Junkers J1 Experimental All-Metal Monoplane Aircraft
The sole, all-metal and revolutionary Junkers J1 monoplane aircraft constructed during World War 1 met its fate in an Allied bombing raid during World War 2.
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German engineer Hugo Junkers championed the idea of an all-metal aircraft to reduce the need for complicated, drag-inducing external bracing and multiple wing members common to most designs leading up to, and those appearing during, World War 1 (1914-1918). He therefore concentrated his efforts on monoplane form relying on corrugated steel sheet skinning with a steel understructure to produce his first all-metal aircraft - the pioneering Junkers "J1" - regarded as the first practical all-metal aircraft anywhere in the world. His work was only furthered by Junkers & Co's involvement in the Grand War that overtook Europe during the summer of 1914.
In July of 1915, Junkers received the go-ahead to develop a two-seat all-metal aircraft based around his all-metal concept. Desired specifications included a maximum speed of just over 80 miles per hour. This work produced the J1 which incorporated many traditional aircraft elements of the period including a nose-mounted engine (driving a two-bladed propeller), an open-air cockpit, slab-sided fuselage and fixed wheeled undercarriage. Of note was the monoplane wings in play which were mid-mounted along the forward fuselage sides - no external bracing of any kind was used. The tail unit was conventional, sporting a single (all-moving) fin with low-set horizontal planes. Dimensions included a wingspan of 42.4 feet, a length of 28.3 feet and a height of 10 feet. Empty weight was 2,030lb against a MTOW of 2,380lb. Power came from a Mercedes D.II six-cylinder water-cooled inline piston engine developing 120 horsepower. The engine drove a two-bladed propeller at the nose in traditional fashion.
Testing of the aircraft began before the end of 1915 and a first-flight was recorded on December 12thof that year. A brief "hop" action resulted in damage to one of the wings which grounded the design until January 1916. An altitude of 260 feet was reached later that month and more funding followed to further drive the project.
The J1 served out its time in the air as a technology demonstrator and was never a candidate for formal military service in World War 1. It was used to prove the Hugo Junkers concept of an all-metal aircraft viable. Only one J1 aircraft was built.
The J1 prototype survived up until December of 1944 at which point it was destroyed in an Allied bombing raid. At the time, the aircraft resided as a showpiece with the Deutsches Museum of Munich.
For its time in aviation history, the revolutionary J1 managed a top speed of 110 miles per hour and its handling and stability were described as sound by test pilots. Performance was also slightly better than some of its contemporaries.