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[Randy Reid]

Jeff,

do you know if the rivet holes are still nominal size or have they been enlarged(torn) as the piece was removed from the sub-structure? If the holes are still nominal size, it indicates the rivets were removed prior to removing the sheet, possibly prior to replacing it. When we repaired damaged sheet stock, most of the time at least some of the sub-structure could be reused. This artifact may have been the scrapped pieces from another aircraft repair, maybe even from another island.

Also I do not think this is fuselage or wing skin as it is too thin, even for a patch. Although I have seen duct tape used and it is pretty thin. From the number of support structure members, my guess is that the sheet would be a load bearing shelf, or possibly floor boards or cargo floor.

anyway, luck to you if you can figure it out, and if there is an A&E on the forum, maybe he can chime in.

Randy

[Jeff Victor Hayden]

There's quite a few places where the artifact could fit in to the Consolidated PB4Y-1, size, rivet patterns, distance between rows of rivets and convergence of rows of rivets...?

[JNev]

Jeff

There has been a lot of work done to try to match this piece to the Electra.  I wish Ric or Jim Thompson could chime in here as they did the lion's share of the effort.

I'm curious what you think of the attempt to match the skin to the roof of the Electra over the cabin door.  This seemed to be the best match we could find, although the air vent scoop seems to discount the possibility.  Maybe with your background you can see a match in a way that we didn't.

 

you can also find in the Ameliapedia other material such as rivet pattern rubbings, and photos of the roof and air scoop from other Electras that we were trying to match

http://tighar.org/wiki/2-2-V-1

Thoughts?

Andrew

Thanks Andrew.

I respect the excellent work that has been done so far and have reviewed at least most of it, but am needing to review further I am sure.  One question I have for that review is: "was the possibility of a cover for the lav window considered", hence this string.  I don't see that it was - and I see that possibility as a prime candidate (and very hard to find direct evidence by which to 'match' - we're stuck looking for photos of that NR16020-unique feature).

The top section you have shown is an intriguing area due to the stringer lines, etc.  On the positive - it is 'similar'.  The negative for this area may be that the artifact itself displays an irregular pattern compared to what I'd expect to find 'match-drilled' to existing structure: the original skins on the Electra appear to be fixture-controlled - very neat rows, generally; it would follow that the existing stringers there would duplicate that neat fixture pattern.  The 'field' rivet lines in the artifact are more irregular than I would expect to find on the original airframe.  The small #3 rivet holes tend to suppor this too - I don't believe you'd find that in the primary skin / stringer structure in that area - not as a reasonable repair.

Could a 'patch' over a damaged area work like that?  Yes, if you discounted the 'match-drilling' to pick-up existing stringers, etc.

My thought about the 'window cover' is actually an extension of that thought: given that a large opening is being covered, the mechanic was somewhat 'free' to place 'field rivets' as he chose; the logical approach when doing such field work would be to follow nearby patterns - but not necessarily duplicate them perfectly. 

That could explain some of the irregular lines / spacing that we see in the artifact: irregular tapering, and slightly less-than straight lines.  A hand-fit installation is very much suggested by what I see - and that would be consistent with a 'cover panel' to cover such a window.  No existing stringers or stiffeners would be present in the middle of the window, and the thought is that light stiffeners may have been added to offset the vibration / oil can effects one finds in a large light gage sheet.

I need to go back into the Wiki and study what TIGHAR has done in more detail.  I don't know that they're 'wrong' in any regard - but I do still see a 'covering' for that 'weird window' in the lav as a strong candidate for the reasons mentioned.

Randy,

The holes appear mostly intact (not elongated, torn or oversized by force).  A few appear to have been drilled to 'next size', i.e. occasionally you will find a couple or three in a row that were 'drilled up' to a #4 rivet (AWG #30 hole / about 1/8").  Many of the holes were observed to be slightly 'dimpled' by stress - as if the skin and whatever was behind it were somewhat forcibly separated from each other.

I agree that the skin is not too thin for a 'patch' - the question is 'where would .032" be appropriate' and therefore expected to be found: not where there are .040" skins, at least as a norm (it is not normal to go down in gage for a repair or alteration for reasons of strength and stiffness).  The skin could be a patch therefore in an area where .032" skin was originally used - if convention followed.  It could also therefore logically be used for the 'window cover' I've described - either as consistent with surrounding skins aft of the cabin area, or as a stand-alone sufficient covering for the intention of covering the window opening, as we can see was done at some point (we see the window in early shots, the window covered in others, apparently later).

I would love to hear from other A&Ps (or AE's).  I have my experience, but many others have theirs, of course - and that makes the base wider and deeper, of course.

Jeff Victor -

I agree there are areas on the PB4Y-1 where the skins appear to have similar patterns.  I think TIGHAR has looked at this, but it may be worth re-visiting.  One thing that would make me consider that prospect critically would be the apparent vintage of the artifact (pre-war, lower production rates) compared with that of the Consolidated bird (WWII - mass production goods, different markings as I understand it).  But, if a 'match' is made, it could tell us a great deal!

