Dewoitine D.520

The Dewoitine D.520 was a French fighter aircraft that entered service in early 1940, shortly after the opening of World War II. Unlike the Morane-Saulnier M.S.406, which was at that time the Armée de l'AirTemplate:'s most numerous fighter, the Dewoitine D.520 came close to being a match for the latest German types, such as the Messerschmitt Bf 109. Because of a delayed production cycle, only a small number were available to meet the Luftwaffe. Template:TOClimit

Design and development

Design of the D.520 started in November 1936 at the private design firm led by Emile Dewoitine. Trying to address problems in earlier designs, he created a fighter using only the latest techniques and engines. The new design was to be able to reach 520 km/h (320 mph) and became known as the "520". Only months later, the firm was conglomerated into one of a number of design-and-manufacturing pools, in this case SNCAM. Still known as the D.520, work on the design continued at the new company.

The prototype D.520 flew on 2 October 1938, powered by the new 660 kW (890 hp) Hispano-Suiza 12Y-21 liquid-cooled engine. The aircraft managed to reach only 480 km/h (300 mph) in flight tests, much slower than expected. Most of the problem seemed to come from greater than expected drag from the underwing radiators, so these were merged into a single radiator under the fuselage. After minor damage in a landing accident, the engine was changed to a newer -29 and included exhaust ejectors for added thrust, along with a variable pitch propeller. These changes were enough to allow the aircraft to reach its design speed.

The prototype was followed in 1939 with two airframes with a new sliding canopy and a larger tail unit. These were armed with a 20 mm cannon firing through the propeller spinner (a feature also found on many German and Russian designs) and two 7.5 mm (.295 in) machine guns in small pods under the wing. The third also included a small tailwheel instead of the original skid. Flight tests went fairly well and a contract for 200 production machines to be powered by the newer -31 engine (later replaced by the -45) was issued in March 1939. A contract for an additional 600 aircraft was issued in June reduced to 510 in July.

With the outbreak of war, a new contract brought the total to 1,280, with the production rate to be 200 machines per month from May 1940. The Aéronautique navale then ordered 120. Another Armée de l'air order in April 1940 brought the total to 2,250 and increased quotas to 350 a month.

The first production D.520 flew in November, powered by the 620 kW (830 hp) 12Y-31 and armed with two 7.5 mm (.295 in) machine guns in housings underneath the wings. It had a curved, one-piece windshield and a sliding canopy. The rest of the production machines were delivered with the 690 kW (930 hp) 12Y-45 engine with a new supercharger and a Ratier three-blade propeller (a few had the -49 of 680 kW/910 hp). They were armed with a 20 mm cannon firing through the propeller hub and four MAC 1934 7.5 mm (.295 in) machine guns in the wings. The curved, one-piece windshield from the prototypes was replaced with one containing an optically-flat panel.

As the first batch of machines rolled off the production lines, they failed acceptance tests due to insufficient top speed and troublesome cooling. Redesigned compressor intakes, a modified cooling circuit and propulsive exhaust pipes proved to be effective remedies for these shortcomings, but as early examples had to be retrofitted with these improvements, the type was not declared combat-worthy until April.

Operational history

Battle of France

The Groupe de Chasse I/3 was the first unit to get the D.520, receiving its first aircraft in January 1940. These were unarmed and used for pilot training. In April and May, they received 34 production machines, which proved to be very popular with the pilots. In comparative trials on 21 April 1940 at CEMA at Orleans-Bricy against a captured Bf 109E-3, the German machine had a 32 km/h (20 mph) speed advantage owing to its more powerful engine. However, the D.520 had superior maneuverability, matching the turning circle although displaying nasty departure characteristics, spinning out of the turn repeatedly during the tests while the Bf 109, owing to its slats, could easily sustain the turn on the edge of a stall.

When Germany invaded France and the Low Countries, 10 May, 228 D.520s had been manufactured, but the Armée de l'Air had only accepted 75, as most others had been sent back to the factory to be retrofitted to the new standard. As a result, only GC I/3 was fully equipped, having 36 aircraft. They met the Luftwaffe on 13 May, shooting down three Henschel Hs 126s and one Heinkel He 111 without loss. GC II/3, GC III/3, GC III/6 and GC II/7 later completed conversion and all took part in the Battle of France. A naval unit, the 1^er Flotille de Chasse, was also equipped with the D.520. GC II/6 and GC III/7 converted to the D.520, too late to see action.

