Development
Dornier Do17 was German first bomber of the modern design in the early of thirties. Developed for both civil and military purpose it’s got very important place in new growing German air force. First combat experience in Spain revealed its major weakness in the sphere of the close defense. Parallel the type was developed into two variants- bomber and reconnaissance. But in the outbreak of World War 2 their number in the front line units was in decrease and this rate was expanding after Polish campaign. Most of the used variant was Z, which was generally much redesign of the origin project. Even this version was written of first line service and from 1942 mostly served for training of bomber crew.
Yugoslavia had in its service version K. Externally it could be recognized by
its specific long nose, firstly used on V8 prototype and French double row
radials. It was designed from two different versions of German origins, E and M.
Model E had a partially fabric covered wings and M had completely metal covered
wings. Initially K should present reengined resemblance of Do17E-1 with long
nose but this was later changed and Yugoslav type featured more differences and
many new innovations, later applied to the newest version of German Do17 planes.
Yugoslav model of Do17 had increase in all aspects such as top speed, bomb load,
range and firepower. In regards to the German models which were pure bombers, K
version could be specified as a strike bomber.
First
document with new type Do17K was performed in August 1936 and that was offer of
new version of bomber for Yugoslavia. This document was submitted to the
Yugoslav officials and was subject of many changes until the final versions
appeared. Initially, 20 mm cannon were planed for dorsal defense bow but this
never come into life. A thing which was unchanged from the very beginnings was
powerplants and bomber equipment. That included Maga bomb racks, with external
pylon and French aiming device.
In Germany was developed and delivered three versions of the plane. That was Do17Ka-1, Do17Ka-2 and Do17Kb. First two was derived from E model and featured partially fabric covered wings and electro mechanically actuated landing gear while KB model was derived from M model and had hydraulically actuated landing gear, completely metal covered wings and leading edge heating.
In Yugoslavia was made few conversion and only first block of 16 planes were built completely in regards to the German blueprints. In any cays, version produced in Yugoslavia based on M models and hade asymmetric cockpit more. But in following production blocks many of changes was made in a sphere of fuel system, armament, equipment and that was in all cases improvements of the basic design.
