Caproni Ca.135

Infobox Aircraft
name = Caproni Ca.135
type = Medium bomber
manufacturer = Caproni



caption = Ca.135 of the Hungarian Air Force, 1942.
designer = Cesare Pallavicino
first flight = 1 April 1935
introduced = 1937
retired =
status =
primary user = Regia Aeronautica
more users = Hungarian Air Force
Peruvian Air Force
produced = 1936-1941
number built = approx. 140
unit cost =
variants with their own articles =The Caproni Ca.135 was an Italian medium bomber designed at Bergamo in Italy by Cesare Pallavicino. It flew for the first time in 1935, and entered service with the Peruvian Air Force in 1937, and with the Regia Aeronautica (Italian Royal Air Force) in January 1938.

Origins

General Valle (Chief of Staff of the Regia Aeronautica) initiated the "R-plan" - a program designed to modernize Italy's air force, and to give it a strength of 3,000 aircraft by 1940. In late 1934 a competition was held for a bomber with the following specifications:
* Speed: convert|330|km/h|mph|abbr=on at convert|4500|m|ft|abbr=on and convert|385|km/h|mph|abbr=on at convert|5000|m|ft|abbr=on.
* Rate of climb: convert|4000|m|ft|abbr=on in 12½ minutes.
* Range: convert|1000|km|mi|abbr=on with a convert|1200|kg|lb|abbr=on bombload.
* Ceiling: convert|8000|m|ft|abbr=on.The ceiling and range specifications were not met, but the speed was exceeded by almost all the machines entered. At the end of the competition, the "winners" were the Ca.135 (with 204 aircraft ordered), Fiat BR.20 (204), Piaggio P.32 (144), Savoia-Marchetti SM.79 (96), CANT Z.1007 (49) and the Piaggio P.32 (12).

This array of aircraft was proof of the anarchy, clientelarism and inefficiency that afflicted the Italian aviation industry. Worse was the continuous waste of resources by the Italian Air Force. Orders were given for aircraft that were already obsolete. The winners of the competition were not always the best - the BR.20 was overlooked in favour of the SM.79, an aircraft which was not even entered in the competition.

Design

The Ca.135 was to be built at Caproni's main Taliedo factory in Milan, which is why the type had a designation in the main Caproni sequence, rather than in the Caproni-Bergamaschi Ca.300 series. However, the project was retained at Ponte San Pietro and the prototype, completed during 1934-35, (a long construction time for the period), was first flown on 1 April. The project chief was Cesare Pallavicino of CAB ("Caproni Aereonautica Bergamasca").

Although the new bomber was in the "century series" of Caproni aircraft, it resembled the Caproni Ca.310, with its rounded nose, two engines, low-slung fuselage, and wings with a very long chord. Several versions were fitted with different engines and some had noticeable performance differences.

The prototype was powered by two convert|836|hp|kW|abbr=on (at 4,000 m) Isotta Fraschini Asso XI RC radial engines initially fitted with two bladed wooden propellers. It had a length of convert|14.5|m|ft|abbr=on, a wingspan of convert|18.96|m|ft|abbr=on, and a wing surface of convert|61.5|m2|ft2|abbr=on. It weighed convert|5606|kg|lb|abbr=on empty, and had a convert|2875|kg|lb|abbr=on useful load. Structurally, it was built of mixed materials, with a stressed-skin forward fuselage, and a wood and fabric-covered steel-tube rear section, the wings being of metal and wood, using fabric and wood as covering. The wings were more than one third of the total length, and had two spars of wooden construction, covered with plywood and metal. The strength coefficient was 7.5. The tail surfaces were made with wood covered with metal and plywood. The fuel system, with two tanks in the inner wings, held a total of 2,200 litres.

The Ca.135's fuselage's shape was quite different than, for example, the Fiat BR.20. If the latter resembled the B-25, the Ca.135, with its low fuselage more resembled the B-26. Its long nose accommodated the bomb-aimer and a front turret (similar to the Piaggio P.108 and later British bombers). The front part of the nose was detachable to assure a quick escape from the aircraft. It also had two doors in the cockpit roof, to allow the pilots to escape in an emergency. The right-hand seat could fold up to assist entry to the nose.

