David Schwarz (aviation Inventor)
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David Schwarz (; , ;''David'' in isolation: . 20 December 1850 – 13 January 1897)Ernst Heinrich Hirschel, Horst Prem, Gero Madelung, ''Aeronautical Research in Germany: From Lilienthal until Today'', "The Controllable Airship - The Dirigible", pp. 24-25. Springer-Verlag Berlin Heidelberg, 2004, (eBook ) was a Hungarian aviation pioneer. He is known for creating an
airship An airship, dirigible balloon or dirigible is a type of aerostat (lighter-than-air) aircraft that can navigate through the air flying powered aircraft, under its own power. Aerostats use buoyancy from a lifting gas that is less dense than the ...
with a rigid envelope made entirely of metal. Schwarz died only months before the airship was flown. Some sources have claimed that Count Ferdinand Graf von Zeppelin purchased Schwarz's airship patent from his widow, a claim which has been disputed. He was the father of the opera and operetta soprano Vera Schwarz (1888–1964).


Personal life

Schwarz was born in
Keszthely Keszthely (; also known by alternative names) is a Hungarian city of 20,895 inhabitants located on the western shore of Lake Balaton. It is the second largest city by the lake and one of the more important cultural, educational and economic hub ...
,
Kingdom of Hungary The Kingdom of Hungary was a monarchy in Central Europe that existed for nearly a millennium, from 1000 to 1946 and was a key part of the Habsburg monarchy from 1526-1918. The Principality of Hungary emerged as a Christian kingdom upon the Coro ...
, then part of the
Austrian Empire The Austrian Empire, officially known as the Empire of Austria, was a Multinational state, multinational European Great Powers, great power from 1804 to 1867, created by proclamation out of the Habsburg monarchy, realms of the Habsburgs. Duri ...
He was a timber merchant raised in
Županja Županja (, , ) is a town in eastern Slavonia, Croatia, located 254 km east of Zagreb. It is administratively part of the Vukovar-Syrmia County. It is inhabited by 12,090 people (2011). Županja lies on the Sava river opposite Bosnia and He ...
, but he spent most of his life in
Zagreb Zagreb ( ) is the capital (political), capital and List of cities and towns in Croatia#List of cities and towns, largest city of Croatia. It is in the Northern Croatia, north of the country, along the Sava river, at the southern slopes of the ...
,
Kingdom of Croatia-Slavonia The Kingdom of Croatia-Slavonia (; or ; ) was a nominally autonomous kingdom and constitutionally defined separate political nation within the Austro-Hungarian Empire. It was created in 1868 by merging the kingdoms of Kingdom of Croatia (Habs ...
. He was
Jewish Jews (, , ), or the Jewish people, are an ethnoreligious group and nation, originating from the Israelites of History of ancient Israel and Judah, ancient Israel and Judah. They also traditionally adhere to Judaism. Jewish ethnicity, rel ...
. Sources for his date of birth vary. The
OCLC OCLC, Inc. See also: is an American nonprofit cooperative organization "that provides shared technology services, original research, and community programs for its membership and the library community at large". It was founded in 1967 as the ...
cites Rotem, Ẓ. giving it as 7 December 1850, while Brockhaus gives it as 20 December 1850 The OCLC, as well as Brockhaus, show Schwarz's place of birth as
Zalaegerszeg Zalaegerszeg (; ; ; ) is the administrative center of Zala County, Zala county in western Hungary. Location Zalaegerszeg lies on the banks of the Zala River, close to the Slovenian and Austrian borders, and west-southwest of Budapest by road. Hi ...
, Hungary. Although Schwarz had no special technical training, he became interested in technology and developed improvements for woodcutting machinery.


