CANT Z.1007 Alcione

Background During 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 aircraft were to be powered by Isotta-Fraschini Asso XI.RC inline engines and were of wooden construction. The Z.1007 was preferred by both Zappata and the Italian Aviation Ministry, which led to an order for 18 aircraft being placed on 9 January 1936. A further order for 16 aircraft followed on 23 February 1937. The Z.1007 was developed from the CANT Z.506 Airone seaplane, an aircraft that had established numerous world records in the late 1930s. Unlike the Z.506, it was a land-based version and incorporated many improvements, especially of the engines. The first prototype flew in March 1937; during flight testing, it proved to be superior to the Z.1011, being praised for its handling and manoeuvrability alike. Its performance was lower than predicted and Zappata undertook a redesign of the Z.1007 while production of the initial version was limited to the orders placed before the prototype flew. Z.1007bis Zappata had 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 take-off power replaced the less powerful and unreliable liquid cooled engines of the original version. Configuration and problems 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 tri-motor design was a common feature of Italian aircraft of the Second World War. 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 relatively 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 through an opening under the starboard instrument panel. The front and rear 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. Although the rear pilot's view was limited, he was capable of landing or taking off if needed. His primary purpose was to allow the forward pilot to rest, and to add some "muscle" to the controls when needed, as well as acting as an extra set of eyes to notice problems and to monitor gauges while the other was occupied. There were five crew members: the pilot, the co-pilot, 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 tri-motor Italian aircraft of the period the Z.1007 lacked adequate defensive armament, although it was no worse than many contemporary designs, many of which had no rotating dorsal turret, no waist guns, or no ventral gun, or combinations. Other problems were poor engine reliability and a poor power-to-weight ratio due to low powered engines (the three engines of the Z.1007bis were equivalent to twin engines of 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 inhospitable climatic conditions in North Africa and Russia, but allowed the aircraft to float in case of ditching. The surface delamination and deformation greatly added to the aircraft's drag. A total of 660 Alciones were built. Armament The Z.1007 had a defensive armament of two and two machine-guns. The main defensive weapon was a Caproni-Lanciani Delta manually-powered Isotta Fraschini dorsal turret armed with a Scotti or Breda-SAFAT machine gun. Another 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 Breda machine guns, with 500 rpg. Only one of the waist guns could be used at a time since the gunner for this position manned both guns (a practice common with other aircraft, such as the Heinkel He 111, B-25 Mitchell and G4M Betty). Simultaneous attacks from both sides were rare, and waist guns are generally the least effective armament on an aircraft, mostly intended to improve morale and provide a deterrent effect. Allied reports stated that armour was better than usual for an Italian bomber, with the dorsal gunner receiving a large armor plate, plus a small head protection plate of , as well as an thick curved plate which rotated with his turret. There was rear armor plate thick for side gunners, with other all around the machine guns, and armor for ventral machine gun position, which meant that all defensive positions were reasonably protected against light enemy fire and fragments. The pilots were protected with roof and lateral armor, around the seats, overhead, and a armored bulkhead behind them. The Z.1007 had a lengthy and shallow horizontal bomb bay which could carry 1,200 kg (2,650 lb) of ordnance. Many other Italian aircraft had bomb bays which carried the ordnance vertically, tip pointing up, which limited the size and variety of bombs which could be carried internally, a problem shared with the German He 111 bomber. There were also a pair of under-wing hardpoints 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 and a maximum range of 640 km (400 mi), but the standard payload was 1,200 kg (2,645 lb) and 1,000 km (621 mi) 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 operationally. 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, which located the bombardier in the ventral casemate under the rear fuselage, which meant that it was difficult to man the ventral gun while the bombardier was in position, since space was limited. The forward location of the bombardier's compartment provided somewhat better forward visibility, but was still cramped as well as being relatively loud and subject to considerable vibration, largely due to it being directly behind and very close to the central engine. ==Operational history==

