Friday, May 6, 2011

Germany - 1918 Linke-Hofmann R.II

The World's Largest Single-propeller Aircraft

No that is not hyperbole just a fact. Even though it looks sleek this plane was huge. Once I saw a photo of it I knew I needed to do a drawing of it. The only colored example showed a lozenge pattern with a lot of yellows in it. I am not sure of the authenticity of the colors so I made a best guess and did it my way. If someone has a swath of the camouflage or a better guess let me know.

The Linke-Hofmann R.II (Riesenflugzeug - giant aircraft) was a heavy bomber aircraft designed by Paul Stumpf of Linke-Hofmann and built in Germany from 1917.

The Linke-Hofmann R.I had disappointing performance and handling, as well as structural weakness, both prototypes crashing. Linke-Hoffman took a radically different approach for their second Riese Flugzeug, the Linke-Hofmann R.II. Linke-Hofmann sought to realize the benefits of the internal placement of four engines in the design of a heavy aircraft which avoided the drag created by traditional nacelles and additional structural elements such as struts and braces.

The R.II was approximately three times the size of a conventional single engined bi-plane. The Linke-Hoffman R.II was probably the largest single propellor aircraft ever built and flown, with a wing span of 138 ft, length of 66 ft and height of 23 ft. The design was powered by a single 22 ft. 7.5 in diameter propeller. Power was supplied by four 260 h.p. Mercedes D.IVa engines, arranged in two tandem pairs inside the fuselage, driving the propellor through clutches, shafts and gearboxes. Each of the four engines could be disconnected from the shaft by means of special couplings, and R. II was able to perform normal flight with two engines.

The airframe was constructed largely of wood with plwood covering the forward fuselage and a steel-tube v-chassis main undercarriage with two wheels and a tail-skid at the aft end of the fuselage. Two examples of the R.II were completed by the time the Armistice were designated, R 55/17 and R 58/17.

Flight testing of R 55/17 was carried out after the Armistice in 1919, demonstrating acceptable performance and handling, being able to fly happily with only two engines running / connected. Normal endurance was estimated to be 7 hours, but with adjustment of load and a cruising speed of 74mph it was estimated that the R.II could stay aloft for 30 hours. After several test flights the aircraft was destroyed.

There were plans to make it a 12 passenger airliner after the war, but the restrictions of the Versailles Treaty ended further development. Despite its short life, the R. II remained in history (and in the Guinness book of records) as the largest single-propeller aircraft

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