The Dornier Do 20 was a proposed commercial

flying boat A flying boat is a type of fixed-winged seaplane with a hull, allowing it to land on water. It differs from a floatplane in that a flying boat's fuselage is purpose-designed for floatation and contains a hull, while floatplanes rely on fusela ...

designed in the mid-1930s. It was envisaged as an improved and enlarged version of the

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 Claude Dornier in 1924, planning started in late 1925 and after over 240 ...

''Flugschiff'' (flying ship) that first flew in 1929. The Do X was not entirely successful, being under-powered despite using six pairs of engines mounted above the wing, and only three were built. Dornier proposed to overcome the shortcomings of the Do X by replacing the pylon-mounted engines with four pairs of

diesel engines The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-calle ...

each of about 1,000

horse power Horsepower (hp) is a unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors. There are many different standards and types of horsepower. Two common definitions used today are the ...

, each pair fitted into a

nacelle A nacelle ( ) is a "streamlined body, sized according to what it contains", such as an engine, fuel, or equipment on an aircraft. When attached by a pylon entirely outside the airframe, it is sometimes called a pod, in which case it is attached ...

fared into the

leading edge The leading edge of an airfoil surface such as a wing is its foremost edge and is therefore the part which first meets the oncoming air.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 305. Aviation Supplies & Academics, ...

of the wing and driving one of the aircraft's four

propellers A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...

. A model of the aircraft was exhibited at the 1936 International Aviation Exhibition in Stockholm (ILIS) and details were published in the 1937 edition of ''

Jane's All the World's Aircraft ''Jane's All the World's Aircraft'' (now stylized Janes) is an aviation annual publication founded by John Frederick Thomas Jane in 1909. Long issued by Sampson Low, Marston in Britain (with various publishers in the U.S.), it has been published ...

''. No orders were received and no Do 20 aircraft were ever built.

References

Grey, C.G., et al., ed. (1937). ''Jane's all the World's Aircraft'', 1937 Edition. London: Sampson Low, Marston & company, ltd. {{RLM aircraft designations Do 020 Flying boats