Blériot-SPAD S.510

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

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. 

                                      (Airwar.ru)

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 aircraft 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.

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.

The S.510 saw service with the Armée de l'Air (60). Reports that it may have served in the Spanish Republican Air Force during the Spanish civil war are doubtful. There is no evidence that S.510 were ever actually sent and they may have been confused with the Blériot-SPAD S.91 or with the Dewoitine D.510 that were delivered to the Escuadrilla Internacional.

Variants
S.510.01
First prototype а
ircraft.
S.510
Production aircraft powered by 510 kW (690 hp) Hispano-Suiza 12Xbrs engines, armed with 4 x 7.7 mm (0.303 in) MAC 1934 machine-guns, (60 built).
S.710
One prototype only with a butterfly tail, powered by a single 640 kW (860 hp) Hispano-Suiza 12Ycrs V-12 engine.

Specifications S.510
Crew: 1
Length: 7.46 m (24 ft 6 in)
Wingspan: 8.84 m (29 ft 0 in)
Height: 3.72 m (12 ft 2 in)
Wing area: 22 m2 (240 sq ft)
Empty weight: 1,250 kg (2,756 lb)
Gross weight: 1,830 kg (4,034 lb)
Engine: 1 × Hispano-Suiza 12Xbrs V-12 liquid-cooled piston engine, 516 kW (692 hp)
Maximum speed: 370 km/h (230 mph; 200 kn)
Range: 875 km (544 mi; 472 nmi)
Service ceiling: 10,500 m (34,449 ft)
Rate of climb: 14.85 m/s (2,923 ft/min)
Armament: 4 × 7.5 mm MAC 1934 machine гунс