The Blériot-SPAD S.56 was a family of Frenchairliners 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.
similar to the S.56/1, with a 310 kW (420 hp) Gnome & Rhône 9Ab engine. 1 built.[3][2]
S.56/3
similar to S.56/2 with improved landing gear and 280 kW (380 hp) Gnome & Rhône 9Aa engine. 8 built.[4][2]
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. Powered by 310 kW (420 hp) Gnome & Rhône 9Ady engines. 8 built, plus 2 modified from S.56/3s.[5][2]
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.[6] 2 built, plus 6 modified from S.56/3s and 2 from S.56/4s.[2]
^Parmentier, Bruno (30 November 2001). "SPAD S-56/1". Aviafrance (in French). Paris. Retrieved 26 February 2018.
^ a b c d e f g hFilmore, Malcolm (12 February 2011). "French Pre-War Register" (PDF). Air-Britain. Retrieved 25 September 2018. (author obtained from https://www.ab-ix.co.uk/firstfiles.html)
^Parmentier, Bruno (30 November 2001). "SPAD S-56/2". Aviafrance (in French). Paris. Retrieved 26 February 2018.
^Parmentier, Bruno (30 November 2001). "SPAD S-56/3". Aviafrance (in French). Paris. Retrieved 26 February 2018.
^ a bParmentier, Bruno (30 November 2001). "SPAD S-56/4". Aviafrance (in French). Paris. Retrieved 26 February 2018.
^Parmentier, Bruno (30 November 2001). "SPAD S-56/5". Aviafrance (in French). Paris. Retrieved 26 February 2018.
^Parmentier, Bruno (30 November 2001). "SPAD S-56/6". Aviafrance (in French). Paris. Retrieved 26 February 2018.
^Grey, C.G., ed. (1928). Jane's all the World's Aircraft 1928. London: Sampson Low, Marston & company, ltd. p. 87c.
Wikimedia Commons has media related to Blériot-SPAD S.56.
Further reading
Taylor, Michael J. H. (1989). Jane's Encyclopedia of Aviation. London: Studio Editions. pp. 163–64.
World Aircraft Information Files. London: Bright Star Publishing. pp. File 890 Sheet 42.