In 1929, the Dornier Do-X, built by the Dornier Company was recognised as the largest, heaviest and most powerful speed boat. The kick-off began after it was birthed by Claude Dornier in 1924. However, the planning only began in late June 1929 after over two years of hard work.
The Dornier Do-X measured about 157 feet and had a length of 130 feet at first and was run by a 391 kW Siemens-built Bristol Jupiter radial engine, also consisting of six tractor propellers and six pushers installed on six nacelles above the wing, an auxiliary wing was further installed to help stabilize the wing since the air-cooled Jupiter engines were subject to overheating.
Its wings were made up of steel-reinforced duralumin framework covered in heavy linen fabric making it extremely heavy. The Do-X as a result found it hard to elevate to an altitude past 1,394ft. After its 103rd flight in 1930, the Do X was rebuilt, this time with 455 kW, Curtiss V-1570 “Conqueror” water-cooled V-12 engines. The Do-X could then attain the needed altitude of 500 m (1,600 ft) to be able to cross the Atlantic.
The Do-X had a great interior, offering great luxury, it had three decks, the main deck was a smoking room with its wet bar, a dining salon, and seating for the 66 passengers. It was made in a way that it could be changed to a sleeping bed at night for sleeping comfort. The passenger space was an all-electric galley, lavatories, and cargo hold. The cockpit, navigational office, engine control, and radio rooms were on the upper deck while the lower chamber housed the fuel tanks and nine watertight compartments, out of which only seven were important in providing full flotation.
On the 12th of July 1929, the flying ship was set for its first test flight and by the 21st of October, it had its 70th test flight this time with improvements. The Do-X this time had space for 169 members. 150 were passengers (mostly production workers and their families, and a few journalists), ten were aircrew and nine were stowaways.
After a takeoff run of 50 seconds, the Do X slowly climbed to an altitude of 200 m (660 ft). The passengers were asked to crowd together on one side or the other to help make turns. It flew for 40 minutes setting a new world record for the most people carried on a single flight, however, this record was beaten after 20 years.
On November 3 1930, the Do-X departed Friedrichetafen, Germany for a transatlantic test flight to New York. Here it would also be displayed to their market target in the United States. Under the command of Friedrich Christiansen, the Do-X journeyed through the Netherlands, United Kingdom, France, Spain and Portugal smoothly up till 29 November when it had to be halted as the left wing had been consumed by fire. The fire began after the tarpaulin got in contact with a hot exhaust pipe.
The Do-X experienced a six-week break at the Lisbon harbour to enable the damaged parts to be replaced and repaired. It then continued its journey encountering further mishaps and delays along the western coast of Africa.
After spending almost 10 months in transit, the Do-X arrived in New York on 27 August 1931. The Do X and her crew remained there for the next nine months as its engines were overhauled, and thousands of watchers visited the Glenn Curtiss Airport to have a view.
