HOME

TheInfoList



OR:

The Dornier Do X was the largest, heaviest, and most powerful
flying boat A flying boat is a type of seaplane with a hull, allowing it to land on water. It differs from a floatplane in having a fuselage that is purpose-designed for flotation, while floatplanes rely on fuselage-mounted floats for buoyancy. Though ...
in the world when it was produced by the Dornier company of Germany in 1929. First conceived by
Claude Dornier Claude (Claudius) Honoré Désiré Dornier (14 May 1884 – 5 December 1969) was a Franco-German airplane designer and founder of Dornier GmbH. His notable designs include the 12-engine Dornier Do X flying boat, for decades the world's la ...
in 1924, planning started in late 1925 and after over 240,000 work-hours it was completed in June 1929. Dornier Museum, 45 seconds During the years between the two World Wars, only the Soviet
Tupolev ANT-20 The Tupolev ANT-20 ''Maxim Gorky'' (, sometimes romanized as ''Maksim Gorki'') was a Soviet eight-engine aircraft, the largest in the world during the 1930s. Its wingspan was similar to that of a modern Boeing 747, and was not exceeded until the ...
''Maksim Gorki'' landplane of a few years later was physically larger, but at 53 tonnes maximum takeoff weight it was not as heavy as the Do X's 56 tonnes. The Do X was financed by the German Transport Ministry and in order to circumvent conditions of the
Treaty of Versailles The Treaty of Versailles was a peace treaty signed on 28 June 1919. As the most important treaty of World War I, it ended the state of war between Germany and most of the Allies of World War I, Allied Powers. It was signed in the Palace ...
, which forbade any aircraft exceeding set speed and range limits to be built by Germany after
World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
, a specially designed plant was built at Altenrhein, on the Swiss side of
Lake Constance Lake Constance (, ) refers to three bodies of water on the Rhine at the northern foot of the Alps: Upper Lake Constance (''Obersee''), Lower Lake Constance (''Untersee''), and a connecting stretch of the Rhine, called the Seerhein (). These ...
. The type was popular with the public, but a lack of commercial interest and a number of non-fatal accidents prevented more than three examples from being built.


