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Author Topic: 2-2-V-1 wing panel comparisons  (Read 3284 times)

Kevin Weeks

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2-2-V-1 wing panel comparisons
« on: June 25, 2019, 02:46:12 PM »

I had a question regarding wing panel comparisons of nearby wrecks and the artifact. I did some searching of wrecks from Canton Island some time ago and the artifact. I came up with an article about B-24 wing panels that showed a claim that the artifact came from a section of that wing. it was debunked due to thickness and rivet sizing being too large. I was wondering if it was possible that this piece may have come from the wing of a C-47 that crashed on sydney island?? especially since that wing was torn off before the plane struck the ground and burned, never to be recovered.

https://tighar.org/Projects/Earhart/Archives/Research/Bulletins/07_Sydneycrash/07_Sydneycrash.html

this came to me on friday as I walked under the freshly stripped and polished wing of a DC-3 at the new england air museum with my son not 10 feet away from the Lockheed Electra they have.

I have tried searching for a C-47 wing repair manual such as was used to debunk the B-24 claim. it makes sense to me that the C-47 skin would be thinner and use smaller rivets that would closer match the construction of the wing panels in these planes. looking over at the construction of the Electra shows completely different construction/rivet patterns across the entire plane. I had trouble looking at it and seeing how they would deviate from their standard rivet patterns even for a small patch especially being able to compare the two so closely.


has this been investigated?? i would be surprised if it had not.
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Kevin Weeks

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Re: 2-2-V-1 wing panel comparisons
« Reply #1 on: June 25, 2019, 02:59:23 PM »

of course after posting this I did find a very hard to read structural repair manual for a dc-3/c-47.... it's looking like the wing panels are possible too thin in most areas, so we are going from one extreme to the other?? the inner front edge of the wing appears to be the only skin that is .045 thick...

http://www.avialogs.com/index.php/en/aircraft/usa/douglas/dc3c-47/structural-repair-manual-for-the-model-dc-3.html#download

it calls out ad6 rivets which are 3/16 brazier head. great read in general for skin repair and rivet patterns.

just looked at the 2-2-v-1 article again to refresh my memory... seems I was mistaken on the thickness. thickness is .032 and the rivets were 3/32 and 5/32... hmmmm
« Last Edit: June 25, 2019, 03:03:11 PM by Kevin Weeks »
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Ric Gillespie

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Re: 2-2-V-1 wing panel comparisons
« Reply #2 on: June 25, 2019, 03:15:11 PM »

On July 16, 2017 I inspected the portion the DC-3/C-47 wing section at the New England Air Museum alleged to resemble Artifact 2-2-V-1.  At that time the wing section was out behind the museum, stored outdoors with various other bits and pieces of aircraft.  There was no way to check the thickness of the skin but, although there were some general similarities in rivet pattern, the rivet type, rivet size, rivet pitch, and spacing between rivet lines did not match the artifact. Not even close. TIGHAR videographer Mark Smith recorded the investigation.

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Kevin Weeks

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Re: 2-2-V-1 wing panel comparisons
« Reply #3 on: June 25, 2019, 04:07:45 PM »

As I said I would be surprised if you hadnt checked this! I remember you making this trip as I had planned to attend but I had other commitments unfortunately.

The link I attached earlier does show some good information on rivet sizing and repairs for different t skin thickness. I wonder if the specific section could have been the repair from the clipped guy wire that required the plane to be repaired for so long. That would be the only reason for the irregular river placement on a aircraft skin.

Thoughts... not worth much without that velum print to slide over every aircraft that went through canton!
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Greg Daspit

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Re: 2-2-V-1 wing panel comparisons
« Reply #4 on: December 04, 2019, 01:56:27 PM »

On July 16, 2017 I inspected the portion the DC-3/C-47 wing section at the New England Air Museum alleged to resemble Artifact 2-2-V-1.  At that time the wing section was out behind the museum, stored outdoors with various other bits and pieces of aircraft.  There was no way to check the thickness of the skin but, although there were some general similarities in rivet pattern, the rivet type, rivet size, rivet pitch, and spacing between rivet lines did not match the artifact. Not even close. TIGHAR videographer Mark Smith recorded the investigation.

