Французский истребитель SNCASO MB.150: История разработки и прототипы

{|Infobox aircraft type
|type = Fighter aircraft
|manufacturer = SNCASO
|designer =
|first flight = 29 September 1937

The design team, headed by Maurice Roussel, was assembled at Bloch's Courbevoie facility in Paris. Although the C.1 competition was ultimately won by a rival design, the Morane Saulnier M. S.406, it was decided to independently continue with the design's development. During 1936, these efforts culminated in the first attempted flight of the MB.150.01 prototype; unfortunately, the aircraft proved unable to leave the ground during the attempt. In the ensuing disappointment work on the design was temporarily halted, but development was resumed during early 1937. As a result of the CEMA flights, the prototype's performance proved to be sufficiently interesting as to warrant further development. This brought, at the beginning of 1938, a small increase in the aircraft's wing span, the replacement of the twin wing mounted radiators by a single unit installed between the wheel wells, and the installation of an improved 14N 7 engine, which led to the prototype being re designated as the MB.150.01M (M standing for modified).

However, there was no direct production of the MB 150.01 as the aircraft having been deemed to be unsuitable for mass production. Amongst other changes needed, the structure of the airframe had to be redesigned in order to suit mass production. During early April 1938, an order was received for a three further prototypes; these were to explore the possibilities for installing more powerful engines of both French and American origins, such as the Hispano Suiza 14AA, Pratt & Whitney R 1830 Twin Wasp, and further derivatives of the Gnome Rhône 14N engine. Accordingly, this design effort led to the production of the MB.151.01 and MB.152.01 prototypes, which were developed and produced in parallel. According to Christesco, the MB.152.01 was "the first true aircraft" of the series. The manufacturing of the fighter was divided amongst the various branches comprising SNCASO. Under the terms of the armistice, the remaining 25 on the production line were completed and delivered into Vichy service. From there, some eventually made their way into the Luftwaffe after 1942. The final member of the family, the MB.157 had a far more powerful engine and eventually became a very different aircraft as the design evolved from the MB.152 to accommodate the larger and heavier 1,590 hp Gnome Rhône 14R 4 motor. Unfinished at the time of the armistice, it was ordered to be completed and flown under German supervision. Demonstrating superb performance, it was taken to Orly where the power plant was removed for testing within a wind tunnel. The excellence in the design was confirmed by Germans when they completed and tested it in 1942, reaching up to flat speed. It was later destroyed in an Allied air raid.

Upon evaluation, early deliveries were deemed unsuitable for combat operations, principally due to issues with the tailplane; thus, plans were laid for the first 157 production fighters to be stored awaiting modification, while additional production examples were built with the correction made. On 26 September 1939, the first modified MB.152s were delivered to the French Air Force; the first of these fighters were allocated to active squadrons by early October and, by mid November 1939, two separate Groupes de Chasse (fighter groups) had been equipped with 26 MB.152s each. At this point, the type still demonstrated some unfavourable flight characteristics, such as during steep dives. Meanwhile, increasing numbers of MB.151 aircraft were being delivered to be squadrons for training purposes in advance of their anticipated conversion to the MB.152. During the initial stage of the conflict, known as the Phoney War, very few engagements between the MB.152 and the aircraft of the Luftwaffe occurred; in this period, only a single kill of a Junkers Ju 88 was recorded. During the Battle of France, a mixture of MB.151s and MB.152s equipped nine Groupes de Chasse; the MB.152 was the most numerous aircraft remaining in service during the final weeks prior to the signing of the Armistice of 22 June 1940. They proved to be tough aircraft, able to withstand considerable battle damage, rapidly reach high speeds during a dive, and functioned well as a gunnery platform. In air combat they were outmatched by the Messerschmitt Bf 109E on almost every count and proved slower than the twin engined Messerschmitt Bf 110. All Bloch units suffered heavy losses. In the week of heavy air fighting between 10 and 17 May, it was almost commonplace for a Bloch squadron to take off with eight or nine aircraft and come back with only two or three. On their side, the pilots of Bloch MB.152s claimed at least 188 enemy aircraft, for the loss of about 86 Blochs. In comparison with its French contemporaries, according to aviation author Michel Cristesco: "the MB.152 was the least successful in combat and the one that suffered the heaviest losses". By April 1941, the German Armistice Commission had agreed with a proposal to standardise the Vichy Air Force onto the Dewoitine D.520, resulting in all other single engine fighters being phased out. Those that were delivered were still in the process of working up when the Greco Italian War broke out, leading to the wider Balkan Campaign between the major European fighters. The MB.151 fighters flew with the 24th Moira Dioxis (Fighter Squadron) of the Hellenic Royal Air Force, stationed at Elefsina against the Italians and Germans, scoring several air to air victories until 19 April 1941, when the last of Greece's MB.151s was shot down. Instead, Bulgaria later received a series of Dewoitine D.520s to meet their needs.

MB.150
Single MB.150.01 prototype powered by a single Gnome Rhône 14N 07
MB.151
MB.151.01 prototype and MB.151. C1 initial production versions powered by 920hp Gnome Rhône 14N 35 engines (144 built)
MB.152
MB.152.01 prototype and MB.152. C1 up rated production versions produced in parallel with 151. C1, powered by 1,050hp Gnome Rhône 14N 25 engines. (482 built)
MB.153
Single MB.153.01 prototype with Pratt & Whitney R 1830 Twin Wasp engine
MB.154
Proposed version with Wright R 1820 Cyclone engine. Not built. MB.155
MB.155.01 prototype converted from a MB.152 and MB.155. C1 production versions powered by Gnome Rhône 14N 49 engines (35 built)
MB.156
Proposed version with Gnome Rhône 14R engine. Not built. MB.157
Single prototype of advanced version, converted from the MB.152 and equipped with a 1,590hp Gnome Rhône 14R 4 engine.