By the armistice at the end of June, 437 D.520s had been built, 351 delivered. They had 108 confirmed kills and 39 probables, losing 54 to enemy action. As French resistance collapsed in the middle of June, GC I/3, II/3, III/3, III/6 and II/7 flew their aircraft to Algeria to avoid capture. Three more, from GC III/7, escaped to Britain and were delivered to the Free French. 153 machines remained in mainland France.

Under Vichy

In April 1941, the German armistice commission authorized Vichy authorities to resume production of a batch of 1,000 military aircraft for their own use, under the condition that 2,000 German-designed aircraft would be later be manufactured in France and delivered to Germany. As part of this agreement, 550 examples of the D.520 were ordered so as to replace all other single-seat fighters in service. The plan was to have the Dewoitine eventually equip a total of 17 Groupes with 442 aircraft, three escadrilles of the Aéronautique navale with 37 aircraft each plus three training units with 13 aircraft. The agreement stated aircraft of the new batch were to be similar with the ones already in service. From serial number 543 on, however, D.520s used the 12Y49 engine that had a slightly higher rated altitude than the 12Y45. But the German armistice commission explicitly prohibited production of the more powerful 12Y51 or 12Z engines.

D.520s of GC III/6, II/3 and naval escadrille 1AC faced the Allies during the Syria-Lebanon campaign in 1941, where they claimed 31 kills over British and Australian aircraft, while losing 11 of their own in air combat and a further 24 to AA fire, accidents, and attacks on their airfields. On July 10, five D.520s attacked Bristol Blenheim bombers from No. 45 Squadron RAF, which were being escorted by seven Mk I Curtiss Tomahawks (US designation: P-40-CU) from No. 3 Squadron RAAF (3 Sqn). The French pilots claimed three Blenheims, but at least four of these D.520s were destroyed by the Australians, including two by F/O Peter Turnbull. The following day, a Dewoitine pilot shot down a P-40 from 3 Sqn, the only Tomahawk lost during the campaign. This Dewoitine was in turn shot down by F/O Bobby Gibbes.

During Operation Torch, GC III/3 (previously known as GC I/3) opposed the Allies over Oran. Flottile 1F saw action versus the United States Navy F4F Wildcat squadron VF-41 (from the carrier Template:USS), over Casablanca. One D.520 was among 14 US victory claims and the only Allied losses were to ground and friendly fire. Other Dewoitine-equipped units in North Africa like GC II/7 or GC II/3 did not to take part in the fighting. Many D.520s were destroyed on the ground by Allied bombing.

Free French Dewoitines

A very small number of D.520s were briefly operated by Free French Forces for training purposes. Along with the three examples who had evacuated to Great Britain in June 1940, two were recovered from retreating Vichy forces in Rayak in Lebanon. These D.520 were flown by pilots of the Normandie-Niemen unit before the men were sent to the USSR, where they flew the Yakovlev Yak-1 that had many similarities with the D.520.

With the Allies

In December 1942, as French forces formerly under Vichy sided with the Allies, there were 153 D.520s left in French hands in North Africa. They flew a few patrols during the Battle of Tunisia, but were considered obsolete, and their radio sets were incompatible with Allied equipment. From early 1943 on, they were relegated to training duties at the fighter school in Meknes, and progressively replaced by Spitfires and P-39s in combat units.

During the liberation of France, a few examples abandoned by the Germans were used by ad hoc units in ground attacks against the isolated German pockets of resistance on the Western coast.

Postwar service

Postwar, those that remained in France were used as trainers. One example was field-modified as a two seater in late 1945. After further experiments, in March 1946, the Armée de l'air required a batch of 20 D.520s to be so converted. However, only 13 of these D.520 DC are recorded to have been completed. The last flight of a military D.520 occurred in 1953.

Foreign users

As German forces invaded Vichy's so-called "free zone" in November 1942, they captured 246 D.520s; additionally, a batch of 62 was completed under German occupation. Some were used by the Luftwaffe for training purposes. The Germans also transferred 120 D.520s to Bulgaria and 60 to Italy. A number of them were intended for the Romanian Air Force, but the shipment was lost on the way. One source claims that they arrived and were used against the Soviets, but says no details of service are known. Another source claims 150 aircraft were sent to Romania. Yet another source claims the so-called Romanian Dewoitines were in fact in transit to Bulgaria and only flew over Romania in order to get to their final destination. The latter seems the most reliable explanation viewed against the numbers of Dewoitines actually available.

