Born from the same
Regia Aeronautica requirement that spawned the
Caproni-Vizzola F.5,
FIAT G.50,
Macchi C.200,
Meridionali Ro 51 and
Reggiane Re 2000 fighters, the A.U.T.18 flew for the first time on 22 April 1939, powered by a
Fiat A.80 R.C.41 radial engine. The fighter had an all-metal stressed-skin structure, covered in
duralumin, featuring an inwardly-retracting
undercarriage and retractable tail-wheel and was armed with two
Breda-SAFAT machine-guns mounted in the wings just outboard of the undercarriage. Flight trials proved disappointing and lagged behind the other fighters in
Progetto R - the modernisation (
riammodernamento) of the
Regia Aeronautica. With no production orders forthcoming, despite the prototype being returned to the Umbra factory at
Foligno for modifications on 20 February 1940 and a second flight test series from 5 November 1940, no improvement was demonstrated over fighters already in production so the A.U.T.18 was abandoned. ==Operational history==