Dewoitine D.520 Timeline
15 June 1936: The Armee de l'Air high command published specifications 'A23' technical program for a new fighter.
A single seat fighter capable of 500 kph at 4,000 m. and being able to reach 8,000 m. in less than 25 minutes.
The fighter was to be armed with one cannon and two machine guns or two cannons or four machine guns.
The fighter needed to be able to operate from a 400 m. landing strip.
June 1936: Emile Dewoitine left the Societe Aeronautiqui Francaise - Avions Dewoitine (SAF) in order to
have free rein of the project. He formed a private design office with Robert Castello and Jacques Henrat
as its designers.
September 1936: A23 is amended an called for a top speed of 520 kph. Emile submits a project to the
French Air Ministry that was unable to reach the new requirements. It was rejected.
January 1937: A modified project was submitted to the Service Technique Aeronautique (STAe) designated
Dewoitine '520' in reference to the speed needed.
4 March 1937: SAF was nationalised and became the Societe Nationale de Constructions Aeronautiques du
Midi (SNCAM). Emile Dewoitine was appointed Deputy Managing Director. The M.S.405/406 had been
chosen to re-equip the Groupes de Chasse so D.520 development progressed slowly.
3 April 1938: Prototype contract No.513/8 approves the delivery of two 12Y29 engine D.520s and a static test
airframe. The first had to be delivered by 1 November 1938.
13 August 1938: A23's speed requirements were raised and frozen at 570 kph. The range requirement was
1,500 km. and armament requirement was now 1 x 20 mm. + 4 x 7.5 mm. or 2 x 20 mm. + 2 x 7.5 mm.\
2 October 1938: 1st flight of the 1st prototype D.520-01 at Toulouse-Francazals piloted by Marcel Doret.
Engine: Hispano-Suiza 12Y-25: 890 hp./T.O.
The Canopy was removed.
The propeller was 2-blade fixed-pitch and wooden.
Wing leading-edge slots were originally installed.
Radiators in the wings limited maximum speed to 480 kph. (298 mph.) and caused engine overheating.
13 January 1938: D.520-01 reaches 520 kph. (323 mph.) in level flight after modifications.
A single radiator under the center fuselage replaced the two wing radiators.
Fin and rudder areas were increased.
Engine: H.S. 12Y-29: 910 hp./T.O. 920 hp./military later fitted with "jet" exhaust pipes
A 3-blade airscrew was now fitted.
28 January 1939: 1st flight of the 2nd prototype D.520-02 reaching 527 kph./5,000 m. and 8,000 m./13.75 min.
Engine: H.S.12Y-25: 890 hp./T.O.
The canopy was rearward sliding.
Redesigned tail assembly.
New undercarraige design.
The Handley-Page wings slots were deleted.
Provisional armament (not installed): 1 x 20 mm. Hispano-Suiza 404 cannon firing through the prop hub and
2 x 7.5 mm. HAC 34 machine guns in underwing gondolas.
Note: D.520-02 was later re-engined with a H.S.12Y-31 and managed 550 kph./5,000 m. and 8,000 m./12' 52".
March 1939: S.N.C.A. du Midi receives a contract for 200 A/C.
5 May 1939: 1st flight of the 3rd prototype D.520-03 (F-318) with the H.S.12Y-31: 830 hp./T.O., 860hp./military
Steerable non-retracting tail wheel was installed.
31 October 1939: 1st flight of D.520 No.1 (first aircraft off the production line).
Engine: H.S. 12Y-31
Two fuel tanks added to the wings leading edges.
Armor plate behind the pilot seat was added.
Armament: 1 x 20 mm. H.S.404 + 2 x 7.5 mm. drum fed in underwing gondolas.
Curved one-piece windshield.
Tail skid housing.
Fuselage is lengthened 52 cm.
3 December 1939: 1st flight of D.520 No.2 (this was the first true prodution aircraft).
Engine: H.S. 12Y-45: 910 hp./T.O. & military with a Szydlowski-Planiol S39-H3 supercharger.
Ratier-1606M electric 3-blade airscrew was installed.
A flat windscreen was installed.
Tail wheel replaces the skid assembly.
10 January 1940: D.520 No.2 is delivered to CEMA for performance evaluations
535 kph./5,400 m. is reached and 8,000 m./13.9 minutes is attained.
Armament: 1 x 20 mm. H.S.404/60 rds. + 4 x 7.5 mm. MAC 1934 M39/675 rpg. (also listed as 500 rpg.)
14 January 1940: D.520 No.9 (unarmed trainer)was delivered to Escadrille d'experimentation. This unit was
formed at Bricy with pilots and mechanics from CEMA and GCI/3
25 January 1940: D.520 No.3 & No.12 landed at Cannes-Mandelieu (these A/C not cleared for operational
use at this time.
10 May 1940: The 'Phoney War' comes to an end. Group de Chasse I/3 is the first unit to become operational
with the D.520. Pilots liked the sensitive controls, simplicity of the instrument panel and the ease of spin
13 May 1940: 1st combat with the Luftwaffe over Sedan: 3 Henschel Hs 126s & one Heinkel He III were shot
18 - 20 June 1940: CG I/3, II/3, III/6 and II/7 flew there D.520s to North Africa.
25 June 1940: Franco-German armistice. Production of the D.520 "offically ends". Development continues in
Spring 1941: The S.N.C.A. du Midi is absorbed by the S.N.C.A. du Sud-Est. The D.520 had become the
standard fighter of the Vichy Air Force and German Armistice Control Commission authorised the
resumption of production at Toulouse-Blagnac.
1942: Production D.520 No.465 goes throught test trials using an improved H.S. 12Y-45 engine of 935 hp. for
take-off and emergency power. It reaches 568 kph./7,000 m. (see post #3).
11 November 1942: Germany invades unoccupied France. French armed forces are disbanded. D.520s stored
at the Bases de Stockage, awaiting delivery at Blangnac and various Groupes de Chasse were seized by
the Luftwaffe. These aircraft were used as fighter-trainers by J.G.101, J.G.103 and J.G.105. Sixty D.520s
were supplied to the Regia Aeronautica and primarily used by fighter-trainer Gruppi 13, 22, 24 and 167.
About one hundred were given to the Bulgarian Air Force and several more were given to the Rumanian
Air Force, both using their D.520s operationally. Germany seized 1,876 aircraft, 246 were D.520s.
Note: The loss rate among Luftwaffe D.520 trainers was high. The D.520 had a nasty habit of groundlooping
if not monitered closely and the German aircraft & D.520 were very different in nature.
19 August 1944: Forces Francaises de l'Interieur (FFD) fighter unit was formed. It was equiped with D.520s
taken from the Germans. Premier Groupe de Chasse FFI or Groupe Doret. Two escadrilles stationed at
Tarbes-Ossum and Toulouse.
22 August 1944: German forces evacuate Toulouse. S.N.C.A. de Sud-Est and former Armee de l'Air personnel
seized all airworthy D.520s.
16 September 1944: Groupe de Chasse I/8 under Marcel Doret use the D.520 seized at Toulouse to strafe the
retreating columns and attacked the Germans at Royan, Pointe de Grave, Rochefort and Oleron.
Summer 1944: The completion of 150 at Toulouse had brought the total production of D.520s to 905 aircraft.
Air International Vol.52 No.6, June 1997
Air International Vol.53 No.2, August 1997
Le Dewoitine D.520, by Raymond Danel and Jean Cuny
War Planes of the Second World War Fighters Vol.1 by William Green 1968
Edited by CORSNING, 30 March 2016 - 01:59 PM.