Design

The Do X was a semi-cantilever monoplane. The Do X had an all-
duralumin Duralumin (also called duraluminum, duraluminium, duralum, dural(l)ium, or dural) is a trade name for one of the earliest types of age hardening, age-hardenable aluminium–copper alloys. The term is a combination of ''Düren'' and ''aluminium'' ...
hull, with wings composed of a
steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...
-reinforced duralumin framework covered in heavy
linen Linen () is a textile made from the fibers of the flax plant. Linen is very strong and absorbent, and it dries faster than cotton. Because of these properties, linen is comfortable to wear in hot weather and is valued for use in garments. Lin ...
fabric, covered with
aluminium Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...
paint. It was initially powered by twelve
Siemens Siemens AG ( ) is a German multinational technology conglomerate. It is focused on industrial automation, building automation, rail transport and health technology. Siemens is the largest engineering company in Europe, and holds the positi ...
-built
Bristol Jupiter The Bristol Jupiter is a British nine-cylinder single-row piston radial engine that was built by the Bristol Aeroplane Company. Originally designed late in World War I and known as the Cosmos Jupiter, a lengthy series of upgrades and developme ...
radial engine The radial engine is a reciprocating engine, reciprocating type internal combustion engine, internal combustion engine configuration in which the cylinder (engine), cylinders "radiate" outward from a central crankcase like the spokes of a wheel. ...
s in tandem
push-pull configuration An aircraft constructed with a push-pull configuration has a combination of forward-mounted Tractor configuration, tractor (pull) Propeller (aircraft), propellers, and backward-mounted (pusher configuration, pusher) propellers. Historical The e ...
mountings, with six tractor propellers and six pushers mounted on six strut-mounted
nacelle A nacelle ( ) is a streamlined container for aircraft parts such as Aircraft engine, engines, fuel or equipment. When attached entirely outside the airframe, it is sometimes called a pod, in which case it is attached with a Hardpoint#Pylon, pylo ...
s above the wing. The nacelles were joined by an auxiliary wing to stabilise the mountings.''Flight'' p234 The
air-cooled Air-cooled engines rely on the circulation of air directly over heat dissipation fins or hot areas of the engine to cool them in order to keep the engine within operating temperatures. Air-cooled designs are far simpler than their liquid-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
throttle A throttle is a mechanism by which fluid flow is managed by construction or obstruction. An engine's power can be increased or decreased by the restriction of inlet gases (by the use of a throttle), but usually decreased. The term ''throttle'' ha ...
s 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.Marshall, 2003, p.? Many aspects of the aircraft echoed nautical arrangements of the time, including the
flight deck The flight deck of an aircraft carrier is the surface on which its aircraft take off and land, essentially a miniature airfield at sea. On smaller naval ships which do not have aviation as a primary mission, the landing area for helicopters ...
, which bore a strong resemblance to the
bridge A bridge is a structure built to Span (engineering), span a physical obstacle (such as a body of water, valley, road, or railway) without blocking the path underneath. It is constructed for the purpose of providing passage over the obstacle, whi ...
of a vessel. After completing 103 flights in 1930, the Do X was refitted with Curtiss V-1570 "Conqueror"
water-cooled Cooling tower and water discharge of a nuclear power plant Water cooling is a method of heat removal from components and industrial equipment. Evaporative cooling using water is often more efficient than air cooling. Water is inexpensive and no ...
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 wet bar is a small bar used for mixing and serving alcoholic beverages that includes a sink with running water, as opposed to a "dry bar" that does not include a sink. A wet bar can increase the rate at which drinks are served because of the s ...
, 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 A galley is a type of ship optimised for propulsion by oars. Galleys were historically used for naval warfare, warfare, Maritime transport, trade, and piracy mostly in the seas surrounding Europe. It developed in the Mediterranean world during ...
, 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 The diesel engine, named after the German engineer Rudolf Diesel, is an internal combustion engine in which ignition of diesel fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the die ...
in nacelles fared into the wing's
leading edge The leading edge is the part of the wing that first contacts the air;Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 305. Aviation Supplies & Academics, 1997. alternatively it is the foremost edge of an airfoil sectio ...
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. To satisfy skeptics, on its 70th test flight on 21 October there were 169 on board of which 150 were passengers (mostly production workers and their families, and a few
journalist A journalist is a person who gathers information in the form of text, audio or pictures, processes it into a newsworthy form and disseminates it to the public. This is called journalism. Roles Journalists can work in broadcast, print, advertis ...
s), ten were aircrew and nine were
stowaway A stowaway or clandestine traveller is a person who secretly boards a vehicle, such as a ship, an aircraft, a train, cargo truck or bus. Sometimes, the purpose is to get from one place to another without paying for transportation. In other c ...
s. The flight set a new
