Of all-wood construction like its
predecessors, the S.A.I. 403 Dardo (Dart) featured numerous detail refinements
intended to improve combat performance and to facilitate rapid production. The
internal fuel and armament capacities were increased, and the resulting loaded
weight of 5820 lb. called for an increase in wing area to 155.6 sq. it. in
order to maintain the standard of maneuvrability so important to the Italian
airman. The vertical tail surface became larger and more angular, while such
aerodynamic refinements as a fully-retractable tailwheel contributed to a minor
gain in maximum speed of 5 m.p.h. over the S.A.I. 207. Various fuel and
armament combinations were tried in order to make the Dardo suitable for
different roles. Armament ranged from the two 12.7-mm. machine guns of the
light interceptor model to the two machine guns plus two 20-mm. wing cannon of
the general purpose version. A third possibility intended for long-range duties
employed only the wing cannon, plus two 42 U.S. gal. drop-tanks mounted beneath
the wings. The interceptor, lightest of the three versions, weighed only 5459
lb. fully loaded.
3000 aircraft were ordered in January, 1943
to replace the S.A.I. 207 contracts, and production was to be undertaken by
Caproni and Savoia Marchetti in addition to the parent firm. However, this
promising project came to an end with the Italian Armistice. Similar in concept
to lightweight wooden fighters developed by other nations, the Ambrosini
designs were the only fighters of the class which demonstrated both
practicability and truly exceptional performance.
The S.A.I. 403 had a span of 32 ft. 1 3/4
in., a length of 26 ft. 10 3/4 in., and a height of 9 ft. 6 in. Powered by the
750 h.p. Isotta-Fraschini Delta R.C.21/60 inverted-vee engine, the fighter
achieved a maximum of 403 m.p.h. and cruised at 304 m.p.h. An altitude of
19,680 ft. could be reached in 6 min. 40 sec.; service ceiling was 39,810 ft.
Range varied from 582 to 1164 miles, depending on the different fuel and
armament arrangements.
Did the 403 have wooden panels over a wooden frame, or was the structure a one-piece monocoque?
ReplyDelete