Regarding the Youtube video recently posted “C-47 wing inspection” In the video the rivet size was thought to be too large and disqualify a DC3/C-47 wing, per the sample examined, as a possible candidate for 2-2-V-1.
https://www.youtube.com/watch?v=GlVLyOfsZ3c

However, a link in the comment section  has an Analysis Tom Palshaw’s did as a follow up after the video. In that analysis he states the rivets are the same as found on 2-2-V-1.  He also states the larger rivet pitch was found to vary making it a question to examine for a possible fit.
https://istigharartifact2-2-v-1apieceofac-47wing.yolasite.com/

Could discoloration around the rivets or some other factor cause them to appear bigger than they are based on side by side visual comparison?  Was a measuring instrument used to verify the rivet size on the wing examined?  Did Mr. Palshaw do this when he removed a rivet? What is the reason for the conflicting sizes claimed for the rivets?
3971R
 
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Ric Gillespie

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Re: 2-2-V-1 wing panel comparisons
« Reply #5 on: December 04, 2019, 03:24:54 PM »

Could discoloration around the rivets or some other factor cause them to appear bigger than they are based on side by side visual comparison?

There was no discoloration. Both the wing and the artifact are the dull gray of oxidized aluminum sheet.

Was a measuring instrument used to verify the rivet size on the wing examined? 

No.  The size difference was immediately apparent and obvious.

Did Mr. Palshaw do this when he removed a rivet?

I have no idea. He doesn't say.

What is the reason for the conflicting sizes claimed for the rivets?

Somebody is wrong.
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Greg Daspit

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Re: 2-2-V-1 wing panel comparisons
« Reply #6 on: December 04, 2019, 04:33:55 PM »

Could discoloration around the rivets or some other factor cause them to appear bigger than they are based on side by side visual comparison?

There was no discoloration. Both the wing and the artifact are the dull gray of oxidized aluminum sheet.

Was a measuring instrument used to verify the rivet size on the wing examined? 

No.  The size difference was immediately apparent and obvious.

Did Mr. Palshaw do this when he removed a rivet?

I have no idea. He doesn't say.

What is the reason for the conflicting sizes claimed for the rivets?

Somebody is wrong.
It’s hard to tell the size of the rivets by looking at the video. The wing being flat and outside may allow residue from pollution or dust in rain (discoloration) to collect around its rivets.

There may be an optical illusion issue with comparing a circle in a field of smaller holes to a circle surrounded by same size circles.  There are optical illusions that can fool you.  I’m not saying this is one but it would be nice to actually measure the rivets instead of visual comparison. Some examples of known illusions.

https://en.wikipedia.org/wiki/Ebbinghaus_illusion
https://en.wikipedia.org/wiki/Delboeuf_illusion

It would be helpful if he could send us a picture of the rivets with a digital caliper to prove his claim for the size.

Some concerns with his analysis:
1.   The wing from the Sydney crash was painted green.  Not sure if testing was conclusive that 2-2-V-1 never was painted or just no paint was found?
2.   The claim the aluminum was a “Match” to WWII aluminum. A graphic he used is one I did and posted on this Forum.  I did that graphic to show the 3 elements in question might fit between the two time periods.  Not a “match” one way or the other IMO.  Inconclusive.


3971R
 
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Matt Revington

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Re: 2-2-V-1 wing panel comparisons
« Reply #7 on: December 04, 2019, 05:54:11 PM »

A few years ago hyperspectral imaging was done on this object
https://tighar.org/smf/index.php/topic,1456.15.html
That may show any residual paints

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Ric Gillespie

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Re: 2-2-V-1 wing panel comparisons
« Reply #8 on: December 04, 2019, 07:28:03 PM »

It’s hard to tell the size of the rivets by looking at the video.

It wasn't hard in person. That's why we didn't do any measuring.

Some concerns with his analysis:
1.   The wing from the Sydney crash was painted green.  Not sure if testing was conclusive that 2-2-V-1 never was painted or just no paint was found?

