Dewoitine D.520: France’s Best Fighter of 1940

The Dewoitine D.520 was the most capable French fighter aircraft of the Second World War, a single-seat monoplane that entered service in the spring of 1940, just weeks before the German invasion of France. Designed by Emile Dewoitine and his team, the D.520 was fast, agile and well armed, with a 20 mm cannon firing through the propeller hub and four machine guns in the wings, and it was the equal of the German Messerschmitt Bf 109E in many respects. About 900 D.520s were built, and the aircraft fought in the Battle of France, where its pilots claimed 114 confirmed victories against the loss of 85 aircraft, a creditable record for an aircraft that entered service so late and in such small numbers. After the fall of France, the D.520 served with the Vichy French air force in Syria, North Africa and the Mediterranean, and later with the Free French forces, who flew it in combat until 1944.

The D.520’s story is one of promise unfulfilled. The aircraft was ready too late and in too few numbers to change the outcome of the Battle of France, and its production was hampered by the chaos of the French collapse and by the German occupation. Had the D.520 been available in 1939, in the numbers that the French air force needed, the air war over France in 1940 might have been very different. As it was, the D.520’s pilots fought with skill and courage in an impossible situation, and their achievements have earned the aircraft a place in French aviation history as the best fighter that France produced in the Second World War.

Today the D.520 is remembered with pride in France, where a restored example flies at airshows and where the aircraft’s story is told in museums and in books. The D.520’s reputation has grown with time, as historians have recognised its qualities and the courage of its pilots, and it is now regarded as one of the finest fighters of 1940, a worthy opponent for the Bf 109 and a symbol of French aviation at its best.

1. Key Facts

Field	Value
Type	Single-seat fighter
Origin	France
Manufacturer	Societe Nationale des Constructions Aeronautiques du Midi (SNCAM), Toulouse
Designer	Emile Dewoitine
First flight	2 October 1938
Introduced	January 1940
Produced	Approximately 900 (some sources cite 905)
Crew	1 (pilot)
Length	Approximately 8.60 m (28 ft 3 in)
Wingspan	Approximately 10.20 m (33 ft 6 in)
Height	Approximately 2.57 m (8 ft 5 in)
Empty weight	Approximately 2,123 kg (4,680 lb)
Maximum take-off weight	Approximately 2,780 kg (6,129 lb)
Engine	Hispano-Suiza 12Y-45 V-12, approximately 935 hp
Maximum speed	Approximately 535 km/h (332 mph)
Range	Approximately 1,250 km (777 miles)
Service ceiling	Approximately 10,000 m (32,810 ft)
Armament	1 × 20 mm Hispano-Suiza HS.404 cannon; 4 × 7.5 mm MAC 1934 machine guns
Main operators	French Air Force, Vichy French Air Force, Free French Air Force, Bulgarian Air Force

2. Background and Development

France’s Search for a Modern Fighter

In the late 1930s the French Air Force was equipped with a mixture of obsolete biplanes and early monoplanes, and it recognised the need for a modern fighter that could match the German Bf 109. In 1937 the French Air Ministry issued a specification for a new fighter, calling for a top speed of at least 500 kilometres per hour, a good climb rate and a powerful armament. Several manufacturers submitted designs, including Morane-Saulnier, Bloch and Dewoitine, and Dewoitine’s D.520, designed by Emile Dewoitine and his team at Toulouse, was judged the best. The D.520 was a clean, low-wing monoplane with a retractable undercarriage, an enclosed cockpit and a Hispano-Suiza 12Y engine, and it promised to be the fighter that France needed.

The D.520’s development was not smooth. The first prototype flew on 2 October 1938, but it was underpowered and its handling was poor, and the aircraft required extensive modification before it was ready for production. The second prototype, flown in 1939, was fitted with a more powerful engine and a revised wing, and it performed well, reaching a speed of 535 kilometres per hour in trials. The French Air Force ordered the D.520 into production in 1939, but the production programme was slow to start, hampered by the need to tool up the factory at Toulouse and by the shortages of materials and skilled labour that afflicted French industry in the months before the war.

Production and the Race Against Time

The D.520 entered service in January 1940, with the first aircraft delivered to Groupe de Chasse I/3, and production gathered pace in the spring of 1940. By May 1940, when Germany invaded, about 200 D.520s had been built, and only a handful of squadrons were equipped with the type. The French Air Force had ordered more than 2,000 D.520s, but the German advance disrupted production, and the factory at Toulouse was threatened. In June 1940, as France collapsed, production was moved and then halted, and the D.520’s production run ended with about 900 aircraft built. The race against time had been lost: the D.520 was ready, but it was ready too late.

