Sikorsky S-40.  The exposed struts and wires caused Charles Lindbergh to call the plane a "flying forest."
Sikorsky S-40. The exposed struts and wires caused Charles Lindbergh to call the plane a “flying forest.”

The first Pan American plane to be called a “Clipper,” the S-40 grew out of Juan Trippe and Charles Lindbergh’s desire for a strong, sturdy, high-capacity four-engined transport to serve as an ocean liner of the air.

Originally conceived in late 1928, the S-40 made its first test flight April, 1931, and on October 10, 1931, First Lady Lou Hoover, wife of President Herbert Hoover, christened the first S-40 “American Clipper” with a bottle of Caribbean water (since Prohibition law still made alcohol illegal in the United States).

On November 19, 1931, the American Clipper made its first passenger flight, to Cristobal in the Panama Canal Zone, via Kingston, Jamaica and Barranquilla, Colombia.  Pan American technical advisor Charles Lindbergh was in command of the flight as far as Baranquilla, with Basil Rowe as copilot.

Sikorsky S-40
Sikorsky S-40

The largest plane built in America at the time, the plane had a gross take-off weight of 34,000 lbs and could carry 38 passengers in luxurious wood-paneled compartments on flights of up to 500 miles, or 24 passengers on flights of up to 900 miles.

It was with the S-40 that Pan Am first pioneered the maritime theme that became so strongly associated with the airline, not only calling the ships “clippers,” but dressing its crew in naval-style uniforms and using maritime terminology, to give passengers a sense of security and professionalism, and encourage people to think of airliners as an alternative to ocean liners.

"Ocean Liner of the Air"
“Ocean Liner of the Air”

Used throughout Pan Am’s extensive Latin American route system, the S-40 became a familiar sight at Pan Am’s Miami, Florida base, and flew to destinations throughout South and Central America including Buenos Aires, Santiago, Rio de Janeiro, Bogota, and Lima.  The three S-40’s operated by Pan American eventually flew approximately 10 million miles over the course of their careers.

Sikorsky S-40
Sikorsky S-40 at Miami

Based on the tried-and-true design of the eight passenger Sikorsky S-38, the S-40 was a giant leap forward in terms of size and range, but the plane was not especially streamlined, and the drag from its exposed struts, wires, and engines limited its speed, range, and fuel efficiency.

The exposed struts, wires, and uncowled engines of the "flying forest."
The exposed struts, wires, and uncowled engines of the “flying forest.”

Unhappy with the S-40’s design from the time it was first proposed, Pan Am technical advisor Charles Lindbergh said it would be like “flying a forest through the air.”  Although primarily operated as a flying boat, the S-40 was built as an amphibian to allow for emergency landings when flying over land, and had retractable landing gear (using shock absorbers adapted from railway cars) which added to the aircraft’s weight and further reduced its performance.

Never completely happy with the relatively primitive nature of its design, Pan Am asked Sikorsky to work on an improved model (the Sikorsky S-42 clipper) even as the S-40 was first entering service, and only three S-40 clippers were ever built::

  • NC-80V: American Clipper
  • NC-81V: Caribbean Clipper
  • NC-752V: Southern Clipper
Sikorsky S-40
Sikorsky S-40 at Miami

S-40 Technical Details

  • Length: 77′
  • Wingspan: 114′
  • Gross Weight: 34,000 lbs
  • Engines: Four Pratt & Whitney Hornet radial engines (initialy 575 hp, later 660 hp)
  • Range: 900 miles
  • Max Speed: 137 MPH
  • Cruise speed: 115 MPH

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Don Mitchell
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Don Mitchell

A little known fact, the structural analysis of the S-40 was done by Karel Jan Bossart, famous for development of the Atlas missile at Convair twenty years later.

Larry
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Rope makers usually relishes confusing us with science and/or extraordinary polysyllabic names.
Listen up try to cut through the guff somewhat.

Brooks Jackson
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Brooks Jackson

I am a collector of First Flight Air Mail Covers and I recently purchased an Air Mail Cover that is postmarked Buenos Aires, and dated 17 Nov. 1931. The cover is addressed to a company in New Orleans, La. There is no back-stamp on the rear of the cover. It has a hand-stamp on the front which reads as follows: FIRST FLIGHT The “American Clipper” CANAL ZONE — U. S. A. NOV. 25, 1931 The information I have obtained from your website and your posts plus other sources indicates that the “The American Clipper” departed from Miami on the 19th… Read more »

Brooks Jackson
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Brooks Jackson

I am a collector of First Flight Air Mail Covers and I recently purchased an Air Mail Cover that is postmarked Buenos Aires, and dated 17 Nov. 1931. The cover is addressed to a company in New Orleans, La. There is no backstamp on the rear of the cover. It has a handstamp on the front which reads as follows: FIRST FLIGHT The “American Clipper” CANAL ZONE — U. S. A. NOV. 25, 1931 The information I have obtained from your website and your posts plus other sources indicates that the “The American Clipper” departed from Miami on the 19th… Read more »

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Brad
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I’m doing a college paper on the Sikorsky flying boats. According to what I have found, there were only three S-40 aircraft ever built. They originally came with wheels in 1931 and sold for $139,000. NC-80V “American Clipper” (the first Pan Am Clipper); NC-81V “Caribbean Clipper”; NC-752V “Southern Clipper”. In 1935, all three were converted to 660 hp P&W supercharged Hornet engines and had landing gear removed to save 1200 lbs. Gained cruise of 5 mph; 115 before mod, 120 after mod. When Pan Am retired the S-40 in 1940, all three went to the Navy for training until scrapped… Read more »

Gary
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Gary

I’ve seen references to the S40 as both a flying boat and as an amphibian, and seen photos of them both with wheels (not beaching gear) and without. Were some of the three built without wheels and some with, or were the wheels removed sometime during their career? Or what?

Doyle
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Doyle

After my Great-Aunt passed away, I got her pictures. She had lived in Miami for several years. In her collection was several pictures of a Pan American Airways S-40 American Clipper. The number on the plane is NC-80V. Does anyone have any information on this plane.

Jim Huff
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Jim Huff

Early during WWII, Pan American made one of its plush S-40 airplanes available to the Navy to train its aviation navigators. My father was one of those navigators, and according to his notes, the S-40 had so much drag that it couldn’t get up off the water unless the sea was a bit choppy. Dad’s name was John A Huff. Note that his remembrance fits rather well with Charles Lindbergh’s assertion that this plane was “like flying a forest through the air.”

Rodrigo Blanco
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I’ve been restoring photos of Barranquilla, Colombia, and I came across this one: http://gigapan.org/gigapans/93968

American Clipper !

Rob Mulder
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Hi,
Thank you for the offer, but the book has been published last year and has been a success. Thank you for your offer.

Regards
Rob

kenny slagle
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kenny slagle

hey mark im back found in my grandpas storey about the s-40 toilet he said they had a sump.that created alot of problems so they eliminated it they they took out the sump and the tank and just left a hole right through to the skies but what was happening is after take off and when the plane was climbing the airstream would go up through this hole and if you went to urinate you would create a fountain and if you went there for something else you can imagine what happened. so he used a screwdriver and locked the… Read more »

kenny slagle
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kenny slagle

have a picture of the s-40 in my grandpas stuff with lindberg and crew 4 people total could send maybe if interested

kenny slagle
Guest
kenny slagle

mark in my grandpas story with lindberg in the s-40 he said that they had a toilet for the ladies and a toilet for the gentleman at the bottom of the toilet he said there was a tank which would hold the refuse and a lever to to release water to wash out before take off have another story of a toilet in a plane i believe was an open hole to the sky but too much air came in or something can get details later thanks kenny

kenny slagle
Guest
kenny slagle

my grandpa joie carrero was a pan am steward on the inauguration flight with charles lindberg he tape recorded his stories before he passed but its too long for this it was in the s-40 from miami,to camaguey,cuba,kingston,jamacia:barranquilla,colombia and panama. he did say that they had a plane of vips on the 32 seat plane and his job was to dump the toilet before take off one time he forgot and a cuban man in a white suit got sea of airsick went into bathroom when they got to miami it was night and the weather was rough they had… Read more »

Vanuel G. Baker, USN (Ret)
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Vanuel G. Baker, USN (Ret)

G’afternoon Mark; I know nothing about the S-40, however, I had the happy experience of taking a trip from Miami,FL. to San Juan P.R. in 1941 aboard one of Pan Am’s S-42s. The toilet had no holding tank. While we were over land (which was but a few minutes while leaving Haiti), the toilet remained locked. I’m almost certain that the S-40 had the same.
Respectfully, VGB

Mark
Guest
Mark

I’m working on a project regarding the Sikorsky s-40 and I need to get answers to a few questions. I know there were several compartments. Were they doors watertight? Which ones could and could not be locked? Was there one washroom or two? I know one compartment near the front, I think the third after the flight deck and a baggage compartment (which had dual uses) had some chairs on the port side and the starboard was one bathroom. I’ve seen a breakout of the plane from an issue of Popular Mechanics in 1931 which seems to indicate another bathroom… Read more »

Rob Mulder
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Hi

Great website. I am writing a book about the single Norwegian Sikorsky S-43 (LN-DAG Valkyrien) and I wondered if we could use the “coloured” photograph of the S-40 in Miami. That would be great to have in my book.

Hope to receive a positive answer from you.

Regards
Rob

King George
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King George

Looking for additional drawings for building a RC model. Can someone help.

King George

King George
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King George

Looking to build this as my next RC model. Would like to find drawings showing structs and wires. Can someone help.

King George