Thanks guys.  I'm going to keep digging - into the TIGHAR materials Andrew suggested and for more pix of the Electra: the more I consider this the more convinced I am that we have a non-original pattern here, and that's the 'place' to look - where would a non-original skin go on NR16020.  I don't want to overlook other areas, but the aft lav window still sticks out as a candidate to me.

LTM -

[Ricker H Jones]

The Harney drawings show skinned over escape hatches (both sides) centered above the trailing edge of the wing root.  The drawing doesn't indicate whether this was done during initial construction or as a later retrofit.  The rivits as shown do not appear to match the artifact, however.
Rick J
 

[Jeffrey Pearce]

For a newcomer, is there something like a final report that discusses the effort to match the large piece of material that looks like part of an aircraft exterior to other electras of Earhart's model?

[Martin X. Moleski, SJ]

For a newcomer, is there something like a final report that discusses the effort to match the large piece of material that looks like part of an aircraft exterior to other electras of Earhart's model?

I've collected some material on the wiki.  I'm not sure how up-to-date it is.  It does not include any of the recent discussions here since the symposium.

[Greg Daspit]

http://tighar.org/Publications/TTracks/14_1/Back_to_Square_One.html
Is it possible the repair theory is still correct, only they changed their mind about adding stiffeners and removed them? Then covered the thin patch with a another thin layer.  This doubled the thickness and therefore they did not need the stiffeners. In the post repair pictures you only see the outer layer, but could the repair layer theorized still be below serving as an inner laminated layer?
edit: maybe the structure below, not seen on the inner layer is an opening in the outer layer to allow adjustment of the inner layer so holes could align.

[JNev]

Gregory -

A lot of things are possible - NR16020 was not only extensively repaired but was an experimental airplane by her licensed use - the "NR" registration amounted to 'restricted' for that reason.

What you surmise is perhaps quite possible if a given area of repair was also affected by some need to do a local modification.  It would be unusual to simply delete stringers or stiffeners, but a doubler would be a rational substitute if it was necessary.  The small field rivets would seem odd - but that is a possibility.

I still favor the possibility of a window cover (lavatory area, right side) for now - but that's my notion of a 'rational' site for now.  What you have described is a very good possibility.

LTM -

[Jeffrey Pearce]

How is a replacement piece of a plane's exterior attached to the plane to secure it into position?

[Tim Collins]

Jeff

There has been a lot of work done to try to match this piece to the Electra.  I wish Ric or Jim Thompson could chime in here as they did the lion's share of the effort.

I'm curious what you think of the attempt to match the skin to the roof of the Electra over the cabin door.  This seemed to be the best match we could find, although the air vent scoop seems to discount the possibility.  Maybe with your background you can see a match in a way that we didn't.

 

you can also find in the Ameliapedia other material such as rivet pattern rubbings, and photos of the roof and air scoop from other Electras that we were trying to match

http://tighar.org/wiki/2-2-V-1

Thoughts?

Andrew

I wouldn't be so sure that the air scoop vent necessarily discounts the possibility of this location. The question should be what is the shape of the vent hole beneath the scoop ? What may be overlap of the scoop housing with the skin of the plane?  Is there a margin of error associated with the positioning of the air scoop in the drawings - say, within +/- an inch or two either way? I'd like to think this has already been considered, but I think it's nonetheless important to reiterate.

[Andrew M McKenna]

Here is the vent hole as seen on the NEAM L-10

http://tighar.org/wiki/File:NEAM_04.JPG

It does not reach back to the apparent end of the scoop, or into the territory of 2-2-v-1, the hole is all forward of the stringer / structural element forward of the artifact as projected on the overlay.

Andrew

[Ted G Campbell]

Andrew,
The black "cord like" material running along the stringer look much like the "cord, wire, cable, etc." we see in the rov stills.

Do we have other photos in this series?

Ted Campbell

[Andrew M McKenna]

Only what is in the Wiki

http://tighar.org/wiki/2-2-V-1

Jim Thompson may have more.

amck

[Greg Daspit]

http://tighar.org/wiki/2-2-V-1

What I find interesting is the holes that attach the rear of the scoop in the picture attached don't show up on 2-2-V-1.
However, the fasteners in this picture of another plane (I assume another plane)shows the fasteners at the rear of the scoop are of a different type where they should overlap the 2-2-V-1 panel than the fasters at the front part of the scoop.

Maybe they put the different rear fasteners in at a later time when they determined they needed them? However on AE's plane they did not get the chance to see the need for the rear fasteners?

Is it known who put the fasters in this picture and when? Who's plane is it?

[Jeffrey Pearce]

So a plate of metal that is affixed to the exterior of the fuselage sometime after the plane was built is accomplished solely by riveting the new plate into parts of the existing plates and nowhere else?