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Author Topic: Sikorsky S-38 aircraft  (Read 13510 times)

Jeff Victor Hayden

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Sikorsky S-38 aircraft
« on: July 25, 2013, 01:13:36 PM »

This thesis examines the effects on a Sikorsky S-38 aircraft after 50 years+ in sea water. It's heavy going reading but, gives us some idea of the processes which contribute to the degradation of an airplanes structure in sea water. This one was not hung up on the side of a seamount though.

http://repository.tamu.edu/bitstream/handle/1969.1/ETD-TAMU-3002/GUJARATHI-THESIS.pdf
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Matt Revington

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Re: Sikorsky S-38 aircraft
« Reply #1 on: July 25, 2013, 01:54:50 PM »

That is fascinating.  Is the aluminum on the Electra of the copper alloy type (2024) described in that thesis?

The Electra wreckage should be in much deeper water than the 90 feet for the Sikorsky so it should be at a lower oxygen content level and corrode slower, hopefully.  There was no coral at the Sikorsky wreck but the attachment of barnacles reduced corrosion , perhaps coral coverage of the Electra would also reduce the rate of corrosion.
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Jeff Victor Hayden

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Re: Sikorsky S-38 aircraft
« Reply #2 on: July 25, 2013, 07:44:03 PM »

'From the early 1930's onward, virtually all American all-metal aircraft - civilian and military - were skinned with the same alloy. Back then it was known as 24ST ALCLAD.  Today it's called 2024 ALCLAD - a sheet of alloy with excellent strength properties sandwiched between thin layers of pure aluminum for corrosion protection. It was a patented ALCOA product until the need to boost aircraft production at the outbreak of WWII prompted the government to allow other manufacturers (Kaiser, Reynolds, etc.) to produce it.  Earhart's Electra, my Dad's B-17, your A-1, and my Beech Debonair were all made of the same stuff.'
http://tighar.org/smf/index.php/topic,997.msg20898.html#msg20898

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Jeff Victor Hayden

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Re: Sikorsky S-38 aircraft
« Reply #3 on: July 25, 2013, 08:01:50 PM »

It's a very thorough thesis Matt and, the photographs of the samples are very interesting too. There are quite a few factors which influence the corrosion rate and you pointed out one, the oxygen content. Others are temperature, salinity, turbulence, pressure and the growth of flora and fauna. Sure was a weird looking plane though even for the 1930's.
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John Balderston

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Re: Sikorsky S-38 aircraft
« Reply #4 on: July 25, 2013, 11:15:09 PM »

Great choice posting an aluminum corrosion study based on a Sikorsky S-38!  As you likely know the S-38 played a key role in Pan American Airways establishing routes in the Caribbean and to South America.  Fred Noonan worked for PAA as a navigation instructor in Miami and station manager in Port-au-Prince, Haiti in the early 1930's when PAA was operating the S-38.  PAA's Caribbean routes proved to be the "laboratory" for establishing trans-Pacific routes.  The S-38 design was the foundation for the S-40 and more importantly the S-42, which PAA used to pioneer the Pacific routes in Spring 1935 while the Martin M-130 "China Clipper" was still in the factory.  FN was of course instrumental in planning the Caribbean and Trans-Pacific routes, and served as flight navigator for pioneering trans-Pacific flights in both the S-42 and M-130.  When AE and FN attempted the equatorial world flights in Spring 1937 PAA had already been conducting routine weekly operations between the US and Asia for nearly a year and a half using FN's routes and navigation methods.  Great stuff - facts are almost always more interesting than fiction!
John Balderston TIGHAR #3451R
 
« Last Edit: July 25, 2013, 11:43:16 PM by John Balderston »
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Jeff Victor Hayden

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Re: Sikorsky S-38 aircraft
« Reply #5 on: July 26, 2013, 12:12:54 AM »

Thanks for the link John, very informative. Here's a couple of clips of the S-38 in action.

http://youtu.be/n9ERfeD-jCM



http://youtu.be/_WsPqI5QhaM


http://youtu.be/UyC2D9Av-CY
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Jeff Lange

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Re: Sikorsky S-38 aircraft
« Reply #6 on: July 26, 2013, 05:51:47 AM »

Amazing that some still exist! I get the impression of a flying shoe looking at it from the sides. Wonder how much it would cost to add a rating for that to ones license?
Jeff Lange

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Bill de Creeft

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Re: Sikorsky S-38 aircraft
« Reply #7 on: July 26, 2013, 10:42:22 AM »

Single engine Sea, is all, I'm pretty sure.(Sorry ! should have remembered; it has two engines !?!...so MEL&S...even nicer)

When I was a kid, Osa & Martin Johnson used to have a pair of them in the newsreels at the movies (10 cents); always exciting to see them. One giraffe and one zebra...but that's from memory

I know where there is one at the bottom of a lake in Alaska...but it's under 60 feet of glacial silt, last i heard, and millions of dollars were involved and still no airplane...So I have personally given up gracefully to ever having one!?!

