CANT Z.1007

Cant Z.1007 Alcione
Role Medium bomber
Manufacturer CANT
Designer Filippo Zappata
First flight March 1937
Introduction May 1939
Status Retired
Primary users Regia Aeronautica
Italian Co-Belligerent Air Force
Luftwaffe
Produced 1938–1943
Number built 660


The CANT Z.1007 Alcione (Kingfisher) was a three-engined medium bomber, with wooden structure. Designed by ingegner Filippo Zappata, who also designed the CANT Z.506[1] it had "excellent flying characteristics and good stability"[2] and was regarded by some as "the best Italian bomber of World War II" although its wooden structure was easily damaged by the climate, like those experienced in North Africa and in Russia.[1] It was used by the Italian Regia Aeronautica, Italian Co-Belligerent Air Force, Aeronautica Nazionale Repubblicana and Luftwaffe during World War II.

Design and development

Background

In 1935, Filippo Zappata, the chief designer of the Cantieri Aeronautici e Navali Triestini (CANT), designed two medium bombers, the twin-engined CANT Z.1011 and the three-engined CANT Z.1007. Both were to be powered by 619 kW (830 hp) Isotta-Fraschini Asso XI.RC inline engines and were of wooden construction. The Z.1007 design was preferred by both Zappata and the Italian Aviation Ministry, with an order for 18 aircraft being placed on 9 January 1936. A further order for 16 more aircraft followed on 23 February 1937.[3]

The Cant Z.1007 was developed from the CANT Z.506 seaplane, an aircraft that had established many world records in the late 1930s. It was a land-based version and incorporated many improvements, especially on the powerplant.

The first prototype flew in March 1937, proving superior to the Z.1011, with its handling and manoeuvrability being praised. Its performance, however, was lower than predicted, and Zappata therefore started a major redesign of the Z.1007, production of the initial version being limited to the existing orders placed before the prototype flew.[3]

The Z.1007 was a mid-winged monoplane with a retractable tailwheel undercarriage. It had a crew of five, consisting of two pilots, a flight engineer, a radio operator and a bombardier/navigator. It could carry 800 kg (1,760 lb) of bombs, and was fitted with a defensive armament of a 12.7 mm (.5 in) Breda-SAFAT machine gun in an open dorsal position and a 7.7 mm machine gun in a ventral tunnel. After much experimentation with the prototype, the production aircraft were fitted with annular radiators so their profile was similar to radial engines that would be fitted to the improved later versions. Delivery of production Asso powered Z.1007s started in February 1939, with production ending in October that year.[4]

Z.1007bis

Zappata had, meanwhile, continued the development of a considerably changed version, the Z.1007bis, to resolve the problems with the original aircraft. While the new version was of similar layout, it was a new design. Three Piaggio P.XI RC.40 radial engines (a derivative of the French Gnome-Rhône 14K) of 736 kW (986 hp) takeoff power replaced the less powerful and unreliable liquid cooled engines of the original version. The bis was longer with wings of greater span and area, while the aircraft was considerably heavier, weighing 580 kg (1,280 lb) more unladen, with a maximum takeoff weight 888 kg (1,960 lb) greater, while it carried heavier offensive and defensive armament.[5]

The prototype bis first flew in July 1939, with testing proving successful. The Z.1007bis was ordered into large scale production, deliveries of pre-production aircraft starting late that year.[6]

