Sikorsky S-42

https://en.wikipedia.org/wiki/Sikorsky_S-42

The Sikorsky S-42 was a commercial flying boat designed and built by Sikorsky
Aircraft to meet requirements for a long-range flying boat laid out by Pan
American World Airways (Pan Am) in 1931. The innovative design included wing
flaps, variable-pitch propellers, and a tail-carrying full-length hull. The
prototype first flew on 29 March 1934, and, in the period of development and
test flying that followed, quickly established ten world records for
payload-to-height. The "Flying Clipper" and the "Pan Am Clipper" were other
names for the S-42.

During the inaugural flight of Sikorsky's previous flying boat, the S-40, on
November 19, 1931, the pilot and Pan American Airways consultant, Charles
Lindbergh, who considered the S-40 a monstrosity, engaged designer Igor Sikorsky
in a conversation about what he thought the next airplane should look like. The
conversation continued that night at the hotel in Jamaica. Sikorsky argued that
design development should be incremental and that the safe approach would be a
larger S-40. Lindbergh argued that a sleeker design, with a range in still air
of 2,500 miles, was needed.

In June 1931 Pan Am president Juan Trippe had requested designs from six
aircraft companies for an aircraft able to span the oceans. The new design would
need increased lifting capacity to carry enough fuel and 300 pounds of mail, but
no passengers, for a 2,500 miles (4,023 kilometers) nonstop flight against a 30
mph (48 km/h) wind, at a higher cruising speed than the norm for similar flying
boats at that time. Of the six companies tenders had been sent to, only Sikorsky
and Martin provided submissions. Sikorsky offered the S-42. The other offer was
the more ambitious Martin M-130.

The new Sikorsky design, the S-42, had major aerodynamic improvements over the
S-40. Igor Sikorsky said, "in its very outline the S-42 represents simplicity.
Diverting sharply from the past Sikorsky designs, external bracings have been
reduced to a minimum. The tail, instead of being supported by outriggers, is
attached directly to the hull." The S-42 had a high wing loading which required
flaps to provide acceptable takeoff and landing speeds. Though Lindbergh
approved of the S-42, it fell far short of his proposed range Stripped of all
accommodations, with extra fuel tanks in the fuselage, the S-42 was just able to
fly proving flights across the Atlantic and Pacific oceans. Pan Am would have to
wait for the Martin M-130 to have an airliner capable of flying the Pacific with
a payload.

Pan Am's S-42s were used primarily on the Miami - Rio de Janeiro route. In 1937
S-42s also operated a New York-to-Bermuda service. 1940 saw S-42 flights between
Seattle and Alaska. An S-42 was also used between Manila and Hong Kong.

Notable Crashes

Samoan Clipper was one of ten Pan American Airways Sikorsky S-42 flying boats.
It exploded near Pago Pago, American Samoa, on January 11, 1938, while piloted
by famous aviator Ed Musick. Musick and his crew of six died in the crash. The
aircraft was carrying only airmail and express freight; no passengers were
aboard.

On April 11, 1936, a Pan Am S-42 named Puerto Rican Clipper crashed on takeoff
from Port of Spain, Trinidad & Tobago, killing three of 25 on board. The pilot
swerved to avoid a fishing boat that was in his path but one pontoon struck the
boat and the aircraft overturned.

On October 3, 1941, Pam Am Flight 203, an S-42A named Dominican Clipper, crashed
on landing in the harbour at San Juan, Puerto Rico, killing two of 27 on board.
After the approach to San Juan, the aircraft hit the water in a nose-low
attitude while moving sideways; after the first contact the aircraft swerved
violently to the right and broke apart.

On December 8, 1941, a Pan Am S-42B named Hong Kong Clipper II (formerly Bermuda
Clipper and Alaska Clipper) was destroyed on the water at Kai Tak Airport, Hong
Kong, during a Japanese bombing raid.

On July 27, 1943, a Pan Am S-42B named Bermuda Clipper (formerly Pan American
Clipper III) caught fire and burned out while docked at Manaus; there was no one
on board.

On August 8, 1944, Pan Am Flight 218, an S-42 NC 823M, named Hong Kong Clipper
(formerly West Indies Clipper and Pan Am Clipper I) on a return trip from San
Juan to Miami with intermediate stops at Port-au-Prince and Antilla, Cuba,
crashed shortly after taking off from Antilla. After striking, bow first, the
flying boat left the water in a slightly nose-high attitude, then returned, and
by the third time, stalled. There were 17 fatalities (all passengers) out of the
26 passengers and five crew.

The aircraft developed an oil leak shortly after taking off from Pago Pago
harbor, and the crew decided to return to port. However, the S-42, fully loaded
with fuel, was too heavy to land safely in the limited space of the harbor, so
the crew elected to dump fuel before landing. While fuel dumping was in
progress, there was a fire and explosion which destroyed the aircraft, killing
all aboard. The exact cause of ignition for the fire could not be determined.


Role
Flying boat airliner

National origin
United States

Manufacturer
Sikorsky Aircraft

Designer
Igor Sikorsky

First flight
March 29, 1934 (prototype)

Introduction
1934

Status
Retired, none remaining

Primary user
Pan American Airways

Number built
10

Developed from
Sikorsky S-40

Flying for Pan American Airways, a total of ten S-42s were built, manufactured
by the Vought-Sikorsky Aircraft Division of the United Aircraft Corporation in
Stratford, Connecticut. The prototype first flew on March 30, 1934.

The S-42 flew only for Pan American Airways. The S-42 Pan Am Clipper surveyed
the route from the US West Coast to China, making the first survey flight from
Alameda, California to Pearl Harbor, Hawaii in April 1935. (It never flew
scheduled passengers from California to Hawaii.)

In March 1939 a Pan Am S-42 was scheduled to leave Miami at 0730, stop overnight
in San Juan, Port of Spain, Belem and Recife, and arrive at Rio de Janeiro at
1530 on the fifth day. (It returned to Miami, and passengers to Buenos Aires
continued on DC2/DC3s.)

In early 1942 the U.S. Navy acquired one S-42 which it used as a transport in
the Caribbean and to South America.

Specifications (S-42-A)

General characteristics
Crew: four
Capacity: up to 37 day passengers or 14 sleeper berths
Length: 68 ft (20.73 m)
Wingspan: 118 ft 2 in (36.03 m)
Height: 17 ft 5 in (5.3 m)
Wing area: 1,329 ft² (123.5 m²)
Empty weight: 19,764 lb (8,984 kg)
Loaded weight: 38,000 lb (17,273 kg)
Powerplant: 4 × Pratt & Whitney R-1690 Hornet, supercharged radial engine, 660
hp (492 kW) each

Performance
Maximum speed: 188 mph (300 km/h)
Range: 1,930 miles (3,088 km)
Service ceiling: 15,704 ft (4,788 m)
Rate of climb: 1,000 ft/min (305 m/min)
Wing loading: 28.6 lb/ft² (140 kg/m²)
Power/mass: 0.07 hp/lb (0.11 kW/kg)




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