CANT Z.511

Cantieri Riuniti dell'Adriatico (CRDA)

Industry	Shipbuilding and aircraft manufacturing
Headquarters	Monfalcone , Italy
Key people	Filippo Zappata (aircraft designer)

The CANT Z.511 was a long-range seaplane powered by four engines, developed by Filippo Zappata at the Cantieri Riuniti dell'Adriatico (CRDA) firm. Initially conceived for transatlantic passenger service between Central and South Atlantic regions, it was subsequently modified for use as a military transport and specialized raider aircraft.

Design and development

Development commenced in late September 1937 on a large twin-float seaplane equipped with four engines, following the technical department of CRDA's acceptance of requirements from the LATI (Compagnia Ala Littoria) airline, established in 1939Template:Fix/category. LATI sought a long-range seaplane capable of transporting mail, cargo, and passengers to destinations in Latin America.

Although these initial plans were halted by the onset of World War II, the aircraft design was later adapted for extended maritime patrol missions. The military variant featured armament including ten single-mounted 12.7 mm (0.500 in) machine guns positioned along the sides, two dorsal turrets, and ventral gun mounts. Proposals also included fitting a 20 mm (0.787 in) cannon either in a forward turret or within a glazed nose section, as well as additional machine guns mounted at the tail Template:Fix/category.

For offensive operations, the aircraft was modified to carry up to 4,000 kg (8,800 lb) of ordnance housed internally within a bomb bay and externally on wing hardpoints. These could accommodate up to four launch racks for 454 mm (17.9 in) air-launched torpedoes intended for surface target engagement Template:Fix/category, or alternatively deploy human torpedoes such as the Maiale or midget submarines for special mission profiles.

The initial powerplants were considered insufficiently powerful, prompting Zappata to request permission to import 1,193 kW (1,600 hp) Wright R-2600 Double Cyclone engines from the United States. However, worsening international relations prevented approval. In its civilian configuration, the CANT Z.511 was theoretically capable of carrying sixteen passengers over distances exceeding 5,000 km (2,700 nmi; 3,100 mi). When converted for military transport duties, it utilized four 1,119 kW (1,501 hp) Piaggio P.XII R.C.35 engines, providing only marginal performance for an aircraft with a maximum takeoff weight around 34 t (75,000 lb), achieving a maximum range near 4,500 km (2,400 nmi; 2,800 mi).

Operational history

File:CANT Z.511.jpg

The initial test flights of the Z.511 took place at Monfalcone, Venezia Giulia (northeastern Italy) from October 1940 until March 1942. During the period from 28 February to 1 March 1942, test pilot Mario Stoppani successfully executed takeoffs and landings with a fully loaded aircraft amid turbulent sea conditions, encountering waves approximately 1.5 m (4.9 ft) high and winds ranging between 55–65 kilometres per hour (30–35 kn; 34–40 mph). Following these trials, the Z.511 prototype was relocated to Grado, Venezia, situated further from the unstable Yugoslavia border, for additional assessments. Its final test and operational sortie was conducted on 1 September 1943, just two days before the signing of the Italian Armistice.

Following the split of Italian military forces, one unit was seized by the Fascist Aeronautica Nazionale Repubblicana. However, this particular aircraft had sustained damage three weeks earlier due to strafing by British fighter aircraft while it was undergoing its concluding tests at Lake Trasimeno. Subsequently, it was moved to the seaplane base at Vigna di Valle, where sabotage was carried out by base personnel aiming to prevent its capture by either the Allies or Nazi Germany. The second aircraft, which remained incomplete at the CRDA manufacturing plant, was held by Axis forces before being dismantled.

References

• John & Elke Weale, Combat Aircraft of World War Two (pp. 193–205), Arms and Armour Press, London, 1978.
• World War Two Magazine, Article: "Germany, Italy and Japan each formulated plans to attack the U.S. mainland, but these were postponed... for too long" by Frank Joseph (pp. 10–20), Empire Press Inc., March 1993.
• Spanish Military Review "Serga", (Historia Militar del Siglo XX), Article "CANT, la oficina aeronáutica de Cantieri Navale Triestino", authored by Carlo D'Agostino (translated into Spanish by D. Garcia) (pp. 42–48), Almena Ediciones, No. 10, March–April 2001.

External links

• Cantieri Z-511 IdroGigante photographs