Caproni Ca.66
| Industry | Aerospace |
|---|---|
| Founded | 1914 |
| Headquarters | Italy |
The Caproni Ca.66 was an Italian four-engine night bomber aircraft created to modernize the post-World War I Italian Air Force. Only two units of this biplane were ever constructed.
Design and development
Beginning in 1914, Caproni had been manufacturing a succession of multi-engine bombers, many of which were deployed extensively by the Italian Air Force. The Ca.66 was developed following a reassessment of Italian air force needs after World War I, initiated by the new Fascist government in 1922. This aircraft represented a second wave of designs aimed at replacing enhanced wartime models. Unlike previous Caproni bombers that featured a twin-boom aircraft configuration, the Ca.66 adopted a traditional fuselage layout. It was powered by four engines and designed as a biplane with an upper wing of reduced span; however, it did not qualify as a true sesquiplane since the ratio of wing areas was approximately 0.6.[1][2]
Both wings had rectangular shapes when viewed from above, but only the lower wing incorporated a dihedral angle of 3.5°, along with overhanging balanced ailerons. Their structure combined wood and metal components covered with fabric, built around paired spars. The thick airfoil sections provided inherent structural strength, enabling a single-bay biplane configuration supported by pairs of parallel interplane struts inclined inward between the spars.[1][2]
The aircraft's 200 horsepower (150 kW) SPA 6A engines were arranged in push-pull pairs mounted midway between the wings. Each engine was equipped with its own cylindrical Lamblin radiator positioned beneath it; the tractor engines’ radiators were offset outward, while those on the pusher engines were placed inward. The engine assemblies were attached to near-vertical faired struts connecting upper and lower wing spars, further reinforced by additional bracing struts extending to both upper and lower fuselage sections.[1][2]
The fuselage’s main structure and covering were entirely wooden, featuring a rectangular cross-section and measuring 12.50 metres (41.0 ft) in length. Only the protruding nose section was constructed from metal with an oval shape. Crew accommodations included four seats: a gunner's station at the very front, side-by-side pilot seating located ahead of the propellers and lower wing leading edge, and a dorsal gunner’s position partially beneath the trailing edge of the upper wing. The fuselage tapered aft into a conventional fin with straight tapering and a balanced rudder extending below the fuselage keel beyond its end. The horizontal tail was biplane in design with curved leading edges and braced together by parallel vertical struts on each side. Three additional struts connected the tailplane to the lower fuselage longeron—one from the rear attachment point and two forming a forward-reaching V from the front point.[1][2]
The Caproni’s conventional landing gear featured main wheels on independent cranked axles extending from the lower longerons beneath each engine, spaced 3.52 metres (11.5 ft) apart. Each axle end was supported by three steel struts: two attached to the forward wing spar and one to the rear spar.[1] The forward pair incorporated elastic shock absorption within the wing structure.[2] Although both undercarriage and engine mount struts were designed for aerodynamic fairings, surviving photographs show these fairings were not installed, despite their depiction in official three-view drawings.[1][3]
Armament included ten 100 kilograms (220 lb) bombs carried on racks controlled by the co-pilot.[2] The forward gunner operated a 7.7 -mm[convert: unknown unit] machine gun mounted flexibly, mirrored by another flexible 7.7 -mm[convert: unknown unit] gun for the dorsal gunner who also had an additional rearward and downward firing weapon.[2][3]
The exact date of the Ca.66’s maiden flight remains unclear. While some sources suggest it flew as early as 1922—aligned with its development programme—the French publication Les Ailes referred to it as a "new Caproni" in October 1924.[1][2] Only two units were produced,[3] despite its success in winning an Air Ministry competition held at Montecelio.[2]