Dornier Do X

https://en.wikipedia.org/wiki/Dornier_Do_X

The Dornier Do X was the largest, heaviest, and most powerful flying boat in the
world when it was produced by the Dornier company of Germany in 1929. First
conceived by Dr. Claude Dornier in 1924, planning started in late 1925 and after
over 240,000 work-hours it was completed in June 1929.

During the years between the two World Wars, only the Soviet Tupolev ANT-20
Maksim Gorki landplane of a few years later was physically larger, but at 53
metric tons 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, which forbade any aircraft
exceeding set speed and range limits to be built by Germany after World War I, a
specially designed plant was built at Altenrhein, on the Swiss portion of Lake
Constance.

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.

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 aluminum paint.

It was initially powered by twelve 391 kW (524 hp) Siemens-built Bristol Jupiter
radial engines in tandem mountings (i.e. a "push-pull" configuration), with six
tractor propellers and six pushers mounted in six strut-mounted nacelles above
the wing. The nacelles were joined by an auxiliary wing whose purpose was to
stabilize the mountings. The air-cooled Jupiter engines were prone to
overheating and could barely lift the Do X to an altitude of 425 m (1,400 ft).
The engines were supervised by a flight engineer, who also controlled the 12
throttles and monitored the 12 sets of engine gauges. The pilot would ask the
engineer to adjust the power setting, in a manner similar to the system used on
maritime vessels, i.e. an engine order telegraph. Indeed, many aspects of the
aircraft echoed nautical arrangements of the time, including the flight deck,
which bore a strong resemblance to bridge of a vessel. After completing 103
flights in 1930, the Do X was refitted with 455 kW (610 hp) Curtiss V-1570
"Conqueror" water-cooled V-12 engines. Only then was it able to reach the
altitude of 500 m (1,650 ft) 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, instead using fuselage mounted "stub wings" to
stabilize the craft in the water, which also doubled as an embarkation platform
for passengers.


Role
Long-range airliner, flying boat

Manufacturer
Dornier

Designer
Dr. Claude Dornier

First flight
12 July 1929

Primary user
Regia Aeronautica

Number built
3

The Flugschiff ("flying ship"), as it was called, was launched for its first
test flight on 12 July 1929, with a crew of 14. In order 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
journalists), ten were aircrew and nine were "stowaways" who did not hold
tickets. The flight set a new world record for the number of persons carried on
a single flight, a record that was not broken for 20 years. After a takeoff run
of 50 seconds the Do X slowly climbed to an altitude of 200 m (650 ft). As a
result of its size, 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 historical film shows "fliegt mit 170
personen") at a maximum speed of 170 km/h (105 mph) before landing on Lake
Constance.

To introduce the airliner to the potential United States market the Do X took
off from Friedrichshafen, 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, England, France, Spain, and Portugal. The
journey was interrupted at Lisbon on 29 November, when a tarpaulin made contact
with a hot exhaust pipe and started a fire that consumed most of the left wing.
After sitting in Lisbon harbor 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, from which it crossed the ocean to Natal in Brazil, where
the crew were greeted as heroes by the local German émigré communities.

The flight continued north via San Juan 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
Airport) to tour the leviathan of the air. The economic effects of the Great
Depression dashed Dornier's marketing plans for the Do X, and it departed from
New York on 21 May 1932 flying via Newfoundland and the Azores to Müggelsee,
Berlin where it arrived on 24 May and was met by a cheering crowd of 200,000.

Specifications (Do X1a)

General characteristics
Crew: 10-14
Capacity: 66-100 passengers
Length: 40 m (131 ft 4 in)
Wingspan: 48 m (157 ft 5 in)
Height: 10.25 m (33 ft 7 in)
Wing area: 450 m2 (4,844 ft2)
Empty weight: 28,250 kg (62,280 lb)
Max. takeoff weight: 56,000 kg (123,460 lb)
Powerplant: 12 × Curtiss Conqueror water-cooled V12, 455 kW (610 hp) each

Performance
Maximum speed: 211 km/h (131 mph)
Cruise speed: 175 km/h (109 mph)
Range: 1,700 km (1,056 mi)
Service ceiling: 3200 m (10498 ft)
Wing loading: 94 kg/m2 (19.3 lb/sq ft) (at 46 tons weight)




*