Morane-Saulnier M.S.406

The Morane-Saulnier M.S.406 is a French fighter aircraft developed and manufactured by Morane-Saulnier starting in 1938. It was France's most numerous fighter during the Second World War and one of only two French designs to exceed 1,000 in number. At the beginning of the war, it was one of only two French-built aircraft capable of 400 km/h (250 mph) – the other being the Potez 630.

In response to a requirement for a fighter issued by the French Air Force in 1934, Morane-Saulnier built a prototype, designated MS.405, of mixed materials. This had the distinction of being the company's first low-wing monoplane, as well as the first to feature an enclosed cockpit, and the first design with a retracting undercarriage. The entry to service of the M.S.406 to the French Air Force in early 1939 represented the first modern fighter aircraft to be adopted by the service. it was considered underpowered and weakly armed when compared to its contemporaries and the M.S.406 was outperformed by the Messerschmitt Bf 109E during the Battle of France.

The type was capable of holding its own during the so-called Phoney War from September 1939 to 10 May 1940. Upon the invasion of France in May 1940, approximately 400 Moranes were lost. Out of these, around 150 were lost to enemy fighters and ground fire, while another 100 aircraft were destroyed on the ground during enemy air raids; the remainder were deliberately destroyed by French military personnel to prevent the fighters from falling into German hands. French M.S.406 squadrons had achieved 191 confirmed victories, along with another 83 probable victories. Limited production of the type continued in France for sometime after the Armistice of 22 June 1940 under German supervision.

The M.S.406 was exported to a range of customers. Out of 160 aeroplanes ordered by Poland, none had reached Polish territory before the outbreak of war, with the first consignment sent on 29 August 1939. Of particular note was its service in the hands of Finnish and Swiss air forces; both operators chose to develop indigenous derivatives of the M.S.406, such as the Finnish Mörkö-Morane). By the end of the war, the majority of M.S.406s and its derivatives were out of service, having been rendered obsolete by rapid advances in fighter aircraft technology. Its final use was as an advanced trainer aircraft in Finland, prior to the last examples of the type being scrapped during 1952.

Design and development

Origins

During 1934, the Service Technique de l'Aéronautique (Aeronautical Technical Service) of the French Air Force issued the "C1 design" requirement for a new and modern single-seat interceptor fighter. First flown by French aerobatic pilot Michel Détroyat, the prototype demonstrated the type's favourable flying characteristics from the onset. Early test flights were flown with a fixed undercarriage, which was replaced by a retractable counterpart later on.

Development of the M.S.405 proceeded fairly slowly; testing revealed the need to modify the wing planform and dihedral, while the Chauvière-built propeller was replaced by a Levasseur-built counterpart. The second prototype was able to attain a speed of during testing.

Production

thumb|right|Aircraft cockpit instruments (Swiss D.3800 variant)

During the late 1930s, there was a growing perception that a major conflict between Germany and France was not only looming but increasingly unavoidable. As part of its rearmament, the French Air Force placed an order for 1,000 M.S406 airframes during March 1938.

During late 1938, production of the M.S.406 commenced; the first production example performed its maiden flight on 29 January 1939.

According to Botquin, the M.S.406 had attracted considerable foreign attention during the late 1930s, and had shown signs of commercial promise early on.

On 23 August 1939, in response to the diplomatic crisis emerging over the Invasion of Poland, all French Air Force units were mobilised as part of preparations to be ready for imminent combat operations. Various M.S.406-equipped units were deployed along the border with Germany stretching between Luxembourg and Switzerland, intended to support the sizable ground elements of the French Army from the air. During the Phoney War opening phase of the Second World War, a time of relatively low combat intensity, the type's activities focused upon air defence operations with the aim of countering the prolific aerial reconnaissance and probing activities of small groups of Axis-aligned fighters coming over the border, in addition to escorting friendly reconnaissance aircraft. On the eve of the invasion, a total of 10 Groupes de Chasse were equipped with M.S.406 fighters, along with a number of defensive units which were almost exclusively equipped with either the M.S.406 or Bloch MB.152 aircraft.

thumb|Monument in [[Longpont (Aisne) where a French pilot Lieutenant André Monty was shot down in June 1940 by three Bf 109s and buried among his MS.406 remains.]]

