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[Diane James]

@ Ric,

Thank you for the response. 

Among other things, you wrote: "The markings seem to be spots where there is more oxidation as if the aluminum under the horizontal stiffeners was not as well protected as the surrounding metal."

Maybe every time it got wet in sea water the parts under the strips were the last to dry out, maximizing corrosion opportunities.

"... the tear at the top where the vertical stiffener may have been anchored to the circumferential at Sta. 307."

And may not have been. As I said in my response to Jeff above, I don't see a compelling reason to think the guy who fabricated this thing in Miami would have needed anything to do with the previously cut fuselage former except to avoid it. He's just covering a window hole, not repairing a previously engineered modification.

The" engineered" part is an assumption on my part. Do we have the drawings etc. from the original modification of installing the navigator's window? Was Lockheed the source, or at least in on it? Is there any reason to think that engineering relied, improbably, on the new window assembly actually carrying structural loads? I'm assuming not, and thus the "patch" wouldn't need to either.

"... The strange thing is that there is no apparent evidence of the vertical stiffener on the interior of the sheet ..."

Hoo, boy!  I am just now catching on to this. So what we have taken as being a vertical stiffener was on the OUTSIDE of 2-2-V-1.  Are you saying that what makes it visible is a linear dent where the metal has been pushed out around it, from the inside toward it?

I'm no photo interpreter, but I don't see any pic of the shiny patch over the window location where I see a stiffener on the outside. That's a puzzle.  Ain't this fun!?

Back to the question I asked Jeff above:  if 2-2-V-1 is positioned with its farthest forward edge in the location shown in period photos, and without any reference to where the vertical mark or the tear lie in relation to the fuselage ring former at STA 307, does the artifact fit the hole?

Thanks,
Diane

[Ric Gillespie]

"... the tear at the top where the vertical stiffener may have been anchored to the circumferential at Sta. 307."

And may not have been. As I said in my response to Jeff above, I don't see a compelling reason to think the guy who fabricated this thing in Miami would have needed anything to do with the previously cut fuselage former except to avoid it. He's just covering a window hole, not repairing a previously engineered modification.

You're assuming the vertical member was part of the original patch installation.  It's also possible that it was added later in response to the "oil-canning" evident in the Darwin re-fueling photo.

The attached air-to-air photo was taken from a Royal Netherlands East Indies Airlines DC-2 as the Electra approached Bandoeng, Java on June 21, 1937. The patch appears duller than it did three weeks earlier in Miami but is otherwise unchanged.

A week later, shortly before noon on June 28, Earhart and Noonan arrived in Port Darwin, Australia.  The aircraft was fueled later that afternoon for the next morning’s flight to Lae, New Guinea. A photograph taken during the fueling (attached below) shows irregularities in the patch that suggest "oil-canning" (flexing of the sheet).  “False color” imaging of the Darwin refueling photo by forensic imaging specialist Jeff Glickman suggests the presence of an underlying vertical structure in the vicinity of Fuselage Station 307.

The" engineered" part is an assumption on my part. Do we have the drawings etc. from the original modification of installing the navigator's window? Was Lockheed the source, or at least in on it? Is there any reason to think that engineering relied, improbably, on the new window assembly actually carrying structural loads? I'm assuming not, and thus the "patch" wouldn't need to either.

The window was installed sometime in late 1936/early 1937. The aircraft was based at Burbank’s Union Air Terminal which was home to Lockheed Aircraft and also Paul Mantz Air Service.  Hollywood stunt pilot Paul Mantz was Earhart’s technical advisor.  Who it was that installed the window is not known but there are no drawings or engineering orders for the window in the surviving Bureau of Air Commerce records for the aircraft.  By contrast, the engineering orders for Lockheed’s repair of NR16020 following the Hawaii crash in March are in the Bureau of Air Commerce file for the aircraft. The lack of paperwork on the windows, the absence of any public discussion of them, and the questionable structural wisdom of their installation suggest that they were something that Earhart/Manning/Mantz did without involving Lockheed engineers or government inspectors.

