The SABCA S.XII (or S.12) was a response to a July 1930 Belgian government call and funding for an all-Belgian multi-engine aircraft able to carry a useful load of between 350–500 kg (770–1,100 lb).
[4][5] Two of the three Renard Type 120 89 kW (120 hp), five-cylinder radial engines were mounted on frames below the wing within the bracing struts.
At the aft, the fuselage was a flat-faced, rectangular section structure based on four steel longerons and fabric covered externally.
[4][5] The enclosed cockpit was just ahead of the leading edge of the wing; its pilot sat on the left, though there was provision for a second seat with dual controls.
A passengers' cabin, with long strip windows and 2.23 m (7 ft 4 in) in length, seated four and contained a toilet and baggage space at the rear.
The fin was quite small but the balanced rudder was generous and extended down to the keel; overall, both horizontal and vertical surfaces were straight-edged and round-tipped.