15 seconds after take-off. It is estimated the Natter reached , at which point it nose-dived and hit the ground with great force about 32 seconds later, some kilometres from the launch site.Bachem 1952, pp. 89–96. Unknown at the time, one of the Schmidding boosters failed to jettison and its remains were dug up at the crash site in 1998.Pallud 2011, pp. 2–21. The pilot was likely unconscious long before the crash. Bachem surmised Sieber had involuntarily pulled back on the control column under the effect of the 3 G acceleration. Examination of the canopy, which fell near the launch site, showed the tip of the latch was bent, suggesting it may not have been in the fully closed position at launch.Lommel 1998, photograph purporting to show the canopy from M23. The pilot's headrest had been attached to the underside of the canopy and as the canopy flew off the pilot's head would have snapped back suddenly about , hitting the solid wooden rear upper cockpit bulkhead, and either knocking Sieber unconscious or breaking his neck.Bachem-Werk 1945a The accident reinforced Bachem's long held belief that the take-off and flight in the vicinity of the target bombers should be fully automated. The canopy latch was strengthened and the headrest was attached to the backboard of the cockpit. Before the introduction of the autopilot in the test programme, the control column would have a temporary locking device on it, which would allow the machine to ascend vertically to at least and then be removed by the pilot."Aktennotiz: Stellungnahme zu der Erprobung M23 (Senkrechtstart der bemannte Triebswerkmachine)." Sonderkommando der Waffen SS (Waldsee-Württemberg), March 1945. The Walter motor probably ceased operation because the Natter was virtually upside-down and air may have entered the intake pipes in the propellant tanks, starving the motor.Gooden 2006, p. 81. Sieber had become the first man to take off vertically from the ground under pure rocket power, 16 years before Yuri Gagarin's Vostok 1 pioneering, peacetime orbital flight. Following Sieber's death, several pilots offered to take his place, and three more manned launches were performed in quick succession. The RLM now decided that the Natter had displayed an acceptable standard of reliability to warrant operational evaluation, and preparations were made for 10 fully armed aircraft at Kirchheim, near Stuttgart. Production The SS ordered 150 Natters, and the Luftwaffe ordered 50, but none were delivered by the end of the war. Much debate has surrounded the number of Natters built at the Bachem-Werk and their disposition. According to Bachem, 36 Natters were produced at the Bachem-Werk in Waldsee by the end of the war.Christopher, p.154, gives this number. Up to April 1945, 17 aircraft had been used in unmanned trials comprising five gliders, all slung under an He 111 in the Mistelschlepp configuration prior to launch, and 12 VTO examples. Five aircraft were prepared for manned trials, four gliders and one VTO version. The M3 was flown twice, and then rebuilt at which time it was given the new code BM3a but was never flown. The total number of launches to early April 1945 was 22, as was the total number of Natters constructed up to that time. Bachem reported further that there were 14 more finished or almost finished aircraft in April 1945. Four of these were prototype A1 operational Natters built for test launching from a wooden pole launcher, which had been designed for field deployment.Bachem-Werk 1945b This new launcher was also constructed on the Heuberg, not far from the experimental steel tower. There is documentary evidence for two pole launches in April but not three as claimed by Bachem in his post-war presentation. The documentation for this third flight may have been destroyed by the SS at war's end. Ten A1 operational Natters, called K-Maschinen, were constructed for the Krokus-Einsatz ("Operation Crocus"). The fate of these 14 A1 Natters was as follows: Three were fired from the vertical launch tower according to Bachem, four were burnt at Waldsee, two were burnt at Lager Schlatt, Oetztal, Austria, four were captured by US troops at Sankt Leonhard im Pitztal, Austria and one, which had been sent as a sample model to a new factory in Thuringia, was captured