During the relentless fighting that followed, Allied forces suffered a high rate of attrition and were unable to keep up with the level of damage being sustained. The rapid advance of German forces led to repeated retreats and abandonment of bases, rendering most repair and replacement efforts disorganized, along with ground crews often having to destroy large numbers of their own fighter aircraft on the ground to prevent their capture. While there were isolated incidents of favourable results being achieved with the type even against the capable Bf 109 — 100 km/h faster than the Morane — the 406 was usually outclassed by the Luftwaffe fighters. The story of GC III/7 was typical. On 15 May, nine Moranes of this fighter unit encountered a dozen Bf 109s over Mézières. The Messerschmitts stayed a few thousand feet above their French opponents and dived in pairs to attack, with a single firing pass, before climbing back and then repeating the attack. Three M.S.406 went spinning down in flames; a fourth Morane, riddled with bullets, crash-landed at Soissons and was wrecked, while a fifth pilot was wounded in the head by splinters, forcing him to land. Six days later, on 21 May, 17 Moranes of the same unit intercepted 50 Dorniers over Compiègne, escorted by as many Bf 109s. Before the Morane could close in to open fire, the Messerschmitts jumped them and shot down four Moranes almost at once. Two more were too badly damaged to be repaired. On their side, the French pilots claimed two Bf 109s. The M.S.406 holds the unfortunate distinction of being the least effective French fighter in service during the Battle of France, which Botquin suggests was due to its relatively low firepower. According to Botquin, the deployment of the type from this point onward reflected the fighter's relative obsolescence; it was reduced to relatively minor roles, being used mainly for training purposes in mainland France. Both Switzerland and Turkey also operated the type; the Swiss actually downed a number of both German and Allied aircraft during the 1944–45 period.

Before the Pacific campaign proper, Vichy authorities in French Indochina were engaged in a frontier war against Thailand, during 1940–41. A number of M.S.406s stationed in Indochina downed several Thai fighters before all French Air Force units were withdrawn from the theatre.

In Finnish service

The M.S.406 had a parallel career in Finland. In February 1940, the first 30 French fighters were allocated to LeLv 28, commanded by Major Jusu. Total Finnish kills in Moranes were 121. The top Morane ace in all theatres was W/O Urho Lehtovaara, with 15 of his 44.5 total kills achieved in Moranes. The Finnish nicknames were Murjaani ("moor" or "Negro"), a twist on its name, and Mätimaha (roe-belly) and Riippuvatsa (hanging belly) because of its bulged ventral fuselage.

Variants

M.S.405

The M.S.405 was a low-wing monoplane of mixed construction, being furnished with a fabric-covered wooden tail and a bonded metal/wood material (Plymax) skin fixed to duralumin tubing. Plymax consisted of a thin sheet of duralumin bonded to a thicker sheet of plywood. It was the company's first low-wing monoplane design, as well as the first with an enclosed cockpit, and the first to feature retractable landing gear. The new Hispano-Suiza 12Ygrs engine driving a two-pitch Chauvière propeller powered the first prototype, M.S.405-01, which flew on 8 August 1935. The added thrust boosted the top speed to at , resulting in an improvement of about over the M.S.406 at the same height. Production of the M.S.410 had only just started in May 1940, when the German attack resulted in the conversion programme being stopped, by which point only five examples of the type had been completed.

M.S.411, M.S.412

A single example of the M.S.411 was constructed by converting the 12th aircraft of the pre-production line with the 406 wing and the Hispano-Suiza 12Y-45 engine. A later modification was started as the M.S.412 with the Hispano-Suiza 12Y-51 engine, but this was not completed by the time the war ended.

M.S.450

In 1939, Hispano started prototype deliveries of the new Hispano-Suiza 12Z engine of . One was fitted to a modified M.S.410 to create the M.S.450, giving dramatic improvements in performance, especially at altitude. However the engine did not enter production before France fell, and the similarly modified Dewoitine D.520 (the D.523) was considered a better design for the engine anyway.

Other variants

thumb|Morane Saulnier MS.430 photo from L'Aerophile December 1936

The M.S.406 airframe was also used in a number of other projects.

;M.S.430: a two-seat trainer built by inserting a "plug" in the central fuselage with an extra cockpit for the trainee pilot, and using the much less powerful Salmson 9AG radial engine.

; M.S.435: a more powerful two-seat trainer version with the Gnome-Rhône 9K engine.

Swiss variants

thumb|D-3801, a Swiss development of MS-406

thumb|Morane D-3801 J-143 (Association Morane Charlie-Fox)

D-3800

In 1938, Switzerland obtained a license for local production of the MS.406. Two MS.406H fighters were supplied to Switzerland in September 1938 and April 1939 to serve as pattern aircraft as the D-3800, retaining the earlier wing design of the 405, but powered by the newer Hispano-Suiza 12Y-31 engines as used by the MS.406.

Pre-production started with a run of eight aircraft from EKW with engines built by Adolph Saurer AG driving a new Escher-Wyss EW-V3 fully adjustable propeller. Instruments were replaced with Swiss versions and the drum-fed MAC machine guns with locally designed and built belt-fed guns, eliminating the wing-bulges of the French version, and avoiding the freezing problems encountered by French guns. The first of these aircraft was completed in November 1939. The pre-production models were then followed with an order for a further 74 examples, which were all delivered by 29 August 1940. In 1942, a further two were assembled with spares originally set aside for the original production run.