world record A world record is usually the best global and most important performance that is ever recorded and officially verified in a specific skill, sport, or other kind of activity. The book ''Guinness World Records'' and other world records organizatio ...
for the number of people carried on a single flight, a record that would stand for 20 years. After a takeoff run of 50 seconds the Do X slowly climbed to an altitude of . Passengers were asked to crowd together on one side or the other to help make turns. It flew for 40 minutes Flug Revue claims it was the 42nd flight and lasted 53 minutes, and a historical film shows "" Dornier Museum, 118 seconds) at a maximum speed of before landing on
Lake Constance Lake Constance (, ) refers to three bodies of water on the Rhine at the northern foot of the Alps: Upper Lake Constance (''Obersee''), Lower Lake Constance (''Untersee''), and a connecting stretch of the Rhine, called the Seerhein (). These ...
. To introduce the airliner to the potential United States market the Do X took off from
Friedrichshafen Friedrichshafen ( or ; Low Alemannic: ''Hafe'' or ''Fridrichshafe'') is a city on the northern shoreline of Lake Constance (the ''Bodensee'') in Southern Germany, near the borders of both Switzerland and Austria. It is the district capital (''K ...
, Germany, on 3 November 1930, under the command of Friedrich Christiansen for a transatlantic test flight to New York. The route took the Do X to the Netherlands, the United Kingdom, France, Spain, and Portugal. The journey was interrupted at
Lisbon Lisbon ( ; ) is the capital and largest city of Portugal, with an estimated population of 567,131, as of 2023, within its administrative limits and 3,028,000 within the Lisbon Metropolitan Area, metropolis, as of 2025. Lisbon is mainlan ...
on 29 November, when a
tarpaulin A tarpaulin ( , ) or tarp is a large sheet of strong, flexible, water-resistant or waterproof material, often cloth such as canvas or polyester coated with polyurethane, or made of plastics such as polyethylene. Tarpaulins often have reinf ...
made contact with a hot exhaust pipe and started a fire that consumed most of the left wing. After sitting in Lisbon harbour for six weeks while new parts were fabricated and the damage repaired, the flying boat continued with several further mishaps and delays along the Western coast of Africa and by 5 June 1931 had reached the islands of
Cape Verde Cape Verde or Cabo Verde, officially the Republic of Cabo Verde, is an island country and archipelagic state of West Africa in the central Atlantic Ocean, consisting of ten volcanic islands with a combined land area of about . These islands ...
, from which it crossed the ocean to Natal in Brazil. The flight continued north via
San Juan San Juan, Spanish for Saint John (disambiguation), Saint John, most commonly refers to: * San Juan, Puerto Rico * San Juan, Argentina * San Juan, Metro Manila, a highly urbanized city in the Philippines San Juan may also refer to: Places Arge ...
to the United States, reaching New York on 27 August 1931, almost ten months after departing Friedrichshafen. The Do X and crew spent the next nine months there as its engines were overhauled, and thousands of sightseers made the trip to Glenn Curtiss Airport (now LaGuardia) for sightseeing tours. The
Great Depression The Great Depression was a severe global economic downturn from 1929 to 1939. The period was characterized by high rates of unemployment and poverty, drastic reductions in industrial production and international trade, and widespread bank and ...
dashed Dornier's marketing plans for the Do X, and it departed from New York on 21 May 1932 via
Newfoundland Newfoundland and Labrador is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region of Labrador, having a total size of . As of 2025 the population ...
and the
Azores The Azores ( , , ; , ), officially the Autonomous Region of the Azores (), is one of the two autonomous regions of Portugal (along with Madeira). It is an archipelago composed of nine volcanic islands in the Macaronesia region of the North Atl ...
to Müggelsee, Berlin, where it arrived on 24 May and was met by a cheering crowd of 200,000. The Do X2 entered service in August 1931, and the X3 followed in May 1932. Both were initially based at the
seaplane A seaplane is a powered fixed-wing aircraft capable of takeoff, taking off and water landing, landing (alighting) on water.Gunston, "The Cambridge Aerospace Dictionary", 2009. Seaplanes are usually divided into two categories based on their tech ...
station at
La Spezia La Spezia (, or ; ; , in the local ) is the capital city of the province of La Spezia and is located at the head of the Gulf of La Spezia in the southern part of the Liguria region of Italy. La Spezia is the second-largest city in the Liguria ...
, on the
Ligurian Sea The Ligurian Sea is an arm of the Mediterranean Sea. It lies between the Italian Riviera ( Liguria) and the island of Corsica. The sea is thought to have been named after the ancient Ligures people. Geography The sea borders Italy as far as ...
, and reassigned to various other bases during their service. Both orders originated with SANA, then the Italian state airline, but were requisitioned and used by the Italian Air Force primarily for prestige flights and public spectacles. After plans for a first-class passenger service (Genoa–Gibraltar) were deemed unfeasible, the X2 and X3 were used for officer training cruises, aeronaval manoeuvres, and publicity flights. In April 1936, a plan was floated for a trans-Atlantic service between Berlin and New York via Lisbon and
Charleston, South Carolina Charleston is the List of municipalities in South Carolina, most populous city in the U.S. state of South Carolina. The city lies just south of the geographical midpoint of South Carolina's coastline on Charleston Harbor, an inlet of the Atla ...
, with intermediate stops in the Azores and Bermuda, but it never came to pass.