Hoo, boy!  I am just now catching on to this. So what we have taken as being a vertical stiffener was on the OUTSIDE of 2-2-V-1.  Are you saying that what makes it visible is a linear dent where the metal has been pushed out around it, from the inside toward it?

I don't think so. I think it's more likely that the impressions on the interior surface of the sheet are just a lot harder to see. If there was stiffener it was on the inside of the aircraft.

Back to the question I asked Jeff above:  if 2-2-V-1 is positioned with its farthest forward edge in the location shown in period photos, and without any reference to where the vertical mark or the tear lie in relation to the fuselage ring former at STA 307, does the artifact fit the hole?

That's where Jeff and I disagree.

[Ric Gillespie]

Here is the false color image that reveals what may be a vertical stiffener.

[Jerry Germann]

Welcome Diane,

Here are some images of the skeleton and the skin layer thicknesses installed on the Electra.....

[Diane James]

Ric said: "...If there was stiffener it was on the inside of the aircraft."

Whew, I'm glad I misunderstood that.   

OK, so if trace evidence of a vertical stiffener is on 2-2-V-1's inside surface, the stiffener had to have gone either under or over the horizontal stiffeners. But it's not riveted in place. It would be curious to see if microscopic examination of the rivet holes could reveal if the horizontals lay flat across the piece or if the horizontals left stress-signs in the rivet holes of being riveted down over the vertical piece. It's hard to tell from the photos, but maybe a close look would give it away.  I think if we understand the nuances of 2-2-V-1's attachments we may better understand the artifact.

Ric, did I understand your answer above to mean that you do believe 2-2-V-1 is not oversize if the front of it is aligned with the location shown in period photographs?

[Diane James]

Ric said:  "You're assuming the vertical member was part of the original patch installation.  It's also possible that it was added later in response to the "oil-canning" evident in the Darwin re-fueling photo."

If it underlies the horizontal reinforcement strips it has to have been assembled before or when they were. That's why I hope it's possible to have a lab microscopically determine what lay over what. If a vertical was instead laid over the horizontals from inside the fuselage it could very well be a late addition.

[Jerry Germann]

Diane , Here are some interior views;

[Greg Daspit]

The patch and the coaming are evident only in old photographs. I have not seen an opinion from a Photogrammetry expert that the patch matched the coaming or that there was a gap between patch edge and other skin edges and if so how big. Still it was interesting to study the modern photos with measuring tape in them and how the varying dimensions relate to rivet rows at Sta. 320 and Sta. 293 5/8 on the Wichita Plane.

The artifact is curved overall and has dents in several places, so measurements have varied depending on the method used and how much deformity was allowed for.  I have seen three different methods of taking measurements of the artifact.

Method 1- The un-flattened artifact. No deformity taken out and the artifact has its narrowest width. The un-flattened artifact was compared to the Wichita plane by holding it directly next to it. (for those who see huge dents in the patch based in old photographs this may be a reasonable method)

Method 2- The overall curvature taken out of Artifact 2-2-V-1 by pressing it down and taking a measurement with a steel tape. The width appeared to be 24 ¼” wide with this method. See attachment.

Method 3- A sticky  tape was put on Artifact 2-2-V-1 while still in its deformed un-flattened and dented shape.  How much the tape follows dents and deformities in the artifact is not clear to me.  Jeff Neville’s report notes the readings of this tape suggests the artifact was 24-5/8 wide.

A sticky tape was also placed on the newly re skinned Wichita plane and the distance between rivet rows at the bottom suggests a 25 7/16” width between vertical rivet rows at Sta. 320 and Sta. 293 5/8.  This may be different on Earhart’s plane based on reskinning or 2 different jigs used. However it should be noted that  in all 3 measurement methods, the artifact appears  to fit between the vertical rivet rows on the Wichita Plane with room to spare, if needed

[Diane James]

@ Jerry   

Thanks, those interior views of the Lockheed help me understand.

