The World’s First All Metal Aircraft – The Junkers J1

A revolution in aircraft manufacturing was under way when on December 12, 1915, at the Döberitz airfield west of Berlin, the Junkers J1 took off for her maiden flight. The J1 was the first aircraft built completely of metal - other than all contemporary planes which were manufactured of wood, struts, tension wires, and canvas. It was the era of biplanes, of those ‘flying boxes” and their death-defying pilots, and all experts of the time believed that aircraft could only be constructed of light material, and not of a heavy material like metal. Their opinion: “There’s no way metal can fly.” Yet one visionary saw the future of aviation differently: In the opinion of Professor Hugo Junkers (1859-1935) the future of aircraft not only consisted of aerial competitions and air battles, but in the transport of passengers and goods. And only a metal aircraft could achieve that.

The J1 was the world’s first aircraft to also feature another innovation: an unbraced, cantilever monoplane wing with a thick profile guaranteeing the wing’s inner stability. Already in 1910 Professor Junkers had received a patent for his concept of the “thick wing.” In his own wind tunnel he then tested a multitude of wing profiles, confirming his expectation that a thick wing resulted in no more resistance than the thin, curved wing profiles common at the time. Instead, the thick wing allowed for a much better uplift and could carry additional load. Both Junkers’ innovations - the metal construction and the self-supporting thick wing - are influencing aircraft manufacturing still today.

As duralumin, a particularly strong aluminum alloy, had only just been invented and was difficult to obtain, the Junkers J1 was still built of steel. However, Junkers’ employees at his Dessau plant, where Junkers gas heaters were built, were experts in processing extremely thin sheets of metal, with a thickness of only 0.1 to 0.2 millimeters. The smooth exterior of the aircraft was reinforced internally by corrugated iron. This modern structure was later also used in other aircraft, like the Boeing B-17 in 1935.

The J1 was not intended for mass production, but rather served to demonstrate these new technologies. Less than two years later, in 1917, Junkers introduced the J7, the first monoplane made of corrugated duralumin which would become typical for all subsequent Junkers aircraft.. Four years after the J1, in 1919, the Junkers F 13 started for her maiden flight. The F 13 was the world’s first all-metal transport aircraft, and it became a huge commercial success. Over the next decade, a whole family of passenger and freight planes followed, such as the W 33 and W 34, the three-engine aircraft G 24 and G 31, the four-engine G 38, and finally the legendary three-engine Ju 52, nicknamed “Tante Ju” [Aunt Ju].

Considered a milestone in aviation technology, the Ju 1 was exhibited from 1926 at the Deutsches Museum in Munich, Germany. In December 1944 it was destroyed during a World War II bombing raid. 100 years after the first flight of the J1, the Junkers Technology Museum in Dessau, Germany, intends to build a full-scale replica of this pioneering aircraft, financed through a crowd funding campaign at Kickstarter. For more information on the campaign and how to support it, visit www.J1-project.com. For information on the life and work of Prof. Hugo Junkers, as well as on his aircraft and other products, visit www.junkers.de.

Specifications of the Junkers J1

Engine: 1 x Daimler DII with 88 kW (120 hp)
Wingspan: 12,95 m
Length: 8,62 m
Height: 3,11 m
Empty weight: 900 kg
Loading capacity: 180 kg
Take-off Weight: 1,080 kg
Top speed: 170 km / h