EKW C-36 series
The first indigenous Swiss high-performance design, a multi-purpose "air cruiser" designed immediately before WWII.
With the need to replace the Fokker C.V's design work started on a low-risk biplane successor, the C-35, and a high performance machine to replace the C-35 - the C-36. However work on the C-36 was slowed as Switzerland attempted to leapfrog ahead with acquiring manufacturing rights to either the Bf 110 or Potez 63. Eventually these plans fizzled out, and effort returned to the C-36. But time had been lost, and the first prototype only flew in May 1939. But the aircraft did not last long, and during highspeed testing both wings failed and the aircraft was destroyed.
The wing was reworked, but the second prototype with the upgraded wing and a higher powered engine was only able to start flying in November.
Now the decision was made to increase potential speed of the aircraft, and the wing was again re-engineered to allow retractible undercarriage, and so the initial definitive model was ordered in a batch of 10 aircraft, with the first flying in September 1941. Even with the wing modifications the high-speed problems had not been resolved, and Air Force pilots complained about wing flutter until another aircraft was lost due to wing failure. The solution was found to be removing the wingtips, and all aircraft were modified, and further production was of this new C-3603-1 version, with 150 aircraft ordered. The aircraft continued in service successfully until 1953.
A heavier armed and powered version was designed towards the end of WWII as the C-3604, and a small run of 13 aircraft was produced.
As the war ended the C-3603-1 looked for a new lease of life, and 2 aircraft were modified as advanced trainers.
But the life extension for the aircraft came from conversion to target tugs after the end of the War. Initial modifications were unremarkable, but the definitive tow system was a significant extension to the cabin. Aircraft were even modified for night towing with mounted lighting systems.
But the final modification was the most spectacular and significant, as 23 aircraft were converted to turbo-prop tugs with various high visibility colour schemes. Due to the significantly lighter weight of the new Lycoming engines, to keep the aircraft's balance the engine was relocated significantly forward, while an additional tailplane was needed to counteract the forces of the new engines. The aircraft were finally retired in 1987, and several are still flying as private warbirds.