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[Mark Pearce]

The "Canton Island Scenario" is not popular around here I know but the evidence supporting it grows stronger and stronger.

I don't know about the relevancy of 'popular', why don't we continue to focus on that which is objective and not worry about popularity?  Of course many of us want to solve the mystery beyond doubt and no question we all tend to have favored ideas for reasons we each understand, no problem.  Keep feeding good information that can be evaluated and I'm happy, for one. 

Can you quantify "stronger and stronger" please?  I still see reasons to look, but I'm not sure that I see evidence in-hand that persuades me that Canton 'just has to be the place'.  What we need is conclusive results so far as possible, not fog...  What am I missing?

Jeff,
Now that we know the true significance of "AN-A-13" and when it came into use...

"The specification [AN-A-13] had to appear sometime between 1941 and 1943".

...and if Ric found three examples of labeling that exactly match the font seen on 2-2-V-1, how could
AN-A-13 markings appear on a sheet of aluminum alleged to be from 1937?

Re-read "Matching the Markings"
http://tighar.org/Publications/TTracks/1993Vol_9/Markings.pdf

"Although it wasn’t much to go on, we reasoned that if we could match the size and style of the letters with labeling surviving on other aircraft we might be able to complete the picture. An exhaustive search of aircraft of World War Two and earlier vintage produced only three examples of aluminum bearing these exact markings:  In all three cases, the entire sequence of labeling reads: ALCOA T. M. .032" ALCLAD 24 S – T 3 AN – A – 13"

Now, re-read this message from a few days ago, but beware- "AN-A-13" does in fact appear on sheet thinner than .032" as Ric found and reported way back in 1993.

http://tighar.org/smf/index.php/topic,1426.msg30572.html#msg30572

"The 1943 edition of ALCOA's Aluminum in Aircraft booklet clearly describes AN-A-13 as a "recent" specification that "permits a reduction in the thickness of the cladding on alclad sheet 0.064 and thicker." Unless the specification was later amended, the AN-A-13 designation should not appear on sheet thinner than 0.064.  Ergo, it was never on 2-2-V-1.

"We also now know what "recent" means.  I dug out my 1941 copy of ALCOA's Aluminum in Aircraft booklet. The wording is identical to the 1943 edition except no mention of AN-A-13 (see below).  The specification had to appear sometime between 1941 and 1943."

[Mark Pearce]

Mark Pearce -

What about our friend the PBM-5 up at Howland?  Were you ever able to locate any technical detail on construction? 

We have the one living example at Pima (I'd love to go see it) - any headway into tech data for that bird?  There she sits in pieces with hunks hacked out (damn that's poetic...) and old repairs in evidence...

Talk about sitting ducks, despite the distance and lack of clear channels to migrate - although we know the crew rescue involved some circular travels that could have yielded fruit.

Any luck?

Jeff,
"Our friend the PBM-5 up at Howland" is really a PBM-3D.
[See- http://www.vpnavy.com/vp16_mishap.html]

I'm sorry Jeff, but considering what has come to light concerning WW2 era Alclad labeling, and the font seen on 2-2-V-1, I don't think there is much point continuing to investigate the chances 2-2-V-1 may be a fragment of AE's missing Lockheed.  Just as you say above, "What we need is conclusive results so far as possible, not fog."

There is nothing foggy here as far as I can see.  If Ric is certain the font on the piece is a sure match for the three labels he found and describes in "Matching the Markings", 2-2-V-1 can not be older than ca. 1943.  If you refuse to accept this, and still feel the need to eliminate the PBM as a possible 'donor', you can buy a CD/download copy of a PBM-3S,-3D Structural Repair Manual at the link below.  It will cost you $19.95 however.

"Martin PBM-3S, -3D Mariner Handbook of Structural Repair RAAF"
http://www.flight-manuals.com/raaf505.html

If you'd rather hold onto your money, you can learn more about the PBM-5 at this link- free of charge.

http://legendsintheirowntime.com/PBM/PBM_IA_4509_DA.html
"Design Analysis of the Martin PBM-5 Mariner", by E G Riley, Project Engineer, The Glenn L Martin Company

[Tim Mellon]

For a minute there I thought this hole might be where 2-2-V-1 came from.