Variants

D.520

• Main production version, sometimes designated D.520 S (for série - production) or D.520 C1 (for chasseur - fighter, single-seat).

Direct derivatives

In 1940, SNCAM had several projects to fit the D.520 airframe with more powerful engines. These developments were halted by the June armistice.

D.521

• engine replaced by a Rolls-Royce Merlin III, one example built, project cancelled.

D.522

• engine replaced by a Allison V-1710 C-1, project abandoned after the armistice (22 June 1940).

D.523

• engine replaced by slightly different sub-variants of the 820 kW (1,100 hp) 12Y51, with Szydlowski-Planiol supercharger. D.523 Prototype was completing pre-production trials in June 1940.

D.524

• Version powered by Hispano-Suiza 12Y-89ter engine. One prototype built, never flew.

D.525

• development version of the D.523

D.530

• planned version with a 1,044 kW (1,400 hp) Rolls-Royce Merlin or a 1,342 kW (1,800 hp) Hispano-Suiza 12Y.

Related pre-war projects

HD.780

• Seaplane derivative of the D.520, one prototype built, never flew, development cancelled with the armistice.

D.790

• Carrier-born derivative project, none built.

D.550

• Unarmed aircraft built for speed record attempt, with airframe loosely based on the D.520 but using weight-saving construction techniques. One example built.

D.551 & D.552

• Military developments of the D.550. 12 examples built, none flew. Development was resumed in 1941, but quickly terminated by the Germans.

Post-armistice developments

Several projects were initiated after the June 1940 armistice. They all were terminated with the German occupation of Southern France in November 1942.

D.520 amélioré

• Single production D.520 experimentally fitted with minor improvements so as to improve top speed with unchanged engine.

D.520 Z

• D.520 airframe with 12Z engine and minor improvements. One example built. Development resumed after the war (as SE.520Z), but eventually cancelled in 1949.

M.520 T

• Different airframe loosely based on the D.520. None built.

Postwar derivative

D.520 DC (double commande – dual control)

• Two-seater trainer conversion, at least 13 built.

Markings

Apart from the first prototype and postwar examples, D.520s sported the usual French camouflage of dark blue-grey, khaki, and dark brown with light blue-grey undersurfaces. The camouflage pattern was not standardized. The national markings were the standard light blue-white-red roundels on the wingtips, as well as on the rear fuselage, and the rudder flag.

Specific markings were applied during the Vichy era, consisting of white outlined fuselage roundels with a white fuselage stripe, and from mid-1941 on, the infamous "slave's pajamas" with red and yellow stripes on the engine cowling and tail surfaces.

Operators

Main operators

Template:Country data Bulgaria Bulgaria

• Bulgarian Air Force

Template:FRA

• Armée de l'Air
• Aéronautique navale

Template:Country data France Free France

Forces Aériennes Françaises Libres (as trainers only)

Template:Country data Germany

• Luftwaffe

Template:Country data Italy

• Regia Aeronautica

Intended operators

Template:ROM

Romanian Air Force

Survivors

The three remaining D.520s known to exist today are:

Dewoitine D.520 n°603

On display at the Conservatoire de l'air et de l'espace d'Aquitaine in Bordeaux-Mérignac.

Dewoitine D.520 n°655

Under restoration at the Naval Museum in Rochefort.

Dewoitine D.520 n°862

Currently on display at the Musée de l'Air et de l'Espace. It has been repainted as n°277 used by GC III/6 in June 1940.

Dewoitine D.520 n°408

Aircraft was restored to flying condition in the 1970s. Painted as n°90 used by the GC I/3 in 1940, it performed at various airshows in Europe, but was destroyed in a fatal crash in 1986.

