Two M.S.406H fighters were supplied to Switzerland in September 1938 and April 1939 to serve as pattern aircraft for a licence-manufactured version. These were hybrids, mating the M.S.405 airframe with the HS 12Y31 engine of the M.S.406 and Swiss-specified instrumentation, armament and radio.
Production was initiated by the Eidgenossisches Konstruktions-Werkstatte as the D-3800, the Hispano-Suiza 12Y31 engine being manufactured by Adolph Saurer AG. The drum-fed 7.5mm wing guns were replaced by belt-fed weapons, the two-pitch Chauviere propeller was supplanted by an Escher-Wyss EW-V3 controllable-pitch unit, and the original M.S.405 wing structure was retained (rather than the simplified and lighter wing of the M.S.406). A pre-series of eight D-3800s was built in 1939, and the first series aircraft was delivered in January 1940. Seventy-four series D-3800s were built, the last of these being delivered on 29 August 1940, and later, in 1942, two further aircraft were assembled from spares. During 1943, all D-3800s underwent modification of cooling and hydraulic systems to standardise with the D-3801, and were fitted with similar ejector exhausts. Employed for advanced training after withdrawal from first-line service, the last D-3800s were scrapped in 1954.
Take-off weight; 2480 kg / 5467 lb
Empty weight; 1800 kg / 3968 lb
Wingspan; 10.62 m / 34 ft 10 in
Length; 8.17 m / 26 ft 10 in
Height; 2.71 m / 8 ft 11 in
Wing area; 17.10 sq.m / 184.06 sq ft
Max. speed; 475 km/h / 295 mph