Introduction The first Asso-powered Z.1007s were used to equip the 50° Gruppo of the 16° Stormo from May 1939. These Asso-powered aircraft, despite being designated as bombers, were not considered suitable for operational use as a result of their engines being relatively unreliable as well as the aircraft's high maintenance requirements and their defensive armament being considered to be inadequate. Accordingly, they were typically used as trainer aircraft instead. The 47° Stormo was equipped with some of the first production aircraft at Ghedi. Production of the type was relatively slow, only fifteen aircraft were being completed every month at most. Gradually, Z.1007s were delivered to a number of different Stormi, such as the 9°, where it substituted the SM.79 and BR.20. Upon Italy's entry into the Second World War 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 Z.1007bis. Second World War The Z.1007 Asso replaced the Savoia-Marchetti SM.81s of 16° Stormo while 47° Stormo was equipped with Z.1007Bis, but operational readiness was only attained in August, when around thirty 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 deployed to Africa. The British destroyer was sunk by an explosion caused by a Z.1007 bombing during 1941. 35° Stormo was dispatched to Africa in the bombing role; these three-engine aeroplanes were used occasionally in Russia too. During 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. By November 1942, there were 10 Gruppi equipped with 75 Z.1007s, with just 39 serviceable aircraft. During 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. 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. 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 this war theatre that the wooden structure of the CANT Z.1007s began to show its weaknesses. The heavy rains damaged it, forcing continuous repairs by the ground crews. Yugoslavia The CANT Z.1007s opened hostilities against Yugoslavia, on 6 April 1941, bombing Mostar airfield. During that short invasion, Regia Aeronautica deployed 49 CANT Z.1007 bis, 26 of 47° Stormo, 15 of 95° Gruppo (of 35° Stormo) and eight of 50° Gruppo (of 16° Stormo). Three days after the armistice, on 11 September, the Z.1007s that were in Perugia, joined by eight more, took off for the base of Alghero in Sardinia, losing two of their number to German flak. On 16 September, these bombers attacked German vessels that were carrying troops and equipment from Sardinia to Corsica, and one more aircraft was lost to flak. On 15 October, the Z.1007s, then based in Sardinia, were grouped with those in Southern Italy to form the Raggruppamento Bombardamento Trasporti (Unit for bombing and transport), under the badge of the Aeronautica Cobelligerante Italiana (ACI or Air Force of the South, Aeronautica del Sud), Italian Co-Belligerent Air Force in English. The worst day for the co-belligerent Z.1007s was 14 May 1944, when Gruppo 88 sent twelve Z.1007s to Tito's forces to deliver supplies. The aircraft dropped 96 food containers on Kolasin, Montenegro, but on the way back nine bombers lost contact with the escort of Macchi C.205s and Reggiane Re. 2001s and were attacked over the Adriatic sea by 7/JG 27 Messerschmitt Bf 109s. Five Alcioni were shot down into the sea by the German pilots (who mistakenly claimed Savoia-Marchetti SM.84) and two more landed heavily damaged at the Lecce-Galatina air base in Apulia. 26 Italian aviators were killed, and more injured. From that day on, the remaining Z.1007s were used for military purposes only under cover of darkness. ==Variants==

A total of 560 CANT Z.1007s were built, 450 of them of version 1007bis that appeared in late 1939. 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 minutes and 28 seconds, and 5,000 m (16,400 ft) in 10 minutes and 44 seconds (Z.1007 bis in 12 minutes and 42 seconds, Z.1007 Asso in 14 minutes and 34 seconds). 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 twenty, 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 in the Mediterranean theatre. They were also the first victims of P-40 Tomahawks over Alexandria. ;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 , 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. ==Operators==

; • Zrakoplovstvo Nezavisne Države Hrvatske ; • Luftwaffe operated captured aircraft ; • Regia Aeronautica • Italian Co-Belligerent Air Force • Aeronautica Nazionale Repubblicana ; • Free French Air Force operated captured aircraft ==Specifications (Z.1007bis)==