The CANT Z.501 Gabbiano (Italian: Gull) was a high-wing central-hull flying boat, with two outboard floats. It was powered by a single engine installed in the middle of the main-plane and had a crew of 4–5 men. It served with the Italian Regia Aeronautica during World War II, as a reconnaissance aeroplane. During its debut in 1934, it set a world distance record. It was obsolete by 1940, but was still used throughout World War II, suffering many losses. A few remained in service until 1949. Filippo Zappata was one of the foremost Italian aircraft designers. He worked for Cantieri Aeronautici e Navali Triestini (CANT) for some years, but went to France in 1927 to work for Blériot. He returned to Italy at the prompting of Italo Balbo and resumed work at CANT on a series of new aircraft. The first of these was the Z.501, designed to replace the Savoia-Marchetti S.78. The prototype Z.501 was first flown in 1934 by test pilot Mario Stoppani. The aircraft had a very slim fuselage, a high parasol wing and a single wing-mounted engine nacelle. In the prototype a 560 kW (750 hp) inline Isotta Fraschini Asso-750.RC engine was fitted, with an annular (circular) radiator that made the installation resemble a radial engine, although it was actually a liquid-cooled inline. Some versions of other planes such as the Ju 88 and Fw 190D had this same feature. The engine nacelle was extended to carry a rear-facing machine gun, while other guns were mounted in the centre fuselage and nose. All were 7.7 mm (.303 in) Breda-SAFAT machine guns. Bombs up to 640 kg/1,410 lb (4 × 160 kg/350 lb) were carried under the wings. The aerodynamic low-drag design was typical of Zappata-designed aircraft, as was the wooden construction. Production of the Z.501 began in 1935 with 24 aircraft ordered from CANT, and 30 from Aeronautica Sicula, a company in Palermo. Registration numbers started with MM.35168. For operational history and military service, click here.