Configuration and problems

Overhead view

The Z.1007 had a standard monoplane configuration, with a mid-set wing, single tail, retractable undercarriage and a crew of five or six. It had a wooden structure and a clean shape that was much more aerodynamic than the competing SM.79. The Z.1007 had three engines, with one engine in the nose and two in the wings. The trimotor design was a common feature of Italian aircraft of World War II. The aircraft had a slim fuselage as the two pilots sat in tandem rather than side-by-side as in most bombers of the period. Visibility was good and the aircraft was almost a three-engine fighter. This slimness reduced drag but also somewhat worsened the task of the two pilots. Both pilots seats were offset to port to allow a passageway for the bombardier to enter his compartment below the pilot's feet (directly behind the central engine), by ducking under the instrument panel, similar to the setup on an Avro Lancaster, De Havilland Mosquito or Bristol Blenheim. Both instrument panels contained flight and navigation instruments, while the engine monitoring gauges were located to starboard where the rear pilot could see them past the front pilot's shoulder (Cockpit picture showing instruments and bombardiers access way: (http://www.ww2incolor.com/italian-forces/PILOTI-CZ1007.html). Although the rear pilot's view was limited, he was capable of landing or taking off if needed; however his primary purpose was to allow the pilot to rest, and to add some "muscle" to the controls when needed (as well as acting as the always helpful extra set of eyes to notice problems or to monitor gauges while the other is occupied). There were five crewmembers; the pilot, the copilot, a bombardier/navigator/ventral gunner, a dorsal gunner/radio operator, and waist gunner/flight engineer. The radio equipment was located in the center section between the dorsal turret and the waist position. Like most trimotor Italian aircraft of the period the Z.1007 suffered from poor defensive armament, although it was no worse than many other contemporary designs (it was designed with a dorsel turret, a ventral gun (which the Avro Lancaster lacked in most variants), and beam guns. Many other types lacked one or more of these features. Other issues were poor engine reliability and a weak power-to-weight ratio due to low powered engines (the three 1,000 hp engines of the Z.1007bis were equivalent to twin engines of 1,500 hp each, but this was slightly offset by the added weight of the third engine). The Z.1007 also suffered longitudinal stability problems that were partly rectified later by the adoption of a twin tail arrangement. The Z.1007's wooden structure suffered cracks, separations and surface delamination due to the difficult climatic conditions in North Africa and Russia. The surface delamination and deformation greatly added to the aircraft drag. A total of 660 Alciones were built.

Armament

The Z.1007 had a defensive armament of four machine guns: two 12.7 mm (.5 in) and two 7.7 mm (.303 in). The main defensive weapon was a Caproni-Lanciani Delta manually powered Isotta Fraschini dorsal turret armed with a 12.7 mm (.5 in) Scotti or Breda-SAFAT machine gun.[5] The turret had a good field of fire, although it had blind spot behind the tail (as did all turreted aircraft without rear gunners or twin vertical stabilizers).[7] The 12.7 mm (.5 in) Breda was a standard weapon for Italian bombers and the field of fire was improved by the twin-tail configuration on later models. An electrically powered Breda V turret carrying a similar armament was substituted in late production aircraft.[8] Another 12.7 mm (.5 in) was in the ventral position behind the bomb bay, with a field of fire restricted to the lower rear quadrant of the aircraft. There were also two waist position 7.7 mm (.303 in) Breda machine guns, with 500 rpg.[9] Only one of the waist guns could be used at a time since the gunner for this position manned both guns (a practice employed at times by other bombers like the B-25 Mitchell and G4M Betty). Many others (for example, the Avro Lancaster and other RAF types) had no beam guns at all, but since beam attacks were very rare, beam guns were one of the least effective armaments an aircraft carried and a lack of gunners was far less serious than a missing dorsal or tail turret, or to a lesser extent, a ventral or nose gun. Allied reports stated that armour was better than usual for an Italian bomber, with a large (.76 m/2 ft 6 in × 1.1 m/3 ft 6 in, plus a small head protection one of .36 m/14 in × .20 m/8 in) 8 mm (.31 in) curved plate for rear protection of dorsal gunner (rotating with his turret), 5 mm (.20 in) for side gunners with other 6 mm (.24 in) all around the machine guns, and 6 mm (.24 in) for ventral machine gun position, this meant that all defensive positions were reasonably protected against enemy fire. The pilots were protected, even if an armoured windscreen was not available, with 5 mm (.20 in) roof and lateral, 6 mm (.24 in) around the seats, 5 mm (.20 in) over their heads, and a 6 mm (.24 in) armoured bulkhead behind them.

The Z.1007 had a horizontal bomb bay which could carry 1,200 kg (2,650 lb) of ordnance. Many other Italian (and US) aircraft had vertical bomb bays which not only limited accuracy(?), but also limited the size of bombs carried internally. There were also a pair of under-wing hard points which could carry up to 1,000 kg (2,200 lb) of bombs, giving the Z.1007 a potential 2,200 kg (4,900 lb) payload to a maximum range of 640 km (400 mi), but the norm was 1,200 kg and 1,000 km range. The Z.1007's external hardpoints were a rarity in the bombers of the Regia Aereonautica. The Z.1007 could also carry two 454 mm (17.7 in), 800 kg (1,760 lb) torpedoes slung externally under the belly in an anti-shipping role, an option never used in service. The bombardier's position was just below and ahead of the pilot, behind the central engine (he could look up at the rudder pedals and see the pilot's face). This improved the layout compared to the SM.79, that had the nacelle almost in the tail section, with the double task of being a defence position with a machine gun mounted there (although it's not clear why a forward position for a bombardier is in any way superior to a rearward position; in either case the view was limited to downward, which is the important area for a bombardier. The forward position of the bombardier is mostly tradition, and dates from the days when communicating with the pilot was vocal or by means of a crude mechanical indicator showing heading adjustments.)

