Dewoitine D 520

One of the best french fighters of World War 2 and of the few to be available in quantity, the D520, although less powerfull than the most potent Me 109, had many wins it credited until the surrender , after which he returned to be produced in order of German To equip Italy , Romania and Bulgaria.

History
The D.520 was Dewoitine from 1936 based on the Dewoitine D.500 by a team led by French designer Emile Dewoitine developed. Much of this work took place after the nationalization of the arms factories in France In March 1937, which also Dewoitine affected, was officially within the SNCAM ( Societe Nationale de Constructions du Midi Aéronautiques , later in the EADS Group merged ) instead. The development followed the Specification C1 for a 520 km / h speed fighter, which was agreed by the Technical Service of the Armée de l' Air published in 1936.

After the first Prototype could not muster the necessary speed, the project was modified and came together with the Morane- Saulnier MS.450, the Caudron CR.780 and Loire-Nieuport LN.60 in January 1937 in the testing. It turned out to a clear need for improvement, which delayed the progress of the project. Only in January 1939, a second prototype was completed, which could demonstrate satisfactory achievement and in February of the year for renewed testing by the CEMA in Villacoublay reached. This was soon followed by a third prototype, with a stronger Hispano-Suiza- 12Y -31 engine was fitted.

Because of the delays that had arisen with the development of competition types, the Armée de l' air , finally decided to order a pilot series of 200 copies, with option for another.

Use
To use the D.520 came from 13 May 1940. At the outbreak of the western campaign with Germany on 10 May 1940 but only 36 machines to use, too few to give the French armed forces a chance against the Bf 109 of the German Luftwaffe. The increasingly high volume production just seemed at the time, so that the entry into force of the armistice on 24 June 1940 no fewer than 294 operational units were delivered to front line units , of which about 50 were destroyed in air combat and about 5 by German flak.

Overall, before the Armistice (25 June ) 403 machines to the Armée de l' Air delivered. In May and June of 1940 D.520s 108 safe and 39 probable, a total of 147 kills of enemy aircraft reached : 7 142 Italian and German. A large probability is that most of these firings actually took place, but at least 60-70 % of that, in contrast to completely implausible reports of shooting down RAF fighters during the same period. Sun met on 9 each other in June 1940, the German II / JG 27 Bf 109E with its French and some of the GC I / 3 with their D.520s. Both units and their pilots were kampferfahren and dominated their aircraft ( new aircraft types, this is not initially the case). On their return reported the Französ. Pilots six kills. In fact, six German fighters (Bf 109) shot down - and a D.520, which made a successful belly landing. German authors such as Ring and Girbig (Book Jagdgeschwader 27) And Jochen Prien in his book series about the German fighter formations ( Volume 3, mainly on the western campaign , undated , published about 2000 ) , they confirm this level of losses against the D.520. This example can be taken as an indication that the D.520 was generally superior in aerial combat, the Bf 109E, even if its top speed was slightly lower (532 to 570 km / h ).

The D.520 was also supported by the Vichy regime in North Africa, Syria and of the Allied nations and Germany Bulgaria, Italy and Romania used.

In late 1944, the remaining D.520 taken over by the French forces, and then used against the retreating German troops ( a total of more than 900 machines produced). After the war, some of the machines turned into double seated training aircraft, then the designation D.520 DC (Double commande) Received. In September 1953, the last D.520 was retired in France.

Production and use from 1940 to 1944
The production of the D.520 was stopped with the conclusion of the armistice. Mid-1941 contracts were signed on a joint aircraft program between the Empire and the French government. It was intended to produce a total of 350 in Toulouse D.520 for the Armée de l' Air. By the end of 1941, 74 aircraft, built by the end of 1942 a total of 312 aircraft. After the German occupation of southern France, the production started in September 1943 to 116 or more 128 aircraft. This was built during this period, a total of 428 or 440 aircraft.

During the German occupation in November 1942 a total of 246 D.520 were captured, which were forwarded to the Chief of Air Force training system. Some of the planes went to Bulgaria. On 31 January 1944 flew a total of 44 D.520 still in the Air Force, 30 September 1944 only seven. The demonstration of the use of aircraft was a fighter pilot in the schools JG 101 to 107 and JG - hunting teachers review body. In the loss records of the Air Force to 30 September 1944 a total of 137 accidents recorded, of which about half total losses.