In the mid-fuselage there was a 12.7 mm gun turret, manned by the co-pilot. A seat for the flight engineer was later fitted. The wireless operator's station, in the aft fuselage, was fitted with the AR350/AR5 (the standard for Italian bombers), a radiogoniometer (P63N), an OMI AGR.90 photographic-planimetric machine or the similar AGR 61. The aircraft was also equipped with an APR 3 camera which although not fixed, was normally operated through a small window. The wireless operator also had a 12.7 mm machine gun in the ventral position. All this equipment made him very busy; as a result, an extra man was often carried. The aircraft had very wide glassed surfaces in the nose, cockpit, and the central and aft fuselage; much more than was usual in other Italian aircraft.

The aircraft was fitted with three machine guns, of 12.7 mm calibre in the turrets, and a 7.7 mm calibre gun in the nose. All had 500 rounds, except the 7.7 which had only 350.

The bombload, like most Italian bombers, was less than impressive in terms of total weight, but was relatively flexible, depending on the role - from anti-ship to close air support:
* 2 × 800 kg bombs (the heaviest in the Regia Aeronautica) plus 2 × 50 kg, and 2 × 31 kg, for a total of 1,862 kg (not counting the total true weight, because the 50 kg actually weighed around 70 kg).
* 2 × 500 kg + 4 × 100 kg (true weight 130 kg) + 2 × 31 kg, total nominal 1,462 kg
* 4 × 250 kg
* 8 × 100 kg + 8 × 50 kg + 4 × 31 kg, total 1,324 kg
* 16 × 50 kg + 8 × 31 kg, total 1,048 kg
* 24 × 31, 20, 15, or 12 kg.
* 120 × 1 or 2 kg bomblets
* 2 torpedoes (never used, but hardpoints were fitted)The aircraft had a better bomb capacity than most of its contemparies (the SM.79 could carry: 2 × 500 kg, 5× 250 kg, 12 × 100 kg or 50 kg bombs, or 700 × 1-2 kg bomblets).

Performance

The aircraft was underpowered, with a maximum speed of convert|363|km/h|mph|abbr=on at convert|4500|m|ft|abbr=on, and a high minimum speed (there were no slats, and maybe not even flaps) of convert|130|km/h|mph|abbr=on. The ceiling was only convert|6000|m|ft|abbr=on and the endurance, at 70% of throttle was convert|1600|km|mi|abbr=on. The weight was too high, with total of convert|8725|kg|lb|abbr=on and not convert|7375|kg|lb|abbr=on as expected.

The total payload of convert|2800|kg|lb|abbr=on was shared between the crew (320 or more kg), military equipment (200 kg of weapons, over 100 kg of radio and other equipment), fuel (max. 2,200 litres, 1,500 kg) oil, oxygen and bombs, so with the maximum bombload there was almost no possibility of carrying a full load of fuel (the other Italian bombers were generally capable of 3,300-3,600 kg payload): around 500 kg with the maximum, modest fuel load (the BR.20 and SM.79 had 3,600 litres), or with the maximum bomb load, almost nothing was available with fuel, and the lack of power made take-offs when over-loaded impossible, in fact take-offs were problematic even with a normal load.

Take-off and landing distances were convert|418|m|ft|abbr=on and convert|430|m|ft|abbr=on. The range was good enough to assure convert|2200|km|mi|abbr=on with 550 kg and convert|1200|km|mi|abbr=on with 1,200 kg.

The production version was fitted with inline liquid-cooled Asso XI RC 40 engines, giving convert|900|hp|kW|abbr=on at convert|4000|m|ft|abbr=on, so that aerodynamic drag was reduced, and three-bladed metal propellers, and were theoretically more efficient machines. This new engine gave the aircraft a maximum speed of convert|400|km/h|mph|abbr=on at 4,000 m., and could climb to 2,000 m in 5.5 minutes, 4,000 m in 12.1 minutes and 5,000 m in 16.9 minutes.

Despite this, the aircraft was still underpowered, which lead to the 1939 Ca.135Mod, fitted with convert|1000|hp|kW|abbr=on Piaggio P.XI engines.

