9th November 2004.

HR Dewoitine D.520 of GC II/7, 4th escadrille, Vichy Air Force, Tunisia 1942.

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HISTORY:

The Dewoitine D.520 was perhaps the best fighter available to the Armee de l'Air during the German invasion of France in May of 1940. It was yet another example of a combat aircraft which flew on both sides during World War 2.
 
The D.520 was a single-seat, single engined low-winged fighter powered by a liquid-cooled Hispano-Suiza 12Y Vee-type engine. It was designed in November 1936 by a team led by Emile Dewoitine, who was at that time the director of a private design office. It was designed in response to a specification issued in 1937 for a single seat fighter. It was designed around the 900hp Hispano-Suiza 12Y-21 liquid-cooled engine, and was to have a maximum speed of 323 mph (520 km/hr). The designation D.520 was assigned, the 520 standing for the maximum speed in kilometers per hour. Provisions were made for the future installation of an appreciably more powerful 1200 hp engine then under development by Hispano-Suiza. 

Dewoitine's design office was later absorbed by the Societe Nationale de Construction Aeronatiques du Midi (SNCAM), and he was named deputy managing director of the firm. The first of three prototypes (the D.520-01) flew on October 2, 1938 at Toulouse-Francazal with Marcel Doret at the controls. It was powered by a Hispano-Suiza 12Y-21 liquid-cooled engine rated at 890 hp. For the preliminary trials, the D.520-01 had a two-bladed wooden propeller and the cockpit canopy was removed. The engine was cooled by a set of radiators which were submerged underneath the wing. This arrangement was found to produce excessive drag which limited maximum speed to 298 mph and the radiator was later moved to a position underneath the fuselage. In addition, the vertical tail was increased in area to correct some lateral instability. After a wheel-up landing on November 28, the aircraft was re-engined with a 12Y-29 power plant and was fitted with a "jet" exhaust manifold which replaced the former separate pipes. These modifications enabled the aircraft to achieve its design maximum speed of 520 km/hr. The D.520-01 achieved 513mph in a dive on February 8, 1939.
 
The second prototype (D.520-02) flew for the first time on January 28, 1939. It had a completely redesigned vertical tail, a backwards-sliding cockpit canopy, and an armament of one 20mm cannon firing through the propeller hub and two machine guns mounted in gondolas underneath the wing. The D.520-02 was transferred to the Centre d'Essais du Materiel Aerien (CEMA) at Villacoublay. When re-engined with a 12Y-31 engine in place of its original 12Y-29, it achieved a maximum speed of 341 mph at 17,060 feet, and could reach an altitude of 26,240 feet in 12 min 53 sec. 
It was soon joined by the third prototype (D.520-03), which flew for the first time on March 15, 1939. It differed in having a different type of supercharger and a steer able, non-retractable tail wheel replacing the tail-skid. 
Flight trials at CEMA went fairly well, and an initial contract for 200 production machines to be powered by the 12Y-31 engine (later replaced by the 12Y-45) was issued in March of 1939. A contract for an additional 600 D.520 fighters was issued in June of 1939. This was later reduced to 510 in July. On the outbreak of war in September of 1939, a new contract brought the total of D.520s on order to 1280, with the production rate to be 200 machines per month from May 1940 onward.
 
Successive amendments to this order on April 19, 1940 called for a total of 2250 machines, with the production rate being 350 per month. In addition, 120 machines were ordered by the Aeronavale in January 1940. 
The first production D.520 flew on November 2, 1939. It was powered by the 830 hp Hispano-Suiza 12Y-31 engine, and was armed with two 7.5-mm machine guns in housings underneath the wings. It had a curved, one-piece windshield. The fuselage was about 20 inches longer than that of the prototypes, and the engine cowling was modified. Two additional fuel talks were fitted in the wing leading edge. Armor plate was fitted behind the pilot's seat. 
The second production machine had a 910 hp Hispano-Suiza 12Y-45 engine with a supercharger and an electric 3-bladed propeller. It was armed with a 20-mm cannon firing through the propeller hub and four 7.5-mm machine guns in the wings. The curved, one-piece windshield was replaced by windshield containing an optically-flat panel. 
As an alternative to the Hispano-Suiza engine, it was decided in October of 1939 to fit a Rolls-Royce Merlin III engine. Although the project was cancelled in November (the Merlin being allocated instead to the Amiot 353/356 bomber), the 41st D.520 was experimentally fitted with the Rolls-Royce Merlin III engine. The wing armament was omitted. The aircraft was designated D.521, and flew for the first time on February 9, 1940. A maximum speed of 354 mph was attained.
 
