The CANT Z.511 was a four-engine long-range seaplane designed by Filippo Zappata of CRDA -"Cantieri Riuniti dell'Adriatico", meaning "Re-united Shipyards of the Adriatic Sea". Originally designed for the Central and South Atlantic passenger routes, it was later adapted as a military transport and special raider. These plans were cancelled on the outbreak of World War II, but a version of the aircraft was adapted for long-range maritime patrol, armed with 10 single-mount 12.7 mm (.5 in) machine guns in both sides, in two upper turrets, and belly positions. Plans were made to install 20 mm cannons in a front turret or in a glazed nose position, and more machine guns in a tail position.
The first flight was on the 19th October 1940 commanded by Mario Stoppani and CRDA's Guido Divari, Designer Filippo Zappata was also on board. Between February and March 1942, Mario Stoppani succeeded in taking off and landing fully loaded in very rough seas, with 1.5 m (5 ft) waves and winds of 55–65 km/h (34-40 mph). The aircraft apart from being under powered with unreliable engines It was very good in all other areas.
The fuselage was manufactured in two levels: the lower one forms a luggage compartment having a length of 15 m and a height of approximately 1 m, while the upper layout options were 16 reclining seats that could be transformed into berths, or 48 places in 4 compartments. The luggage compartment was accessible in flight, and from it through two narrow passages (going on all fours) the motor units and the outer fuel tanks can be inspected. In vicinity of the inner engines it was also possible to descend from an internal ladder down inside the floats (that could contain stores) or from a lateral hatch to control mooring operations.
In March 1942 the prototype was transported to Grado, Venezia (further away from the insecure Yugoslavian border) for further evaluations; the last test and operational flight occurred on 1 September 1943, the same day that the Italian Armistice was signed.
After the division of the Italian forces, one aircraft was appropriated by the Fascist Aeronautica Nazionale Repubblicana. However, it had been damaged only three weeks before by British fighters, which had strafed it on Lake Trasimeno where it was undergoing final trials. It was transferred to the seaplane base at Vigna di Valle. There it suffered from sabotage by base personnel to prevent it falling into the hands of either the Allies or the Germans. The other aircraft, still under construction at the CRDA factory, was retained by Axis forces and scrapped for the metal, which was sent to Germany.
Total Aircraft Built: 2
Crew: Six
Capacity: 16 passengers or 48 (civil)
Length: 28.50 m (93 ft 6 in)
Wingspan: 39.86 m (130 ft 9 in)
Height: 11.0 m (36 ft 1 in)
Wing area: 195.0 m² (2,098 ft²)
Empty weight: 20,692 kg (45,522 lb)
Loaded weight: 34,200 kg (75,240 lb)
Useful load: 2,000 kg (4,400 lb)
Powerplant: 4 × Piaggio P.XII RC.35 radial engines, 1,120 kW (1,500 hp) each
Performance
Maximum speed: 424 km/h at 4,000 m (228 kn, 262 mph)
Cruise speed: 330 km/h (177 kn, 203 mph)
Range: 4,532 km (2,447 nmi, 2,796 mi)
Service ceiling: 7,550 m (24,764 ft)
Rate of climb: 4.16 m/s (820 ft/min)
Armament
10 × Breda-SAFAT or Cannone-Mitragliera da 20/77 (Scotti) 12.7 mm (.5 in) machine guns in both sides, two upper turrets, and belly positions.
Up to 4,000 kg (8,800 lb) bombload in internal bomb bay and mounted on outer wing positions
