Caproni Campini N.1
Recognised as the world's first jet aircraft, until the secret flight Germany's Heinkel 178 was made public.
Although often mocked as a failed attempt to create a jet engine, the motorjet with a piston engine driving the compressor section, was a very promising line of research also followed by the USA and USSR and had the advantage of not requiring the high-temperature metalurgy we take for granted now - but that crippled the Nazi jet-engine programmes. The N.1's performance was poor, but this is down to the use of a piston engine too small to provide enough power for the aircraft.
Campini had been working on the design of his engine since 1931, and had been progressively designing aircraft around the engine. With Italian govenment support Campini worked with Caproni to build 2 prototypes of the N.1, given serial numbers CC1 and CC2 (the 2nd aircraft is now a museum piece and its serial number is often incorrectly used to describe the model name).
Performance was very poor, but in Mussolini-style the aircraft were lauded, and the concept of the engines was carried forward into providing afterburner boost to the Ca.183bis and Re.2005R, neither of which flew before the Italian armistice.