[Steve Treadwell]

Why is the new stiffener at Sta. 307 assumed to be in the same position as the original vertical member that was cut out?  If you just want to put in a stiffener to prevent oil-canning wouldn't the easiest thing be to put it next to the uncut parts of the original, side-by-side either just fore or just aft of 307 and screw or rivet them together (screws or rivets oriented in a fore and aft direction)?

[Bill Mangus]

That's a great explanation, Steve.  Makes a lot of sense and is exactly the kind of fix that could be done quickly, a field expedient fix.

@Jeff N.

Jeff, does this explanation change how your measurements effect the fit of 2-2-V-1 into the window opening?

[JNev]

@ Jeff

Thank you for those clarifications. 

Jeff, I sense that you are aware that your data rains on an otherwise exciting parade. I view your report on 2-2-V-1 as the product a serious researcher seeking replicable facts.  The facts are the facts, and the consequences of those facts fall where they may.

As a newbie, even though I have been a lurker I am free of any prior politics regarding 2-2-V-1, and I certainly don't think you are in any sort of opposing camp just because you discovered data that doesn't fit. TIGHAR has an object that seems in very many ways to fit the patch installed at Miami, and you have measurement data that says it seems too big to fit. That makes you a researcher not a critic.

Thanks for that distincition and credit, Diane.  I actually was not enthusiastic about my findings; I was an early and earnest proponent of the idea of this artifact possibly fitting as the lavatory window cover.

You wrote: "Another oddity of the '307 feature' is the lack of fastener holes there - why bother re-installing that missing segment of the 307 ring former only to allow it to simply lie in contact without benefit of stiffening / strengthening fasteners? "

And that is my point. Some structural engineer (we hope!) at some point determined that the Electra could be safely flown with a navigator's window sized piece cut out of its fuselage on the right side.  That included cutting and removing a fair-sized piece of the circumferential ring former at STA 307. The airplane proceeded to successfully fly in that condition.

When the transparent window was replaced in Miami there would have been no need to repair the previously cut former. To properly repair the former would have required the scrap that was removed when the opening was cut, or a similar section from a salvaged or factory new part. None of those were likely to have been quickly available to whoever created the patch in Miami. Other than speculation that a repaired former might have underlain the vertical feature on the patch, I haven't seen any indication that the former was repaired.

While it was logical to initially think the prior location of the fuselage former would be where a vertical reinforcement would be located on the patch by the person fabricating it, there is really no structural reason to have located it there.  He was only reinforcing a window, not repairing structure. 

I initially believed something close to what you have proposed - that we may have been looking at a simple cover that had no need of particular 'beef' to reinforce anything.  The photos we have suggested that to me; then to explain the horizontal holes, I was one (possibly among others) who very early conjectured that light bracing might have been added as an expedient means to a) stiffen the panel against ordinary oil canning (not as primary structure but to simply stiffen an otherwise unsupported web), and / or b) to help maintain some representation of the compound curvature in that area - which is slight, but desireable to duplicate as best one can; when working with an un-formed flat piece of metal, light bracing can assist in that effort if one has limited means.

TIGHAR later conjectured that the covering might really relate to a more urgent structural need, e.g. after a scare from a hard landing, etc., and significant 'oil canning' (dent) has been suggested by at least a couple of photos of the 'patch'.  This led to thoughts of stiffeners added after the skin-over in Miami perhaps.  I don't fully agree with those ideas - not saying impossible, but not likely; I don't see the evidence of a hard landing others have reported at times and doubt that this simple scab patch was any more than a covering fit over the window opening as best a mechanic could do under somewhat hurried and limited circumstances for working the metal.  But that of course is merely my own conjecture, arrived at by what I've been able to study, in my own way.  YMMV.

As to establishment / re-establishment of the vertical member: I would avoid 'would', we cannot known; but while it is possible that a vertical addition could have been made separate from the existing STA 307 remnant, why would one do so?  As a sheet metal mechanic in a former life and now engineering employee of 20 years since mostly leaving a very active sheet-metail working life, I don't see the logic.  Which also calls into question my own former logic about impromptu horizontal light bracing, I suppose - fairly enough. 