Specifications (Dewoitine D.520C.1)

General characteristics

• Crew: 1
• Length: 8.6 m (28 ft 3 in)
• Wingspan: 10.2 m (33 ft 6 in)
• Height: 2.57 m (8 ft 5 in)
• Wing area: 15.97 m² (172 ft²)
• Empty weight: 2,036 kg (4,489 lb)
• Loaded weight: 2,676 kg (5,900 lb)
• Max takeoff weight: 2,780 kg (6,129 lb)
• Powerplant: 1× Hispano-Suiza 12Y-45 liquid-cooled V12 engine, 690 kW (930 hp)

Performance

• Maximum speed: 535 km/h (289 kn, 332 mph)
• Range: 1,250 km (675 nmi, 777 mi)
• Service ceiling: 10,000 m (33,000 ft)
• Rate of climb: 14.3 m/s (2,820 ft/min)
• Wing loading: 167 kg/m² (34.2 lb/ft²)
• Power/mass: 257 W/kg (0.156 hp/lb)

Armament

• Guns:
  
  • 1 × 20 mm Hispano-Suiza HS.404 cannon
  • 4 × 7.5 mm (0.295 in) MAC 1934 machine guns

See also

Related development

• D.521
• D.522
• D.523
• D.524
• D.525
• D.530

Comparable aircraft

• Arsenal VG.33 C1
• Caudron C.714 C1 "Cyclone"
• SNCAO C.A.O.200.
• Bloch Bl 155
• Curtiss P-40
• Hawker Hurricane
• Messerschmitt Bf 109
• Rogozarski IK-3
• Supermarine Spitfire
• Yakovlev Yak-1
• Mikoyan-Gurevich MiG-3
• Lavochkin LaGG-3

Related lists

• List of aircraft of the Armée de l'Air

References

Bibliography

• Bączkowski, W. Dewoitine D.520 (in Polish). Warszawa, Poland: Books International, 1998.
• Belcarz, Bartłomiej. Dewoitine D 520. Sandomierz, Poland/Redbourn, UK: Mushroom Model Publications, 2005. ISBN 83-89450-09-7.
• Breffort, Dominique and André Jouineau. French Aircraft from 1939 to 1942, Volume 2: From Dewoitine to Potez. Paris, France: Histoire & Collections, 2005. ISBN 2-915239-49-5.
• Brindley, John F. French Fighters of World War Two, Volume One. Windsor, UK; Hylton Lacy Publishers Ltd., 1971. ISBN 0-85064-015-6.
• Brown, Russell. Desert Warriors: Australian P-40 Pilots at War in the Middle East and North Africa, 1941-1943. Maryborough, Australia: Banner Books, 1983. ISBN 1-875-59322-5.
• Danel, Raymond. The Dewoitine 520 (Aircraft in Profile number 135). Windsor, Berkshire, UK: Profile Publications Ltd., 1971 (reprint from 1966).
• Danel, Raymond and Jean Cuny. Docavia n°4: le Dewoitine D.520 (in French). Paris, France: Editions Larivière, 1966.
• Dewoitine D 520 (bilingual French/English: various authors). Brussels, Belgium: DTU, 1997. ISBN 2-912749-00-X.
• Ehrengardt, Christian-Jacques. Les avions français au combat: le Dewoitine D.520 (in French). Paris: Aéro-Editions, 2004.
• Green, William. War Planes of the Second World War, Volume One; Fighters. London: Macdonald & Co.(Publishers) Ltd., 1960 (tenth impression 1972). ISBN 0-356-01445-2.
• Herington, John. Second World War Volume III – Air War Against Germany and Italy, 1939–1943 1954 (1st edition) Canberra: Australian War Memorial (Australian official history).
• Marchand, Patrick. Dewoitine D.520 (Ailes de Gloire nr. 8) (in French). Le Muy, France: Les éditions Along, 2002. ISBN 2-914403-11-9.
• Pelletier, Alain. French Fighters of World War II in Action (Aircraft Number 180). Carrollton, TX: Squadron/Signal Publications, Inc., 2002. ISBN 0-89747-440-6.
• Tillman, Barrett. Wildcat Aces of World War 2. Oxford, UK: Osprey Publishing. 1995. ISBN 1-855324-86-5.
• Winchester, Jim. "Dewoitine D.520." Fighters: The World's Finest Combat Aircraft- 1914 to the Present Day. Bath, UK: Parragon Publishing, 2003. ISBN 1-40543-843-6.

External links

Wikimedia Commons has media related to:

Dewoitine D.520

• Preserved D.520s
• Front, Side and Top - views
• A set of 3D assembly instructions
• French tactical trials of captured Bf 109E-3 vs. Dewoitine 520 and Bloch 152

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