The Caproni Ca.90 was a heavy bomber biplane built by the Italian company Aeronautica Caproni in the late 1920s; while winning some world records relating to the transport of loads at high altitudes, it was built in a single specimen and remained in the prototype stage.

At the time of its construction, the Ca.90 was the largest land aircraft built up to then, a record it held until 1934, surpassed only by the construction of the Soviet Tupolev ANT-20.

The structure of the Ca.90 was made entirely of steel tubes while the upholstery was in canvas, except in the bow section which was instead covered in corrugated sheet of duralumin. The fuselage, with a rectangular section, housed at the bow end a position for a machine gunner, below which was that of the bomber observer; immediately behind these positions was arranged a first part of the fuel tanks which was followed by the cockpit with dual controls with the two pilots arranged side by side. Other fuel tanks were arranged behind the pilots, followed by the compartments for the bomb launchers and three other positions for the machine gunners (two dorsal and one ventral).

The configuration of the wing planes was of the inverted sesquiplana type, characterized by the significantly greater opening of the lower wing than the upper one (almost 12 metres). The lower wing rested on the upper part of the fuselage and was connected to the upper wing plane by two pairs of uprights integrated by diagonally arranged and crossed metal cables. In the central part of the upper wing plane there was a cockpit position, armed with machine guns. The empennage was of the monoplane and cruciform type.

The landing gear was fixed, with double wheel main elements, of the interrupted axle type; supported by two legs equipped with oil-pneumatic shock absorbers and by two connecting struts with the lower part of the fuselage, it was integrated at the rear by a single-wheel, adjustable, elastically sprung element.

The engines were six Isotta Fraschini Asso 1000: they were liquid-cooled 18-cylinder W engines, each capable of delivering the power of 1,000 HP. They were arranged in groups of two, in tandem, in a push-pull configuration: two groups rested on the lower wings, in correspondence with the undercarriage attachments, while the third group was suspended between the two wing planes, supported by a steel tube frame. The front engines drove a two-bladed propeller, the rear ones a four-bladed type.

Armed with seven machine guns, the Ca.90 was designed to carry up to 8,000 kg of bombs, even if the transportable load could vary according to the flight range required for the type of mission.

Taken in the air on 13 October 1929, although employed by the Regia Aeronautica in the ambit of the 62nd Squadron “Experimental Heavy Bombardment”, it was unable to fully express its potential: despite the conquest of some world records, it was not commercially successful and was built in a single copy. In essence it was the Air Ministry under the leadership of Italo Balbo that rejected the project, as Balbo was not a supporter of large-scale aerial bombing. Later Caproni attempted to commercialize the Ca.90 in the United States by starting a joint venture with the Curtiss Airplane and Motor Company, but this project also failed due to the great depression.

On February 22, 1930, piloted by Domenico Antonini, it won the endurance and climb-to-altitude records with a payload of 10 000 kg flying for 1 h and 31 min and reaching the maximum altitude of 3 231 m (a second, more recent source reports the maximum altitude of 3 256 m).

The operational use of the Ca.90 with the Regia Aeronautica was limited to the 62nd Squadron “Sperimentale Bombardamento Pesante” (also called “Squadriglia Bombardieri Giganti”) with the Italian air force.

From the Ca.90 project, a seaplane version was developed, called Ca.91.

Engines: 6 x Isotta Fraschini Asso 1000, 1000 hp
Wingspan Upper: 34,90 m / 114 ft 6 in
Wingspan Lower: 46,60 m / 153 ft 2.5 in
Length: 26,95 m / 89 ft 9 in
Height: 10,80 m
Wing area: 496,60 sq.m
Empty weight: 15 000 kg
MAUW: 30 000 kg / 66,140 lb
Max speed: 205 km/h / 130 mph
Endurance: 7 h 00 min
Range: 2796 mi
Ceiling: 4 500 m
Bombload: 8 000 kg

Developed in 1925 from Caproni’s earlier Ca 66, the Ca 73 was a large two bay biplane having with the lower wing mounted on top of the fuselage and the much shorter span upper wing supported above it by struts. The tail unit was biplane horizontal surfaces and a single fin and rud¬der. The power plant, mounted centrally between the wings, was two 400 hp Lorraine engines mounted in tandem, driving a tractor propeller at the front and a pusher propeller at the rear. The Ca 73 carried nose, dorsal and ventral single machine guns for defence and its bombs were attached to the fuselage sides beneath the lower wing.

Subsequent versions included the Ca 73 bis (400 hp Lorraines) and Ca 73 ter (490 hp Isotta Fraschini Asso engines); the latter was later redesignated Ca 82, and carried its bombs attached directly to the lower wing.

Caproni also produced developed versions designated Ca 88 (originally Ca 73 quater) and Ca 89, of which the latter had a cockpit windscreen, glazed bomb aiming panels in the nose, a dorsal turret, and a retractable ventral gun. In over eight years’ service, the Ca 73 series served also as paratroop trans¬ports and ambulance aircraft.