First airship thoughts

Schwarz first became interested in airships during the 1880s. This occurred while working away from home supervising the felling of some forest land. As the work took longer than planned, he had his wife send him books to while away the evenings. These included a
mechanics Mechanics () is the area of physics concerned with the relationships between force, matter, and motion among Physical object, physical objects. Forces applied to objects may result in Displacement (vector), displacements, which are changes of ...
textbook. Although Schwarz became excited, it is not certain that this inspired him to build his own airship. His lumber business suffered due to his obsession and, like other aviation pioneers, his project attracted mockery. Nevertheless, his wife Melanie supported him. Schwarz proposed
aluminium Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...
, then a very new material, for construction. Having worked out the design of an all-metal airship, Schwarz then offered his ideas to the Austro-Hungarian war minister. Some interest was shown, but the government was not ready to provide financial support. The Russian
military attaché A military attaché or defence attaché (DA),Defence Attachés
''Geneva C ...
, a technically educated man, advised Schwarz to demonstrate his airship in
St. Petersburg Saint Petersburg, formerly known as Petrograd and later Leningrad, is the second-largest city in Russia after Moscow. It is situated on the River Neva, at the head of the Gulf of Finland on the Baltic Sea. The city had a population of 5,601, ...
, where an airship using Schwarz's ideas was built in 1893. Schwarz, and later his widow, assumed that test flights would also be made there, but this did not happen. He began construction in late 1892, with the industrialist Carl Berg supplying the aluminium and necessary funding. Problems arose during gas-filling: on inflation, the framework collapsed. Schwarz apparently intended the metal skin to contain the gas directly without internal gas bags. The Russian engineer Kowanko pointed out that the lack of a
ballonet A ballonet is an inflatable bag inside the outer envelope of an airship which, when inflated, reduces the volume available for the lifting gas, making it more dense. Because air is also denser than the lifting gas, inflating the ballonet reduces ...
would cause stresses on the skin during ascent and descent. Also, the skin was not airtight,Robinson 1973, pp. 6-7 The first airship's specifications were: * Power: four cylinder engine weighing producing at 480 rpm * Volume: * Empty weight: * Gross lift: * Ballast and fuel: * Equipment and three people: * Net lift: The circumstances of Schwarz's return are unclear; there were reports of a hasty departure from Russia.


Second airship in Berlin

In 1894, Carl Berg procured a contract to build an airship for the Royal Prussian government, referring to Schwarz as the originator of the idea. Berg already had experience working with the then novel aluminium, and was to later manufacture components for
Zeppelin A Zeppelin is a type of rigid airship named after the German inventor Ferdinand von Zeppelin () who pioneered rigid airship development at the beginning of the 20th century. Zeppelin's notions were first formulated in 1874Eckener 1938, pp. 155â ...
's first airship. With financial and technical help from Berg and his firm, the airship was designed and built. Construction began in 1895 at the
Tempelhof Tempelhof () is a locality of Berlin within the borough of Tempelhof-Schöneberg. It is the location of the former Tempelhof Airport, one of the earliest commercial airports in the world. The former airport and surroundings are now a park call ...
field in Berlin. For a time the Prussian Airship Battalion placed its grounds and personnel at Schwarz's disposal. The components were produced in Carl Berg's Eveking Westphalia factory and, under the direction of Schwarz, assembled in Berlin. A gondola, also of aluminium, was fixed to the framework. Attached to the gondola was a Daimler engine that drove aluminium propellers. One of the propellers was used to steer the craft. In June 1896 Carl Berg sent a card to his stepfather from Moscow apparently indicating that he had searched for information on Schwarz and became cynical of delays and was nearly convinced he had been swindled. Due to delays, the airship was first filled with gas and tested on 9 October 1896, but the results were not satisfactory because the hydrogen delivered by the ''Vereinigte Chemische Fabriken'' from Leopoldshall (part of Staßfurt) was not of the required purity and so did not provide enough lift. However, some sources claim that a test was performed on the 8th October 1896. It was determined that gas with a density of 1.15 kg per cubic metre was needed. Gas of that quality could not be obtained for some time, and a test flight could not be made until November 1897, roughly ten months after Schwarz's death. Mentschl Ch. p. 429 German: ''Ein erster Füllungsversuch im Herbst brachte allerdings ein unbefriedigendes Ergebnis, da sich das verwendete Wasserstoffgas als ungeeignet erwies. S. erlebte den Flug seiner Erfindung nicht mehr. Erst im November 1897 fand''