by the Red Army. Consequently, the total of 36 test and operational aircraft constructed at the Bachem-Werk can be accounted for. However, Natter carcasses were used for a variety of ground-based purposes; for example, as a static booster rocket, armament and strength testing and pilot seat position tests. Some fuselages were reused after flight testing; for example, the M5, 6 and 7.Bachem-Werk 1945c Of the four Natters captured at Sankt Leonhard im Pitztal, two went to the United States.Gooden 2006, pp. 115–120. Only one original Natter built in Germany in the Second World War survives in storage at the Paul E. Garber Preservation, Restoration, and Storage Facility in Suitland, Maryland, under the auspices of the Smithsonian Institution. The fate of the other Natter brought to the US is unknown. There is no documentary evidence that a Natter was ever flown from Muroc Field. The tail section of one of the Natters at Sankt Leonhard im Pitztal was broken off while it still rested on its trailer.Gooden, Brett. Natter photographic archive, 2011. Stability In early February 1945 the positions of the centre of gravity for the A1 operational machine during its flight profile were giving the RLM and the SS cause for concern. They wanted these figures to be decided upon for the upcoming construction of the A1 aircraft for Krokus-Einsatz (Operation Crocus), the field deployment of the Natter.Aktenvermerk über eine Besprechung am 8-2-45, "Für die Flugeigenschaftsprüfung…" (in German). Berlin-Aldershof: DVL, February 1945. The position of the centre of gravity is expressed as a percentage of the chord (distance between the leading and trailing edges) of the main wing. Thus 0% is the leading edge and 100% is the trailing edge. In the manned glider trials the centre of gravity had been varied between 20 and 34%. At a meeting of engineers held on 8 February, the variations in the centre of gravity expected in the A1 Krokus machine were discussed. At take- off with the weight of the four solid boosters, the centre of gravity would be brought back to 65%, but after releasing these rockets it would move forwards to 22%. The free flight by Zübert on 14 February had showed unequivocally that the little Natter had excellent flying characteristics as a glider. The centre of gravity problem was solved initially by the addition of one-metre-square auxiliary tailfins that were released simultaneously with the jettisoning of the boosters. The Krokus aircraft had vanes that would direct the Walter rocket exhaust gases so as to assist vehicle stabilisation at low speed similar to those used in the V-2 rocket. Legacy A captured Ba 349 A1 Natter on display for Open Days at Freeman Field, Indiana September 1945. The swastikas are neither authentic nor positioned according to German military specifications. French forces had captured Waldsee by 25 April 1945 and presumably took control of the Bachem-Werk.De Lattre de Tassigny 1952, p. 493 Shortly before the French troops arrived, a group of Bachem-Werk personnel set out for Austria with five A1 Natters on trailers.Lommel 2000, p. 112.Gooden 2006, p. 106 At Bad Wörishofen, the group waited for another squad retreating from Nabern unter Teck with one completed Natter. Both groups then set out for the Austrian Alps. One group with two Natters ended up at the junction of the river Inn and one of its tributaries, the Ötztaler Ache, at Camp Schlatt. The other group went to St. Leonhard im Pitztal with four aircraft. US troops captured the first group at Camp Schlatt around 4 May and the second group on the following day.Gooden 2006, pp. 106–107. At some time during the project, the Bachem-Werk was ordered to give complete details of the BP-20 Natter to the Japanese, but there was doubt over whether they had received them. They were, however, known to have a general knowledge of the Natter and showed considerable interest in the project. Operation Krokus launch pads at Hasenholz wood An operational launch site for the first Ba 349A-1 operational Natters under the code name Operation Krokus was being established in a small wooded area called Hasenholz, south of the Stuttgart to Munich autobahn and to the east of Nabern unter Teck. Around the end of February and the beginning of March the Todt