David Schwarz and the idea of the all-metal aerostat

20 December 1852, the Hungarian-Croatian aviation pioneer and shnorrer David Schwarz was born in Keszthely, halfway between Budapest and Zagreb.

“The aerostat interested me most of all and by that time I had sufficient knowledge to calculate how large a balloon must be to rise in the air with passengers. Since then the idea of the all-metal aerostat has never left my mind.” (Konstantin Tsiolkovsky)



 contemporary drawing of Schwarz’s airship preparing to take off


It was just a year after the airship “La France” made the first fully controlled free-flight in 1884 when the Russian almost-universal genius Konstantin Tsiolkovsky pondered the concept of an all-metal dirigible in the small town of Borovsk somewhere in Kaluga province. Rubber-skinned airships had the tendency to let the hydrogen escape after a period of time that was difficult to predict with fatal consequences to possible flight durations and those rubber-coated fabric coverings stretched over a length of more than 150’ holding over 60,000 cubic feet of hydrogen were not very durable anyway. Airtight metal envelops seemed to be a theoretical alternative and Tsiolkovsky had it all drawn up, a metal-clad design that would allow the airship to preserve constant buoyancy at all altitudes and temperatures and even the necessary control of the filling gas could be handled with measured release of the exhaust gas of the ship’s engines. But, unfortunately, metal like tin or bronze tends to be rather brittle or very heavy but then, during the late 1880s, aluminium was discovered and produced as high-strength material.




"La France" in her hangar in 1884


Tsiolkovsky’s project description for designing an all-metal prototype was sent to the VII Aeronautic Department of the Russian Technical Society with the request to construct a prototype and was promptly refused in 1891. They already had another design, that of David Schwarz, previously demonstrated to the Ministry of War of the Danube Monarchy where it went down like a lead balloon. Schwarz was an autodidact and a timber merchant by trade, but his idea to use aluminium for the inner framework, the rigidly mounted nacelle as well as the balloon skin, made from 0,2 mm aluminium sheet, was quite revolutionary. Project cost for the design of the airship ran out of the rudder, though, and the planned 1,500 roubles had become more than a 100,000 after two years and the skin still wasn’t airtight. Schwarz’s Russian all-metal airship prototype very probably never flew and in 1894 he deemed it proper to quit the place in the dead of the night without leaving a forwarding address.




ZMC-2 in 1929 - the only successful Metal-clad airship yet


A year later, Schwarz had persuaded a new investor in Berlin, the entrepreneur and aluminium fabricator Carl Berg and his engineers revised the original plans of the airship. With the support of the Prussian Feldluftschiffereiabteilung, the army’s aeronautical department, the project was realised at Tempelhof over the next two years. Schwarz did not live to see it completed, though. He died in Vienna at the age of 44 of cardiac failure on 13 January 1897, but in November of the same year, the first all-metal airship took off at Tempelhof for a first flight, broke free from its lanyards and had to be crash-landed by its pilot. Berg, after some belated inquiries about Schwarz’s exploits in Russia, felt swindled and decided not to pursue the project any further and sell what he had so far to Count Zeppelin and the first truly successful experimental rigid airship, Zeppelin LZ 1, flew from its floating hangar on Lake Constance near Friedrichshafen on 2 July 1900. It took until 1929 for the first and only operational metal-skinned airship ever built to be completed, the ZMC-2, manufactured by the Detroit Aircraft Corporation and operated from Lakehurst until 1941. After that, no more all-metal airships had been built, even though the concept was more or less sound.



And more about David Schwarz on:

http://en.wikipedia.org/wiki/David_Schwarz_(aviation_inventor)

and metal-clad airships on:

http://en.wikipedia.org/wiki/Metal-clad_airship