Death and maiden flight

Schwarz did not live to see his airship fly. Between 1892 and 1896 he traveled frequently, which affected his health. Shortly before his death he received news that his airship was ready to be filled with gas. On 13 January 1897 he collapsed outside the "Zur Linde" restaurant in Vienna, and died minutes later from heart failure, aged 44. Historical sources speak of a ''blutsturz'' (a term meaning either
hemoptysis Hemoptysis or haemoptysis is the discharge of blood or blood-stained sputum, mucus through the mouth coming from the bronchi, larynx, vertebrate trachea, trachea, or lungs. It does not necessarily involve coughing. In other words, it is the airw ...
or
hematemesis Hematemesis is the vomiting of blood. It can be confused with hemoptysis (coughing up blood) or epistaxis (nosebleed), which are more common. The source is generally the upper gastrointestinal tract, typically above the suspensory muscle of du ...
). David Schwarz was buried in Zentralfriedhof, Vienna. Carl Berg required confirmation of Schwarz's death, suspecting he had fled to sell his secrets. Nevertheless, Berg resumed the work with Melanie, Schwarz's widow, and together with the Airship Battalion they completed the airship with the addition of a gas relief valve. This second airship had these specifications:Robinson 1973, p. 6 * Volume: * Length: * Diameter: * Engine: Daimler * Four propellers: one of diameter between the gongal and the envelope, two of diameter mounted on brackets either side of the envelope, and a fourth of diameter revolving in the horizontal plane mounted below the gondola to drive the craft up or down. * Envelope: 0.2 mm aluminium plates riveted to framework. A later structural analysis based on the drawings concluded that it was defective, with the skin taking most of the
shear stress Shear stress (often denoted by , Greek alphabet, Greek: tau) is the component of stress (physics), stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross secti ...
es: distortions of the skin can be seen in a photo of the craft in flight. The second airship was tested with partial success at Tempelhof near Berlin, Germany, on 3 November 1897. Airship Battalion mechanic Ernst Jägels climbed into the gondola and lifted off at 3 p.m. However, the airship broke free of the ground crew and, because it rose quickly, Jägels disengaged the vertical axis 'lift' propeller. At an altitude of about the drive belt slipped off the left propeller, resulting in the ship "... urningbroadside to the wind, nd with the result thatthe forward tether broke free." As the ship rose to the drive belt slipped off the right propeller, the airship thus losing all propulsion. Jägels then opened the newly fitted gas release valve and landed safely, but the ship turned over and collapsed and was damaged beyond repair.


Legacy

About the time of the trial flight and for decades after, various accounts, sometimes conflicting or misleading, were written of the events. Later, Berg, as well as his son, would write negatively of his experiences with Schwarz. Some sources state that Count
Ferdinand von Zeppelin Graf, Count Ferdinand von Zeppelin (; 8 July 1838 – 8 March 1917) was a General (Germany), German general and later inventor of the Zeppelin rigid airships. His name became synonymous with airships and dominated long-distance flight until the ...
purchased Schwarz's patent from his widow in 1898, while others claim that the count used the design. However, Hugo Eckener, who worked with Count Zeppelin, dismissed these claims: Cvi Rotem (1903–1980) wrote the only known biography of Schwarz, titled ''David Schwarz: Tragödie des Erfinders. Zur Geschichte des Luftschiffes''. Rotem wrote that both Berg and Schwarz wished to keep their work secret. From 3 December 2000 to 20 April 2001 the ''Museen der Stadt Lüdenscheid'' held an exhibition which covered Berg, Schwarz and Zeppelin history from 1892 to 1932, with displays of documents, photographs and airship remnants.


Notes


References


Bibliography

* * * * Robinson, Douglas H., ''Giants in the Sky''. Henley-on Thames: Foulis, 1973 * * Schnitzler, Norbert. 2000
WWW-Tipp der Woche 24/2000
(German summary of museum exhibition) * (als
1996 Gutenberg version


External links

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{{DEFAULTSORT:Schwarz, David 1850 births 1897 deaths Engineers from Zagreb Croatian Austro-Hungarians Croatian people of Hungarian-Jewish descent Aviation inventors Airship designers Aviation history of Germany Croatian balloonists Inventors from Austria-Hungary Hungarian Jews Engineers from Austria-Hungary