Dornier The Yugoslav Saga 1926 - 2007

Claude Dornier’s contribution in the field of aviation started with the recognition by Count Zeppelin, who immediately following his employment at Luftshiffbau Zeppelin, discovered young engineer’s potential and provided him with a team and tools to succeed. (...)


Dornier Do D


The story of Dornier Do D began on 6 February 1924 when Dornier Metallbauten GmbH signed a contract with Kawasaki Dockyard & Co. Ltd from Kobe for the development and construction of a total of eight airplanes. This included the development and construction of a single engine military torpedo and reconnaissance floatplane as well as single engine land airplanes. To speed up the development process, Dornier decided to base the new floatplane on the projects already under development, the Do B, which became the civilian airplane Komet III, and Do C, a light bomber and reconnaissance airplane. A sequential designation Do D was assigned, and the project development continued at a rapid pace. Due to its military role, the Do D project relied more on the Do C type. It borrowed its fuselage design and landing gear was replaced with floats which had to be placed at such an angle to allow for the weapons to be carried below the fuselage.
Construction of the first Do D for the Japanese licensee, under W.Nr. (Werke Nummer - Construction number) 57, began in March/April 1924. It was powered by a 375 hp (horsepower) 12 cylinder Rolls-Royce Eagle IX engine coupled with a four blade wooden propeller and radiator in the nose. The cockpit was located below the wing. According to the Dornier factory documents, this floatplane was 90% complete as of 27 September 1924 and was fully complete in the early October 1924 but the exact date of the first flight remains unknown. Following several test flights, the official hand off to the Japanese delagation took place on 29 October at Manzell. In 1925 it took part in the official Japanese Navy bid for torpedo bomber and was the only one to satisfy the strict reqirements. Despite this, Kawasaki was unable to secure a production order. It was registered with the (IAACC) Inter-Allied Aeronautical Commission of Control officially as a civilian airplane since Germany was prohibited from developing and constructing military airplanes and this registration was officially received on 10 November 1924.
In 1926 a new 600 hp 12-cylinder BMW model VI engine became available. As soon as the type approval was granted, series production began and many airplane manufacturers considered it for their designs. Accordingly, in 1926/1927 the Do D series development continued with BMW VI engine without reduction gear, now under the designation Do D bis. Different versions were tested, with enclosed and open float struts, cockpit forward below the wing or behind the wing, belly or side radiator, different tail designs and wing arrangements.

Dornier zdj  1

In the early 1920, PV KSHS did not posses floatplanes which could be used as torpedo carriers or bombers which significantly limited its ability to protect the vast coastline along the Adriatic Sea. The domestic industry lacked the technical expertise as well as the machinery to produce a modern floatplane which satisfied the demands set forth. Several state commissions visited European aviation manufacturers to familiarize themselves with the floatplanes available and evaluate which supplier shall be awarded the contract. As a result, in June 1926 Dornier received a contract from KSHS for the purchase of 10 Do D bis through a Zürich based Aero Metall AG. Another factor which influenced this decision was the fact that these floatplanes were to be paid from the war reparations fund. They were assigned W.Nr. 131 to 140 and were produced at Manzell. They differed from the base Do D also in that they had different radiators which were now located on each side of the fuselage as well as a new square window also on the fuselage directly below the wing trailing edge. The first Do D was completed in November and the factory validated that all the requirements were met. The first three were delivered to PV KSHS in January 1927, the next three in March, three by the middle of the year with exception of W.Nr. 139, which was used to attain eight world records between 16 July and 10 August 1927. This floatplane was modified for the occasion by adding the transmission to the BMW VI engine and using a more efficient propeller. It was registered on 13 July in Swiss airplane register as CH 177 and on 15 September, after the record flights, it was duly removed. These flights were conducted by three Dornier pilots: Georg Zinsmaier, Richard Wagner and Egon Fath. Before the delivery to PV KSHS in mid September 1927, the engine was reverted to the original configuration. The following world records were secured:
16 July – Maximum altitude of 5,851 m with 1000 kg load
4 August – Maximum speed of 190.435 km/h over a distance of 100 km with a load of 2,000 kg
8 August – Distance covered of 1,600 km with a load of 1,000 kg
8 August – Maximum speed of 175.600 km/h over a distance of 1,000 km with a load of 1,000 kg
10 August – Distance covered of 2,100 km without load
10 August – Distance covered of 2,100 km with 500 kg load