Junkers J 1
The Junkers J 1, nicknamed the Blechesel ("Tin Donkey" or "Sheet Metal Donkey"), was the world's first practical all-metal aircraft. Built early in World War I, when aircraft designers relied largely on fabric-covered wooden structures, braced with struts and exposed rigging lines, the Junkers J 1 was a revolutionary development in aircraft design, being built and flown only 12 years after the Wright Brothers had first flown the "Flyer I" biplane in December 1903. Herr Junkers' experimental all-metal aircraft never received an official "A" nor an "E-series" monoplane designation from IdFlieg and the then-designated Fliegertruppe, probably because it was primarily intended as a practical demonstration of Junkers' metal-based structural ideas, and was officially only known by its Junkers factory model number of J 1. It should not be confused with the later, armoured all-metal Junkers J 4 sesquiplane, accepted by the later Luftstreitkräfte as the Junkers J.I (using a Roman numeral).