Operational history

The first Asso-powered Z.1007s were used to equip the 50° Gruppo of the 16° Stormo (i.e. the 50° Gruppo of the 16° Stormo) from May 1939. The Asso powered bombers were not considered suitable for operational use, however, owing to the unreliability of their engines and high maintenance requirements, while their defensive armament was considered inadequate. They were therefore used as trainers. In 1942, it was proposed to modify the remaining 16 Z.1007s for weather reconnaissance, re-engining them with Isotta Fraschini Delta engines, but only one aircraft was converted.[5] The Z.1007 participated in the bombing campaign over Malta and in the campaigns in North Africa and on the Eastern Front. Although fast, these bombers were vulnerable when hit and prone to catch fire.

The 47° Stormo was equipped with some of the first production aircraft at Ghedi. Only four were in service at 10 June 1940. The production was slow with 15 machines made every month at best. With time the aircraft was used by different Stormi like the 9° and substituted the SM.79 and BR.20.

Cant Z.1007 Asso replaced SM.81s in 16° Stormo, 47° Stormo had Z.1007Bis but operational readiness was only reached in August, when around 30 machines were sent to Sicily to attack Malta. Stormi 16°, 12°, 35°, and 47° operated over Greece with some losses. 175a Squadriglia da ricognizione (reconnaissance squadron), and later 176a, were used in Africa. The British destroyer HMS Juno was sunk by an explosion caused by a Z.1007 bombing in 1941. 35° Stormo was sent to Africa in the bombing role. The first large-scale use of the CANT took place when the Italian invasion of Greece started at the end of October 1940. These three-engine aeroplanes were used occasionally in Russia too.[10] In 1942, Z.1007s were used by four groups and two wings in the Mediterranean theatre, in anti-ship role and against Malta, often escorted by Italian and German fighters.

In November 1942, there were 10 Gruppi equipped with 75 Z.1007s, with just 39 serviceable aircraft.[11]

As part of Italian and German efforts to stop the British operation Pedestal convoy to re-supply Malta in August 1942, a few Z.1007 Alciones of 51° Gruppo Autonomo based in Alghero, Sardinia, flew reconnaissance missions on the convoy between bombing and raids. Only on 14 August, at the end of that "Mid-August Battle", three Z.1007bis bombed the convoy from high altitude.[12] Another Z.1007bis took part in the battle, carrying out a first in the war special mission, later copied by Allied air forces. The plan of Generale Ferdinando Raffaelli to use a CANT Z.1007 to radio-guide a "SIAI Marchetti SM.79 ARP (Aereo Radio Pilotato, "Aircraft Radio Guided") bomber. The SM.79, without crew and armament, but packed with explosives and equipped with a radio control device, was to be used as a "Flying Bomb" against big naval targets.[11] As the Pedestal Convoy was off the Algerian coast on 12 August 1942, the SM.79 "Drone", the Z.1007bis guide aircraft and escort of five FIAT G.50 fighters flew out to intercept the ships. Once the SM.79's pilot had set his aircraft on a course toward the Allied ships, he bailed out leaving the Z.1007bis crew to guide the flying bomb the rest of the way by radio. The radio, however, malfunctioned. With nothing to guide it, the SM.79-Drone cruised along until it ran out of fuel and crashed on Mount Klenchela, on the Algerian mainland.

World War II

When Italy entered World War II on 10 June 1940, Regia Aeronautica had two Stormi equipped with the "Alcione". One was the 16°, with 31 aircraft, equipped with the Isotta Fraschini engine and so declared "non bellici", "not suitable for war." The 47° Stormo had just received four CANT bis.[13]

Malta

A CANT Z.1007 bis bomber of the Italian Regia Aeronautica getting ready for a bombing mission over Malta; the photograph was taken in Sicily in 1941.

