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DORNIER DO X: LEGENDARY FLYING BOAT

On July 12th 1929 after 570 days of intensive work, the hangar doors opened in the Swiss town of Altenrhein to set free a true giant. Under the critical eyes of numerous cameramen, journalists, technicians and workmen the Dornier Do X slid into the water of Lake Constance. While the morning sun reflected off the shining aluminium body of the boat, eight of the twelve engines each with an output of 525h.p., (385.61 kW) screamed across the lake. About one hour later at around nine o'clock in the morning, the remaining four engines joined in the song of the eight other four-bladed propellers. After a few steering manoeuvres Dornier's Chief Pilot Richard Wagner put his foot down and lifted the 37 ton maiden Valkyrie gently out of the water and performed the maiden flight of the then biggest flying boat. Claude Dornier was once more able to triumph over any doubters with his vision of a giant flying boat. " It was one of the biggest moments of my life."

Even the press came out with passionate remarks, like the Berlin Lokal-Anzeiger: "Do X, the hotel ship. A miracle of German Technology. A tremendous novelty in aviation history. This is no longer a plane, but a ship, a real ship, which is able to lift out of the water and will fly through the air. If you look at it, this giant, incomparably bold work, visions become reality, which were fiction only three years ago".

After a testing phase in the summer of 1929, with numerous measurements and static tests, which resulted in slight structural alterations to the boat's fuselage, critics claimed that apart from her own weight, the Do X was unable to transport another payload.

Claude Dornier prepared a spectacular demonstration for these doubters. On 21 October 1929, a foggy Monday morning, 159 employees and members of the press as well as 10 crew members gathered at the entry hatch of the Do X.

All guests used light wicker chairs as makeshift seats, which were placed between the bare aluminium girders and ribs inside the giant. Just after 11 o'clock the Do X took off after 50 seconds, which seemed to last forever, with an overall weight of 44.768 tons. The airship with its 169 passengers stayed airborne for 53 minutes and flew over Bregenz, Lindau and Friedrichshafen. With this important 42nd flight the Do X achieved an unofficial record for transporting passengers, which was only broken in 1949, when the military transport aircraft Lockheed Constitution took up operations. She had 168 passengers and 11 crew on board.

On 20 February the flight test of the Do X was regarded as complete. She had undertaken 71 flights and been airborne for 37 hours. The German Aviation Test Centre examined the aircraft officially. The giant went to the German Reich, which had commissioned it.

At that time Dornier was already thinking of testing the Do X on longer flights. However, a few problems had to be sorted out first. The 12 air cooled Siemens-Jupiter Engines showed a decline in output when run continuously. This was compensated by higher revs, which in turn lead to cooling problems, which could not be solved satisfactorily. The nine cylinder- Siemens Star Engines were the most powerful ones available in Germany. Installing foreign products was out of the question, because the German Government insisted on engines made in Germany. This demand, which had purely been made for military reasons, was no longer relevant in the spring of 1930, because the Navy had lost interest in the Do X. During the construction period the project was taken on and paid for by the Reich's Ministry of Transport, the RVM. To this end a contract was signed on 28 June 1928. Continual changes before the aircraft's certification led to increased costs. It goes without saying that the RVM was disgruntled. Originally a cost of Reichsmark 2,370,900 had been estimated. Calculations were adjusted in 1930 and the new amount was Reichsmark 3,549,182.61.

Dornier was able to borrow the Do X free of charge of the RVM for the intended long distance flight. The air cooled Siemens-Jupiter Engines were replaced by water-cooled American Curtiss-Conqueror Engines. The 12 engines were on loan from Curtiss. The company probably made them available for advertising purposes. The necessary operational safety was guaranteed with an additional output of almost 1,400 hp. After alterations, which included the luxurious refitting of the passenger deck, the new Do XIa flew for the first time powered by new engines on 4 August 1930.

The planned advertising campaign was to be started on 5 November 1930. The 12 strong crew was under the command of the former Navy Pilot Friedrich Christiansen. Pilots were Captain Horst Merz, who was "on loan" from Lufthansa, and the American Captain Clarence Schildhauer. Harvey Brewton, a representative of Curtiss, checked the engines during the entire flight. The Do X took off for Amsterdam from Lake Constance. Within the next three weeks the enthusiasm of the public grew with each further destination, (Calshot/England, Bordeaux, France, Santander and La Coruna/Spain as well as Lisbon/Portugal). In each port many visitors poured onto the boat. 1,200 came to see her in Amsterdam alone. However, only the rich were able to afford round trips. Still, seeing the colossus, engraved the name Do X indelibly in the population's memory. During short stages the crew was accompanied by a few guests. They were mainly members of the press, who had been invited by Dornier.

However, a serious breakdown at Lisbon Port on 29 November messed up the time schedule. A tarpaulin, which had been blown onto the exhaust of the auxiliary engine, caught fire and ignited the cloth covering of the left wing. The necessary repair works lasted until the end of January 1931, because materials took about six weeks to arrive from Altenrhein.

The aircraft took off for her flight across the Atlantic to South America on 31 January. After 7 hours and an average speed of 190km/h the flying boat reached its stop Las Palmas.

