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 design featured wing flaps, variable-pitch propellers, and a full-length hull that supported the tail directly. The prototype first flew on 29 March 1934, and set ten world records for payload-to-height.<ref name="Sikorsky_1934">Template:Cite web</ref><ref name=jma>Template:Cite book</ref> The "Flying Clipper" and the "Pan Am Clipper" were other names for the S-42.

Design and development

File:Sikorsky S-42 Brasilian Clipper.jpg

Sikorsky S-42, aircraft registration NC-822M, "Brazilian Clipper", Pan American Airways, 1934

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.<ref name="Daley, Robert 1980, pages 102–103">Daley, Robert, An American Saga, 1980, Random House, New York, Template:ISBN, pages 102-103</ref><ref name="ReferenceA">Delear, Igor Sikorsky: His Three Careers in Aviation, Dodd, Mead & Co., 1969</ref> Sikorsky argued that design development should be incremental and that the safe approach would be a larger S-40. Lindbergh argued that a low drag design, with a range in still air of Template:Cvt, was needed.<ref name="Daley, Robert 1980, page 103">Daley, Robert, An American Saga, 1980, Random House, New York, Template:ISBN, page 103</ref>

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 Template:Cvt of mail, but no passengers, for a Template:Cvt nonstop flight against a Template:Cvt headwind, 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.<ref name="Daley, Robert 1980, pages 109–110">Daley, Robert, An American Saga, 1980, Random House, New York, Template:ISBN, pages 109-110</ref> 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."<ref name="Sikorsky_1934"/> The S-42 had a high wing loading which required flaps to provide acceptable takeoff and landing speeds.<ref name="Sikorsky_1934" /><ref name="ReferenceA"/> Though Lindbergh approved of the S-42, it fell far short of his proposed range.<ref name="Sikorsky_1934" /> 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.<ref name="Gunston, Bill 1980, page 86">Gunston, Bill, The Illustrated Encyclopedia of Propeller Airliners, 1980, Windward, London, Template:ISBN, page 86</ref> Pan Am would have to wait for the Martin M-130 to have an airliner capable of flying the Pacific with a payload.<ref name="Daley, Robert 1980, pages 169–175">Daley, Robert, An American Saga, 1980, Random House, New York, Template:ISBN, pages 169-175</ref>

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.<ref name="Daley, Robert 1980, page 320">Daley, Robert, An American Saga, 1980, Random House, New York, Template:ISBN, page 320</ref>

British Marine Aircraft Ltd. was formed in February 1936 to produce S-42A flying boats under license in the United Kingdom but nothing came of this. The company built a factory on the western side of the Hamble peninsula with a slipway to Southampton Water. When the deal fell through, the company was sold to Henry Folland, who renamed it Folland Aircraft Limited.<ref name="Cruddas, Colin 2001, page 26">Cruddas, Colin, In Hampshire's Skies, 2001, Tempus Publishing Limited, The Mill Brimscome Port. Stroud, Gloucestershire, GL5 2QG, Template:ISBN, page 26</ref><ref>Fagan, Dave. "Hamble." Template:Webarchive Aviation in Hampshire UK 1900 to 2000. Retrieved: July 5, 2009.</ref>

Operational history

File:Sikorsky Aircraft Corporation ad Model S-42 Clipper Flying Boat 1937.jpg

1937 ad for S-42 Clipper

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.<ref>Template:Cite web</ref>

Pan American was the sole customer for the S-42. 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.<ref>Template:Cite magazine</ref>

According to Sikorsky, "Later on, another Pan American S-42 inaugurated the longest over ocean airline in the world from San Francisco to New Zealand. Finally in July, 1937, another S-42 Clipper made the first regular airline crossing of the North Atlantic Ocean starting from the United States, flying first to England by the northern route, and then to Portugal by the Bermuda-Azores route.<ref name=is/>

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.

All Sikorsky S-42s were either scrapped or destroyed in crashes.

In 1947, inventor Lemuel Stewart purchased the fuselage of S-42 NC-822M Brazilian Clipper from Pan Am for $750.00, converted it to a six-room houseboat, and kept it docked in a boat canal in Miami, Florida. Its ultimate fate is unknown.<ref>"Clipper Makes Home for Floridians." Wilbur Jennings via AP Newsfeatures, Paducah Sun-Democrat, Paducah, KY, April 30, 1947.</ref> Template:Clear

Sikorsky S-42 aircraft of Pan American Airways<ref>Template:Cite web</ref><ref>Template:Cite web</ref><ref>Template:Cite web</ref>

