By late
World War I, developments in aircraft technology made older
bomber designs unable to penetrate targets defended by modern
fighters. Caproni's response to this problem was to uprate the power significantly on the existing
Ca.3 design, with some versions of the Ca.5 eventually carrying engines with nearly five times the total power that the first Ca.1 had. Apart from greater power, various refinements were made to the design, including modifications to the main
nacelle and
undercarriage, and completely new wings. The first prototype flew in late
1917 and the type remained in production until
1921. Some 659 of all versions were built by Caproni, and another three were licence-built in the US (two Ca.44s by Standard, and one Ca.46 by Fisher). Planned licensed production in France was cancelled with the end of the war. During the war, Caproni designated these aircraft according to the total power of their engines. Afterwards, the company redesignated them. ==Design==