Morane-Saulnier MS.406
The Morane-Saulnier M.S.406 was a French single-seat fighter, the production development of the M.S.405 prototype that first flew on 8 August 1935, built to a 1934 French Air Force requirement. It was France's most numerous fighter of the Second World War: 1,037 were completed in France before the collapse of June 1940, with limited production continuing under German supervision afterwards, and Wikipedia's accounting puts the French-built total at 1,176. Outmatched by the Messerschmitt Bf 109E in speed, armour and armament, though able to out-turn it, French squadrons flying it were credited with 269 confirmed victories, against 696 confirmed victories for French single-engined fighters as a whole in 1940. After the armistice it fought on with Vichy forces in Syria, Madagascar and Indochina; Finland flew it in the Winter and Continuation Wars and re-engined 41 aircraft with captured Soviet engines as the Mörkö-Morane; and Switzerland built it under licence as the D-3800 and developed the D-3801, which served until 1959. The examples preserved today are Swiss D-3801s.
Why It Mattered
When the Second World War began, no French fighter was more numerous than the Morane-Saulnier M.S.406, the production version of the M.S.405 prototype. It looked thoroughly modern, and for its maker it was a string of firsts: Morane-Saulnier's first low-wing monoplane, its first design with an enclosed cockpit, and its first with a retractable undercarriage. Numbers, though, could not make up for performance. Against the Messerschmitt Bf 109E the Morane was some 50 mph too slow, and too lightly armoured and too lightly armed, though it could out-turn the German fighter. Even so, French M.S.406 squadrons were credited with 269 confirmed victories; France's single-engined fighters as a whole were credited with 696 before the collapse of June 1940. France's defeat did not end the type's career: Vichy aircraft fought on against the Allies, Finland flew the Morane against the Soviet Union, and Swiss licence production kept the design in service into the 1950s.
Design Notes
The M.S.405 was drawn up in response to a French fighter specification issued in July 1934. For all its modern outline, its structure was old-fashioned: a series of bulkheads joined by aluminium tubes and wire-braced struts, skinned with Plymax, a composite of plywood and aluminium. The first prototype flew on 8 August 1935, powered by a Hispano-Suiza 12Ygrs engine, but development took three years and the second prototype did not appear until January 1937. Changing the engine to the 860 hp Hispano-Suiza 12Y-31 brought the new designation M.S.406, and the fourth pre-production aircraft with that engine flew on 20 May 1938. Its armament paired one 20 mm cannon mounted in the engine with a 7.5 mm machine gun in each wing. Those wing guns were a weakness: unheated, they often froze at altitude, and each carried only 300 rounds.
Operational History
Production was slow to build: only twelve M.S.406s had been delivered to the Armée de l'Air by the start of 1939, though by that September the lines were turning out eleven aircraft a day. In all, 1,037 M.S.406s were completed in France before the collapse of June 1940. When Germany attacked on 10 May 1940, 229 Moranes were operational; by the armistice, only just over 70 still were. Three hundred were lost during the battle — 150 of them away from combat, to accidents, deliberate destruction and other causes; 100 fell in aerial combat and 50 to ground fire. Limited production continued after the armistice under German supervision, and Vichy M.S.406s fought the Allies in Syria and Madagascar and met Thai aircraft over Indochina. Germany used captured Moranes mainly for training, passed others to Italy, and delivered 48 to Croatia in 1943. Finland had received its first 30 M.S.406s in February 1940 and flew them in the Winter War, making 259 operational sorties and being credited with 16 Soviet aircraft shot down. The Finns later bought more from Germany and, in time, re-engined 41 of their aircraft with captured Soviet Klimov M-105 engines as the Mörkö-Morane. Switzerland took yet another path: it built the fighter under licence as the D-3800, 82 aircraft from the federal factory at Emmen, and then developed the more powerful D-3801.
Afterlife
By the end of the war, most M.S.406s and their derivatives were out of service, overtaken by the rapid advance of fighter design. Finland kept its Moranes on as advanced trainers after the fighting ended, and the last of them were scrapped in 1952. In Switzerland the D-3800s served as advanced trainers until 1954, and the D-3801s, retired as fighters in 1948, stayed in service as trainers and target tugs until 1959. The Moranes preserved today are the Swiss derivatives rather than French-built M.S.406s: a D-3801 is on display at the Musée de l'Air et de l'Espace at Le Bourget, and D-3801 J-276 at the Flieger-Flab-Museum at Dübendorf.