Sikorsky S-39

Sikorsky S-39
Country	USA
Role	Flying boat
First flight	1930s
Built	21

The Sikorsky S-39 was an American light amphibious aircraft produced by Sikorsky Aircraft during the early 1930s. The S-39 was a smaller, single-engine version of the S-38.

Source: Sikorsky S-39 on Wikipedia

Sikorsky S-39C Walk Around
Photographer	Vladimir Yakubov
Localisation	Fantasy of Flight, Polk City
Photos	136

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The Quintessential Single-Engine Personal Amphibian

The Sikorsky S-39 was a five-seat, single-engine light amphibious aircraft designed and built by the Sikorsky Aviation Corporation in the early 1930s. Developed directly as a scaled-down, single-engine derivative of the highly successful twin-engine S-38, the S-39 was engineered to cater to private aviators, business executives, and commercial operators seeking a versatile “air yacht.” Combining a high-mounted parasol wing, a single Pratt & Whitney Wasp Junior radial engine, a twin-boom tail layout, and retractable landing gear, the S-39 offered exceptional utility for operating from both lakes and conventional runways. It achieved legendary status during the Great Depression through high-profile scientific expeditions and its service with the Civil Air Patrol during World War II.

Attribute	Technical Specification (Sikorsky S-39 Standard)
Role	5-Seat Personal Luxury Amphibian / Utility Transport
Crew	1 Pilot + 4 Passengers
Powerplant	1 × Pratt & Whitney R-985 Wasp Junior 9-cylinder air-cooled radial engine (300 to 400 hp)
Maximum Speed	190 km/h (119 mph / 103 knots) max speed \| ~156 km/h (97 mph) cruise speed
Gross / Takeoff Weight	1,814 kg (4,000 lbs) maximum gross weight \| ~1,215 kg (2,678 lbs) empty weight
Service Ceiling / Operational Range	5,486 m (18,000 ft) ceiling \| ~640 km (400 miles) maximum range
Wing Structure & Dimensions	Wingspan: 15.85 m (52 ft) \| High parasol wing with all-metal spars and fabric covering
Hull Construction	All-metal duralumin hull structure with hydrodynamic steps for quick water takeoff
Military Variants	US Army Air Corps (Y1C-28 / C-28 evaluation and coastal utility transports)
Production Total	21 units produced by Sikorsky at Stratford, Connecticut (1929–1932)

Design Engineering: Scaled Efficiency, Boom Tails, and Retractable Skids

Scaled-Down S-38 Architecture: Igor Sikorsky retained the structural success of the S-38 by keeping the high parasol wing, twin tail booms, and short wooden/duralumin hull layout, while streamlining the design down to a single center-mounted engine nacelle mounted above the cockpit.
Pratt & Whitney Wasp Junior Power: By matching the airframe with the newly introduced Pratt & Whitney R-985 Wasp Junior radial engine, the S-39 delivered outstanding power-to-weight performance, permitting smooth water takeoffs even when fully loaded with five adult passengers and luggage.
Hand-Crank Retractable Landing Gear: Like its larger sibling, the S-39 incorporated a main landing gear assembly that retracted upward along the hull sides, allowing the pilot to transition seamlessly between tarmac runways and water landings in under thirty seconds.
Hydrodynamic Duralumin Hull: The hull featured advanced duralumin anti-corrosion plating and hydrodynamically placed bottom steps, allowing the hull to break water suction (“unstick”) quickly during takeoff runs on calm lakes or ocean swells.

Operational History: Giraffe Camouflage, African Safaris, and WWII Patrols

Martin and Osa Johnson’s *Spirit of Africa*: The most famous S-39 ever built was NC52V, painted in a distinctive giraffe-pattern camouflage by world-renowned wildlife filmmakers Martin and Osa Johnson. Named *Spirit of Africa*, it was flown thousands of miles across uncharted territories in East and Central Africa to film wildlife from the air.
US Army Air Corps Evaluation (Y1C-28): Recognizing its versatile amphibious nature, the US Army Air Corps purchased an S-39 in 1932 (designated Y1C-28) for evaluation as a light coastal utility transport and communication aircraft.
Civil Air Patrol Coastal Anti-Submarine Patrols: During the early years of World War II, several privately owned S-39s were drafted into the US Civil Air Patrol (CAP). Stationed along the Atlantic and Gulf coasts, CAP aircrews flew S-39s on low-altitude anti-submarine patrols to spot German U-boats and rescue downed Allied pilots.
Enduring Vintage Icon: Due to its low production numbers and striking appearance, surviving S-39s are highly prized treasures in vintage aviation. Rebuilt airframes—including faithful airworthy restorations painted in the legendary Johnson giraffe pattern—continue to captivate crowds at major airshows.