--- I'd never post anything in this thread if I felt I need to have two dozen hints ready when I make my guess
An idea about a subject helps - and 10 minutes with Google does the rest... ---
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What aircraft?
1) It was developed in response to an air force requirement for replacing an obsolete aircraft.
2) According to press reports, it was claimed to be the best climbing aircraft in the world - at the time.
3) The manufacturer's name will ring very familiar to anybody who is likely to read this.
4) The country of origin did not adopt it for military use.
5) About 60 were built
6) 50 went to one export customer, and two other countries bought single examples (for evaluation?)
7) One or two were used in a war - but this design was getting a bit old by that time, so was probably used as a trainer only.
8) It used a license built version of a widely used engine.
9) It could be armed with 2 or 4 machineguns.
10) The war where it played "some" role did not directly involve any of the countries that bought it for military use.
11) It was built with metal construction wings - but wooden wings were, apparently, offered as an option.
12) One example was experimentally fitted with a variable pitch propeller.