The aircraft was dogged by bad luck and on 3 February there was another mishap. Shortly before take-off the Do X collided with the swell, which came rolling in. The boat suffered a heavy blow, and the wings were almost torn off. The aircraft was stuck in Las Palmas for the next three months because of the necessary improvements to her structure. At Claude Dornier's request the very experienced Flight Captain Cramer von Clausbruch joined the crew and replaced Clarence Schildhauer. Von Clausbruch was known to be an experienced South American pilot, who intuitively recognised the Dornier Wale's possible ground effect and was able to take advantage of it. On 3 May the journey finally continued to the African Continent. In Bolama/West Africa or rather on the near by situated Island Bubaque the aircraft was stranded again, because adverse weather conditions did not allow take off within the next four weeks. On 30 May 1931 the Atlantic leg could at last be attempted. The South American Continent was reached via the Capverdian Islands at Natal/Brazil on 5 June. The enthusiastic reception in South America made the crew forget the strain of the past months. In the following eight weeks the Do X visited many towns along the South American coast, before taking off for the USA from Trinidad via San Juan and Cuba on 20 August.

On 22 August the Do X arrived in Miami. The crew finished their journey on 27 August 1931 via Charleston and Norfolk at New York Harbour. However, the enthusiastic reception, the American President Hoover also bid them welcome, was overshadowed by the series of accidents and the latest news from home. The Dornier Metallbauten GmbH faced financial ruin. The world economic crisis was to blame. Furthermore, the Company Curtiss demanded that Dornier should take ownership for the 12 Conqueror Engines, since they needed basic maintenance after 300 hours in service. Dornier could not afford the outstanding amount of Reichsmark 300,000. The journey, which had started in triumph, was to come to a sudden end.

Without financial support by the Reich's Ministry of Transport, the aircraft was unable to return to Germany. The RVM had given the authority to try to use her profitably in the USA. The attempts to have the aircraft chartered and then sold for the cell price of Reichsmark 1,500,000 were unsuccessful. Even the "Dornier Corporation of America", which was founded in 1929 in conjunction with General Motors, did not resolve anything. General Motors cancelled the license contract for financial reasons. Without any prospects for a positive outcome, the Do X was finally prepared for hibernation in New York.

In the meantime the RVM, who owned the flying boat, was looking for a practical solution. In agreement with the Reich's Ministry of Finances Dornier was given a further loan to pay the running costs. It was also settled that the Curtiss Engines were bought at the then current market value of Reichsmark 327,199.21

Having spent eight months on dry dock, the Do X took off again on 14 May 1932. On 19 May she set off for her journey home after some test flights. On Tuesday, 24 May, after being away for one and a half years, Claude Dornier's masterpiece arrived in the German capital Berlin and touched down on the Müggelsee.

The advertising tour, which had started with such high hopes in 1930, was a huge success as far as publicity was concerned. However, from an economic point it almost ruined Dornier. The technological experiment had failed. Practically the Do X proved to be unsaleable. Only two further models were sold to Italy. Claude Dornier seemed to have had premonition of this. He maintained as early as 1929 that the Do X had only been an experiment. He did not intend to use this flying ship for regular Atlantic crossings.

The loan contract with the RVM ended on 23 June 1932. The German Aviation Test Centre, (DVL), is the RVM's official representative, and the Do X was passed on to it, which meant that it was within the Reich's administration.

The return to the hangar in Altenrhein was also to serve as a tour through Germany. The RVM was hoping that, "a fair amount of money could be made with promotional flights and viewing. It was hoped that in this way some of the money spent on testing the aircraft could be recouped".

On 23 June the Do X took off for her 233rd flight and thus started her German Tour over East Prussia, Danzig, Northern Germany and the towns situated along the Rhine. After having visited Zurich, the penultimate city for her to visit, she finally returned to her home hangar in the Swiss Altenrhein on 14 November.

After mooring for some months, it was planned to take her on another European trip. The intended route was along the Danube to Istanbul. On 29 April, only ten days after the journey started, Captain Horst Merz misjudged the landing in Passau and put the tail of the 40meter long boat into the water first. Unfortunately the angle was much too steep and the aircraft's control surfaces on the tail were ripped off. This happened on 9 May 1933 and meant a temporary stop to the Do X. After repairs and only a few further flights, the new owner, the Reich's Aviation Ministry, (the RLM), decided to finally take this proud giant out of service. This happened in October 1934.

At the end of May the disassembled Do X was handed over to the "Deutsche Luftfahrtsammlung Berlin", i.e. the German Aviation Collection Berlin. After the official opening of the Museum in the Berlin exhibition halls, situated near the Lehrter Station in June 1936, the Do X was the central eye-catcher in the entrance hall. The increasingly frequent air attacks on the Reich's capital during World War II, made it necessary to evacuate the museum's exhibits. Unfortunately the Do X had to stay behind because suitable accommodation could not be found. A direct hit from a British air mine in November 1943 meant the demise of the previously proud airship. Before the ruins of the former Aviation Collection was cleared in the first few years after the war had ended, old metal collectors and souvenir hunters had already cannibalised the aluminium framework of the Do X. Today there exist only parts of the control surfaces, which broke off during the hard landing on the Danube. They are exhibited in the Dornier Museum in Meersburg.

From page 16 of FLUG REVUE 6/99