Organisation was in action, constructing each set of the trios of concrete foundations (or "footings") for the launch towers. These three launch pads and their towers were arranged at the corners of an equilateral triangle, 120 m per side. The specific locations are said to be , and .Google Earth. (Just south of Holzmaden, three Krokus launch pads marked and photographs of each pad shown). In the centre of each of the three concrete footings is a square hole approximately 50 centimeters deep, which once served as the foundation for the launch tower. Beside each hole is a pipe, cut off at ground level, which was probably once a cable pit. These three concrete pads were noticed by a surveyor in the autumn of 1945, but not rediscovered until 1999.Lommel 1951, pp. 128–136 In March 1945 eight pilots, who were experienced, mostly highly decorated and volunteers for the first operational flights, started training at the Lager Heuberg. This training continued until the first half of April at which time they moved to the Hasenholz operational area.Lommel 1951, pp. 108–111 The first three manned and fully armed A1 Krokus examples were scheduled to be launched from 20 April, which was Hitler's birthday. But on that day the US 10th Armored Division drove its tanks into Kirchheim unter Teck to the northwest of Hasenholz wood. The next day it crossed the autobahn and headed straight for the Natter operational area. The Natter group subsequently retreated to Waldsee. File:Bachem Ba 349 Natter launch pad.jpgLast preserved Bachem Ba 349 Natter launch pad in the Hasenholz. File:Bachem Ba 349 Natter launch pad ruins.jpgRuins of the two Bachem Ba 349 Natter launch pads in the Hasenholz. Surviving aircraft and replicas The surviving Bachem Ba 349A-1 at the Smithsonian Institution's Paul E. Garber Preservation, Restoration, and Storage Facility in Suitland, Maryland Only one original A1 Natter survives; it is stored in the Paul E. Garber Preservation, Restoration, and Storage Facility in Suitland, Maryland, US. It is in a poor state of repair and is no longer accessible to the general public. The evidence supports the proposition that this machine was captured by US troops at St. Leonhard im Pitztal, Austria in May 1945. The Natter displayed at the Deutsches Museum is said to have been reconstructed partly from sub-assemblies that survived the end of the war.Lommel 1998, p. 140. This machine is of the experimental type as launched from the steel tower and is painted to look like an M17. There are several static reproductions of Natters around the world, for example at the Planes of Fame Air Museum, Chino, California and Fantasy of Flight, Polk City, Florida, US. Film In 2010 Oliver Gortat and Philip Schneider made a documentary film about the Bachem Ba 349.Natter in german Specifications (Ba 349B-1) Ba 349 See also References ;Notes ;Bibliography * Angelucci, Enzo. The Rand McNally Encyclopedia of Military Aircraft, 1914–1980. San Diego, California: The Military Press, 1983. . * Bachem, Erich. "Einige grundsätzliche Probleme des Senkrechstarts. Probleme aus der Astronautischen Grundlagenforschung" (in German). Proceedings of the Third International Congress on Astronautics. Stuttgart: Gesellschaft für Weltraumforschung, September 1952. * Bachem, Erich. "Projekt 'Natter' (BP-20/Barak 1) (in German). Transcript in Horst Lommel, Der erste Raketenstart der Welt. Waldsee- Württemberg: Bachem-Werk GmbH, August 1944. * Bachem, Erich. "Zur 'Natter'-Frage!" (in German). Bachem-Werk. Waldsee-Württemberg, December 1944. * Bachem-Werk. "Vorläufiger Kurz-Erprobungsbericht von Gerät 'Natter' Baumuster M16" (in German). Transcript in Horst Lommel, Der erste Raketenstart der Welt. Waldsee-Württemberg, December 1944. * Bachem-Werk. "Vorläufiger kurzer Erprobungsbericht über M23" (in German). Waldsee-Württemberg, March 1945(a). * Bachem-Werk. "Wochenbericht Nr. 13 (abgeschlossen am 1-3-45)" (in German). Waldsee-Württemberg, March 1945(b). * Bachem-Werk (April 1945c). Kurz-Erprobungsbericht. Waldsee-Württemberg. * de Bok, René and Jules Huf. "Saboteur of collaborateur, Duitse getuigenissen lijnrecht tegenover Bethbeder", Gebhardt quotation (in German). Elseviers Magazine, Zorell, April 1978. * Bratt, R.W. and J.R. Ewans. Report on the BP-20 aircraft (Natter), Evaluation Report 83., June 1945. * Dryden, Hugh L. German Guided Missile Development. Memorandum for the Commanding General Army Air Forces, October 1945. * Felkin, S.D. Natter – German rocket interceptor. ADI (K), Report No. 303/1945, May 1945. * Ford, Brian. German Secret Weapons: Blueprint for Mars (Ballantine's Illustrated History of World War II, Weapons Book No. 5). New York: Ballantine Books, 1969. . * Gooden, Brett A. Projekt Natter, Last of the Wonder Weapons: The Luftwaffe's Vertical Take-Off Rocket Interceptor. Crowborough, UK: Classic Publications, 2006. . * Green, William. Rocket Fighter (Ballantine's Illustrated History of World War II, Weapons Book No. 20). New York: Ballantine Books, 1971. . * Green, William. Warplanes of the Third Reich (4th (1979) ed.). London: Macdonald and Jane's Publishers Ltd., 1970. . * Grieger, M. "Fakten der NS-Illusion. Produkte und Projekte der deutschen Rüstungswirtschaft am Ende des zweiten Weltkrieges", quoting NS 33/36, Fol. 10RS(in German). Informationsdienst Wissenschaft und Frieden 8, No. 1, November 1990. * Klöckner; Kreyser. "Flugprotokoll der Erprobung 'Natter' BM1" (in German). Ainring, November 1944 * Köster. "Projekt 'Natter'. Ballistisch-taktische Stellungnahme, insbesondere für Bewaffung MK 108 bezw, R4M oder Rohr-Batterie 108, TLR/Fl.6/III" (in German). Berling, November 1944. * De Lattre de Tassigny, Jean. The History of the French First Army. London: George Allen and Unwin Ltd., 1952. * Lommel, Horst. Das bemannte Geschoß Ba 349 'Natter': Die Technikgeschichte (in German). Zweibrücken: VDM Heinz Nickel, 2000. . * Lommel, Horst. "Der erste bemannte Raketenstart. Essener Allgemeinen Zeitung; Peter Berthold: 'Ich sah die letzte Wunderwaffen', April 1951. * Lommel, Horst. Der erste bemannte Raketenstart der Welt (2nd ed.) (in German). Stuttgart: Motorbuch Verlag, 1998. . * Lommel, Horst. Vom Höhenaufklärer bis zum Raumgleiter: Geheimprojekte der DFS, 1935–1945 (in German). Stuttgart: Motorbuch Verlag, 2000. . * Magerstädt, Albert. "Flugzeug- Fertigungskennblatt, Baumuster 8-349, Raketenjäger, Natter BP 20" (in German). RLM, October 1944. * Maloney, Edward T. Kamikaze: The Okha Suicide Flying Bomb, Bachem Ba 349A 'Natter' and Fzg 76 'Reichenberg' (Aero Series 7). Fallbrook, California: Aero Publishers Inc., 1966. * Millikan, Clarke B. Natter Interceptor Project. CIOS Report No. XXX-107. London: HMSO, July 1945. * Miranda, Justo and Paula Mercado. Vertical Takeoff Fighter Aircraft of the Third Reich (Luftwaffe Profile Series No. 17). Atglen, Pennsylvania: Schiffer Publishing, 2001. . * Myhra, David. Bachem Ba 349 Natter (X-Planes of the Third Reich). Atglen, Pennsylvania: Schiffer Publishing, 1999. . * Pabst, Otto E. Kurzstarter und Senkrechtstarter Koblenz. Bonn: Bernard & Graefe, 1984, p. 166\. . * Pallud, Jean P. "First manned rocket launch." After the Battle, No. 151. Essex, UK: Battle of Britain International Ltd., February 2011. * Proctor, G.E.F. German Target-Defence Interceptors, A.I.2 (g), Report No.2347, May 1945. * Reyle (1998). Technischer Stand Projekt ‘Natter’ End February 1945. Transcript in Horst Lommel, Der erste Raketenstart der Welt. Stuttgart: Motorbuch Verlag. * Speer, Albert and Ulrich Schlie, ed. Alles, was ich weiß (in German). Munich: F.A. Herbig Verlagsbuchhandlung, 2001. . * Wacke. Zusammenstellung der 3- u. 6-Komponententenmessung am Gerät 'Natter' (Model BP 20-07) (in German). DVL Berlin-Aldershof: Institute für Aerodynamik, January 1945. * Wilde. "Besrechung am 20-2-45 in Stetten a. k. M. über Meßwertübertragung aus der Natter." Hochfrequenzabteilung der Forschungsanstalt Graf Zeppelin, February 1945. * Zübert, Hans. Freiflug M8 14-2-45, Flugbericht der Piloten Zübert (in German). Neuburg: DVL, Berlin- Aldershof, February 1945. External links * Abfangjagdflugzeug Bachem Ba 349 "Natter" (in German) * U.S. Intelligence Report Photos * The Adder Affair – Bachem Natter feature from a 1950's issue of RAF Flying review * YouTube Video Overview of the Bachem Ba 349 Program Ba 349 1940s German fighter aircraft Rocket-powered aircraft Aircraft with auxiliary rocket engines World War II fighter aircraft of Germany Research and development in Nazi Germany Mid-wing aircraft Aircraft first flown in 1945 Tailsitter aircraft "