Print

[Jeff Carter]

I think we have to be careful in looking at that tracing. That drawing was taken from tracings of a deformed piece of metal and it looks like the dimension strings are off, or the dimension might be to an interpreted guide line estimated for a string.  It may be a paper laid flat and then dimensions taken from that paper, which may not be indicative of what the original curved form was.  You may have to stretch a tape over the metal from each hole to hole to get a better idea of the taper and also determine how much the metal was stretched as well.

Looking at some pictures of the artifact it looks like it tapers different than this drawing would indicate. But that is only looking at a picture.
The taper and deformation is something I wish we had information on. It is hard to see by looking at a picture or a tracing. That computer technology to rebuild a crumpled sheet looks interesting.

Any chance one of these could be borrowed:
http://www.youtube.com/watch?v=IuowYkKY8WI

[JNev]

I think we have to be careful in looking at that tracing. That drawing was taken from tracings of a deformed piece of metal and it looks like the dimension strings are off, or the dimension might be to an interpreted guide line estimated for a string.  It may be a paper laid flat and then dimensions taken from that paper, which may not be indicative of what the original curved form was.  You may have to stretch a tape over the metal from each hole to hole to get a better idea of the taper and also determine how much the metal was stretched as well.

Looking at some pictures of the artifact it looks like it tapers different than this drawing would indicate. But that is only looking at a picture.
The taper and deformation is something I wish we had information on. It is hard to see by looking at a picture or a tracing. That computer technology to rebuild a crumpled sheet looks interesting.

We seem to have some added complexity in that the distortion is not all just from being 'bent'.  As Kevin Weeks pointed out, 2024 T3 state aluminum can stretch up to 15% before cracking occurs - and we have odd cracks in this, mid-panel in some cases.  We can't know for sure, short of some extremely sophisticated analysis of the piece to determine locally remaining ductility throughout, etc., just how deformed it is in the normal plane.

Not to say we can't get a reasonable working representation - which the adaptation you've shown here might be.  I think as a practical matter we just have to make some allowance for the amount of distortion that may be present - even 10 to 15% in terms of flat pattern measurements in some areas showing extreme stress (like cracks).

Ric,

Are you bringing 2-2-V-1 with you to Dayton?  Could be important to help researchers learn first-hand about the qualities of this artifact and help us have a more productive effort.

[Jeff Carter]

One has to be very careful in considering large permanent strain deformation which for aluminum alloys requires very large forces, typically tens of thousands (10,000's) psi.

I think we have to be careful in looking at that tracing. That drawing was taken from tracings of a deformed piece of metal and it looks like the dimension strings are off, or the dimension might be to an interpreted guide line estimated for a string.  It may be a paper laid flat and then dimensions taken from that paper, which may not be indicative of what the original curved form was.  You may have to stretch a tape over the metal from each hole to hole to get a better idea of the taper and also determine how much the metal was stretched as well.

Looking at some pictures of the artifact it looks like it tapers different than this drawing would indicate. But that is only looking at a picture.
The taper and deformation is something I wish we had information on. It is hard to see by looking at a picture or a tracing. That computer technology to rebuild a crumpled sheet looks interesting.

We seem to have some added complexity in that the distortion is not all just from being 'bent'.  As Kevin Weeks pointed out, 2024 T3 state aluminum can stretch up to 15% before cracking occurs - and we have odd cracks in this, mid-panel in some cases.  We can't know for sure, short of some extremely sophisticated analysis of the piece to determine locally remaining ductility throughout, etc., just how deformed it is in the normal plane.

Not to say we can't get a reasonable working representation - which the adaptation you've shown here might be.  I think as a practical matter we just have to make some allowance for the amount of distortion that may be present - even 10 to 15% in terms of flat pattern measurements in some areas showing extreme stress (like cracks).

Ric,

Are you bringing 2-2-V-1 with you to Dayton?  Could be important to help researchers learn first-hand about the qualities of this artifact and help us have a more productive effort.

[Jerry Germann]

.mis-alignment with the grain of the metal

Looks like classic rolled-on with the grain labeling to me.

I agree , it is rolled on labeling, it would be hard to duplicate the wave pattern in several rows by hand.  It seems as if the machine were set to stamp this perticular pattern , as I don't see any smearing of the lettering that would suggest the sheet slipped while stamping. It is this wave pattern that lead to my misaligned with the grain comment. Looking at 2-2-V-1, the A D in perticular, it seems to me , that the A is in a somewhat lower position the the D, which makes me wonder if what we are seeing is the ending of an upsweep of a similar pattern, or do you believe this is due to the misaligment ?  As far as the etching, ....is it scratched on?, or is it what one would see after paint is exposed to fire? If one takes a pop/beer can and exposes it to fire , though the paint burns off, one usually can see a remaining image of what once was. As far as the ink stamp font, I have looked through the Tighar files but can't locate it, could you post a photo of one of the three known ink stamp font images that seem to match the one on 2-2-V-1? 
Ok , found it.
http://tighar.org/Publications/TTracks/1993Vol_9/Markings.pdf

[Doug Ledlie]

Seems odd that the NTSB didn't note any stretching of the artifact...

http://tighar.org/Projects/Earhart/Archives/Documents/NTSB_Report/ntsbreport.html

Any somehow uniform stretching to the degree suggested would, by definition, result in a measurable thinning of the original material ie an original 0.032 thickness would now be significantly less

Testing procedures discussed here
http://www.engineersedge.com/material_science/ductility.htm

[Ric Gillespie]

Any chance one of these could be borrowed:
http://www.youtube.com/watch?v=IuowYkKY8WI

Looks like a great way to create an accurate 3D representation of the artifact as it is but I don't see how it could help us "un-damage" it.

