Z.501 Gabbiano
The Z.501 Gabbiano ("Gull") single-engined flying boats were designed by Italian engineer Filippo Zappata, his first after joining Cantiere Navale Triestino after his return from the French firm Blériot. The aircraft had very slim fuselages and high parasol wings which housed the engine nacelles. The construction was mostly wooden. On 19 to 20 May 1934, a pre-production Z.501 Gabbiano aircraft established a new seaplane flight distance record of 4,130-km flying from Monfalcone, Italy to Massawa, Eritrea in 26 hours and 35 minutes. After that record was broken by a French aircraft one month later, on 16 Jul another attempt was made, and it broke the record again by a flight to Berbera, Somaliland in 25 hours. Production of the Z.501 Gabbiano aircraft began in 1935.
With the Italian military service, Z.501 Gabbiano aircraft were modified with machine gun turrets and reinforced airframes. To compensate for the added weight of the military equipment, 880-hp engines were used instead of the original 750-hp engines. A few were sent to Spain for use during the Spanish Civil War, but most remained in Italy. A number were exported to the Romanian military. Pilots reported that the aircraft were easy to fly, but the wooden fuselages were susceptible to break-ups in rough seas.
By the time Italy entered WW2 in 1940, 202 Z.501 Gabbiano aircraft were in service in 15 squadrons, and their primary functions were maritime patrol/reconnaissance and air-sea rescue. They proved to be ineffective in military use, however. By the end of 1940, a stunning 62 aircraft were lost as they were too slow and difficult to maneuver, therefore extremely vulnerable to hostile fighters. Nevertheless, new orders to replace the destroyed units were made largely to fulfill Italy's need for aircraft. By the end of 1941, 100 Z.501 Gabbiano aircraft were in service in 15 squadrons; by mid-1942, 108 aircraft were in service in 11 squadrons; by end of 1942, 199 were in service (though only 88 were operational); at the time of the Italian Armistice in Sep 1943, 84 were in service in 3 squadrons (only 40 were operational). In addition to patrol/reconnaissance and air-sea rescue duties, they were also sometimes anti-submarine aircraft; during WW2, they were credited with destroying about six British submarines.
During the design's production life, 218 units were built by Cantiere Navale Triestino and 236 were built by Aeronautica Sicula. The last of the Z.501 Gabbiano aircraft were retired from service in 1950.