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Boeing Clipper

The Boeing 314 Clipper was an American long-range flying boat produced by Boeing from 1938 to 1941.

One of the largest aircraft of its time, it had the range to cross the Atlantic and Pacific oceans.

For its wings, Boeing re-used the design from the earlier XB-15 bomber prototype.

Pan Am’s Clipper fleet was pressed into US military service during World War II, and the flying boats were used for ferrying personnel and equipment to the European and Pacific fronts.

The aircraft were purchased by the War and Navy Departments and leased back to Pan Am for a dollar, with the understanding that all would be operated by the Navy once four-engined replacements for the Army’s four Clippers were in service.

Only the markings on the aircraft changed.

The Clippers continued to be flown by their experienced Pan Am civilian crews.

American military cargo was carried via Natal, Brazil to Liberia, to supply the British forces at Cairo and even the Russians, via the Persian Corridor.

The Model 314 was then the only aircraft in the world that could make the 2,150-statute-mile (3,460 km) crossing over water.

The Army gave the aircraft the designation C-98, but the Navy, which used a different designation system at the time, disregarded this designation and operated the aircraft under the company designation B-314.


Model 314

Initial production version with 1,500 horsepower (1,100 kW) Twin Cyclone engines, six built for Pan Am.

Model 314A

Improved version with 1,600 horsepower (1,200 kW) Twin Cyclones with larger diameter propellers, additional 1,200 US gallons (4,500 l; 1,000 imp gal) fuel capacity, and revised interior.

Still air range approx 4,700 miles.

Six built, three for Pan Am and three sold to BOAC.


Five Model 314s pressed into military service with the U.S. Navy


Four Model 314s pressed into military service with the U.S. Army Air Forces





68 day passengers and / or 36 sleeping passengers / 5 short tons (4,536 kg) of mail and or cargo


106 ft (32 m)


152 ft (46 m)


20 ft 4.5 in (6.210 m)



NACA 0018


NACA 0010

Empty weight

48,400 lb (21,954 kg)

Gross weight

84,000 lb (38,102 kg)

Fuel capacity

5,408 US gal (4,503 imp gal; 20,470 l) in wing and sponson tanks


4 × Wright 709C-14AC1 Twin Cyclone 14-cylinder air-cooled radial piston engines,

1,600 hp (1,200 kW) each


3-bladed Hamilton Standard fully feathering constant-speed propellers


Maximum speed

210 mph (340 km/h, 180 kn) at 6,200 ft (1,890 m)

Cruise speed

188 mph (303 km/h, 163 kn) at 66.5% power at 11,000 ft (3,353 m)


3,685 mi (5,930 km, 3,202 nmi) normal, 4,900 mi (4,258 nmi; 7,886 km) at maximum loaded weight.

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