We asked that question early on.  A lab found no trace of paint on the artifact. Impossible to know if it was never painted.  One thing we know for sure;  2-2-V-1 was scrubbed around in an abrasive environment long enough wear all of the edges smooth.  It's not surprising that any trace of paint is gone.
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Greg Daspit

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Re: 2-2-V-1 wing panel comparisons
« Reply #9 on: December 05, 2019, 05:07:29 PM »

If in a follow-up inspection it was found that the rivets are -3, I think it would be helpful if Tom Palshaw could provide documentation showing how he measured them.  I think he has a good case here if he can confirm or document better that the rivet sizes match.

Based on what I could see in the video, the rivet row spacing and pitch appeared to be close to a match.  It would be helpful if they were both measured and documented by photograph so we can verify.

I agree with the reasoning that a structural member on the aircraft next to the edge that failed by folding is not needed. Someone could have placed their own edge to help fold it straight.

The picture he posted on his web site clearly shows that the larger rivet row has a pitch that varies. I question how one could claim to match or disqualify something spaced like that without a lot more samples that all showed the same spacing irregularities. It is interesting that both the wing and artifact have an irregular pitch or anomalies though. For now I don't think that row not being exactly the same is a disqualifier.

 Here is what I would like to see tested and documented somehow for further review: (Others may have better ideas)
1.   Confirm the rivet hole sizes. The physical test of fitting a -3 into the holes and then failing to fit a -4  in the holes seems conclusive that the holes are for -3. But this physical test was not done on the wing. A rivet was removed at a later date so if that test could still be done it would be a good to document it. Photos of a rivet gauge used in the process may help the viewer.
2.   Confirm the size of all rivet heads by measurement. Document by photograph of digital caliper or head rivet gauge. A sample of a few rivet heads should be examined. Do same for new rivets out of the box.
3.   Confirm both the spacing and pitch of rivets. I think adhesive measuring tape works better for the viewer of photos.  It stays flush so is not distorted by being off the surface when photographed at an angle. Place tape next to each row to determine pitch and one or two strips perpendicular to the rows to get their spacing.  This includes measuring both the larger rivet rows. Even if the pitch varies the distance between rows can be verified.
4.   Measure the thickness of the metal. I don’t know what the best tool for this would be with the metal in place? Whatever tool is used, photograph it being used.
5.   Check for  labels that still may be viewable on the aluminum. Based on the new font/ label designation information, it may help to know where it was manufactured
3971R
 
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Ric Gillespie

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Re: 2-2-V-1 wing panel comparisons
« Reply #10 on: December 06, 2019, 11:07:24 AM »

Based on what I could see in the video, the rivet row spacing and pitch appeared to be close to a match.

But there is more to it than just row spacing and pitch.  If 2-2-V-1 is from the wing of a C-47, all aspects of the artifact must match. Beyond row spacing and pitch, the following must also match:

• rivet size (shaft diameter)
The rivet on 2-2-V-1 has a shaft diameter of 3/32 inch - source NTSB Laboratory.

• rivet length (shaft length)
The rivet on 2-2-V-1 has a shaft length of 3/16 inch - source NTSB Laboratory.

• rivet material
The rivet on 2-2-V-1 has a dimple in the center of the head, signifying it is made of A17ST alloy - source "Aircraft Maintenance and Repair" Northrop Aeronautical Institute, 1955. See attached PDF of rivet coding.

• rivet head type
The rivet on 2-2-V-1 is a "brazier" head. A brazier head rivet has a low profile, minimizing drag. There are two kinds of brazier head rivets,  the "full brazier head" and the "modified brazier head".  As early as 1930 and as late as 1941and possibly later, the "modified brazier head" was known as the "mushroom head."  The rivet on 2-2-V-1 is what is now known as a "full brazier head" rivet. See attached illustration.
Lockheed Electras had dimpled "full brazier head rivets" identical to the rivet on 2-2-V-1.  See photo below.
The photo of the rivets on the C-47 wing at NEAM is included below for comparison.