Operational service

The aircraft arrived late in respect to the others (like the BR.20), and with a totally unsatisfactory technology. Despite this there was an order for 32 aircraft by the Regia Aeronautica on 19 June 1937. In January 1938, over a year after the BR and SM bombers, they started to enter into service.

panish civil war

In 1938 seven aircraft were earmarked for the "Aviazione Legionaria" to serve in the Spanish Civil War. These "Tipo Spagna" ("Spanish Type") aircraft were refitted with Fiat A.80 RC.41 engines, rated at 1,000 hp (746 kW).

Crews from 11 Wing were sent to Taliedo (just outside Milan) to take the first seven aircraft - designated Ca.135S - to Spain. One was damaged on take-off, and the other six landed at Ciampino near Rome, where two suffered damage on landing. After repairs and some modifications, not until late 1938 were all seven aircraft ready to leave for Spain. During the flight two were forced by icing to return to Italy, and three crashed into the sea. Only two arrived at Palma de Mallorca, and there they remained unused for six months.

Italy

Production of the aircraft was initially of only 32 aircraft, of which eight were Ca.135S's, and some were converted into the Ca.135Mod. In 1938 the first Ca.135Bis were built. They were fitted with 1,000 hp Piaggio P.XI RC.40 engines, with Piaggio P.1001 three-blade metal propellers. Length was 17.7 m, wingspan 18.8 m, and wing surface 60 m2. Armament was still only two 12.7 mm guns and one 7.7 mm, but the nose was redesigned to be more aerodynamic. Another 32 aircraft were ordered and built between 1939 and June 1940.

They were not successful aircraft, being heavily criticized by the Italian pilots. Unable to be used operationally, they were sent to flying schools, and then exported to Hungary. The first batch of Ca.135s flown by 11 Wing were phased out by late 1938. Twenty-five were still available at Jesi airfield, though only four were in flying condition, while the others were probably in maintenance for engine replacement. In 1940 there were at least fifteen Ca.135S and Ca.135Mod at the Malpensa flying school, though the poor condition of these aircraft meant that they were scrapped in November 1941. With the scrapping of the first batch and the selling of the second, all sixty-four Ca.135s left the service of the Regia Aeronautica without performing a single operational mission.

Hungary

In the 1938 Imperial Japanese Army Air Force evaluation the Ca.135 P.XI had lost to the Fiat BR.20, but the Hungarian Air Force nonetheless ordered the aircraft. It is likely that these Hungarian Ca.135's had Manfred Weiss WM K-14 engines in place of the Piaggio P.XI's, since Hungary used these engines in its versions of the Reggiane Re.2000 and the Heinkel He 70. Both the Piaggio P.XI and the Manfred Weiss WM K-14 were licensed versions of the French Gnome-Rhône 14K Mistral Major.

The Hungarians operated up to 100 Ca.135s with some success against the Soviet Union in the Eastern Front in 1941 and 1942 once Hungary had committed its forces in that sector during during World War II.

These aircraft constituted almost the entire heavy bomber force of Hungary and were ordered in exchange for the Ca.310, which were rejected and returned to Caproni in exchange for these new, more powerful, aircraft. The second Ca.135 series, rejected by the Italians, and a new one of 35 aircraft was delivered between 1940 and 1941 after an order originally made in 1937, but only confirmed in 1939, after a trial was made by Hungarian pilots at Guidonia, that surprisingly found it satisfactory. Hungary was almost entirely equipped with Italian aircraft at the beginning of the war. The 4° Bombardment Group operated these aircraft until late 1942, when the survivors, worn out, were used as training aircraft. The Hungarians did not love the Ca.135Bis, but it was all they had, and so they did their best. One of the squadrons, the I/4, (originally equipped with eight aircraft, one soon lost on landing, and then replaced with another four aircraft) performed, up to October 1941, 265 attacks, 1,040 sorties, and dropped around 1,600 tons of bombs, evidently helped by the short range (200-300 km) that allowed them to use the aircraft's maximum bomb load. Two aircraft were shot down, another two lost in accidents, and 11 aviators lost. The average over these four months was over 8 missions flown and 14 tons of bombs dropped each day.