[Ric Gillespie]

I'm sorry Jeff, but considering what has come to light concerning WW2 era Alclad labeling, and the font seen on 2-2-V-1, I don't think there is much point continuing to investigate the chances 2-2-V-1 may be a fragment of AE's missing Lockheed.

You're welcome to stop investigating 2-2-V-1 if you choose but let me remind you that AN-A-13 does not appear on the artifact.  All we have are the letters AD in the same font used on aluminum that bears the AN-A-13 designation. We do not know that this was the first or only time that ALCOA used that font. How many pre-war aircraft have we looked at to see what the labeling looked like?

Maybe you are still foggy about the evidence here, but if Ric sees a font on the piece that is a sure match for the three labels he found and describes in "Matching the Markings", 2-2-V-1 can not be older than ca. 1943.

I could match the font to the labeling on a hundred wartime aircraft and it wouldn't prove that the font is unique to wartime aluminum.  Similarly, we could find that same font on pre-war aircraft and it would't prove that 2-2-V-1 is a pre-war piece of metal. 

As you note, the presence of AN-A-13 on a Japanese aircraft contradicts the conclusion that AN-A-13 only appeared on aluminum after sales of aluminum to Japan were cut off. Seems to me there is still an abundance of fog surrounding the AN-A-13 designation.

 

[Greg Daspit]

Where is the picture of cn1052 from and when was it taken?

[Ric Gillespie]

Where is the picture of cn1052 from and when was it taken?

I took that photo at the New England Air Museum in 1993 when c/n 1052 was all torn apart during restoration.  That flap actuator cover was old and beat up.  I don't know whether it was original construction.

[Greg Daspit]

Using the Purdue Archives you can zoom in and see some lettering fonts. The example linked may not be the same metal but it's amazing what you can see in those images if you zoom in

[Mark Pearce]

All we have are the letters AD in the same font used on aluminum that bears the AN-A-13 designation.

That may be all we need to identify 2-2-V-1 as dating to the WW2 era, and not 1937.  As you say, the letters "are rendered in a distinctive sans serif type style."

Regardless of how or when the Japanese acquired Alcoa alcad, we agree the AN-A-13 designation "...had to appear sometime between 1941 and 1943".

http://tighar.org/smf/index.php/topic,1426.msg30572.html#msg30572

Here are examples of Alclad labeling to study.   

http://www.airstream.com/files/library/ba001792c0a731f5.pdf
http://www.ilmasotakoulunkilta.fi/IlmaSK/ilmaskmma.nsf/sp?open&cid=Content6685E&screen=blogentryscreen&blogid=Content6685E
http://s982.photobucket.com/user/GunnerySgtJackson/media/B24crashsite020.jpg.html?sort=3&o=76
http://www.airforums.com/forums/f381/can-aluminum-skin-be-welded-92625.html
http://colesaircraft.blogspot.com/2012/11/anatomy-of-p-51-mustang-loss.html
http://vanislesecret.blogspot.com/2007/09/historic-64-year-old-dakota-crash-site.html
http://aluminiumidler.blogspot.com/2010/04/endcapitus.html
[repro] http://www.vulturesrowaviation.com/helldiver10_2010.html
http://746project.wordpress.com/parts/right-wing/right-wing/dsc01995/ [black ink? maybe not alclad]
http://746project.wordpress.com/parts/right-wing/left-wing/ (http://746project.files.wordpress.com/2012/11/dsc02016.jpg?w=1200&h=&crop=1)
http://www.network54.com/Forum/149674/thread/1266421967/1266668813/HELP+NEEDED-WW2+wreck+parts+identification-B-17--
http://www.questmasters.us/B-24_Page_8.html
http://i.imgur.com/OdDawew.jpg
http://i.imgur.com/kEvPkaN.jpg
http://i.imgur.com/rwZcVZq.jpg
http://www.pacificwrecks.com/douglas/wrecks/mavis/mavis.html
http://www.pacificwrecks.com/aircraft/c-47/43-16261/index.html
http://commons.wikimedia.org/wiki/File:B17F_-_Woman_workers_at_the_Douglas_Aircraft_Company_plant,_Long_Beach,_Calif.jpg
http://commons.wikimedia.org/wiki/File:Production_of_B-24_bombers_and_C-87_transports.jpg
https://www.warrelics.eu/forum/battlefield-archaeology/recent-finds-ww2-uk-airfield-7466/
http://www.flickr.com/photos/mikebull/255312057/in/set-72157594303862783
http://www.flickr.com/photos/mikebull/255312128/in/set-72157594303862783
http://www.flickr.com/photos/mikebull/255318615/in/set-72157594303862783/
[russian] http://aviaforum.ru/showthread.php?t=36096
http://s290.photobucket.com/user/Starfire94C/media/Stringer24ST_zpsd72819dc.jpg.html
http://tighar.org/smf/index.php?topic=1048.15
http://forum.keypublishing.com/showthread.php?47463-Liberator-crash-at-Fairy-Lochs-1945
http://www.fold3.com/image/37129850/
http://www.fold3.com/image/32184644/
http://texashistory.unt.edu/ark:/67531/metapth41192/m1/1/sizes/xl/
http://texashistory.unt.edu/ark:/67531/metapth40951/m1/1/sizes/xl/
http://texashistory.unt.edu/ark:/67531/metapth41051/m1/1/sizes/xl/
http://commons.wikimedia.org/wiki/File:Joe_Cobb,_former_%22fat_boy%22_in_the_original_%22Our_Gang%22_comedies,_now_helps_build_B-25_bombers_at_the_Inglewood..._-_NARA_-_195480.jpg
http://commons.wikimedia.org/wiki/File:Workers_assembling_the_bottom_of_an_aircraft_-_NARA_-_196496.jpg

