The design of this Swiss aircraft goes back to 1939 when the prototype two seater EKW C-3601 first flew. Fitted with twin fins, the aircraft was powered by a 1000 hp Hispano-Suiza HS-51 12Y piston engine, and was designed for multi purpose roles - including that of fighter, ground attack and light bomber. This prototype was destroyed after only a few flights, but had shown sufficient promise for further development.The all metal design was put into production by the Federal Eidg. KonstruktionsWerkstatte (EKW) aircraft factory at Thun as the C-3603, and was one of the first home designs put into large scale production for the Air Force. The aircraft was fitted with two machine guns in the wings, plus a rearward facing one operated by hand by the second crew member/observer. Over 150 were delivered to the Swiss Air Force from 1942, being used to patrol Switzerland's neutral air space (along with Swiss Messerschmitt 109's), with six squadrons being equipped during World War Two, the C-3603's served until 1952 when they were replaced by DH Vampire jet fighters. In the late 1940's twenty were converted as target tugs, plus a further twenty in the early 1950's, remaining in this secondary role for a further fifteen years. The aircraft were now beginning to show their age, and the Swiss Air Force sought a replacement. Instead of a new type, a C-3603 was re-engined by FlugzeugWerk (F + W) at Emmen with a 1,100 hp Lycoming T53-L turbo-prop, housed in an extended nose. This necessitated the addition of a third tail fin, as well as other minor modifications. Trials with the prototype during August 1968 were satisfactory, and a further twenty three conversions were undertaken by F + W between 1969 and 1973 - the type now becoming the C-3605 Schlepp [Basic translation = Tug]. Although not as fast as the C-3603, this did not matter in its new role. The Schlepp continued to serve the Air Force as a target tug until fatigue problems began to show up in the mid 1980's, resulting in the types withdrawal from military service in the summer of 1987. Most were then sold off at auction at Lodrino in December 1987.
