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Curtiss SOC Seagull

United States (1935)

Detailing the development and operational history of the Curtiss SOC Seagull Scout / Artillery Spotting Recoverable Biplane Floatplane.

 Entry last updated on 12/7/2017; Authored by Staff Writer; Content ©

  Curtiss SOC Seagull  
Picture of Curtiss SOC Seagull Scout / Artillery Spotting Recoverable Biplane Floatplane
Picture of Curtiss SOC Seagull Scout / Artillery Spotting Recoverable Biplane Floatplane

By 1940, the Curtiss SOC Seagull series could be found on just about every American warship in the Pacific - the line fought on until 1945.

For its short time in the air, which lasted from the mid-1930s into the mid-1940s, the Curtiss SOC "Seagull" served American naval forces as a recoverable scout-minded floatplane. Some 322 of the type were completed (258 of the stock coming from Curtiss factories, the rest from the Naval Aircraft Factory - NAF) and the aircraft saw service throughout the Second World War (1939-1945). It was retired as soon as the conflict ended as its role was overtaken by other systems.

The sole prototype XO3C-1, known to Curtiss as the Model 71, completed its first-flight in April of 1934 and this form was powered by the Pratt & Whitney R-1340-12 air-cooled radial engine. The aircraft carried its powerplant in the nose and this installation drove a two-bladed propeller. A biplane wing arrangement was featured and these were interconnected via N-style struts and cabling reminiscent of the First World War fighters. The crew of two sat in tandem under a greenhouse-style canopy. The tail unit utilized a single vertical fin and mid-mounted horizontal planes.

Two versions of the aircraft were eventually developed - one with floatplane gear for waterborne operation and one with a traditional wheeled undercarriage (tail-dragger arrangement). The floatplane gear involved a large central float under the fuselage with smaller outboard floats held under the lower wing element. In the wheeled form, the main legs were fitted under center mass as usual, complete with aerodynamic spats, and a tail wheel brought up the rear. An arrestor hook could also be installed for carrier-based, flightdeck recoveries.

Service introduction of the SOC (the "Seagull" name was not given until 1941) was had on November 12th, 1935 and these early birds were stationed on USS Marblehead, a USN light cruiser warship. Production ranged into 1938 with the aircraft serving in the reconnaissance and artillery-spotting roles.

Curtiss-Wright was formed by the merger of the Curtiss Aeroplane and Motor Company and Wright Aeronautical - two storied concerns of American aviation, established in 1916 and 1919, respectively. The design of the Seagull was attributed to Alexander Solla.
The USN contracted for 135 of the aircraft in 1933 and this was based around the initial SOC-1 (Model 71A) standard complete with floatation equipment (power was from a Pratt & Whitney R-1340-18 engine). The aircraft had an overall length of 31.4 feet, a wingspan of 36 feet and a height of 14.8 feet. Empty weight was 3,800lb against an MTOW of 5,500lb. Maximum speed reached 165 miles per hour but cruising was typically 135mph or less. Range was out to 675 miles and the listed service ceiling became 15,000 feet. Rate-of-climb reached 915 feet-per-minute.

Armament involved a fixed, forward-firing 7.62mm Browning M2 AN machine gun for the pilot at front and a flexibly-mounted 7.62mm Browning M2 AN machine gun for the observed at the rear. Light bombing duties could be had by carrying up to 650lb of conventional drop loads.

The follow-up SOC-2 variant (Model 71B) was similar in most respects but featured a wheeled undercarriage for land-based operations. Power was form a Pratt & Whitney R-1340-22 engines. Forty of the SOC-2 models were contracted for.

The XSO2C-1 (Model 71C) was a one-off prototype intended as an improved variant but was not ordered for serial production.

The SOC-3 (Curtiss Model 71E) was based in the SOC-2 but differentiated by its interchangeable undercarriage capability (from land to sea and back as needed). Curtiss managed production of 83 of this form and the NAF followed with 64 of their own. In the latter case the aircraft were designated as SON-1.