The "Alcione" had its baptism of fire on 29 August 1940, when a formation of 10 CANT Z.1007 "bis" monoderiva of 106° Gruppo bombed Luqa airfield. The 106°, based on Chinisia, Trapani, in Sicily, was soon joined by the whole 47° Stormo Bombardamento Terrestre with 33 aircraft. When the war with Greece broke out, the 47° was moved onto that front. The CANT Z. came back on Malta in 1941, with 9° Stormo Bombardamento terrestre, still based on Chinisia, with 29° and 33° Gruppo, equipped with 25 "Alcione". The 9° was later joined by 50° Gruppo, based on Sciacca.[13] The Italian units were joined by Luftwaffe II Fliegerkorp, but when the German aircraft were moved to North Africa, the CANT bombing mission on Malta were reduced. The Italian bombers had to face the strengthened defences of the island, that used radar combined with Bristol Beaufighter night fighters. The "Alcione" started a third wave of night attacks on Malta between 10 and 20 October 1942. The 9° Stormo and the 8° Gruppo of 43° Stormo had on line 30 CANT but only 12 were operational.[13]

Battle of Britain

The Z.1007 saw action during the later stages of the Battle of Britain from November 1940 to January 1941. The Regia Aereonautica sent six Z.1007Bis of the 172a Squadriglia to Belgium in the strategic reconnaissance role for the Corpo Aereo Italiano. Upon arrival in September the Italian command realized the Luftwaffe had already photographed nearly every inch of S.E. England and there was really nothing for them to do. They were used in force only once, on 11 November 1940, when five were used as a decoy (without bombs or guns) to draw RAF fighters away from the main Italian attack on a convoy and the port facilities around Harwich by 10 Fiat BR 20 bombers. The plan failed. No Z.1007s were lost over Britain, although one of the six originally sent was lost in September on the ferry flight to its base in Belgium.

Greco-Italian War

During the invasion of Greece, the Regia Aeronautica deployed the largest number of CANT.Zs. On 28 October 1940, first day of invasion, 47° Stormo Bombardamento Terrestre (based on Grottaglie airfield) and 50° Gruppo of 50° Stormo (based on Brindisi airfield) had on line 44 Alcione. On 5 November, those units were joined by 41° Gruppo of 12° Stormo, with 16 aircraft.[14] The Stormi suffered few losses, among them two made by a PZL P.24, manned by Second Lieutenant Marinos Mitralexis, who managed to bring down one of the two CANT Z.1007s by ramming its tail. During January 1941, 41° Gruppo was replaced by 95° Gruppo of 35° Stormo. It was in that war theatre that the wooden structure of the CANT started to show its weaknesses. The heavy rains damaged it, forcing continuous repairs by the ground crews.[15]

Yugoslavia

The CANTs opened hostilities against Yugoslavia, on 6 April 1941, bombing Mostar airfield. During that short invasion, Regia Aeronautica deployed 49 CANT. ZBis, 26 of 47° Stormo, 15 of 95° Gruppo (of 35° Stormo) and eight of 50° Gruppo (of 16° Stormo).[12]

Final deployment

In June 1943, the Z.1007s at Perugia, originally equipped with 30 machines, dropped to 19 with 13 serviceable in September. At the Armistice there were approximately 72 machines in service, with 40 of them sent to southern Italy. They were used as fast transports, with the ICAF proposing to use them as bombers in the Pacific theatre.

Reassessment

The worst day for Z.1007s was 14 May 1944, when 88° Gruppo sent 12 Z.1007s carrying supplies to Tito's forces. Five were shot down and two damaged by German fighters, 26 Italian aviators were killed. From that day on, it was employed only at night for military purposes.

Z.1007ter was an improved version, that should have used Alfa 135 engines of 1,040 kW (1,400 hp). This version was dropped because of the advent of the Z.1018 and the unreliability of the engines. There was another -ter proposal with P.XIX engines (858 kW/1,150 hp), and production was started in 1942, with a total of around 150 made. Test pilots were more impressed by this machine than the Z.1018, faster but with less power (because of the layout with only two P.XII engines), while the range was improved from 2,000 km (1,240 mi) to 2,250 km (1,400 mi) with 2,460 kg (5,420 lb) fuel and 900 kg (1,980 lb) bombs. So, while the Z.1018 had 2,013 kW (2,700 hp), already Z.1007Bis had 2,237 kW/3,000 hp (1,946 kW/2,610 hp at take off) and Z.1007ter 2,572 kW (3,450 hp).

