The Morane-Saulnier M.S.450 was an improved version of the M.S.406 developed for a French fighter requirement of 1937 but that didn't enter production. It was developed in response to a C1 (single seat fighter) requirement issued by the Service Technique Aéronautique on 27 February 1937.
The M.S.450 used more up-to-date construction methods than the M.S.406. The earlier aircraft had a tubular metal framework, covered with fabric at the rear and Plymax (plywood bonded to aluminium) at the front. The M.S.450 had a dural monocoque fuselage, although retained the Plymax covering for the wings. It was powered by the 1,050hp Hispano-Suiza 12Y51 (also used on the M.S.412/ D-3801 produced in Switzerland). The M.S.450 was armed with one engine mounted 20mm cannon and two wing mounted machine guns. The M.S.450 was very similar in appearance to the M.S.406,
The M.S.450 lost out to the Dewoitine D.520. The D.520 was ordered into production a month before the first M.S.450 made its maiden flight on 14 April 1939. Work on the M.S.450 continued and a second prototype made its maiden flight in November 1939.
Work on the design continued in Switzerland, where a small number of more refined aircraft were produced as the Doflug D-3802 (M.S.540) , followed by one example of the post-war Doflug D-3803.
Engine: Hispano-Suiza 12Y-51
Wing span: 34ft 9 1/4in
Length: 28ft 10 1/2in
Height: 9ft 0 1/4in
Maximum Take-off Weight: 5,512lb
Max Speed: 348mph
Service Ceiling: 32,800ft
Range: 466 miles
Armament: One 20mm cannon in engine, two 7.5mm machine guns in wings