Development and Technology
Even with Dewoitine experimented initially with the final configuration of the Hunter (see the Development of the Bf 109). It was the period of transition towards verstrebungsfrei built fighters with high aerodynamic quality. Sun had the first of three prototypes flew for the first time in 1938, is still an open cockpit , which should probably get a better view of the pilot benefits. Already on the second prototype, however, a cockpit canopy was used as the D.520 So not been able to achieve the desired speed of 520 mph. Nor could the 654 kW ( 890 PS) satisfying engine, the Hispano- Suiza delivered. The 12Y -31 used was not cooled sufficiently for the predetermined aerodynamics.

The production version of the D.520 was then by Hispano -Suiza 12Y -45 Series engines with a capacity of 670 kW ( PS 910 ) is driven. The drive was completed by an electrically adjustable 3-blade Propeller. The fuselage was extended to the prototype. The series machines were given extra armor and armed with a 20 -mm cannon that fired through the propeller hub, and four 7.5- mm-MGs in the wings.

It built a total of 910 D.520 all variants (including the three prototypes).

Other variants
In an effort to improve the performance of the D.520 and meet the bottlenecks in the production of the native Hispano -Suiza engines, has been experimenting with various other engines. It originated until the French surrender in June 1940 following the developments of D.520 : Even after the surrender, the design was in the unoccupied part of France (Vichy France) Process. This created the following variations: In November 1942, also occupies the hitherto unoccupied part of France from the Germans and halted all further developments.
 * D.521 with a 768 kW (1044 hp) Rolls- Royce Merlin III. The engine proved to be too heavy for the structure. The D.521 was therefore never in series.
 * D.522 with a ( U.S. ) Allison V -1710C-1. The project was discontinued after the French surrender.
 * D.523 was a 809 kW (1100 hp) Hispano -Suiza 12Y -51 and one - Szydlowski Planiol turbocharger . In June 1940, the first Vorserientests were almost completed and the variant was close to mass production.
 * D.524 with a 883 kW (1,200 hp) Hispano -Suiza 12Y - 89ter . A prototype was built but never flown.
 * D.525, a planned development of the D.523.
 * D.530, a planned development with even more powerful engine (1400 hp Rolls- Royce Merlin or 1800 hp Hispano -Suiza 12Y ).
 * D.520 amélioré, a series machine with minimal design changes, with which the maximum speed should be improved.
 * D.520Z, a powerful version with a 1177 kW (1600 hp) Hispano -Suiza 12Z- engine. It has built a prototype, the tests but were prevented by the German authorities. They were after the liberation of France resumed in 1944, but finally finished 1949th
 * M.520T, A variant with a modified hull design, but which was never built.

After the war, D.520 to 13 two-seater training version D.520 DC (Double commande, dual control) converted and used by the Armée de l' air.

The design of the D.520 was direct basis for the development of the following other types of Dewoitine :
 * HD.780: Seaplane variant of which only one prototype was built.
 * D.790: Concept of a Aircraft carrier Version for Aéronautique Navale.
 * D.550: record unarmed aircraft variant with reduced weight, of which a copy was built in 1939 and flew. destroyed in 1944.
 * D.551: On D.550 -based military version with 809 kW (1100 hp) Hispano -Suiza 12Y -51 engine. Before the French capitulation only a few were built that were not flown. The 1941 work was resumed by the Germans but soon stopped.
 * Hispano -Suiza HS.50: Version with Hispano -Suiza 12Z- engine, SNCASE developed on request of Spain, based on the D.551 . Volume production in Spain, it did not come. It has been in Seville merely a non- airworthy demonstration framework

Operators

 * France


 * Vichy France
 * Bulgaria


 * Deutsches Reich
 * Italy
 * Italian Social Republic
 * Romania

Specifications

 * Model: D 520SD520_3v.jpg
 * Wingspan: 10.2 m
 * Length: 8.75 m
 * Height: 3,4 m
 * Weight: 2,100 kg (empty) and 2,800 kg ( loaded)
 * Engine: A Hispano -Suiza 12Y -45, 12 cylinders in line (910 hp)
 * Maximum speed: 530 km / h
 * Maximum ceiling: 11.000 m
 * Normal Range: 1240 km
 * Armament: Cannon 404 Hispano -Suiza 20 mm ( propeller shaft ) and four MAC 1934 machine guns of 7.5 mm ( wings)