Morane-Saulnier M.S.405

The Morane-Saulnier M.S.405 was developed to a requirement of a French fighter specification made by the French Air Ministry in July 1934. Even if it was a monoplane, it was in many other ways an outdated design. While Messerschmitt and Supermarine were using all-metal stressed skin constructions, with the metal surface of the fuselage provided structural strength, Morane-Saulnier built their aircraft using technology employed in previous biplanes. Structural strength was provided by a series of bulkheads connected by aluminium tubes, connected by wire-braced struts. The aircraft was skinned with Plymax , which was a composite material made of both plywood and aluminium. Thanks to that skin method the aircraft resembled the Hawker Hurricane, which was built using similar methods.
It was armed with just three guns, one 20mm Hispano-Suiza H.S.404 firing through the propeller's hub and two 7,5mm MAC 1934 machine guns in the wings, quite underarmed for 1939-1940.
The first prototype flew for the first time on 8th August 1935 and was powered by an Hispano-Suiza 12Ygrs engine which yielded 824 hp of power for take-off and 848 hp at 4000 m (13123 ft) high. It had a top speed of 480 km/h (298 mph) at 4000 m (13120 ft) high. It was a nice top speed for the year 1935, however, it would take up to three years of development. The second prototype didn't appear until January 1937 and was powered by an improved Hispano-Suiza 12Ycrs engine. This second prototype showed promising results and on 1st March 1937, the French placed a pre-production order of 16 models.
The first of the pre-production aircraft, flew for the first time on 3rd February 1938 at Centre d'Essais de Materiel Aérien (CEMA). The No.2 was sent to Reims for operational testing, after which, it was decided to change the engine again. This time a Hispano-Suiza 12Y-31 would be fitted and thus the first prototype for the M.S.406 was built, which was the one that entered mass-production. The first production order for the M.S.406 was placed in April 1938 and in May the M.S.405 flew with a new engine.
Three of the pre-production M.S.405 were used for experiments which resulted in new designations, like the No.3 which had fuel tanks placed in the wings to make space to fit a dummy parachutist. This experimental aircraft was called Morane-Saulnier M.S.407L.P.
The No.12 was fitted with a Hispano-Suiza 12Y-45 engine and became the prototype for the Morane-Saulnier M.S.411 (which was also a development of a previous M.S.410 variant). It flew for the first time on 24th January 1939 and it had a fixed-radiator (while the ones equipped with the 12Y-31 had a retractable one.
The No.13 had the same fixed radiator as the No.12 but included compartments in the wings for flares. It was given the designation of Morane-Saulnier M.S.408. This aircraft became the prototype for the Swiss-produced variant D-3800.
Apparently some M.S.405 were used during the Phony War and the German Invasion of France mixed with the more advanced M.S.406. However by that time there were so few of them that most of them were used testbeds for other types of engines as we've shown.

Sources:
1. http://www.historyofwar.org/articles/weapons_MS405.html
2. https://en.wikipedia.org/wiki/Morane-Saulnier_M.S.406#M.S.405
3. https://www.valka.cz/Morane-Saulnier-MS-405-C-1-t71689
4. Signal Squadron - Aircraft In action 180 - French Fighters of World War II in Action
5. Salamander Books - The Complete Book of Fighters
6. AJ Press - Monografie Lotnicze - Morane-Saulnier M.S.406