The D.520’s late arrival was a consequence of the French aircraft industry’s difficulties in the late 1930s, when political turmoil, strikes and the nationalisation of the industry had disrupted production. The D.520 was a good aircraft, but it was a victim of the circumstances of its birth, and its story is a reminder that, in war, the timing of a weapon’s arrival can matter as much as its quality. The D.520’s pilots, who flew it in the Battle of France, knew that they were flying the best fighter France had, and they flew it with skill and determination.

Emile Dewoitine

Emile Dewoitine was one of France’s leading aircraft designers, whose career included the D.500 series of fighters in the 1930s and the D.520. Dewoitine was a brilliant engineer, but his career was marked by controversy, and after the war he was accused of collaboration with the Germans, a charge that was later dropped. Dewoitine’s designs were known for their clean lines and their good handling, and the D.520 was his masterpiece, the culmination of a decade of fighter design. The aircraft’s reputation is a testament to Dewoitine’s skill, and to the quality of the team that worked with him at Toulouse.

3. Design

Airframe, Wings and Cockpit

The D.520 was a low-wing monoplane of all-metal construction, with a semi-monocoque fuselage and a distinctive rounded nose housing the Hispano-Suiza engine. Its wings were thin and lightly loaded, with a small dihedral, and they housed the four 7.5 mm machine guns and the fuel tanks. The undercarriage retracted inwards into the wings, and the cockpit was enclosed under a framed canopy that gave the pilot good visibility in most directions. The aircraft’s shape was clean and elegant, with a small frontal area and a smooth finish, and its pilots praised its handling, which was light and responsive, and its stability as a gun platform.

The D.520’s airframe was built for performance rather than for ruggedness. The aircraft was lighter than the Bf 109, and its wing loading was lower, which gave it good manoeuvrability, particularly in a turn. The cockpit was comfortable and well laid out, with the instruments arranged for easy reading, and the aircraft’s controls were harmonised, a quality that its pilots appreciated. The D.520’s design was a success, and it was the equal of any fighter of its period in handling and in performance.

Engine and Performance

The D.520 was powered by the Hispano-Suiza 12Y-45, a liquid-cooled V-12 engine producing about 935 horsepower, which drove a three-blade propeller. The engine was a development of the 12Y series, which had powered the Morane-Saulnier MS.406 and other French fighters, and it was a reliable and well-proven design. The D.520’s maximum speed was about 535 kilometres per hour, its climb rate was good, and its range was about 1,250 kilometres, a useful figure for operations over France. The aircraft’s service ceiling was about 10,000 metres, and its performance was comparable to that of the Bf 109E, which was its main opponent in 1940.

The D.520’s performance was good, but it was not outstanding. The aircraft was slightly slower than the Bf 109E, and its engine, while reliable, was less powerful than the German Daimler-Benz DB 601. The D.520’s strength was not speed but agility and handling: its pilots could out-turn the Bf 109, and they used this advantage in combat. The aircraft’s performance was adequate for its role, and its pilots learned to use its strengths and to avoid its weaknesses.

Armament: Cannon and Machine Guns

The D.520’s armament was one of its strengths. It carried a 20 mm Hispano-Suiza HS.404 cannon firing through the propeller hub, with 60 rounds, and four 7.5 mm MAC 1934 machine guns in the wings, with 500 rounds per gun. The cannon was a powerful weapon, capable of destroying a German bomber with a few hits, and it was the D.520’s main advantage over the MS.406, which was armed only with machine guns. The armament was heavier than that of the early Bf 109, and it gave the D.520 a punch that German pilots respected. The cannon’s low rate of fire and small ammunition supply were weaknesses, but the D.520’s pilots learned to use the cannon sparingly and accurately.

4. Variants

D.520: The Main Production Version

The D.520 was the main production version, with about 900 aircraft built. The aircraft was produced in a single version, with minor changes during production, including improvements to the radio, the gunsight and the fuel system. The D.520’s production was interrupted by the fall of France, and the aircraft was built in two phases: the first, before the armistice, for the French Air Force, and the second, after the armistice, for the Vichy French air force, under German supervision. The Vichy-built aircraft were used in Syria, North Africa and the Mediterranean, and they were the D.520s that fought the Allies in 1941 and 1942.