The aircraft was later converted back to standard D.520 configuration. 
The Groupe de Chasse I/3 were the first unit to get the D.520, receiving its first planes in January of 1940. At first, the D.520s issued to this Groupe was unarmed training versions, and GC I/3 was assigned the task of shaking out the bugs. In April and May, GC I/3 was issued with 34 "war-cleared" D.520s at Cannes-Mandelieu. The D.520 was very popular with its pilots, who praised it for the sensitiveness of its controls, the simplicity of its control panel, and the ease of recovery from a spin.
 
In comparative trials on April 21, 1940 at CEMA at Orleans-Bricy against a captured Bf 109E-3, tests showed that the German machine had a 20 mph speed advantage owing to its higher power. However, the D.520 had superior maneuverability owing to its superb handling properties.
 
On May 10, 1940, when Germany invaded France, only GC I/3 were equipped with the D.520, a total of 79 D.520s being taken on charge. GC I/3 was hastily thrown into action, the D.520 meeting the Luftwaffe for the first time on May 13, shooting down three Henschel Hs 126s and one Heinkel He 111 without loss to themselves. GC II/2, GC III/3, GC III/6 and GC II/7 were later to receive the D.520, and all took part in the battle for France. A naval unit, the 1o Flottile de Chasse, was also equipped with the D.520. GC II/6 and GC III/7 had also converted to the D.520, but had been formed too late to see any action. By the time of the Franco-German Armistice of June 25, 1940, 437 D.520s had been built, and 351 of these had been delivered to operational units. The Armee de l'Air D.520s gave a good account of them, and gave better than they got. By the time that the battle for France had come to an end, D.520-equipped squadrons had accounted for 108 confirmed kills and 39 probable. A total of 85 were lost on operations, with 54 of these losses being due to direct enemy action.

As French resistance to the German advance began to collapse, between the 18th and 20th of June, GC I/3, II/3, III/3, III/6, and II/7 flew their aircraft to North Africa. 153 machines remained behind in unoccupied France. Three D.520s of GC III/7 escaped to Britain and were incorporated into the Free French 1st Fighter Group formed at RAF Odiham.
 
After the Armistice, the German victors allowed the Vichy government to maintain a reduced air force. Under the terms of the agreement, no D.520 unit was to remain in service on the French mainland, and all surviving D.520 aircraft in France were dispersed and stored. In North Africa, GC I/3, II/3, III/6, and III/7 as well as Aeronavale Escadrille 1AC (the former AC1) were allowed to remain in service with their D.520s.
 
In April 1941, the German authorities agreed to allow the resumption of aircraft manufacture in unoccupied France. When SNCAM was dissolved, its plants were absorbed by S.N.C.A. du Sud-Est (SNCASE). The Vichy Air Force adopted the D.520 as its standard fighter, and the German Armistice Commission permitted production of the D.520 to resume at Toulouse-Blagnac. 550 D.520s were ordered on June 23rd. They were to replace all other single-seat fighters in service in Vichy, and in a second stage of the program, the D.520 was to equip newly-formed units. By the middle of 1943, it was anticipated that the Vichy government would be able to field an Armistice Air Force equipped with 17 D.520-equipped Groups with 442 front-line aircraft, three Aeronavale Escadrilles with 37 aircraft, plus 3 training units with 13 aircraft.
 
The first batch of 22 aircraft was delivered in August of 1941. In 1942, the D.520 number 465 was flown with an improved Hispano-Suiza 12Y-45 engine, a modified radiator, and inboard hinged wheel doors. By December 31, 1942, 349 aircraft had been delivered, 197 of which were powered by the 12Y-49 engine. This brought total production of the D.520 to 775 aircraft.
 
By October of 1942, nine Vichy Groups de Chasse had been equipped with the D.520. In addition, the 1o Flotille de Chasse had been equipped with the D.520. Vichy D.520s saw some action against British forces in the Levant and had escorted Vichy bombers in an attack on Gibraltar.
 
