Caproni Ca.4

Ca.4
Caproni Ca.40 heavy bomber prototype
Role	Heavy bomber; later variants included airliners
Manufacturer	Caproni
First flight	1917
Introduction	1918
Primary users	Italian Army United Kingdom (Royal Naval Air Service) United States
Number built	44 to 53

The Caproni Ca.4 was an Italian heavy bomber of the World War I era.

Development

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 twin booms carried a single elevator and three fins. The main landing gear was fixed and consisted of two sets of four wheels each. 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.

Description

The Ca.4 was a three-engine, twin-boom triplane of a wooden construction with a fabric-covered 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.

• 1. No nacelle - presumably not a combat configuration.
• 2. A tall, narrow nacelle that housed approximately 12 internal bombs vertically and another 18–20 strapped to the outside.
• 3. A shorter nacelle that may be the lower half of the tall nacelle but with no external bombs.
• 4. No nacelle but with a single long bomb/torpedo slung under the bottom wing.

Variants

The Ca.48 airliner

The Ca.52 (Caproni Ca.42) - second production series of Ca.4-Ca.40 family - Aircraft of N°227 Squadron Royal Naval Air Service

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.

• Ca.40 - single prototype.
• Ca.41 - production variant, essentially similar to the prototype and powered by 3 Fiat A.12 inline engines of 210 kW (280 hp). A few Ca.41s were powered by 186 kW (250 hp) Isotta-Fraschini engines instead. These were referred to internally by Caproni as the Caproni 750 hp. Forty-one built.
• Ca.42 - powered by Liberty 298 kW (400 hp) inline engines and known internally as the Caproni 1,200 hp. Twelve built.
• Ca.43 - single example of a floatplane variant.
• Ca.48 - Airliners converted from Ca.42s after World War I; the Ca.48 first flew in 1919. The double-deck passenger cabin mounted between the booms seated a total of 23 passengers who entered via the nose nacelle; 16 of them sat in the lower cabin on long benches alongside its walls with large windows providing them with good views, and the other seven passengers sat on an upper deck, as did the pilots. The Ca.48 was powered by three 298-kilowatt (400-horsepower) Liberty L-12 engines. Although it is unlikely that the Ca.48 ever entered airline service, a Ca.48 did visit the First Aviation Exhibition Amsterdam of August–September 1919, where it was very popular with visitors, among whom was Prince Hendrick (1876–1934), Prince Consort of the Netherlands (1901–1934).
• Ca.51 - single example of a considerably enlarged design with biplane tail and tail barbette. Three × 522 kW (700 hp) Fiat A.14 engines.
• Ca.52 - Ca.42s built for the RNAS. Six built.
• Ca.58 - Ca.48s re-engined with Fiat A.14 or Isotta-Fraschini V.6.
• Ca.59 - as for the Ca.58, but this designation used for customers outside Italy.

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.

Service history

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, surpassed only by that of the Imperial German: Zeppelin-Staaken R.VI. If it had been flown with other engines, its performance would have suffered.

Operators

• Italy : Corpo Aeronautico Militare
• UK
• USA

Specifications

Ca.42

General characteristics

• Crew: 4 (pilot, co-pilot, front gunner, and rear gunner/mechanic)
• Length: 13.10 m (42 ft 11 in)
• Wingspan: 29.90 m (98 ft 1 in)
• Height: 6.30 m (20 ft 8 in)
• Wing area: 200 m² (2,150 ft²)
• Empty weight: 6,709 kg (14,791 lb)
• Max. takeoff weight: 7,500 kg (16,535 lb)
• Powerplant: 3 × Isotta Fraschini, 201 kW (270 hp) each

Performance

• Maximum speed: 140 km/h (76 kn, 87 mph)
• Range: 700 km (378 nmi, 438 mi)
• Service ceiling: 3,000 m (9,800 ft)
• Rate of climb: 125 m/min (410 ft/min)

Armament

• 4 × 6.5 mm FIAT-Revelli machine guns, two in forward mounting and one in each of two rearward positions.
• 1,450 kg (3,200 lb) of bombs

Ca.48

Interior of lower main passenger cabin of Ca.48 airliner, which accommodated 17 of the 23 passengers.

Data from The civilian transport aircraft of Caproni (1918-1939)

General characteristics

• Crew: 2 (pilot, co-pilot)
• Capacity: 23 passengers
• Length: 13.20 m (43 ft 3.7 in)
• Wingspan: 29.90 m (98 ft 1 in)
• Height: 6.30 m (20 ft 8 in)
• Wing area: 200 m² (2,150 ft²)
• Empty weight: 4,000kg (8,818 lb)
• Max. takeoff weight: 7,200 kg (15,873 lb)
• Powerplant: 3 × Liberty L-12, 298 kW (400 hp) each

Performance

• Maximum speed: 140 km/h (76 kn, 87 mph)

See also

Related lists

• List of military aircraft of Entente Powers in WWI
• List of bomber aircraft
  

References

• Caproni Ca.4
• AEREI ITALIANI (Italian)
• Quest for Performance: The Evolution of Modern Aircraft, Chapter 2: Design Exploration, 1914-18
• The civilian transport aircraft of Caproni (1918-1939)

External links

• "The Caproni Bombing Triplane CA-4-1915" (PDF). Flight XI (25): 797–799. June 19, 1919. No. 547. http://www.flightglobal.com/pdfarchive/view/1919/1919%20-%200797.html. Retrieved January 12, 2011.  Contemporary technical description of the Ca.41 and Ca.42 (focusing on the latter) with photographs and drawings.

Video

• Film footage of Caproni Ca.42