[Kevin Weeks]

Using the Purdue Archives you can zoom in and see some lettering fonts. The example linked may not be the same metal but it's amazing what you can see in those images if you zoom in

well Greg, that is one very interesting image... I haven't followed along the font front enough to recognize the differences that Mark and Ric have been debating but it looks to me like that says
"4ST, ALC"

which would be 24ST ALCLAD or 24ST ALCOA....

anyone care to comment on the font?? is this a new combination of lettering or??

[Jeff Carter]

I would guess repeated "ALC24ST" as shown in this earlier Electra picture posted:
http://tighar.org/smf/index.php/topic,1426.msg29814.html#msg29814

Using the Purdue Archives you can zoom in and see some lettering fonts. The example linked may not be the same metal but it's amazing what you can see in those images if you zoom in

well Greg, that is one very interesting image... I haven't followed along the font front enough to recognize the differences that Mark and Ric have been debating but it looks to me like that says
"4ST, ALC"

which would be 24ST ALCLAD or 24ST ALCOA....

anyone care to comment on the font?? is this a new combination of lettering or??

[Matt Revington]

Mark

I have looked at most of your examples and they certainly show the AN-A-13 designation has a "foggy"history.  I may have missed it but were any of the markings you identified on the exterior face of the aircraft and so far as is possible to tell do they appear to have been rolled on with the direction of the grain of the aluminum sheet or stamped on without regard to the grain?  As far as I have read the grain can be identified on unpolished sheets by the direction of small scratches from the rollers that formed the sheets.

[Kevin Weeks]

I would guess repeated "ALC24ST" as shown in this earlier Electra picture posted:
http://tighar.org/smf/index.php/topic,1426.msg29814.html#msg29814

Using the Purdue Archives you can zoom in and see some lettering fonts. The example linked may not be the same metal but it's amazing what you can see in those images if you zoom in

well Greg, that is one very interesting image... I haven't followed along the font front enough to recognize the differences that Mark and Ric have been debating but it looks to me like that says
"4ST, ALC"

which would be 24ST ALCLAD or 24ST ALCOA....

anyone care to comment on the font?? is this a new combination of lettering or??

Ahh nice... The 24ST designation is very early From what I can tell.  It follows the firm of the earlier 17ST designation.

[Mark Pearce]

Using the Purdue Archives you can zoom in and see some lettering fonts. The example linked may not be the same metal but it's amazing what you can see in those images if you zoom in

well Greg, that is one very interesting image... I haven't followed along the font front enough to recognize the differences that Mark and Ric have been debating but it looks to me like that says
"4ST, ALC"

which would be 24ST ALCLAD or 24ST ALCOA....

anyone care to comment on the font?? is this a new combination of lettering or??

Yes, that is one very interesting image.

