caproni tried other ways to improve this powerful biplane, first with the 746 kw (1,000 hp) piaggio p.xi radial engine, then with a 746 kw (1,000 hp) isotta fraschini l.170 liquid-cooled powerplant, and the redesigned sesquiplane wings as the ca.173. none of these proposals were successful, at least not enough to pique the interest of the "regia aeronautica". in any case, both engines were far from being sufficiently reliable and were never adopted in large numbers by the italian air force.