Take a concept and make it bigger. The twentieth century lived and breathed that approach, sometimes with excellent results and at other times with outcomes better left forgotten. The Dornier Do X flying boat of 1929 sits somewhere in between: incredibly popular with the public, this monster promised to revolutionize passenger air travel through sheer power, carrying twelve engines on its wings and weighing 28 tons... not counting its 16,000 liters of fuel.
In 1905, humanity could barely build stable aircraft using fabric and metal frames. Twenty-five years later, we were already building flying hotels 40 meters long, with endless promises of luxury, quality, and long range. That brings us to the Dornier Do X, a creature developed by the Franco-German designer Claude Dornier. The original idea for this aircraft dates back to 1924, and with an investment of 240,000 hours of work, it became a reality in June 1929.
A Fortress Defying Every Limit
Funding for the Dornier Do X came through the German Ministry of Transport, in an attempt to circumvent the limits imposed by the Treaty of Versailles. Its standard configuration used a total of twelve Bristol Jupiter engines with a power of 391 kW (or 525 horsepower) each, fueled by 16,000 liters of fuel (and another optional 8,600 liters). Despite the impressive numbers, the Jupiters were air-cooled, so they suffered frequent overheating and could barely lift the Do X to a maximum altitude of 425 meters.
In fact, its configuration was so complex that it needed a flight engineer on board, who received orders from the captain to increase or reduce power with a nautical telegraph, and the flight deck essentially functioned as a command bridge. After accumulating 103 test flights in 1930, the Do X was upgraded with twelve Curtiss V-1570 Conqueror V12 engines of 455 kW with liquid cooling. This upgrade allowed it to reach a maximum altitude of 500 meters, enough to cross the Atlantic.
The Dornier Do X could carry 66 people on long-distance flights, or 100 on short-distance. The maximum number of passengers was tested on October 21, 1929, with a total of 169: 150 passengers (a combination of workers, their families, and some journalists), ten crew members... and nine stowaways. It took 50 seconds to take off, and to make the necessary turns, they asked passengers to move from one side of the cabin to the other.
Three Units and a Stately End
Dornier built a total of three units. The Do X2 entered service in August 1931, and the X3 did the same in May 1932, both with Italian flag. However, the Great Depression ruined Dornier's plans to promote its flying boat in the United States, and the original Do X came under Lufthansa's control when its operating funds ran out. A hard landing near Passau damaged its tail in 1933, and it served as an exhibit until its bombing by the RAF in November 1943. The Dornier Museum in Friedrichshafen still preserves part of its tail.
Source and more photos: Rare Historical Photos