Performances were improved with a max speed of 490 km/h (300 mph) at 6,150 m (20,180 ft) instead of 456 at 4,600 m (15,100 ft). Climbing to 3,000 m (9,800 ft) in 6 min 28 sec, and 5,000 m (16,400 ft) in 10 min 44 sec (Z.1007 bis in 12 min 42 sec, Z.1007 Asso in 14 min 34 sec). Armament and armour were also improved. The dorsal turret was a Breda model, waist guns were replaced by 12.7 mm (.5 in) weapons. The ceiling was raised to 9,000 m (29,500 ft) from 8,400 m (27,600 ft).

Z.1007s were used mainly as night bombers and reconnaissance, they were also used for long range reconnaissance, with excellent results. Some, at least 20, were equipped with an auxiliary tank that gave 1,000 km (620 mi) extra endurance. Some were adapted for flare drops when day missions were too dangerous. One modification for photo missions had six robot machines in a ventral gondola plus another in the fuselage. The long range and the ceiling helped these aircraft to obtain good results until the Spitfires appeared on the Mediterranean theatre. They were also the first victims of P-40 Tomahawks over Alexandria.

Another development was the Z.1015, proposed as a record-breaking version of the Z.1007 in 1938 but not considered until 1942, when the Alfa 135s were substituted by Piaggio P.XII engines. It could reach a speed of 563 km/h (350 mph), thanks to a total of over 2,982 kW (4,000 hp) installed. It was tested successfully as a torpedo aircraft, but it was not used operationally and did not enter production.

The few Z.1007ter still flying after the Allied invasion of Sicily went on to fight with the Italian Social Republic, Italian Co-Belligerent Air Force and the 'Luftwaffe. A total of 560 CANT Z.1007s were built, 450 of them of version 1007bis that appeared in late 1939.[10]

Operators

 Independent State of Croatia
 Germany
 Kingdom of Italy

Specifications (Z.1007bis)

Data from The Encyclopedia of Weapons of World War II[16]

General characteristics

Performance

Armament

See also

Aircraft of comparable role, configuration and era
Related lists

References

Notes
  1. 1 2 De Marchi and Tonizzo 1994, p. 27.
  2. ↑ De Marchi and Tonizzo 1994, p. 31.
  3. 1 2 Green 1992, p. 82.
  4. ↑ Green 1992, pp. 82–83.
  5. 1 2 3 Green 1992, p. 83.
  6. ↑ Green 1992, pp. 84, 86.
  7. ↑ Green 1992, p. 87.
  8. ↑ Green 1992, p. 88.
  9. ↑ Green 1992, pp. 84–85.
  10. 1 2 Angelucci and Matricardi 1978, p. 203.
  11. 1 2 De Marchi and Tonizzo 1994, p. 39.
  12. 1 2 De Marchi and Tonizzo 1994, p. 38.
  13. 1 2 3 De Marchi and Tonizzo 1994, p. 34.
  14. ↑ De Marchi and Tonizzo 1994, p. 37.
  15. ↑ De Marchi e Tonizzo 1994, p. 38.
  16. ↑ Bishop, Chris, ed. The Encyclopedia of Weapons of World War II. New York: Barnes & Noble, 1998. ISBN 0-7607-1022-8.
Bibliography
  • Angelucci, Enzo and Paolo Matricardi. World Aircraft: World War II, Volume I (Sampson Low Guides). Maidenhead, UK: Sampson Low, 1978. ISBN 0-562-00096-8.
  • De Marchi, Italo and Pietro Tonizzo. CANT. Z. 506 "airone"- CANT. Z. 1007 "alcione" (in Italian). Modena: STEM Mucchi Editore, 1994. NO ISBN
  • Garello, Gian Carlo. "Il Cant 1007 Alcione (in Italian)." Storia militare n. 20, May 1995, Albertelli edizioni speciali, Italy.
  • Green, William. "Zappata's Wooden Kingfisher". Air International, August 1992, Vol. 43 No. 2, pp. 81–90. Stamford, UK: Key Publishing. ISSN 0306-5634.
  • Malizia, Nicola. "L'armamento dei velivoli della Regia Aereonautica" (in Italian). Storia militare, September 1999.

External links

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