Span: 25.00 m (82 ft 0.25 in)
Length: 15.10 m (49 ft 6.5 in)
Gross weight: 5000 kg (11023 lb)
Maxi¬mum speed: 175 km/h (109 mph)

Ca.88
Engines: 2 x I.F.Asso 500
Wingspan: 25 m
Length: 15.20 m
Weight: 5700 kg
Max speed: 195 kph
Ceiling: 5500 m

The “Societa de Aviazone Ing Caproni” bureau (better known simply as “Caproni”) proved something of a pioneer in the field, resulting in their first impressive attempt sometime in 1913 as the “Caproni 260hp”. This version sported a “pusher” engine and a pair of “pusher” engines – these 80 hp Gnome rotary engines all being mounted in-line along a central fuselage nacelle. The three man crew sat in the forward part of the nacelle, and two slender fuselage booms carried the triple rudder tail unit. The two pusher systems drove propellers mounted at the tail booms via a tractor arrangement. Prior to the first flight, in October 1914, the two forward engines were re installed with direct propeller drive.

In the post-war years, these respective systems came to be designated as the Ca.30 and Ca.31.
After a period of evaluation, it was determined that the new larger bomber platforms were wholly underpowered. Caproni set to achieve better performance from his “giant” and moved the puller engines to the tips of each tail boom, keeping the pusher system in its centralized nacelle approach from earlier. This allowed each wing-mounted engine to directly drive its propeller more efficiently. The French-based Gnome rotary engines were then replaced with Italian FIAT A.10 inline types and produced the new company designation of “Caproni 300hp”.

A contract was signed for 12 Caproni 300HP bombers powered by three 74.5kW Fiat A.10 engines. First flight occurred in late 1914. A further 150 were delivered during the next two years. These aircraft were also known as Ca.1s and were followed by nine Ca.350HP machines (with the third engine replaced by a 112kW Isotta Fraschini) designated Ca.2.
The Ca.1 featured a wide-span, four-bay, biplane wing assembly. At the center of the wings was fitted the crew nacelle containing the four crew and the third engine. The primary engines were fitted ahead of the twin booms extending aft in a “puller” function arrangement. The third engine on the central nacelle operated in a “pusher” format. The crew consisted of two pilots, a forward gunner and a rear gunner – all fielded in tandem positions. The forward gunner sat in the forward-most compartment. Distinctly, the rear gunner stood in an open air, cage-like pulpit behind the upper wing assembly and ahead of the pusher engine at rear. The twin booms extended aft into a tailplane. The tailplane held three vertical tail fins. The undercarriage was a fixed tricycle featuring two single-wheeled main landing gear legs and a single-wheeled nose landing gear, all supported by struts. The rear of the empennage was supported by a tailskid fitted to the extreme end. Construction was mainly wood covered in fabric.
Bombs were suspended under the central nacelle and there were 2 x 6.5mm FIAT-Revelli machine guns used for defense. These machine guns were fitted to the front gunner tub and the rear gunners pedestal cage.
The 3 x Fiat A.10 6-cylinder, liquid-cooled in-line engines delivered up to 100 horsepower output each. This supplied the massive aircraft with speeds of up to 75 miles per hour as well as a range equal to 344 miles. Her service ceiling was listed at approximately 13,000 feet. Her empty weight ranged in at about 7,200lbs with a gross weight tipping the scales at 8,800lbs. Wingspan was nearly 23 feet with an overall running length of 36 feet plus. She stood 12 feet high.
This revised development led to the Italian Army and the first Italian bomber force. The aircraft was designated officially as the Ca.1 by the Italian Army and production increased by the middle of August 1915. A total of 162 were delivered up to December 1916.
Their first true sortie in Italian Army service occurred on August 20th, 1915, in an attack on Austrian targets at an airfield in Aisovizza. Most Ca.1s were committed to such attacks, primarily against the Austro-Hungarian Empire and the new bomber eventually served in some fifteen total Italian air squadrons during the war effort. Three of these Italian squadrons were known to have operated out of France with another stationed for action out of Libya.

A modified version (for which no post war designation seems to have been allotted) was the Ca 2, in which the ‘pusher’ A.10 engine was replaced by a 150 hp Isotta Fraschini V-4B. Only nine of these were completed.

In the post-war years, the Ca.1 was redesignated Ca.32. The Ca.1/Ca.32s that survived were refurbished to be used as passenger airliners. These could transport up to six passengers in relative comfort and fell under the Caproni designation of Ca.56.
The Caproni Ca.2 (“Caproni 350hp”) was a minor variation (improved engines) on the strengths of the Ca.1 platform. Development ultimately led to the definitive Ca.3 bomber platform.

Caproni Ca.1 / Ca.32
Engines: 3 x FIAT A.10 6-cylinder, 100 hp
Length: 36.25ft (11.05m)
Wing span: 74.61ft (22.74m)
Height: 12.14ft (3.70m)
Maximum Speed: 75mph (120kmh; 65kts)
Maximum Range: 342miles (550km)
Service Ceiling: 13,123ft (4,000m; 2.5miles)
Armament: 2 or 4 x 6.5mm FIAT-Revelli machine guns
Up to 1,874lbs of external ordnance
Accommodation: 4
Hardpoints: 4
Empty Weight: 7,280lbs (3,302kg)
Maximum Take-Off Weight: 8,818lbs (4,000kg)

Ca.2
Span: 34’5″
Length: 32’4″