In short, the more I've studied the thing, the fewer reasons I see for the installer to have departed from the original bracing patterns UNLESS one simply wished to quickly scab a skin over that open window with as little fuss as possible.  Could a vertical stiffener have played into that?  Of course - but it implies more metal forming than the original thinking I had as to where and how this was done - which is bounded, of course, by my ignorance of the actual historic particulars...

How do the artifact's measurements work if the forward edge is aligned as photos show the patch to have been?  If it's moved that far aft, without reference to the vertical or the tear, does it then fit?

It does not fit in that case - IMHO, which is part of my point.  YMMV, of course.

[Greg Daspit]

Why is the new stiffener at Sta. 307 assumed to be in the same position as the original vertical member that was cut out?  If you just want to put in a stiffener to prevent oil-canning wouldn't the easiest thing be to put it next to the uncut parts of the original, side-by-side either just fore or just aft of 307 and screw or rivet them together (screws or rivets oriented in a fore and aft direction)?

Steve, I had similar questions and did a sketch regarding this in this post.
Another question is we don't know what the structure was like for previously added window or if added horizontal framing around that window restricted where a vertical stiffener could be installed, if it was a stiffener. For example if the remaining cut vertical member was fastened to the new horizontal window frame, the fasteners or a possible gusset plate for that connection could interfere with replacing the vertical member in the original location. Why it wasn't riveted is another question and may indicate that it was not a structural member.

[JNev]

That's a great explanation, Steve.  Makes a lot of sense and is exactly the kind of fix that could be done quickly, a field expedient fix.

@Jeff N.

Jeff, does this explanation change how your measurements effect the fit of 2-2-V-1 into the window opening?

No.

I don't find it to be an 'explanation', but honest conjecture about a 'might be', which - no offense intended and with great respect for another's idea, is not a likely possibility to me as a sheet metal mechanic with engineering experience as well. 

Were I to add ad hoc vertical bracing such as I had earlier conjectured as an explanation for the horizonal stiffening of the panel, I see even less reasoning to not pick up the remaining ring structure at STA 307 than I would to abandon the existing longitudenal bracing in this area. 

Why?  Two primary reasons:

More criticality as to shaping - the curvature is greater in the vertical than horizonal (we're looking at the side of a slightly bellied 'barrel', whose 'ends' are at the fore and aft (right and left) of the fuselage section involved; continuity to the existing ring former would in that sense be more critical, in my view.

Relative ease of attachment to existing structure: it is simply easier to base the top and bottom ends of a vertical replacment here at the existing STA 307 structure than to let it 'fly' with nothing else to tack it to but skin (above and below the window opening);
in the case of fore and aft stiffeners, we are simply coming near ring structures beyond the fore and aft ends of the opening and may attach at virtually any location that is convenient, within reason.

These are merely my views - YMMV, of course.  But no, it doesn't change my view of the fit issue.

One danger we face in 'brainstorming' ideas to explain how 2-2-V-1 'might' fit is that we can get way down a path of conjecture that lacks real clues.  What have we seen - other than 2-2-V-1 itself, that supports the idea of off-setting members such as the conjectured vertical bracing (away from STA 307) and conjectured horizontal bracing (along the parallel rivet lines on 2-2-V-1)?  This is one area I suggest we have at times strayed too far in, IMO; I found a personal need to stay more critically grounded in my conjecture and technical review as the study wore on.  To each his own, of course - but that is what I came to, as inconvenient to me as it proved to be.  I don't find it to be a loss, however, but a more robust way to research such things, IMO.

[Steve Treadwell]

No.

I don't find it to be an 'explanation', but honest conjecture about a 'might be', which - no offense intended and with great respect for another's idea, is not a likely possibility to me as a sheet metal mechanic with engineering experience as well. 

Jeff, that's just what it was - a conjecture.  I had not seen the forum thread referenced by Greg Daspit above so was unaware of previous speculation on this point.  It seemed an obvious question to me, but I have no experience with aircraft mechanics or sheet metal work.  In fact, the only mechanical experience I have is of the "shade tree" variety.