The Dornier Do 11 was a

German German(s) may refer to: * Germany (of or related to) **Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ger ...

heavy bomber Heavy bombers are bomber aircraft capable of delivering the largest payload of air-to-ground weaponry (usually bombs) and longest range (takeoff to landing) of their era. Archetypal heavy bombers have therefore usually been among the larges ...

, developed in secret in the early 1930s. It was originally called the Dornier F before being renamed by the ''

Reichsluftfahrtministerium The Ministry of Aviation (german: Reichsluftfahrtministerium, abbreviated RLM) was a government department during the period of Nazi Germany (1933–45). It is also the original name of the Detlev-Rohwedder-Haus building on the Wilhelmstrasse ...

'' (RLM) in 1933, and was considered a

at the time. It came into service in 1932, a continuation of a line of

bomber A bomber is a military combat aircraft designed to attack ground and naval targets by dropping air-to-ground weaponry (such as bombs), launching aerial torpedo, torpedoes, or deploying air-launched cruise missiles. The first use of bombs dropped ...

designs from the

Dornier Do P The Dornier Do P was a German four-engined heavy bomber, manufactured by Dornier Flugzeugwerke in the 1930s. It was built as part of the secret rearmament of Germany, in opposition to the Treaty of Versailles. Design and development Construction ...

in 1930, and the

Dornier Do Y The Dornier Do Y was a German bomber of the 1930s, the second bomber design by Dornier Flugzeugwerke. Development Design on the aircraft began in 1930, to follow up from the other Dornier bomber prototype, the Dornier Do P. The first aircraft ...

in 1931. The line would continue to develop with the

Dornier Do 13 The Dornier Do 13 was a short-lived 1930s German bomber A bomber is a military combat aircraft designed to attack ground and naval targets by dropping air-to-ground weaponry (such as bombs), launching aerial torpedo, torpedoes, or deploying ai ...

and

Dornier Do 23 The Dornier Do 23 was a German medium bomber of the 1930s. Design and development The earlier Do 11 had exhibited several problems, so two initiatives were launched to address those shortcomings. The first resulted in the Do 13. The second effo ...

Design and development

One of the main features the Do 11 tested was a retractable

undercarriage Undercarriage is the part of a moving vehicle that is underneath the main body of the vehicle. The term originally applied to this part of a horse-drawn carriage, and usage has since broadened to include: *The landing gear of an aircraft. *The ch ...

, but, due to problems with the gear, it was often left locked down. The aircraft entered service under the guise of a

freight transport Freight transport, also referred as ''Freight Forwarding'', is the physical process of transporting commodities and merchandise goods and cargo. The term shipping originally referred to transport by sea but in American English, it has been e ...

, and was used with the German

railway Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a pre ...

in conjunction with

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, serving as flag carrier of the country during the later years of the Weimar Republic and th ...

, so that it could be shown publicly. What it was actually used for was as a trainer for the still secret ''

Luftwaffe The ''Luftwaffe'' () was the aerial-warfare branch of the German ''Wehrmacht'' before and during World War II. Germany's military air arms during World War I, the ''Luftstreitkräfte'' of the Imperial Army and the '' Marine-Fliegerabtei ...

''. The aircraft had a number of problems, which resulted in some crashes, and was generally unpopular with pilots. Especially problematic were wing vibrations which resulted in various precautions and modifications. Attempts were made to correct its faults, resulting in the so-called Do 11D, the last model with the Do 11 name. The Do 13 was a "simplified" Do 11 and came next, but had so many problems of its own that it did not fully enter service, with several of the first planes off the

assembly line An assembly line is a manufacturing process (often called a ''progressive assembly'') in which parts (usually interchangeable parts) are added as the semi-finished assembly moves from workstation to workstation where the parts are added in seq ...

crashing. The later Do 23 corrected many faults of the design, but was still a lackluster aircraft, and was withdrawn from service by 1936, and replaced by superior aircraft that had since been developed. The Do 11 is noteworthy as having served in secret and having been the main heavy bomber of the quietly developing ''Luftwaffe'', if only for a short while. It was also the first to have two large

engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gen ...

s as opposed to its predecessors the Y and P, which used three and four engines respectively.

Variants

''Data from: ;Do F :Prototype of the Do 11 before redesignation by the RLM. ;Do 11C :First production version powered by two Siemens-Halske Sh.22B-2 radial engines. ;Do 11D :Second production version with a shorter-span wing, primarily introduced to alleviate extreme vibration of the Do 11C wings.

Operators

; *

Bulgarian Air Force The Bulgarian Air Force ( bg, Военновъздушни сили, Voennovazdushni sili) is one of the three branches of the Military of Bulgaria, the other two being the Bulgarian Navy and Bulgarian land forces. Its mission is to guard and p ...

Specifications (Do 11D)

Notes

References