GC III/6 and II/3 took part in operations in Syria in June-July 1941. They were later joined by Escadrille 1AC. During that operation, they saw combat against RAF aircraft. GC III/6 was credited with 19 confirmed kills and four probable. GC II/2 was credited with three confirmed kills and two probable. Esc. IAC was credited with eight kills. Vichy D.520 losses totaled 32, with 11 being shot down, 12 lost in accidents, 7 being destroyed in the ground, and two being abandoned in Syria when the fighter units flew back to French North Africa. 
At the time of the Operation Torch Anglo-American landings in North Africa in November of 1942, 234 D.520s were in unoccupied France (of which 93 were in service), 173 were in North Africa, and 30 were in Senegal. French-based D.520 units comprised GCs I/1, II/1, and III/9 (which had recently received the D.520 in place of its Bloch 152s), and I/2. GC I/2 escaped with 24 aircraft to Meknes on November 9 to avoid capture by German forces. In North Africa, D.520s equipped GCs II/3, III/3 (formerly I/3, its designation being changed at German request since three of its pilots had fled to Gibraltar on October 14, 1941), III/6, II/7, and II/5 Aeronavale IF Flotille (comprising Escadrilles 1AC and 2AC) was also based in Africa.
 
The Allied landings gave rise to fratricidal air battles in which the D.520s of GC III/3 and II/5 were involved, as well as those of 1F Flotille and the Hawk 75s of GC I/5 and II/5. Losses were heavy on both sides. The Aeronavale lost 19 Dewoitines and seven Martin bombers, and the Armistice Air Force lost 16 D.520s and Hawks. Allied air forces lost 44 aircraft during these clashes.
 
In response to the Allied landings in North Africa, German forces invaded Unoccupied France in November of 1942. On November 27th, all French armed forces were disbanded and all existing D.520s were seized. This included 246 D.520s serving with Vichy units, plus 169 D.520s in various stages of completion at SNCASE.
 
Some of these seized D.520s were transferred to two Luftwaffe fighter training units (JG-103 and JG-105). They were highly praised by Luftwaffe crews for their exceptional maneuverability. However, the accident rate was fairly high owing to the great differences between it and the German aircraft to which the pilots were accustomed. 
Sixty D.520s were transferred to the Regia Aeronautica, and were operated primarily as fighter trainers by Gruppi 13, 22, 24, and 167. About a hundred D.520s were issued to the Bulgarian Air Force, which used them operationally against the US 9th Air Force. Most of these were lost in combat. The Rumanian Air Force operated a small batch of D.520s in combat on the Eastern Front, flying them alongside that air force's Bf 109s. 

Upon the liberation of Southwestern France, a French FFI (Forces Francaises de l'Interieur) fighter Groupe was formed with D.520s that had been captured from the retreating enemy. This unit took part in attacks on retreating German units and provided escort for Allied bombers and strafed artillery positions. In March of 1945, this unit reequipped with the Spitfire Vb, and its D.520s were transferred to GC B I/18 and to a training unit. About 55 D.520s were recovered from the Luftwaffe as the Allied forces advanced eastward, which were later reinforced by another 20 which were brought back from North Africa. 

In postwar years, the D.520 continued to serve with training units in the revived Armee de l'Air. Several were converted to two-seat configuration under the designation D.520 DC (for "double commande"). The last unit to fly the D.520 was the Escadrille de Presentation de l'Armee de l'Air (EPAA), which had previously flown Yak 3s brought back to France from the Soviet Union by the Normandie-Niemen regiment. The last D.520 was finally withdrawn from service in September of 1953.
 
Four D.520s are known to exist in 1966. No. 408 belongs to the Musee de l'Air, No. 603 is on display at the Ecole de l'Air, No. 650 (a DC) is on display at Etampes-Mondesir, and No. 862 is on display at the Luxeuil-Saint Sauveur Air Base

Above text from a site I found while looking for pictures.

History of the aircraft, thanks to Rémi Baudru, from the from the Aeroforum.

This D520 number 232 was coded "9", and flew with the GC II/7, 4th escadrille. This plane was in this escadrille from November 1940 to May 1942 when it was crash landed on a beach of the cap "BON" in Tunisia, due to a mechanical problem. This plane's pilot was Sergeant LE PERFF

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These files have been created from the LR D520 3Dz by Alatriste and Claudio Wilches. This plane features the D-520 cockpit interior by Claudio Wilches, with new corrected wing view 3dz by me.

All the 3dz, and re-mapping work on this model is by Col. Gibbon, but the original splitting up of the LR model was done by Sandbagger, based on my read me, as was the base skin, which Sanbagger converted from scale drawings, and was later painted by Dean H.

New shadow file, and corrected medium distance model by Col. Gibbon.

Over and Out!

Col. Gibbon
