Dornier Do 17/Do 215

Pilot’s and gunner’s stations in Dornier Do 17 E-1. Note two 7.92 mm MG 15 machine guns on flexible mounts.[Kagero Archive]

 

Design and Development
The Dornier Do 17 was designed and built in the Dornier Werke GmbH plant located in Friedrichshafen on the Bodensee (Lake Constance). The company was founded and owned by one of the most renowned German aviation designers, Prof. Claudius Dornier. He was born on 14th May 1884 at Kempten im Allgäu. The son of a French wine importer and his German wife, Claude Dornier was born and grew up in Bavaria. In 1907 he graduated from the Technische Hochschule (Technical University) at Munich, where he had studied Maschinenbau (mechanical engineering). As a young engineer he first worked for a company designing and building steel road and rail bridges. In 1910, he joined the Versuchsanstalt des Zeppelin-Luftschiffbaues, an experimental facility in Friedrichshafen, which constructed airships. There he dealt with the statics and aerodynamics of airships, refined the construction of airscrews and worked on an advanced, mobile hangar for airships. Shortly before the outbreak of the First World War Dornier designed a massive airship (gas capacity of 80,000 cubic metres) for transatlantic communication. When the war broke out, there was no longer a need for an airship line to the United States of America, and the order was duly cancelled. To compensate for it, Dornier received an offer to design a large, multi-engine flying boat for military use.
While designing his flying boat, Dornier relied heavily on steel and duralumin, which made him one of the pioneers of all-metal aircraft construction. His project was designated Rs I. The first prototype was ready in October 1915, but its further development was discontinued before it had a chance to take to the air. It was followed by Rs II, Rs III and Rs IV, which were test-flown. Besides their all-metal construction, Dornier’s flying boats featured engines placed in tandem. This solution was first introduced in the Rs II, due to the lack of more powerful engines. It proved its worth, and was successfully used in many subsequent flying boat designs. Another novelty was the boat’s high-wing configuration with two fuselage-mounted sponsons to improve water stability during start and landing. In 1916 the Zeppelin Werke GmbH plant run by Dornier moved from Seemoos to Lindau-Reutin. There, in 1918, the D I single-seat, all metal fighter aircraft was prototyped, but never made it to series production.
After the armistice had been proclaimed in November 1918, Dornier continued to work in the Zeppelin Werke GmbH at Lindau-Reutin, as well as in the Flugzeugbau Friedrichshafen GmbH in Manzell. In the latter location 20 Zeppelin C II bi-plane observation aircraft were built, of which 19 were delivered to Switzerland.
Since the war was over, Dornier focused on civilian designs. On 31st July 1919, Dornier’s new flying boat, designated Gs I, with a capacity of six passengers, made its maiden flight. The first air tests revealed its great potential, and the aircraft was publicly demonstrated in the Netherlands. However, the Allied Armistice Committee promptly categorized it as a type of aircraft banned by the Treaty of Versailles and ordered the prototype to be destroyed. Furthermore, Dornier was obliged to discontinue his work on two prototypes of the Gs II flying boat (with a capacity of nine passengers). Watched closely by the Allied Armistice Committee, Dornier strove to design aircraft within the limits imposed on the German aviation industry. One of them was the Cs II Delphin flying boat with a capacity of five passengers, first flown on 24th November 1920. It was followed by its land-based counterpart the C III Komet, completed the next year, and the Libelle I (Dragonfly) open-cockpit, parasol wing, monoplane flying boat.
In 1922 Zeppelin Werke GmbH at Lindau-Reutin was re-named Dornier Metallbauten GmbH. In order to circumvent the constraints forced on the Germans by the Treaty of Versailles, Dornier resolved to open branches of his company in other countries. In Italy he established CMASA (Societa di Costruzioni Meccaniche Aeronautiche S.A.) in Marina di Pisa, which was to manufacture flying boats based on the Gs II design. On 6th November 1922 the prototype of the Dornier Wal (Whale) flying boat was first flown. It was to bring Dornier international fame, and was produced under licence in Japan, the Netherlands and Spain. Besides his branch in Italy, Dornier also founded similar plants in Spain, Switzerland and Japan. The Swiss-based facility, which was located in Altenrhein, across Lake Constance from his main office in Germany, became Dornier’s premier construction plant for flying boats. There, the Dornier X was built, then the largest flying boat in the world, powered by 12 engines (mounted in six separate tandem nacelles on top of the wing). The first prototype of this giant design (of 56,000 kg take-off weight) lifted off from the surface of Lake Constance for its maiden flight on 12th July 1929. In the ensuing years two more machines of this type, based on orders from Italy, were built.