Dornier Do X

The Do X was a semi-cantilever monoplane. The Do X had an all-duralumin hull, with wings composed of a steel-reinforced duralumin framework covered in heavy linen fabric, covered with aluminium paint. It was initially powered by twelve Siemens-built Bristol Jupiter radial engines in tandem push-pull configuration mountings, with six tractor propellers and six pushers mounted on six strut-mounted nacelles above the wing. The nacelles were joined by an auxiliary wing to stabilise the mountings. The air-cooled Jupiter engines were prone to overheating and could barely lift the Do X to an altitude of . The engines were managed by a flight engineer, who controlled the 12 throttles and monitored the 12 sets of gauges. The pilot would relay a request to the engineer to adjust the power setting, in a manner similar to the system used on maritime vessels, using an engine order telegraph. Many aspects of the aircraft echoed nautical arrangements of the time, including the flight deck, which bore a strong resemblance to the bridge of a vessel. After completing 103 flights in 1930, the Do X was refitted with Curtiss V-1570 "Conqueror" water-cooled V-12 engines. Only then was it able to reach the altitude of necessary to cross the Atlantic. Dornier designed the flying boat to carry 66 passengers on long-distance flights or 100 passengers on short flights. The luxurious passenger accommodation approached the standards of transatlantic liners. There were three decks. On the main deck was a smoking room with its own wet bar, a dining salon, and seating for the 66 passengers which could also be converted to sleeping berths for night flights. Aft of the passenger spaces was an all-electric galley, lavatories, and cargo hold. The cockpit, navigational office, engine control and radio rooms were on the upper deck. The lower deck held fuel tanks and nine watertight compartments, only seven of which were needed to provide full flotation. Similar to the later Boeing 314, the Do X lacked conventional wing floats, using sponsons (fuselage-mounted stub wings) to stabilize the craft on the water and also act as embarkation platforms for passengers. Three Do Xs were constructed in total. The original operated by Dornier, and two other machines based on orders from Italy, namely the X2, named Umberto Maddalena (registered I-REDI), and X3, named Alessandro Guidoni (registered I-ABBN). The Italian variants were slightly larger and used a different powerplant and engine mounts. Dornier claimed the X2 was the largest aircraft in the world at that time. Each was powered by Fiat A-22R V12 water-cooled engines, with the six engine mounts being covered by a streamlined fairing. A proposed improved version of the Do X designated the Dornier Do 20, in which the pylon-mounted engines were to be replaced by four pairs of diesel engines in nacelles fared into the wing's leading edge and driving four propellers, was promoted in 1936, but never advanced beyond a design study. ==Operation==

The Flugschiff ("flying ship"), as it was called, was launched for its first test flight on 12 July 1929, with a crew of 14. After a takeoff run of 50 seconds) at a maximum speed of before landing on Lake Constance. To introduce the airliner to the potential United States market but it never came to pass. ==Final fates==

Germany's original Do X was turned over to Deutsche Luft Hansa, the German national airline, after the financially strapped Dornier company could no longer operate it. After a successful 1932 tour of German coastal cities, Luft Hansa planned a Do X flight to Vienna, Budapest, and Istanbul for 1933. The voyage ended after nine days when the flying boat's tail section tore off during a botched, overly-steep landing on a reservoir lake near Passau. The Do X remained an exhibit until being destroyed during World War II in a Royal Air Force air raid on the night of 23–24 November 1943. Fragments of the torn-off tail section are displayed at the Dornier Museum in Friedrichshafen. While never a commercial success, the Dornier Do X was the largest heavier-than-air aircraft of its time, and demonstrated the potential for an international passenger air service. In an accident identical to that of Lufthansa's Do X1a, the Italian Do X2 lost its tail section in a botched landing only one month later. After scaling back flights and crew complements during 1934, they were mothballed at Marina di Pisa in 1935, and broken up for scrap in 1937. ==Operators==

; • Dornier Flugzeugwerke • Deutsche Luft Hansa ; • Regia Aeronautica • SANA (state airline) ==Replica project==

A group of enthusiasts, led by former Dornier employee Peter Kielhorn, is working to construct a static (non-flying) replica of the Dornier Do X. The goal is to have the digital Do X completed by 2026 and the full-scale, buoyant (but non-flying) replica ready by 2029, the 100th anniversary of the original's first test flight. ==Specifications (Do X1a)==