Ric and I are not debating differences in font styles at all.  We agree these Alclad label fonts are 'distinctive', and as Ric has said, "In 1936 when Earhart's Electra was built, there was only one supplier of Alclad - ALCOA.  The same was true in 1937 when the aircraft was repaired following the Luke Field accident."
http://tighar.org/smf/index.php/topic,300.msg2806.html#msg2806

Now we can see what Alcoa Alclad markings looked like...  in 1936... on Earhart's Electra.  The 1936 font has serifs, but the font of the letter 'D' on 2-2-V-1 does not. There's an important message here that helps to clear away more of the fog.

In the early 1990's Ric found three Alclad labels - matching the font on 2-2-V-1 exactly as he reports in "Matching the Markings" - that he believed dated to 1935.  It's now clear those three labels date to the WW2 period, since they all included the "recently issued"  US Government specification AN-A-13 for Alcad 24S sheet.  [See pages 8, 14 and 65 here- http://babel.hathitrust.org/cgi/pt?id=uc1.b4444813;view=1up;seq=18
and-
http://tighar.org/smf/index.php/topic,1426.msg30572.html#msg30572

That little letter 'D' reveals a great deal about the history of 2-2-V-1.  Now this 1936 photo of the Electra does too.     

[Mark Pearce]

Mark

I have looked at most of your examples and they certainly show the AN-A-13 designation has a "foggy"history.  I may have missed it but were any of the markings you identified on the exterior face of the aircraft and so far as is possible to tell do they appear to have been rolled on with the direction of the grain of the aluminum sheet or stamped on without regard to the grain?  As far as I have read the grain can be identified on unpolished sheets by the direction of small scratches from the rollers that formed the sheets.

Matt, comparing the 1941 edition of the Alcoa Co. handbook, "Aluminum in Aircraft" with the 1943 edition reveals when the AN-A-13 designation came into use. The 1943 edition tells of the "...recently issued specification AN-A-13...", the 1941 edition makes no mention of it. 

There are a few examples in that list showing Alclad markings on the exterior side - on B-17s if I recall.

I believe it's safe to say that all 'machine rolled' ink stamps are parallel to the grain.  I've never seen an example of the distinctive font found on 2-2-V-1 in a 'hand-stamped' label.  As Ric reported in 1992, "An exhaustive search of aircraft of World War Two and earlier vintage produced only three examples of aluminum bearing these exact markings:...In all three cases, the entire sequence of labeling reads:
ALCOA T. M. .032" ALCLAD 24 S – T 3 AN – A – 13."

The Alcoa engineer Ric spoke with in 1996 was wrong about the meaning of AN-A-13.  I believe he was wrong about the hand-stamping concept too.

http://tighar.org/smf/index.php/topic,1426.msg30572.html#msg30572

The 1941 edition- [see page 9]
http://babel.hathitrust.org/cgi/pt?id=mdp.39015006056306;view=1up;seq=13

The 1943 edition- [see page 9]
http://babel.hathitrust.org/cgi/pt?id=uc1.b4444813;view=1up;seq=5

This is an image from page 9 of the 1943 edition Ric posted earlier.

[Ric Gillespie]

Ric and I are not debating differences in font styles at all.  We agree these Alclad label fonts are 'distinctive', and as Ric has said, "In 1936 when Earhart's Electra was built, there was only one supplier of Alclad - ALCOA.  The same was true in 1937 when the aircraft was repaired following the Luke Field accident."

ALCOA fonts were distinctive in that the company used several different fonts but we have not established that the font we see on 2-2-V-1 was unique to AN-A-13 labeling.

Now we can see what Alcoa Alclad markings looked like...  in 1936... on Earhart's Electra.  The 1936 font has serifs, but the font of the letter 'D' on 2-2-V-1 does not. There's an important message here that helps to clear away more of the fog.

The message is that 2-2-V-1 is probably not from the original construction of NR16020 and, indeed, it only fits the airplane if we make certain assumptions about how the repairs were made.

In the early 1990's Ric found three Alclad labels - matching the font on 2-2-V-1 exactly as he reports in "Matching the Markings" - that he believed dated to 1935.  It's now clear those three labels date to the WW2 period, since they all included the "recently issued"  US Government specification AN-A-13 for Alcad 24S sheet.

Clear as ground fog. How do you explain the presence of post-Pearl Harbor aluminum on a Japanese "Mavis"? (The other photos of the wreck leave no doubt that it is a "Mavis".)
[/quote]