Johnson Wax built a replica of theirs...just beautiful ; I came across a documentary of the process some years back.!!

I was restoring my old Travel Air Monoplane and put "wicker seats" into google , and the Sikorsky popped up, with the whole story of the reproduction and flight of 'grandfather's airplane...haven't taken time to fugure out where the "Carnauba" that is being discussed fits in...Is that the one that sank, or more likely, I hope, the original... and the replica is basking in luxurious
quarters somewhere.

Bill
(AS&MEL&S...when I was young!)
Bill de Creeft

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« Last Edit: July 26, 2013, 01:23:18 PM by Bill de Creeft »
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John Balderston

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Re: Sikorsky S-38 aircraft
« Reply #8 on: July 26, 2013, 10:48:15 AM »

JVH, thanks for the GREAT clips!  Really interesting to see the S-38 in flight - you can clearly see how Igor Sikorsky solved his water ops, structural integrity, weight and balance and aero stability design requirements - form follows function.  And the early photos are great, accompanied by a young Harry James.  Very cool - thanks!
John Balderston TIGHAR #3451R
 
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John Balderston

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Re: Sikorsky S-38 aircraft
« Reply #9 on: July 26, 2013, 10:54:48 AM »

I was restoring my old Travel Air Monoplane

Bill, very nice.  Would you share a photo or link of your baby? 

Cheers, John
John Balderston TIGHAR #3451R
 
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Jeff Victor Hayden

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Re: Sikorsky S-38 aircraft
« Reply #10 on: July 26, 2013, 11:32:05 AM »

From the thesis, the colour of the 2042 is significant. In the 6 samples the colour is the result of the corrosion and, the steel parts exhibit the expected rust colour appearance. The 2042 colour due to corrosion is consistent throughout each sample. The aircraft skin in sample 6 has suffered the worst from corrosion, possibly due to it's thickness?
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Bill de Creeft

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Re: Sikorsky S-38 aircraft
« Reply #11 on: July 26, 2013, 12:42:27 PM »

John...
Only my innate humbleness and the almost crippling modesty of all pilots kept me from cluttering the page with URL's when you ask about the T-Air !!

I'll try and be brief.

But here is the restoration process:   www.alaskaseaplanes.com/resto/index.htm   

And here it is in flight over the glaciers in a video shot from my son's L-19 and with music...('Out of Africa' with the permission of the composer), Yr. Hmbl. Correspondant flying:   www.alaskaseaplanes.com/Aircraft.html   
 
Turn up the volume...

I sold it to a very good home about five years ago and retired...just in time I guess because I now have a pig valve in my heart and am launched on my 82nd trip around the sun ...I had the plane 40 years.!

My whole website is in the green globe symbol in my profile...lots of airplane stuff there plus a few neat old cars tucked away in there and some actual history ...
Thank you for asking !
Bill
Bill de Creeft

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Jeff Victor Hayden

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Re: Sikorsky S-38 aircraft
« Reply #12 on: July 26, 2013, 01:03:29 PM »

"The objective was to study the aluminum alloy used on the aircraft for its chemical and
mechanical properties, suggest the corrosion mechanism of aluminum alloy 2024 in
seawater, and recommend preservation methods for the same."

Phew!!!, at last, all 98 pages read and, some of it understood  ???

Thank you KEDAR GUJARATHI MSc

A fine thesis which will be of great help to Tighar I'm sure.
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John Balderston

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Re: Sikorsky S-38 aircraft
« Reply #13 on: July 29, 2013, 09:25:04 PM »

But here is the restoration process:   www.alaskaseaplanes.com/resto/index.htm   

And here it is in flight over the glaciers in a video shot from my son's L-19 and with music...('Out of Africa' with the permission of the composer), Yr. Hmbl. Correspondant flying:   www.alaskaseaplanes.com/Aircraft.html   
 
Turn up the volume...


Bill, in a word, AWESOME.  I am really enjoying looking at this, and I'm sure I'm not the only one.  Will send PM with complements.  Thank you!  v/r JB
John Balderston TIGHAR #3451R
 
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