Blériot-SPAD S.510

The Blériot SPAD S.510 was the last French biplane fighter to be produced.

Development
Conceived in 1930, this clean, open-cockpit biplane first flew in 1933 and entered service in 1936. Performance was similar to the British Gloster Gladiator. The S.510's armament generally consisted of 4 machine guns (installed as either a combination of 2 fuselage-mounted guns, plus 2 in under-wing gondolas or with all 4 in under-wing gondolas). This gave it a much heavier attack capability than most earlier biplane fighters and equalled that of the final biplanes used by the British and Italians, the Gladiator and Fiat CR.42 Falco.

The S.510 was doomed to obsolescence before it even flew, although when it was designed many pilots and experts strongly believed that biplanes would prove better fighters than monoplanes because of their tighter turning circles.

Largely overshadowed by the faster Dewoitine D.510 monoplane, an order of 60 paircraft was placed in August 1935 when French ace pilot Louis Massot demonstrated the S.510 to excellent effect, showing its superior maneuverability and rate of climb.

Despite its strengths, the S.510 only enjoyed about a year of usefulness. An adequate fighter for 1936, it was quickly outclassed by the new more modern monoplanes developed by Germany, Britain, and France. It had fixed landing gear as well as a weak fuel system and undercarriage.

Operational history
The S.510 entered service in early 1936, being assigned to the GC I/7 in May 1937 and the GC II/7 in July, 1938. They were intended as transition aircraft between the Morane-Saulnier MS-225 and the Morane-Saulnier MS-406 and served in the Weiser Circus, a military acrobatic group. Upon the outbreak of World War 2, the S.510 served in reserve squadrons only. The metropolitan reserves were mobilized into the II/561 based in Havre-Oteville. From January 18, 1940 over a period of weeks, the S.510s were replaced with Bloch MB.151 aircraft, the groupe changing designation to GC III/10. The displaced S.510s returned to their training role. Approximately ten S.510s had been sent to French North Africa where, by the Battle of France, they were mobilized into a fighter group, the GC III/5, but their age allowed them to be used for training flights only.

Operational history
The S.510 saw service with the Armée de l'Air (60), and possibly the Spanish "Escuadrilla Internacional" (15-27?)

Twenty-seven examples were reported delivered to the Spanish Republican Air Force during the Spanish civil war (sometimes the number is 15), but there is no evidence that they were ever actually sent.

Variants

 * S.510.01
 * First prototype aircraft.


 * S.510
 * Production aircraft powered by 690 hp Hispano-Suiza 12Xbrs engines, armed with 4 x 7.7 mm MAC 1934 machine-guns, (60 built).


 * S.710
 * One prototype only with a butterfly tail, powered by a single 860 hp Hispano-Suiza 12Ycrs V-12 engine.

Operators

 * Armée de l'Air
 * 🇪🇸 Spanish Republic
 * Spanish Republican Air Force
 * Escuadrilla Internacional
 * Escuadrilla Internacional