The Blériot-SPAD S.56 was a family of prototype French airliners developed in the 1920s as various refinements of the S.33 design. All S.56 versions shared two new features: the first was a newly designed, all-metal wing, replacing the wooden wing of earlier related designs and the second was a redesigned passenger cabin, replacing the S.33's four single seats in a row with two rows of double seats. A second access door was also added.
S.56/1
basic version with 194 kW (260 hp) Salmson CM.9 radial engine and later a 280 kW (380 hp) Gnome & Rhône 9Aa, (1 built)
S.56/2
similar to the S.56/1, with a 310 kW (420 hp) Gnome & Rhône 9Ab engine, (1 built).
S.56/3
similar to S.56/2 with improved landing gear and 280 kW (380 hp) Gnome & Rhône 9Aa engine. (8 built)
S.56/4
major fuselage revision; cockpit relocated between engine and passenger cabin (in all previous S.33 derivatives, it had been aft of the cabin) and an extra double seat added to the cabin, increasing internal passenger capacity to six. 8 built, plus 2 modified from S.56/3s, powered by 310 kW (420 hp) Gnome & Rhône 9Ady engines.
S.56/5
revised passenger cabin with four seats located in one compartment, and two in a second compartment that could be quickly converted to a freight hold (3 modified from S.56/3s)
S.56/6
similar to S.56/3 but customised for banner towing for the Air Publicité company, powered by a 310 kW (420 hp) Gnome & Rhône 9Ab engine. This aircraft ended up as a transport plane in the Spanish Republican Air Force during the Spanish Civil War.
Spain
Spanish Republican Air Force. S. 56/6
General characteristics
Crew: one pilot
Capacity: 7 passengers
Length: 9.00 m (29 ft 6 in)
Wingspan: 13.13 m (43 ft 1 in)
Height: 4.10 m (13 ft 5 in)
Wing area: 48.6 m2 (523 ft2)
Empty weight: 1,453 kg (3,203 lb)
Gross weight: 2,712 kg (5,979 lb)
Powerplant: 1 × Gnome et Rhône 9Ady, 313 kW (420 hp)
Performance
Maximum speed: 181 km/h (113 mph)
Range: 620 km (387 miles)
