|FIGHTER||Virtual Aircraft Museum / France / Bleriot|
Designed by Andre Herbemont and of generally similar configuration to the Type 41, the Bleriot SPAD 51 had fabric-covered metal wings and a wooden monocoque fuselage, power being provided by a 420hp Gnome- Rhone Jupiter nine-cylinder radial. The first prototype, the Type 51-1, was flown on 16 June 1924, a second modified prototype, the Type 51-2, following on 18 March 1925. Powered by a Jupiter IV and carrying an armament of two 7.7mm MAC (Vickers) guns in the upper wing, the Bleriot SPAD 51-2 was ordered for the Polish air arm, the Lotnictwo Wojskowe, 50 being delivered during 1925-26. A further prototype, the Type 51-3, with an improved propeller, flew on 7 September 1926, this offering a 12km/h speed superiority and improved ceiling over the 51-2. On 30 August 1928, the final derivative of the basic model flew, this being the Type 51-4 with a special 600hp version of the Jupiter. Ten production Type 51-4s were completed, one being sold to Turkey and another to the Soviet Union, these having provision for two fuselage-mounted Vickers and two wing-mounted Darne machine-guns, and a 420hp Jupiter 9Ab.
W.Green, D.Swanborough "The Complete Book of Fighters", 2000
All the World's Rotorcraft