The SOC-4 (Model 71F) were three SOC-3 aircraft set aside United States Coast Guard service. These were later passed back into the hands of the USN who reworked the trio into the carrier-capable SOC-3 standard (complete with arrestor gear). They were redesignated SOC-3A as a result.

The SO2C was a one-off developmental model based in the SOC-3 but given a stretched fuselage and carried the Pratt & Whitney R-1340-35 series engine.

The SOC Seagull series was eventually succeeded by the Vought OS2U "Kingfisher" line (detailed elsewhere on this site). The Seagulls were, in turn, relegated to the training role but some were brought back up to fighting standards when the Curtiss SO3C "Seamew (detailed elsewhere on this site), the Seagull's intended replacement, more-or-less failed in its role. Seagulls remained in both first- and second-line roles until the end of the war in 1945 and were retired quickly thereafter.

The United States Marine Corps (USMC) was the other notable operator of the Seagull line.
Curtiss SOC-1 Specifications
National Flag Graphic
United States
Year: 1935
Status: Retired, Out-of-Service
Type: Scout / Artillery Spotting Recoverable Biplane Floatplane
Manufacturer(s): Curtiss-Wright - USA
Production: 322
Supported Mission Types
Ground Attack
Close-Air Support
Airborne Early Warning
Electronic Warfare
Aerial Tanker
Passenger Industry
VIP Travel
Business Travel
Special Forces
Crew: 2
Length: 31.43 ft (9.58 m)
Width: 36.09 ft (11.00 m)
Height: 14.76 ft (4.50 m)
Empty Weight: 3,803 lb (1,725 kg)
MTOW: 5,445 lb (2,470 kg)

Installed Power
1 x Pratt & Whitney R-1340-18 Wasp radial piston engine developing 600 horsepower. and driving a two-bladed propeller at the nose.

Standard Day Performance
Maximum Speed: 165 mph (265 kph; 143 kts)
Maximum Range: 674 mi (1,085 km; 586 nm)
Service Ceiling: 14,895 ft (4,540 m; 2.82 mi)
Rate-of-Climb: 915 ft/min (279 m/min)

1 x 0.30 cal (7.62mm) Browning M2 AN machine gun in fixed, forward-firing mounting.
1 x 0.30 cal (7.62mm) Browning M2 AN machine gun on trainable mounting in rear cockpit.

Up to 650lb of drop stores for light bombing sorties.

Operators List
United States

Series Model Variants
• XO3C-1 - Prototype Designation; single example constructed; fitted with 1 x Pratt & Whitney R-1340-12 series radial piston engine of 550 horsepower.
• XSOC-1 - Redesignation of XO3C-1 prototype beginning March of 1935.
• SOC-1 - Initial Production Model; fitted with Pratt & Whitney R-1340-18 series radial piston engine of 500 horsepower; interchangeable wheeled or float undercarriage; 135 examples produced.
• SOC-2 - Second Production Model; featuring subtle revisions; fitted with Pratt & Whitney R-1340-22 series radial piston engine; limited to wheeled undercarriage; 40 examples produced.
• XSO2C-1 - Proposed improved SOC; single prototype example constructed.
• SOC-3 - Based on SOC-2 changes; interchangeable undercarriage; 83 examples produced.
• SOC-4 - Improved SOC-3 production models; USCG usage.
• SO2C - Single evaluation model based on SOC-3 production model; lengthened fuselage; fitted with Pratt & Whitney R-1340-35 series radial piston engine.
• SON-1 - 44 examples of the SOC-3 as produced by the Naval Aircraft Factory.
• Curtiss Model 71 - Curtiss company designation for XO3C-1 prototype.
• Curtiss Model 71A - Curtiss company designation for SOC-1 production model.
• Curtiss Model 71B - Curtiss company designation for SOC-2 production model.
• Curtiss Model 71C - Curtiss company designation for XSO2C-1 prototype model.
• Curtiss Model 71E - Curtiss company designation for SOC-3 production model.
• Curtiss Model 71F - Curtiss company designation for SOC-4 production model.

Supported Weapon Systems
Graphical image of an aircraft medium machine gun
Graphical image of an aircraft conventional drop bomb munition

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