Peru

Peru also ordered the Ca.135, and an initial delivery of six aircraft with 815 hp (608 kW) Asso XI RC.45 engines was followed by a contract for 32 others designated the Ca.135 "Tipo Peru" ("Peruvian Type"). The later order had 900 hp (671 kW) Asso XI RC.40 engines in a modified cowling, as well as revised gun placements. These aircraft were used by the Peruvian Air Force in the 1941 Ecuadorian-Peruvian War and proved somewhat successful against Ecuadorian ground units.

Modified aircraft

A single Ca.135 P.XI was modified by Caproni by incorporating a dihedral tailplane and 1,400 hp (1,044 kW) Alfa Romeo 135 RC.32 Tornado radial engines, and given the designation Ca.135 bis/Alfa. The newer and more powerful engines pushed the maximum speed of the aircraft to more than 480 km/h (298 mph).

The final variant was also a one-off, known as the Ca.135 "Raid", it was used to set records and win air races. It was built in 1937 to the order of the Brazilian pilot de Barros, was powered by two 986 hp (736 kW) Asso XIs and provided with additional fuel capacity for a greatly extended range. While attempting a flight from Italy to Brazil in 1937, de Barros and the Ca.135 "Raid" disappeared over North Africa, in another disaster for the image of the aircraft.

Variants

*Ca.135 "Tipo Spagna" : Seven aircraft fitted with Fiat A.80 RC.41 engines for service in Spain.
*Ca.135 P.XI : Medium bomber version, powered by two 1,000-hp (746-kW) Piaggio P.XI RC 40 radial piston engines.
*Ca.135 "Tipo Peru" : Export version for Peru, fitted with two 815-hp (608-kW) Asso XI RC 45 engines.
*Ca.135 bis/Alfa : One aircraft fitted with two 1,400-hp (1044-kW) Alfa Romeo 135 RC 32 Tornado radial piston engines.
*Ca.135 "Raid" : Special long range version, fitted with extra fuel tanks. One built.

Operators

;flag|Hungary|1940
*Hungarian Air Force;flag|Italy|1861-state
*Regia Aeronautica;PER
*Peruvian Air Force

pecifications (Ca.135 P.XI)

aircraft specifications
plane or copter?=plane
jet or prop?=prop
ref=
crew=4 (sometimes 5)
capacity=
payload main=
payload alt=
length main= 14.4 m
length alt= 47 ft 3 in
span main=18.8 m
span alt=61 ft 8 in
height main=3.4 m
height alt=11 ft 8 in
area main=60.0 m²
area alt=645.86 ft²
airfoil=
empty weight main=6,050 kg
empty weight alt=13,340 lb
loaded weight main=
loaded weight alt=
useful load main=
useful load alt=
max takeoff weight main=9,550 kg
max takeoff weight alt= 21,050 lb
more general=
engine (prop)= Piaggio P.XI-RC40
type of prop=14-cylinder radial engines
number of props=2
power main=746 kW
power alt=1,000 hp
power original=
max speed main=440 km/h
max speed alt=273 mph
max speed more=at 4,800 m (15,750 ft)
cruise speed main=350 km/h
cruise speed alt=217 mph
stall speed main=
stall speed alt=
never exceed speed main=
never exceed speed alt=
range main=2,600 km
range alt=1,244 mi
ceiling main=6,500 m
ceiling alt=21,325 ft
climb rate main=
climb rate alt=
loading main=
loading alt=
thrust/weight=
power/mass main=
power/mass alt=
more performance=
armament=
* 3 × 12.7 mm (0.5 in) dorsal Breda-SAFAT machine guns in nose, dorsal, and ventral turrets.
* 1,600 kg (3,527 lb) internal bomb load.
avionics=

References

* [http://www.comandosupremo.com/Ca135.html Comando Supremo - Italy At War] (HTML) Accessed 14 August 2007.
* Mondey, David, "Axis Aircraft of World War II," Chancellor Press 1996. ISBN 1-85152-996-7
* Lembo, Daniele, "Caproni Ca.135" Aerei nella Storia magazine, September 2006. it icon

ee also

aircontent

related=
* Caproni Ca.133

similar aircraft=
* Fiat BR.20

sequence=← Ca.132 -
Ca.133 -
Ca.134 - Ca.135 -
Ca.140 -
Ca.142 -
Ca.146 →

see also=
lists=
* List of bomber aircraft