Remarks: The Ca.1 was a three-engine biplane of a wooden construction, covered with fabric. It had 4 crewmembers in an open central nacelle; front gunner, two pilots and rear gunner-mechanic. The rear gunner manned upper machine guns, standing upon the central engine in a protective "cage", just before a propeller. The Ca.1 had a tricycle landing gear.
Italy and Russia were among the first countries to start developing a heavy bomber air force before World War I. Heavy bombers could carry more payload than standard single-engine aircraft of the period. The first heavy bomber, designed by Gianni Caproni in his Caproni works, was a twin-boom biplane, featuring a layout that included three 67 kW (80 hp) Gnome rotary engines housed one behind the other in a central nacelle, the rearmost driving a pusher propeller, and the other two driving tractor propellers mounted on the fronts of the two booms. Referred to internally by Caproni as the Caproni 260 hp (and retrospectively, after the war, as the Ca.30), this design flew in a slightly modified form (later dubbed the Ca.31) in October 1914.
Test flights revealed power to be insufficient and the engine layout unworkable, and Caproni soon adopted a more conventional approach. The pusher engine was retained in its original location, but the other two engines were moved to the front of the booms where they would turn their propellers directly. With more powerful inline engines, the air arm of the Italian Army became interested in purchasing the Caproni 300 hp (later known as the Ca.32), which they designated the Ca.1. A total of 166 aircraft were delivered between August 1915 and December 1916.
Some Ca.1s survived the war to be rebuilt as airliners, able to carry up to six passengers. This conversion became known as the Ca.56 in Caproni's post-war naming scheme.