The SOC/SON Seagull (Curtiss Model 71) was a U.S. single-engined scout observation biplane aircraft, designed by Alexander Solla of the Curtiss-Wright Corporation for the US Navy. Seagull was ordered by the US Navy on June 19, 1933. The aircraft served on battleships and cruisers in a seaplane configuration, being launched by catapult and recovered from a sea landing. The wings folded back against the fuselage for storage aboard ship. When based ashore or on aircraft carriers the three floats were replaced by fixed wheeled landing gear.
Powerplant (SOC-3): 550hp (410 kW) Pratt & Whitney R-1340-22 Wasp, 9-cylinder air- cooled, radial engine driving a two- bladed, ground- adjustable metal propeller.
Total produced: 309
- XO3C-1 (Model 71) – prototype aircraft tested in March 1934, powered by 550 hp (410 kW) Pratt & Whitney R-1340-12 engine. One built, redesignated XSOC-1 on 23 March 1935.
- SOC-1 (Model 71A, BuNo 9856-9990) – first production version, with 550 hp Pratt & Whitney R-1340-18 engine enclosed in NACA cowling, ailerons added to the top wing, and a large canopy enclosing both cockpits. Interchangeable float and wheeled undercarriage. 135 built.
- SOC-2 (Model 71B, BuNo 0386-0425) – 40 SOC with R-1340-22 engine. Wheeled undercarriage only.
- SOC-3 (Model 71E, BuNo 1064-1146) – sSimilar to SOC-2, but with interchangeable undercarriage. 83 built.
- SOC-3A – SOC-3 modified to operate on wheels from escort carriers
- SOC-4 – (Model 71F) – 3 U.S. Coast Guard SOC-3 Seagulls produced by Curtiss in 1938. All were transferred to the U.S. Navy in 1942 (call numbers V171-V173; BuNo 48243-48245), which modified them to SOC-3A standard, to operate on wheels from escor carriers.
- XSO2C – (Model 71C, BuNo 0950) – prototype based on the SOC-3, but with a 5-foot fuselage stretch and powered by a Pratt & Whitney R-1340-36.
- SON-1 (BuNo 1147-1190) – SOC-3 aircraft produced by the Naval Aircraft Factory, 44 built.
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