• sheet thickness
The 2-2-V-1 sheet has a thickness of 0.032" - Source NTSB Laboratory

• sheet alloy
The 2-2-V-1 sheet alloy is aluminum plus 4.49% copper, 0.62% manganese, and 1.48% magnesium, plus traces of eighteen other elements. So far, the earliest available ALCOA specifications for 24S sheet (1941) are 4.5% copper, 0.6% manganese, and 1.5% magnesium.  No other elements are mentioned.
Aluminum samples from known Electras:
1935 - 4.29% copper, 0.43% manganese, 1.49% magnesium
1935 (same airplane) - 4.06% copper, 0.48% manganese, 1.46% magnesium
1935 (different airplane) - 3.55% copper, 0.45% manganese, 1.46 magnesium

The one WWII sample for which we have a good date of manufacture - B-17 Shoo, Shoo Baby:
1943 - 4.30% copper, .45% manganese, 1.31% magnesium
The alloy percentages in the 1943 B-17 for the elements specified by ALCOA are most similar to one of the samples from a 1935 Electra.
Clearly, no conclusion about the age of 2-2-V-1 can be drawn from the available data.
 
« Last Edit: December 06, 2019, 11:11:51 AM by Ric Gillespie »
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Randy Conrad

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Re: 2-2-V-1 wing panel comparisons
« Reply #11 on: December 09, 2019, 12:14:32 AM »

Hey Ric...Happy Birthday!!! Hey I was on youtube tonight and was watching this one video. At first I thought I had seen it before, that is until they started talking about the wing strength. In the video they talk about the wing is able to stand up to 80,000 pounds, and whats also neat is the placement of rivets and how they go about doing it! Anyway, thought this video may be very helpful and resourceful. But, in actuality, if the wing is able to stand up to 80,000 pounds...then what kind of tramatic incident would do creat excessive damage?

https://youtu.be/MM_sVVqrrA8
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Ric Gillespie

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Re: 2-2-V-1 wing panel comparisons
« Reply #12 on: December 09, 2019, 07:33:07 AM »

Thanks Randy.  That's an excellent tutorial on how Lockheed built airplanes in 1940. The segment about riveting (starting at about 22:52) is especially interesting.  The techniques were probably very similar in 1936 when c/n1055 was built.
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Greg Daspit

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Re: 2-2-V-1 wing panel comparisons
« Reply #13 on: December 11, 2019, 03:13:48 PM »

Tom added some information on the C-47 rivets and how he measured them
https://istigharartifact2-2-v-1apieceofac-47wing.yolasite.com/
3971R
 
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Ric Gillespie

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Re: 2-2-V-1 wing panel comparisons
« Reply #14 on: December 11, 2019, 04:55:46 PM »

I’ve been spending a lot time researching the possibility 2-2-V-1 is from the wing of a C-47.  The rivet pattern on the wing at the New England Air Museum (NEAM) is closer to the pattern on 2-2-V-1 than we originally thought, but it’s not a perfect match. That may be because the wing at NEAM is from a C-47B 43-49197.  The airplane that crashed at Sydney Island was C-47A 43-30739.
The C-47B had a two-stage supercharger for better high altitude performance on the China-Burma-India (“Hump”) route.  There should have been no C-47Bs passing through Canton en route to the Southwest Pacific Theater.
 
Last Saturday, I spent a couple hours with C-47A 42-92841 at the the Dover AFB Air Mobility Command Museum.  With the enthusiastic cooperation of museum staff, I was able to get up on the wing and inspect the area in question but the sloping, slippery surface was a challenge. I’ve attached a few photos.
•  All of the rivets on the Dover C-47A are dimpled A-17ST rivets.  Although they don't show up in Tom Palshaw's photos, the rivets on the NEAM are certainly also dimpled. Un-dimpled rivets are pure aluminum and far too soft for use on load-bearing structures.
•  The rivets on the Dover C-47A  are “full brazier head” rivets as is the surviving rivet on 2-2-V-1.
•  The general pattern of small rivets on the Dover airplane appears to be the same as on the NEAM wing, but it was too dangerous to attempt detailed measurement of pitch and intervals between rows.
• The small rivets on the Dover airplane are #3s.  The small rivets on the NEAM wing are probably also #3s despite our impression back in 2017.
• The double row of large rivets on the Dover airplane is different from the NEAM wing.  The NEAM wing has an inner row of #5s and an outer row of #6s.  On the Dover airplane, the rivets in both rows are #5s.
• Tom Palshaw says there are anomalies in the pitch of the #5 rivets on the NEAM wing (he did not provide photos). There are no apparent anomalies in the pitch of the large rivets on the Dover airplane.
 

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