[Ric Gillespie]

Are you bringing 2-2-V-1 with you to Dayton?  Could be important to help researchers learn first-hand about the qualities of this artifact and help us have a more productive effort.

Absolutely.

[JNev]

One has to be very careful in considering large permanent strain deformation which for aluminum alloys requires very large forces, typically tens of thousands (10,000's) psi.

I think we have to be careful in looking at that tracing. That drawing was taken from tracings of a deformed piece of metal and it looks like the dimension strings are off, or the dimension might be to an interpreted guide line estimated for a string.  It may be a paper laid flat and then dimensions taken from that paper, which may not be indicative of what the original curved form was.  You may have to stretch a tape over the metal from each hole to hole to get a better idea of the taper and also determine how much the metal was stretched as well.

Looking at some pictures of the artifact it looks like it tapers different than this drawing would indicate. But that is only looking at a picture.
The taper and deformation is something I wish we had information on. It is hard to see by looking at a picture or a tracing. That computer technology to rebuild a crumpled sheet looks interesting.

We seem to have some added complexity in that the distortion is not all just from being 'bent'.  As Kevin Weeks pointed out, 2024 T3 state aluminum can stretch up to 15% before cracking occurs - and we have odd cracks in this, mid-panel in some cases.  We can't know for sure, short of some extremely sophisticated analysis of the piece to determine locally remaining ductility throughout, etc., just how deformed it is in the normal plane.

Not to say we can't get a reasonable working representation - which the adaptation you've shown here might be.  I think as a practical matter we just have to make some allowance for the amount of distortion that may be present - even 10 to 15% in terms of flat pattern measurements in some areas showing extreme stress (like cracks).

Ric,

Are you bringing 2-2-V-1 with you to Dayton?  Could be important to help researchers learn first-hand about the qualities of this artifact and help us have a more productive effort.

Thanks, Jeff.  Of course we're looking at .032" T sheet, but that's a sober point.

[JNev]

Seems odd that the NTSB didn't note any stretching of the artifact...

http://tighar.org/Projects/Earhart/Archives/Documents/NTSB_Report/ntsbreport.html

Any somehow uniform stretching to the degree suggested would, by definition, result in a measurable thinning of the original material ie an original 0.032 thickness would now be significantly less

Testing procedures discussed here
http://www.engineersedge.com/material_science/ductility.htm

Not necessarily, maybe it did not occur to them, or maybe it's not so stretched if at all - but since the point came up it seems worth exploring.  Jeff Carter also pointed out that it is problematic to get that much stretching into a panel like this as we see it.

[Mark Pearce]

If Ric found the only matching font as reported in "Matching the Markings"- and I believe he did - 2-2-V-1 must date to the early part of WW2, because the "The specification [AN-A-13] had to appear sometime between 1941 and 1943".

About the examples he found that match 2-2-V-1, he said- "In all three cases, the entire sequence of labeling reads:
ALCOA T. M. .032 ALCLAD 24 S – T 3 AN – A – 13"

http://tighar.org/Publications/TTracks/1993Vol_9/Markings.pdf

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

[Ric Gillespie]

If Ric found the only matching font as reported in "Matching the Markings"- and I believe he did - 2-2-V-1 must date to the early part of WW2, because the "The specification [AN-A-13] had to appear sometime between 1941 and 1943".

If I was right, you're right. I've been wrong before.

[Mark Pearce]

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

Here's another font that does not match.


Another mis-match...


2-2-V-1


And a real mystery... The so-called [Japanese] Mavis...
...that does match "Labeling on fuselage modifications, Lockheed Electra cn 1015."
See page two, "Matching the Markings"
http://tighar.org/Publications/TTracks/1993Vol_9/Markings.pdf
Either this wreck is a mis-identified US plane, or the Japanese were able to - somehow - buy American aluminum after 1941.
 
http://www.pacificwrecks.com/douglas/wrecks/mavis/mavis.html

[JNev]

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.   

Here's another font that does not match.


Another mis-match...


2-2-V-1

I get the markings of latter-day aluminum of a G variant B-17 not matching, but why would a part recovered from a B-17G wreck in Japan prove anything about Canton?  What am I missing?

And a real mystery... The so-called [Japanese] Mavis...
...that does match "Labeling on fuselage modifications, Lockheed Electra cn 1015."
See page two, "Matching the Markings"
http://tighar.org/Publications/TTracks/1993Vol_9/Markings.pdf
Either this wreck is a mis-identified US plane, or the Japanese were able to - somehow - buy American aluminum after 1941.
 
http://www.pacificwrecks.com/douglas/wrecks/mavis/mavis.html

...or the Japanese built something after 1941 out of metal stock that was procured before that year?

[JNev]

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?

[Kevin Weeks]

I found an old blog of a gentleman restoring an amphibious version of the PBY. he has MANY pictures of the rivets and lower hull panels removed. unfortunately he has not posted since 2010! anyone know who this guy is?? maybe he can answer all our PBY related questions....

http://pbyrestoration.blogspot.com/search?updated-max=2010-02-23T18:52:00-08:00&max-results=500&start=10&by-date=false









really though, he does not have good pictures of the top section of the rear fuselage which looks the most promising. take a look at the top of this picture: