Although the Ca.308 Borea civil transport and its Ca.309 Ghibli multi-role colonial warplane half-brother clearly possessed production potential in their basic forms, Cesare Pallavicino appreciated that the concept would offer greater potential in a form revised with an uprated powerplant and retractable main landing gear units. This potential would be military rather than civil, and Caproni encourage Pallavicion to evolve this more potent type in parallel with the Ca.309.
The result was the Ca.310 Libeccio that first flew in prototype form in 4/37 with an airframe that was little modified from that of the Ca.309 except for some local strengthening.
The Ca.310 was therefore based on a fuselage of welded steel tube construction with a covering of light alloy panels and fabric, and this carried a simple tail unit of wooden construction with plywood skin on its fixed portions and fabric covering on its moving portions.
It also had a cantilever low-set wing of plywood covered wooden construction with virtually the full span of its trailing edges occupied by outboard ailerons and inboard split flaps. Thus the only major changes were limited to the forward fuselage and the engine nacelles: the former was revised to incorporate a more effective bombardier position with heavily framed but more extensive glazing on its lower part, and the latter were revised to provide accommodation for a different power plant and main landing gear units that were hydraulically retracted rearward to rest in the underside of the nacelles with only part of each wheel exposed.
A more modest change was the addition above the fuselage, in line with the wing trailing edges, of a manually operated dorsal turret armed with a single rifle-caliber machine gun; this signaled Caproni’s realization that while the Ca.309 would not be required to face aerial opposition in colonial warfare, the Ca.310 would almost certainly face such a threat in the more advanced level of conflict for which it was planned. The uprated power plant comprised two 430 hp Piaggio radial engines.
The Ca.310 had been planned as an export model, but the Italian air force ordered a small batch for evaluation purposes: 16 of these aircraft were sent to Spain in 7/38 for operational trials in the hands of a reconnaissance bomber squadron of the Italian expeditionary force operating alongside the Nationalist insurgents in the Spanish Civil War. Caproni was more successful in the export market, soon capturing orders for Peru for a small batch delivered in 1938; Yugoslavia for 12 aircraft; Hungary for 36 aircraft delivered in batches of 12 from 8/38-10/38 with a power plant of two 470 hp P.VII C.35 radial engines; and Norway for a total of 24 aircraft if its full option was exercised.
Most of these countries soon discovered that the actual performance of the Ca.310 fell below the legend specification, and after discovering this fact with its first four aircraft Norway refused to accept any further deliveries of the Ca. 310, but then agreed to take 12 examples of the Ca.312 whose upgraded power plant offered improved performance. In any event, none of these 32 aircraft had been delivered before Norway was invaded by German forces in 4/40 and the aircraft were taken on charge by the Italian air force. Hungary was also unhappy with its Ca.310s and in 1940 the surviving 33 machines were returned to Italy where they were refurbished by Caproni and reissued to the 50th Stormo d’Assalto as temporary replacements for the groups unsatisfactory Breda Ba.65 attack aircraft.
Potentially the most important customer for the Ca.310 was Great Britain, which was undertaking a major expansion of the RAF in a program that was accelerated after the Munich Crisis of 10/38. A major element in this British program was a much enlarged bomber force, and for successful implementation this required an effective crew trainer. Late in 1938 the British decided that the Ca.310 could be evolved into such a machine. Protracted negotiations continued until after the outbreak of World War II when Italy was still neutral, and in 12/39 the British government told Caproni that it was planning to buy 200 examples of the Ca.310 and 300 examples of the more powerful Ca.313, although further change followed the advent of the Ca.311, when the British decided to replace its planned force of 200 Ca.310s with 100 Ca. 311s.
|Crew||Three – pilot, co-pilot/bombardier/dorsal gunner and radio operator/gunner|
|Users||Italy, Hungary, Norway, Yugoslavia, Peru, Croatia|
|Powerplant||Two 430-hp Piaggio P.VIIC.16 radial engines|
|Typical Range||746 miles|
|Engine||(2) 470 hp Piaggio P.VII C 35 radials|
|Max Speed||218-227 mph at 9,845 ft|
|Cruising Speed||177-194 mph at 11,485 ft|
|Service Ceiling||22,965 feet|
|Armament||Two 7.7mm machine guns fixed forward firing; one 7.7mm machine gun in dorsal turret; up to 882 pounds of bombs|
Article by JDG
Elke Weale, Combat Aircraft of World War II, Bracken Books, 1985.