Proposed Developments

A number of developments of the D.520 were proposed, including the D.521, with a Rolls-Royce Merlin engine, the D.522, with a more powerful Hispano-Suiza engine, and the D.523, with a different armament, but none of these entered production. The most interesting proposal was the D.551, a lightened version of the D.520 with a more powerful engine, which was designed to be faster and more agile, but the project was cancelled when France fell. The D.520’s development ended with the fall of France, and the aircraft’s potential was never fully realised. The proposed versions remain a reminder of what the D.520 might have become, had France not fallen in 1940.

5. Operational History

The Battle of France

The D.520’s combat debut came in the Battle of France, in May and June 1940, when the aircraft equipped Groupe de Chasse I/3, II/3 and III/3, and later other units. The D.520’s pilots flew against the Luftwaffe’s Bf 109s and Bf 110s, and they achieved notable successes, claiming 114 confirmed victories and 39 probables against the loss of 85 D.520s. The D.520’s most famous pilot was Pierre Le Gloan, who scored 18 victories in the D.520, including five in a single day, and who became one of France’s leading aces. The D.520’s performance in the Battle of France was creditable, and it showed that the aircraft was the equal of the Bf 109, but the French Air Force was outnumbered and outmanoeuvred, and the battle was lost.

Vichy Service: Syria and North Africa

After the fall of France, the D.520 served with the Vichy French air force, which operated the aircraft in Syria, North Africa and the Mediterranean. In June and July 1941, Vichy D.520s fought the British and Free French forces in Syria, where they claimed a number of victories but suffered heavy losses. In North Africa, Vichy D.520s fought the Allies during Operation Torch, the Allied landings in November 1942, where they opposed American and British aircraft before the Vichy forces surrendered. The Vichy D.520s’ service was a difficult chapter in the aircraft’s history, fought against the Allies by French pilots who were following the orders of the Vichy government, and it is a reminder of the divisions that the fall of France created in French society.

Free French Service and the End of the War

After the Allied landings in North Africa, the D.520s in French hands were taken over by the Free French forces, who flew them in combat until 1944. The Free French D.520s served in North Africa and in the Mediterranean, and they were used for training and for air defence. The aircraft’s last combat service was with the Free French forces in 1944, when it was replaced by more modern Allied aircraft, including the Spitfire and the P-47. The D.520’s career ended quietly, but its service with the Free French forces was a fitting conclusion to its story, as the aircraft that had fought for France in 1940 fought for the liberation of France in 1944.

Pierre Le Gloan

Pierre Le Gloan was the D.520’s most famous pilot, a young officer who scored 18 victories in the Battle of France, including five in a single day on 15 June 1940, when he shot down four German bombers and a fighter. Le Gloan’s achievements were remarkable, and they demonstrated the D.520’s qualities as a fighter. After the fall of France, Le Gloan served with the Vichy air force in Syria, where he scored further victories, before he was killed in a flying accident in 1943. Le Gloan’s story is part of the D.520’s legend, and it is a reminder of the courage of the French pilots who flew the aircraft in 1940.

6. Performance and Specifications

Strengths in Combat

The D.520’s strengths were its handling, its agility and its armament. The aircraft was light and responsive, with a tight turning circle, and its pilots could out-turn the Bf 109. Its 20 mm cannon gave it a powerful punch, and its four machine guns provided a useful supplement. The D.520 was also a stable gun platform, and its pilots praised its handling in combat. The aircraft’s performance was good, and its pilots, who flew it in the most difficult circumstances, valued its qualities and trusted it in combat.

Weaknesses and Limitations

The D.520’s weaknesses were its speed, which was slightly less than that of the Bf 109E, and its engine, which was less powerful than the German Daimler-Benz. The aircraft’s production was also a weakness: too few D.520s were built, and they arrived too late to change the outcome of the Battle of France. The D.520’s radio equipment was poor, and its pilots often had difficulty communicating with each other and with ground control. The aircraft’s weaknesses were those of a design that was good but not outstanding, and of a production programme that was too slow.

7. Comparison

The D.520 and the Bf 109E

The D.520’s main opponent was the Messerschmitt Bf 109E, and the comparison between the two aircraft is instructive. The Bf 109E was slightly faster and had a better climb rate, but the D.520 was more manoeuvrable and had a heavier armament, with its 20 mm cannon. In combat, the outcome depended on the tactics and skill of the pilots, and the D.520’s pilots, who were well trained, achieved a creditable record against the Bf 109. The comparison shows that the D.520 was the equal of the Bf 109E, and that, had it been available in greater numbers, it could have made a difference in the Battle of France.

