Rohrbach Ro II

The Rohrbach Ro II was an all-metal, 4-seat reconnaissance and bomber flying boat, designed and produced in Germany in 1923.

Development
Founded in 1923 by Dr.-Ing. Adolf Rohrbach, the Rohrbach Metall-Flugzeugbau GmbH designed and built many aircraft using light alloy stressed-skin construction methods that were at the cutting edge of aircraft design in the 1920s. His previous experience with light alloys at the Zeppelin-Staaken factory served Rohrbach well when designing the Rohrbach stressed-skin aircraft.

After designing the unbuilt 'RoI' twin-engined flying boat, Rohrbach developed the 'Rohrbach RoII' flying boat as an all-metal shoulder-winged monoplane flying boat with two tractor engines mounted in nacelles above the wings on struts. Planforms and profiles were kept as simple as possible with rectangular section fuselage frames (with vee planing bottoms), constant chord wings, tailplane and fin with square-cut tips and distinctive protruding servo/trim/balance tabs at wing and fin tips. The two-seat open cockpit sat between the engines at the wing leading edge, with an open gunner/bosun's position at the extreme nose. A very unusual feature of several of Rohrbach's flying boats was the provision of a pair of masts and sails to be rigged in the event of engine failure to allow the aircraft to be sailed back to safety.

At the time of the RoII's production the Versailles Treaty forbade the construction of large aircraft in Germany so Rohrbach set up a Danish company, the 'Rohrbach-Metall-Aeroplan Co. A/S', to build the early Rohrbach aircraft. The strict regulation of the aircraft industry was relaxed in 1926 allowing the Rohrbach series to be built at the Rohrbach Metall-Flugzeugbau GmbH factory in Berlin.

Operational history
The first flight of the RoII took place on 11 November 1923, piloted by Werner Landmann and the aircraft was used in FAI record attempts for speed/load on 24 October 1924. After trials and record attempts were completed the aircraft was sold to Mitsubishi Shoji Kaisha Ltd.. Variations on the Rohrbach RoII theme were produced by modifying the design and fitting different engines;The aircraft produced by the Yokosuka Naval Arsenal was designated Yokosho Experimental Type R-1, Mitsubishi's effort was designated Mitsubishi Experimental Type R Flying-boat (aka Mitsubishi R-2) and Hiro Naval Arsenals aircraft was designated Hiro Experimental R-3 Flying-boat. All three aircraft were used for trials by the Imperial Japanese Navy, but production was not carried out.

Variants

 * Rohrbach Ro II
 * Designed and built in Berlin


 * Yokosho Experimental Type R-1
 * A Rohrbach Ro II assembled in Japan from components produced by Rohrbach in Copenhagen


 * Mitsubishi Experimental Type R.2
 * A second Rohrbach Ro II imported into Japan and completed by Mitsubishi


 * Hiro Experimental R-3 Flying-boat
 * A third Ro II built by the Hiro Naval Arsenal, with detail design improvements and 450hp Hiro-built Lorraine 2 engines

Operators

 * Imperial Japanese Navy

Bibliogaraphy

 * Mikesh, Robert and Shorzoe Abe. Japanese Aircraft 1910–1941. London: Putnam, 1990. ISBN 0-85177-840-2