After designing the successful Ca.3, Gianni Caproni of the Caproni works designed a much bigger aircraft. It shared the unusual layout of the Caproni Ca.3, being a twin-boom aircraft with one pusher engine at the rear of a central nacelle and two tractor engines in front of twin booms, making a push-pull configuration. The most distinguishing feature of the new plane was, that it was built in a rare triplane layout, instead of the more common biplane.
The huge new bomber was accepted the Italian Army under a military designation Ca.4, but it was produced in several variants, differing in factory designations.
The Ca.4 was a three-engine, twin-boom triplane of a wooden construction with a fabric-coverd frame. The open center nacelle was attached to the undersurface of the center wing. It contained the pusher engine, pilot, and forward gunner. At least one variation of the center nacelle seated the crew in a two-seat tandem format with the forward position a gunner/pilot and the rear position the pilot. Others used a forward gunner with side by side pilot positions to the rear of the gunner. Two rear gunners were positioned one in each boom behind the center wing. An engineer or second pilot could also be accommodated there.
Armament consisted of four (but up to eight) Revelli 6.5 mm or 7.7 mm machine guns in front ring mounting and two boom ring mountings. Bombs were suspended in a bomb bay, which was a long and narrow container fixed to a lower wing. Photographs show at least four different arrangements with regard to the bombing nacelle.
Note: during the war, all these aircraft were designated Ca.4 by the Italian Army. At the time, Caproni referred to the various designs by the total power of their engines. After the war, Caproni devised a new designation scheme for their own design - these are used below.
Production figures differ in publications. The most likely number is 38 of all Ca.4 variants (other quoted figures are: 38 of Ca.40 and Ca.41 and 6 Ca.42 or 32 Ca.42 and 21 of other variants). Numerous publications incorrectly refer to all variants as the Ca.42.
Ca.4s were tested by the Italian Air Force in 1917 and began operations in 1918. They were used for attacking targets in Austro-Hungary. In April 1918, 6 Ca.42s were used by the British RNAS (No. 227 Sqn). At least three CA.42s were sent to the USA for evaluation. After the war, the Ca. 4 was replaced in Italy by the Ca.36.
Despite its unstable and fragile appearance, the Ca.4 was well-designed. Its size, without regards to its height, was not any larger than that of other foreign heavy bombers. With Liberty engines, it had a fast speed, similar to other heavy bombers, while its bomb load had one of the largest capacities of that era. If it had been flown with other engines, its performance would have suffered.
Published - July 2009
Copyright 2004-2017 © by Airports-Worldwide.com