Paul Jaray

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Paul Jaray on his J-wheel, ca.1921

Paul Jaray (born March 11, 1889 in Vienna , † September 22, 1974 in St. Gallen ) was an Austrian engineer and aerodynamicist . He made lasting merits with the design of scientifically founded streamlined bodies.

Life

Paul Jaray was born as the fifth child of the Jewish businessman Adolf Járay (until 1869: Jeiteles) from Temesvár and Therese Schönberg in Vienna. He studied mechanical engineering in Vienna (from 1906) and Prague (from 1911) and came to Friedrichshafen in 1912 , where he worked as chief designer in aircraft construction in Friedrichshafen. In 1912 Paul Jaray married Olga Jehle , daughter of a Friedrichshafen doctor, with whom he had three children, including the future architect Werner Jaray . Jaray's sister-in-law Bartha married his colleague, the Zeppelin designer Karl Arnstein , in 1919 .

From 1914 Jaray worked in airship construction at Zeppelin , where he was involved in the development of the LZ 38 to LZ 126 types . There Jaray did research in the field of aerodynamics , a topic that kept him busy for decades. His findings influenced aviation, automobile construction and bicycle technology. Jaray converted to Catholicism in 1917. From 1923 Jaray lived in Switzerland . First he ran an engineering office in Brunnen , from where he worked as a consultant for the British government on the subject of airships. From 1925 he manufactured the Alaphon radio receiver under license , and from 1932 his own radios at Radiodienst und Radiobau AG in Lucerne . In 1937 he left his wife and children. In 1941 Jaray became technical director at Flugzeugbau Farner AG in Grenchen , from 1944 he worked at G. Naef Flugmechanik in Fischenthal . The marriage with Olga Jaray was divorced in 1945, in the same year he married his second wife Martha Steiner, divorced Bernays. In 1950 Jaray lived in Kempten (Switzerland) where his second wife died in 1968. A little later he married Marguerite Leuenberger, his third marriage. Paul Jaray died on September 22, 1974 in St. Gallen .

aviation

Paul Jaray became interested in aviation from an early age. As early as 1912 he registered a patent for an airplane with cantilever wings - an invention that he did not pursue any further. At Zeppelin, he built a wind tunnel in 1919 and examined the flow characteristics of the airships. The result of this research were the Zeppelins LZ 120 “Bodensee” and LZ 121 “Nordstern”. These two were the first completely streamlined airships and were largely based on the findings of Paul Jaray. In these zeppelins, the support body was teardrop-shaped instead of cylindrical as before. Jaray developed the scouting basket into a gondola.

J wheel

Jaray wheel with swing pedals, manufactured in 1925
Jaray wheel 1925, postage stamp 1985

In 1920 Jaray designed a pedal wheel - the J-wheel - in which he applied his aerodynamic knowledge to bicycle construction. In 1922/1923 the Hesperus works in Stuttgart built around 2000 of the J-wheel, which were particularly popular in Holland. Production was stopped in 1923 after fatal accidents caused by material defects.

Automobile manufacturing

On September 8, 1921, Jaray applied for a patent for a streamlined automobile body with the Reich Patent Office in Berlin . Due to patent disputes, his application was not granted until 1926 as DRP 441618:

The lower part of the body has the shape of a half streamlined body and covers the chassis with the wheels, the engine compartment and the passenger compartment. The underside is flat and parallel to the floor surface. On top of this main part is a much narrower streamlined body, which is supported by a truss-like construction, which in turn is built on the chassis.

The Jaray body already designed the basic shape of today's automobiles: the front is rounded and the rear tapered to a point. Both Jaray's aerodynamically optimized shape and the design principle of the rugged shape were ahead of their time. The vehicles with the unusual look of the time were often mocked by the public and the daily press. The trade press, on the other hand, recognized the value of Jaray's invention and tested the predicted advantages with their own tests. Supported by the automobile company Rud. Ley , the following data were determined for the first vehicle built according to Jaray in 1922, the Ley T6 : fuel savings: 41%, performance increase 60%. Speed ​​increase: 40%. A significant advantage of the Jaray body was also the significantly lower dust swirl, which was not inconsiderable in normal body vehicles. These values, achieved solely through the use of a streamlined body, were measured, although the speeds driven at the beginning of the 1920s were very low compared to today. The Ley T6 reached around 80 km / h with a standard body, while the same vehicle with a Jaray body reached 130 km / h. The c w value of the first Jaray-Ley test vehicle measured in the Stuttgart wind tunnel in 1939 was 0.245 - a value that a series vehicle only achieved in 2014.

The Ley T6 was followed by the Audi Type K and the Dixi G7 . With these 3 vehicles, Jaray made advertising trips through Switzerland and Germany. A Jaray racing car built by Ley in 1923 achieved various successes, even in mountain time races such as the popular Gabelbach race .

The Audi Type K had a 3560 cm³, 50 HP (37 kW) four-cylinder engine and reached a speed of 95 km / h with the standard body and 130 km / h with the Jaray body. In the Dixi G7, which had a 1568 cm³ and 24 HP (18 kW) engine, the streamlined shape increased the maximum speed from 80 km / h to 100 km / h.

The Apollo works under the chief designer Karl Slevogt delivered three types Apollo Sport 4 / 20PS from 1924-1925 at the customer's request with a Jaray streamlined body (designed in 1923 on behalf of Apollo), the price for this version was 8,500 marks.

Because of the technical means at the time, but above all because of the unachievable number of pieces in the crisis-ridden 1920s, economical series production of car bodies according to Jaray was out of the question. Initially, there was one-off production on the chassis of almost all well-known vehicle manufacturers.

It was not until years later that Jaray's ideas caught on - initially for racing vehicles (Silver Arrows), but then also for commercially available cars that had to be suitable for the motorway. The first production vehicle was the Tatra 77 in 1934 .

Jaray's body shapes - refined more and more over the decades - and his design principle of the rugged form (all parts such as headlights, wheels, fenders, are integrated into a closed streamlined body; the car floor is closed) continue to shape the design and construction of today's vehicles.

literature

Individual evidence

  1. ^ Gotthilf Lufft company , accessed on January 19, 2012
  2. ^ "R. Conrad: comparative drives with the Jaray streamlined car in Der Motorwagen, issue 23/24 1923
  3. ↑ "Jerry Sloniger Last: The slippery shapes of Paul Jaray in Automobile Quarterly 3/1975
  4. ^ "Sports Cars in Germany 1885-1940", Hans-Heinrich v. Fersen, Motorbuch-Verlag, page 41, The great racing years, Erwin Tragatsch, Hallwag-Verlag, page 33, Chronicle of the automobile, Hans-Otto Neubauer, Chronik-Verlag, page 96

Web links

personal data
SURNAME Jaray, Paul
BRIEF DESCRIPTION Austrian aerodynamicist, father of streamlines
DATE OF BIRTH March 11, 1889
PLACE OF BIRTH Vienna
DATE OF DEATH September 22, 1974
Place of death St. Gallen