Dornier Do 18
The Dornier Do 18 was a German twin-engine flying boat of the 1930s, developed from the Wal line as a transoceanic mail plane for Deutsche Luft Hansa and first flown on 15 March 1935. Its diesel engines and catapult launches from tender ships let Luft Hansa open a South Atlantic mail service and set a non-stop seaplane distance record between England and Brazil in 1938. The Luftwaffe took the type as its coastal reconnaissance flying boat, and a Do 18 shot down over the North Sea on 26 September 1939 was the first German aircraft brought down by British forces in the Second World War.
Why It Mattered
The Do 18 mattered on both sides of the civil-military line. For Deutsche Luft Hansa it was the flying boat that carried German airmail across the Atlantic in the late 1930s, proving the South Atlantic route with catapult launches from tender ships. For the Luftwaffe it was the only military flying boat in service when war came in 1939, and a Do 18 became the first German aircraft brought down by British forces in the Second World War. Its record flight from England to Brazil in March 1938 set a seaplane distance mark that announced the type before either role began.
Design Notes
The Do 18 kept the layout of the Wal flying boats it replaced: a metal hull with stabilising sponsons on either side and two engines mounted above the wing in push-pull tandem. History of War notes that within that familiar arrangement the newer boat was aerodynamically superior to its predecessors. Its Junkers engines were diesels, chosen because they promised much lower fuel consumption than petrol engines of similar power, though they were heavy. The prototype flew with 550 hp Jumo 5c diesels because the planned Jumo 205s were not yet available; production aircraft used the Jumo 205, and the improved Do 18G raised output to 880 hp per engine.
Operational History
Deutsche Luft Hansa received five Do 18s and ran endurance trials across the North Atlantic in 1936, including a catapult launch from the tender Schwabenland at Horta in the Azores that reached New York in 22 hours 12 minutes. From April 1937 the type worked the South Atlantic mail route between Bathurst in Gambia and Natal in Brazil, and the Do 18s crossed the South Atlantic 73 times. In March 1938 a specially prepared Do 18 flew non-stop from Start Point in Devon to Caravelas in Brazil, a straight-line distance of 8,391 km that set a seaplane record. The Luftwaffe's first military version, the Do 18D, entered service in September 1938, and at the outbreak of war 62 Do 18s equipped a Staffel in each of five coastal aviation groups, mostly on North Sea reconnaissance. On 26 September 1939 one of three Do 18s was caught over the North Sea by nine Blackburn Skuas of 803 Naval Air Squadron from HMS Ark Royal; forced down, it was sunk by the destroyer HMS Somali, the first German aircraft brought down by British forces in the war. Production totalled 170 aircraft: 48 built by Dornier at Manzell and 122 by Weser Flugzeugbau.
Afterlife
The type was already obsolescent when the war began, and in 1940 some of its squadrons moved to Norway. By the middle of 1941 only one squadron was still operating the Do 18, the Blohm & Voss BV 138 having superseded it. By 1942 it had been relegated to air-sea rescue duties; aircraft with their armament removed flew in that role as the Do 18N-1, and several others became dual-control trainers designated Do 18H. None survives: the German Wikipedia's account of the type closes by stating that not a single Do 18 was preserved.