Final fates

Germany's original Do X was turned over to
Deutsche Luft Hansa ''Deutsche Luft Hansa A.G.'' (from 1933 styled as ''Deutsche Lufthansa'' and also known as ''Luft Hansa'', ''Lufthansa'', or DLH) was a German airline. It served as flag carrier of the country during the later years of the Weimar Republic and t ...
, 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 Vienna ( ; ; ) is the capital city, capital, List of largest cities in Austria, most populous city, and one of Federal states of Austria, nine federal states of Austria. It is Austria's primate city, with just over two million inhabitants. ...
,
Budapest Budapest is the Capital city, capital and List of cities and towns of Hungary, most populous city of Hungary. It is the List of cities in the European Union by population within city limits, tenth-largest city in the European Union by popul ...
, and
Istanbul Istanbul is the List of largest cities and towns in Turkey, largest city in Turkey, constituting the country's economic, cultural, and historical heart. With Demographics of Istanbul, a population over , it is home to 18% of the Demographics ...
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 A reservoir (; ) is an enlarged lake behind a dam, usually built to water storage, store fresh water, often doubling for hydroelectric power generation. Reservoirs are created by controlling a watercourse that drains an existing body of wa ...
lake near
Passau Passau (; ) is a city in Lower Bavaria, Germany. It is also known as the ("City of Three Rivers"), as the river Danube is joined by the Inn (river), Inn from the south and the Ilz from the north. Passau's population is about 50,000, of whom ...
. While the accident was successfully covered up, the Do X was out of service for three years, during which time it changed hands several times before reappearing in 1936 in Berlin, Hormann writes ''"Am 5.September 1933 flog Chefeinflieger Wagner die DO-X zum Bodensee zurück. Mit dem Fiasko von Passau begann für DO-X der Weg ins Museum." ("On 5 September 1933 chief test pilot Wagner flew the DO X back to the Bodensee (Lake Constance). The Passau fiasco started the DO X's trip to the museum.")'' The Do X then became the centerpiece of Germany's new aviation museum ''Deutsche Luftfahrt-Sammlung'' at Lehrter Bahnhof. The Do X remained an exhibit until being destroyed during
World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
in a
Royal Air Force The Royal Air Force (RAF) is the Air force, air and space force of the United Kingdom, British Overseas Territories and Crown Dependencies. It was formed towards the end of the World War I, First World War on 1 April 1918, on the merger of t ...
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 Dornier Flugzeugwerke was a German aircraft manufacturer founded in Friedrichshafen in 1914 by Claude Dornier. Over the course of its long lifespan, the company produced many designs for both the civil and military markets. History Originall ...
*
Deutsche Luft Hansa ''Deutsche Luft Hansa A.G.'' (from 1933 styled as ''Deutsche Lufthansa'' and also known as ''Luft Hansa'', ''Lufthansa'', or DLH) was a German airline. It served as flag carrier of the country during the later years of the Weimar Republic and t ...
; *
Regia Aeronautica The Royal Italian Air Force (''Regia Aeronautica Italiana'') (RAI) was the air force of the Kingdom of Italy. It was established as a service independent of the Regio Esercito, Royal Italian Army from 1923 until 1946. In 1946, the monarchy was ...
* SANA (state airline)