The D.520 and the MS.406

The D.520’s French predecessor was the Morane-Saulnier MS.406, the main French fighter in 1939 and 1940. The MS.406 was slower, less agile and less heavily armed than the D.520, and its pilots knew it. The D.520 was a significant improvement over the MS.406, and its introduction was a step forward for the French Air Force. The comparison illustrates the progress of French fighter design in the late 1930s, and the D.520’s superiority over its predecessor. The MS.406’s pilots, who flew it in the Battle of France, fought bravely, but they were flying an inferior aircraft, and their losses were heavy.

8. Legacy

France’s Best Fighter

The D.520’s legacy is that of France’s best fighter of the Second World War, an aircraft that was the equal of its German opponent and that was flown with skill and courage by its pilots. The D.520’s story is a reminder of the tragedy of the fall of France, when a good aircraft arrived too late and in too few numbers to change the outcome. The aircraft’s reputation has grown with time, and it is now recognised as one of the finest fighters of 1940, a worthy opponent for the Bf 109 and a symbol of French aviation at its best. The D.520’s legacy is preserved in the restored aircraft that flies at airshows, and in the memories of the pilots who flew it.

The D.520 in French Memory

In France, the D.520 is remembered with pride, and its story is told in museums, in books and in films. The aircraft’s pilots, including Pierre Le Gloan, are remembered as heroes, and their achievements are part of the national memory of the Battle of France. The D.520’s service with the Vichy and Free French forces is also remembered, as a reminder of the divisions of the war and of the eventual liberation of France. The D.520’s legacy is complex, but it is a proud one, and the aircraft deserves its place in the history of French aviation.

9. Surviving Examples

The Flying D.520

A single D.520 survives in flying condition, a restored aircraft that is based in France and that flies at airshows, where its elegant shape and its Hispano-Suiza engine are a reminder of French aviation in 1940. The aircraft, which was built in 1940 and served with the Vichy air force, was restored over many years by enthusiasts, and it is now one of the rarest flying warbirds in the world. The flying D.520 is a precious survivor, and its flights are a tribute to the men who built it and flew it.

Museums and Static Displays

Other D.520s are displayed in museums, including the Musee de l’Air et de l’Espace at Le Bourget, near Paris, where a D.520 is displayed alongside other French aircraft of the period. The museum’s D.520 is a static exhibit, but it is a valuable reminder of the aircraft’s design and of its service. A small number of D.520 components are held by other museums, and the aircraft’s story is preserved in the records of the French Air Force and in the accounts of its pilots. The scarcity of surviving D.520s reflects the aircraft’s small production run and its heavy losses, and it makes the flying example all the more precious.

10. Frequently Asked Questions

Was the D.520 as good as the Bf 109?
The D.520 was the equal of the Bf 109E in many respects. It was slightly slower, but more manoeuvrable, and it had a heavier armament, with a 20 mm cannon. In combat, the outcome depended on the pilots, and the D.520’s pilots achieved a creditable record against the Bf 109.

How many D.520s were built?
Approximately 900 D.520s were built, a small number compared with the thousands of Bf 109s built, reflecting the disruption of French production by the fall of France.

Who was the D.520’s most famous pilot?
Pierre Le Gloan was the D.520’s most famous pilot, scoring 18 victories in the Battle of France, including five in a single day on 15 June 1940.

Did the D.520 fight after the fall of France?
Yes. The D.520 served with the Vichy French air force in Syria, North Africa and the Mediterranean, and later with the Free French forces, who flew it until 1944.

What was the D.520’s armament?
The D.520 was armed with a 20 mm Hispano-Suiza HS.404 cannon firing through the propeller hub and four 7.5 mm MAC 1934 machine guns in the wings.

Where can I see a D.520 today?
A restored D.520 flies at airshows in France, and another is displayed at the Musee de l’Air et de l’Espace at Le Bourget, near Paris.

11. Sources

• William Green, Warplanes of the Second World War: Fighters, Volume One (Macdonald).
• The Musee de l’Air et de l’Espace, Le Bourget, D.520 collection records.
• Osprey Publishing, Aircraft of the Aces series, French fighter volumes.
• Jean Cuny, Dewoitine D.520 (Docavia series).
• The French Air Force Historical Service, D.520 squadron records.
• Wikipedia, Dewoitine D.520.