During 1944, surviving aircraft were modified with new cooling and hydraulic installations, and were fitted with ejector exhausts. These modifications were the same standard as the D-3801 series, making them identical with the exception of the engine installation. At the end of the war the remaining aircraft were used as trainers, until the last one was scrapped in 1954.

D.3801/3803

thumb|left|Swiss D.3801 circa 1941

thumb|D.3801 in 1942

The Swiss continued development of the MS.412 when French involvement stopped following the June 1940 Armistice. The Dornier-Altenrhein factory completed a prototype powered with a licensed-produced HS-51 12Y engine, generating together with the fixed radiator and revised exhausts as tested on the MS.411, in October 1940. The new type retained the armament changes and other improvements introduced on the D.3800. This series was put into production in 1941 as the D-3801 with continued deliveries until 1945 with 207 completed. Another 17 were built from spares between 1947 and 1948.

thumb|right|The re-engine D.3802 in 1946, 12 of which were produced.

The D.3802 was based on the MS.450, emerging as the MS.540, with a Saurer YS-2 engine. The prototype flew in the autumn of 1944, revealing several shortcomings, but it was capable of . 12 were produced seeing limited use with Fliegerstaffel 17 and some other units.

The last development of this aircraft was the D.3803, with Saurer YS-3 engine, and modified dorsal fuselage (with an all-round visibility canopy). The D.3803 was armed with three HS-404 cannon (one in the nose, two in the wings), plus up to bombs and rockets. Despite not having a powerful engine, the type reached at . The performance was impressive, but the last development of this 1935 fighter design had several shortcomings and was not entirely successful. Its development was halted as P-51D Mustangs became available.

Finnish variants

Mörkö-Morane

thumb|left|[[Finnish Air Force|Finnish Morane-Saulnier M.S.406 departing for patrol during the Continuation War at Viitana, Karelia, 17 March 1942.]]

France sent 30 M.S.406s to Finland, between 4 and 29 February 1940. By 1943 the Finns had received an additional 46 M.S.406s and 11 M.S.410s purchased from the Germans. By this point, the fighters were hopelessly outdated, The airframe required some local strengthening and also gained a new and more aerodynamic engine cowling. These changes boosted the speed to .

Originally, it was planned to convert all the 41 remaining M.S.406s and M.S.410s with the Soviet engine, but it took time, and the first front-line aircraft of this type did not reach LeLv 28 until July/August 1944. Lieutenant Lars Hattinen (an ace with six victories) scored three kills with the Mörkö-Morane, one with each Mörkö-Morane in the squadron. More fighters arrived from the factory, though, and the Mörkö-Moranes took part in the Lapland War as reconnaissance and ground attack aircraft. Not all the Mörkö-Morane conversions were completed before March 1945, when the entire re-engining programme was halted.

Operators

thumb|Australian troops with Morane-Saulnier MS.406C1 fighters of Groupe de Chasse I/7, Syria, in July 1941.

thumb|Morane-Saulnier D-3801 J-276 at the [[Flieger-Flab-Museum]]

thumb|The D-3801 preserved at the [[Musée de l'Air et de l'Espace]]

thumb|D-3801 J-276 at Fliegermuseum Dübendorf

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Nationalist Chinese Air Force ordered 12 aircraft in 1938 and they were shipped to Haiphong, but diverted to Escadrille EC 2, which fought against the Japanese and Thai in December 1940. due to the fall of Poland.
Polish Air Force in exile in France operated at least 91 aircraft in several training and combat units:
Groupe de Chasse de Varsovie
Section no.1 Łaszkiewicz GC III/2
Section no.2 Pentz GC II/6
Section no.3 Sulerzycki GC III/6
Section no.4 Bursztyn GC III/1
Section no.5 Brzeziński GC I/2
Section no.6 Goettel GC II/7
Jasionowski Koolhoven Flight
DAT section Krasnodębski GC I/55 based at Châteaudun and Étampes
DAT section Skiba GC I/55
DAT section Kuzian based at Nantes
DAT section Opulski based at Romorantin
DAT section Krasnodębski based at Toulouse-Francazal
Centre d'Instruction d'Aviation de Chasse at Montpellier
Ecole de Pilotage No 1 (Chasse) at Etampes
Ecole de Pilotage at Avord
Centre d'Instruction at Tours
Depot d'Instruction de l'Aviation Polonaise at Lyon-Bron
Montpellier Flight

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Swiss Air Force

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Turkish Air Force received 45 Moranes.

Specifications (M.S.406 C1)

thumb|Morane-Saulnier MS 406 C1