Replica project

A dedicated group of enthusiasts, led by former Dornier employee Peter Kielhorn, is working to construct a static (non-flying) replica of the Dornier Do X. After Dornier transitioned into a successful company, Kielhorn sought a new project and started researching the Do X, connecting with others who shared his fascination. Despite the lack of original plans, they formed an organization called Friends and Supporters Association Do X and partnered with multiple universities to create a digital replica using CAD software, historical drawings, and laser scans of original parts. The project has seen significant progress, with detailed designs for the fuselage and other components completed. 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. The team redesigned the engines using a manual from Wright State University.https://www.do-x-vision.de/en/news-on-the-do-x-replica-project/


Specifications (Do X1a)


See also


Further reading

* Volker A. Behr: ''Dornier Do X. '' Motorbuch Verlag, Stuttgart 2011, ISBN 978-3-613-03329-0. *
Claude Dornier Claude (Claudius) Honoré Désiré Dornier (14 May 1884 – 5 December 1969) was a Franco-German airplane designer and founder of Dornier GmbH. His notable designs include the 12-engine Dornier Do X flying boat, for decades the world's la ...
: ''Aus meiner Ingenieurlaufbahn.'' Eigenverlag, Zug 1966, (Privatdruck). * * Jörg-Michael Hormann: ''Flugschiff DO-X. Die Chronik.'' Delius Klasing, Bielefeld 2006, ISBN 3-7688-1841-1. * Jörg-Michael Hormann: ''Ein Schiff fliegt in die Welt. 75 Jahre Dornier-Flugschiff Do X D-1929.'' Deutsche Post AG, Bonn 2004, ISBN 3-00-014367-X. * Brigitte Katzwandel-Drews: ''Claude Dornier. Pionier der Luftfahrt.'' Klasing, Bielefeld 2007, ISBN 978-3-7688-1970-1. * Peter Pletschacher: ''Grossflugschiff Dornier Do X. Authentische Bilddokumentation des ersten Großraumflugzeugs der Welt, 1929.'' 3. Auflage. Aviatic-Verlag, Oberhaching 1997, ISBN 3-925505-38-5 (enthält auch Informationen zur Do X2 und Do X3). * Fritz Strauß: ''Auf gefahrvollem Flug. Abenteuerlicher Studienflug, der neben spannenden Erlebnissen eine Reihe wissenschaftlicher Erklärungen bietet, die das Interesse für diese Gebiete wecken.'' Loewe, Stuttgart 1932. * Jörg-Michael Hormann: ''Warum Schiffe fliegen mussten. Beginn des Transatlantikluftverkehrs''. In: ''Schiff Classic. Magazin für Schifffahrts- und Marinegeschichte'', H. 1, 2013, S. 48–55. * Dornier GmbH Friedrichshafen Abt. PR, 799 Friedrichshafen ''Do X 1929 / Mit dem ersten Flugschiff Dornier Do X D 1929 über drei Kontinente'' Jubiläumsschrift; Doppelbuchband von Januar 1979. * ''Do X – das größte Flugschiff der Welt''. 73 Bilder, eingeleitet von
Claudius Dornier Claude (Claudius) Honoré Désiré Dornier (14 May 1884 – 5 December 1969) was a France–Germany relations, Franco-German airplane designer and founder of Dornier GmbH. His notable designs include the 12-engine Dornier Do X flying boat, f ...
, erläutert von Erich Tilgenkamp. Schaubücher 41. Zürich: Orell Füssli, 1931


Notes


References


Works cited

* * * * *


External links


A flight aboard the DoX - 1930 (3:03)
*
lufthansa dornier dox

Dornier DO-X over Amsterdam - 1930
{{Authority control Do X 1920s German airliners Flying boats Twelve-engined push-pull aircraft High-wing aircraft Engine-over-wing aircraft Aircraft first flown in 1929