Name	Image	Model	Registration	Delivered	Left service	Notes	Ref.
Brazilian Clipper	File:Sikorsky S42 (crop).jpg	S-42	NC822M	Template:Dts	Template:Dts	Purchased by Lemuel Stewart in 1947 and converted into a home.	<ref>Template:Cite web</ref>
West Indies Clipper	File:Pan American Airways Sikorsky S-42 "Pan American Clipper" in flight over the under-construction San Francisco-Oakland Bay Bridge.jpg		NC823M	Template:Dts	Template:Dts	Later renamed Pan American Clipper & surveyed trans-Pacific route, then re-named Hong Kong Clipper (1937). Sank at Antilla, Cuba.	<ref>Template:ASN accident</ref>
Puerto Rican Clipper			NC824M	Template:Dts	Template:Dts	Swerved to miss boat during takeoff at Port of Spain & destroyed.	<ref name=ASN-824M>Template:ASN accident</ref><ref>Template:Cite news</ref>
Jamaica Clipper		S-42A	NC15373	Template:Dts	Template:Dts	Scrapped in 1946.
Antilles Clipper			NC15374	Template:Dts	Template:Dts	Scrapped in 1946.
Brazilian Clipper	File:Bilstein 00999 Sikorsky S-42 NC15375 Pan American Airlines (PAA).jpg		NC15375	Template:Dts	Template:Dts	Renamed Columbian Clipper. Scrapped in 1946.
Dominican Clipper			NC15376	Template:Dts	Template:Dts	Broke up during landing at Port of San Juan.	<ref>Template:ASN accident</ref><ref>Template:ASN accident</ref>
Pan American Clipper II	File:Sikorsky S-42B NC-16734 Samoan Clipper (4926859496).jpg	S-42B	NC16734	Template:Dts	Template:Dts	Later renamed Samoan Clipper; lost in crash near Pago Pago which killed chief pilot Ed Musick.	<ref>Template:ASN accident</ref>
Bermuda Clipper			NC16735	Template:Dts	Template:Dts	Later renamed Alaska Clipper and then Hong Kong Clipper II; damaged beyond repair while parked at Kai Tak during Battle of Hong Kong.	<ref>Template:ASN accident</ref>
Pan American Clipper III			NC16736	Template:Dts	Template:Dts	Later renamed Bermuda Clipper; destroyed in accidental fire during preparations for take-off at Manaus, Brazil.	<ref>Template:ASN accident</ref>

Variants

S-42

Production aircraft with four 700 hp (522 kW) Pratt & Whitney Hornet S5D1G radial engines, three built: NC 822M, NC 823M, NC 824M.

S-42A

Production aircraft with four 750 hp (559 kW) Pratt & Whitney Hornet S1EG radial engines, longer wings and a 2,000 lb (907 kg) increase in maximum takeoff weight, four built: NC 15373, NC 15374, NC 15375, NC 15376.<ref>Donnelley, James E. "The Crash of NC 15376." webstart.com. Retrieved: April 3, 2010.</ref>

S-42B

Production aircraft with aerodynamic improvements, constant-speed Hamilton Standard propellers and a further 2,000 lb (907 kg) increase in maximum takeoff weight, three built: NC 16734, NC 16735, NC 16736.

British Marine BM-1

Proposed licence-built variant of the S-42A, not built.

Notable accidents and incidents

File:Sikorsky S-42 PAA taking off in 1930s.jpeg

A PAA S-42 taking off

On April 11, 1936, a Pan Am S-42 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.<ref name=ASN-824M/>

On January 11, 1938, Pan Am Flight 1, an S-42B named Samoan Clipper (formerly Pan American Clipper II), exploded near Pago Pago, American Samoa. The flying boat developed an engine problem shortly after takeoff. The pilot elected to dump fuel before making an emergency landing, but the aircraft exploded while fuel dumping was in progress. All seven crew members (including famous aviator Captain Ed Musick), died in the crash.<ref>Template:Cite web</ref><ref>Template:Cite news</ref>

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.<ref>Template:Cite web</ref><ref>Template:ASN accident</ref>

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.<ref>Template:ASN accident</ref>

On July 27, 1943, while docked at Manaus in Brazil a Pan Am S-42B named Bermuda Clipper (formerly Pan American Clipper III) developed an engine fire in response to which a flight engineer pulled the gas dump valve control instead of the fire extinguisher control. The expulsion of fuel spread the fire and the resulting inferno destroyed the aircraft. No one was killed or injured.<ref>Trautman, p. 192</ref><ref name="ASN Manaus">Template:ASN accident</ref>

On August 8, 1944, Pan Am Flight 218, an S-42 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.<ref>Template:Cite web</ref><ref name="ASN Antila">Template:ASN accident</ref>

References

Notes

Bibliography

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External links

• Sikorsky S-42 photos and history
• Sikorsky S-42
• "Atlantic Routine," Flight 1937, contemporary article on S42 and British Caledonian operating across Atlantic
• "The Long-Range Flying Boat, Its Development and Characteristics: A Precis of a Lecture Delivered by Igor Sikorsky," in Flight, 1934 article on the S-42 design
• "Thirty-Two Passenger Flying Boat Meets First Tests," Popular Science Monthly, June 1934, article bottom of p. 37
• "Giant Plane to Cut U.S. - Argentine Time" Popular Mechanics, October 1934, cutaway drawings of purposed S-42, pp. 488–489
• "Sikorsky Sees Dawn to Dusk Trans-Atlantic Flight by Airliners" Popular Mechanics, January 1935, pp. 44-46
• "Pan Americans Flying Boat the Sikorsky S-42", YouTube 3.33 minutes, excellent rare photos of S-42 in service