I am starting this string to further explore the possibility of this artifact having NR16020 as a source.
The artifact (
2-2-V-1) was found in the 'Village' area of Nikumaroro during an early expedition (October 18, 1991) and is clearly an aircraft part. Here is an
earlier (original) report on the item as originally found and discussed, and another on some
forensic analysis performed on the skin by the NTSB.
'What airplane' is of course a very good question. It is not clear is that this 'skin' actually 'must' belong to NR16020 for a variety of reasons. But some of its characteristics are consistent with a number of metal components that would have been in that plane (and of course many others), so the possibility is very interesting.
What is not so clear is if the 'skin' is distinctive enough to be shown to have been attached to the Electra in the past: it may be a modification part that cannot be shown to match another plane, or the Electra, short of recovery of that airplane.
My thought is to further examine the photographic evidence we have, and perhaps even another Electra (or more than one more) as an exension of the effort TIGHAR has already been able to make. It does not appear that TIGHAR has been able to exhaust all possibilities - access isn't easy, and existing historic photographs have their limits.
Note too that even if the part were somehow definitively linked to Earhart's Electra, it still would not prove a presence of the airplane on Niku - it could have been transported there from another place. But it would provide evidence of the airplane being in the vicinity - and either accessible by humans in the past, or in a place where it once gave up parts that washed ashore, etc. This is also admittedly a very tough challenge: such skins don't bear serial numbers, etc.
Is it worth the chase? I believe it is - for the education of the exercise, and for the long-shot chance it may yet prove to be a 'lead'. Besides, it seems like a fun undertaking to be a part of the TIGHAR exercise.
I have a background in aviation maintenance, modification and repair, including extensive sheet metal training and work experience. This makes a few notable things about this artifact stand out to me as indicators for possible fitment on the Electra (or another type perhaps, of course); as mostly mentioned in TIGHAR's data already, the following things can be observed:
- The sheet is .032" thick - if a repair item, the norm would be that it would not be used as a doubler or replacement for a skin or other component of greater thickness;
- The sheet bears rivet holes mostly of 3/32" diameter in neat rows, evenly spaced (and slightly tapered relative to each other implying this 'skin' would have been fitted to a 'transitional' area, i.e. where a fuselage or other structure tapers, etc.) -
J.N. Note: This is a rivet size that is not normally used in 'primary' structure, i.e. what we tend to think of as 'load bearing or carrying members' and including (oddly enough) fairings; there are exceptions to this: some airplanes use this size fastener in lightly-loaded sections of control surface skins where weight is critical and the 'tacking' task is not demanding. The same is true in some fairing assemblies for the same reason, if only light stiffening qualities are required, etc. This suggests a need to look in 'secondary' areas, i.e. places where such a broad skin might only be lightly reinforced by light-weight stringers or stiffeners, attached to relatively light structure with a minimal 'tacking' requirement present, etc.
- The sheet bears one surviving rivet which has a distinctive 'brazier' style head that is common prior to WWII; that style gave way to the AN470 'universal head' rivet around the time of WWII and is largely a 'pre-war' item. It would not be common to find a brazier head rivet used in aircraft produced after war production was accelerated.
- The sheet is 'alclad' and bears markings that are consistent with pre-war aluminum production (a more automated process was begun during war-time production and the machine inked 'signature' is different).
- There are a very few larger diameter rivet holes surviving near at least one edge of the sheet which imply picking-up of a heavier attach point - perhaps an existing row of structurally significant rivets along a stringer or other such component.
J.N. Note: So few of these 'primary' sized holes may make a match extremely difficult as this may be the sole evidence of attachment to any primary / original portion of the parent airframe.
Ignoring for the moment 'other types' and focusing on the Electra for the simple purpose of examining a hypothesis of whether this might be from 'the' Electra, what areas of the airframe might include such an item?
One that I was not aware of prior to the symposium in Washington D.C. was a large window that was cut into the starboard side of the lavatory compartment in the Electra. This was later covered-over in Miami, according to information in the 'Harney Drawings'.
Why consider this location for this sheet?
- Thickness: according to information in TIGHAR's material (linked above) the skins in this area are reduced in thickness from .040" forward to .032" aft; more importantly, a 'window' implies braced 'edges', and to cover it should only require a light skin of this sort in a non-pressurized airplane of the Electra's performance.
- Potential 'brace pattern' - the light rivets imply light bracing, or stiffening, across the 'membrane'; this would be needed to prevent 'oil canning' of such a cover in flight, once installed.
- Edge attachment: unfortunately not so clear, but the surviving larger rivet holes imply an 'edge' that may have been attached to heavier, braced structure which would be typical at the edge of such a window.
- While also appropriate in other areas for similar reasons, 'alclad' would be a desireable selection for an external 'panel' of this sort (so it does not 'prove' anything, but is 'consistent with' a logical choice for such an installation).
This is just one idea (and is one I am trying to investigate further at this time). There are pictures of the starboard side of the Electra on the ground and in flight which show a tell-tale 'window cover' in the lav area as described (well aft of Fred's remaining starboard side 'nav window' in the aft cabin area), but so far I have not found a picture with enough fidelity, for me at least, to identify potentially-telling rivet / brace patterns, etc.
Any help with better pictures of this area would be appreciated, as would thoughts of additional areas where such a panel might find a 'home'. There are of course a number of other possibilities for placement of such a skin.
Thoughts? Ideas? Better pictures of the starboard (right) side of the fuselage in this area (immediately aft of main cabin)?