The Question of 2-2-V-1

[Walter Runck]

The same online source for the Douglas C-47 manual posted on Feb. 25th also has the repair manual for the Consolidated PBY-5.  It's a bit of a surprise to learn that virtually all the skin plating above the chine on the PBY-5 hull was .030" Alcad, or thinner material than might be expected.  That's not the same as 2-2-V-1 and .032 I realize, but the manual does call for repairs to damaged .030 hull skin to be made with .032 material [...and AN456-4 rivets- the 1/8" shank rivets with the same head as the AN455-3 rivet.  See page 94 of 182.]

Nice work Mark.  That's the kind of language and level of detail I would like to find in the Lockheed library, but military customers are more likely to be willing to pay for the fancy documentation and the 10E was a commercial product at the time.

I looked at a small flying boat a couple of weeks ago and was surprised at how light the hull construction appeared to be.  I wasn't able to touch or measure, so no hard data, but I'll post a picture if I can find a good one.

[Ric Gillespie]

That's the kind of language and level of detail I would like to find in the Lockheed library, but military customers are more likely to be willing to pay for the fancy documentation and the 10E was a commercial product at the time.

I think the lack of fancy documentation on the Model 10 is more a function of the state of the industry in 1934-38.  Building airplanes was still almost a cottage industry.  No illustrated how-to manuals were needed by small factories that turned out one or two airplanes at a time. Part numbers were not stamped into parts, etc. 
War in Europe changed everything. Government contracts for thousands of aircraft meant thousands of new employees had to be trained - and fast.  The writing and illustrating of manuals attracted the best talent.  Many of the wartime manuals are better written than anything produced today.

1939-1942 saw a huge change in aircraft manufacture.  Our artifact seems to be telling us that it dates from before that watershed.  If we can prove it with regulations, guidelines or manuals we'll have eliminated WWII aircraft as candidates for the source of 2-2-V-1. 

[Karen Hoy]

What kind of schedule do the restoration employees work? What days might be available?

Thanks,
Karen

[Ric Gillespie]

What kind of schedule do the restoration employees work? What days might be available?

I don't know yet.

[Ted G Campbell]

Ric,
Is there anyway we can lay our hands on a pre WWII piece of Alcad and then do a spectro analysis comparison of a known sample and 2-2-V-1?

Can Alcoa suggest any processing changes we could look for on 2-2-V-1, such as flat plate rolling process marks, heat treatment, rockwell hardness, anodizing chemicals, coefficent of expansion specifications, chemical properties i.e. tin, lead, aluminium content, etc., tensile/shear strength or other physical properties we might be able to test in order to get a date range on 2-2-V-1?

Can we chemically compare 2-2-V-1 to a known original Lockheed 10E sheet metal fragment?

Let's see if we can narrow the field of possibilities!

Ted Campbell

[Ric Gillespie]

Is there anyway we can lay our hands on a pre WWII piece of Alcad and then do a spectro analysis comparison of a known sample and 2-2-V-1?

In 1996 ALCOA cut three large "coupons" out of the artifact (broke my heart) and ran analyses to determine the makeup of the metal. They found it to be identical to the pre-war, wartime, and post-war makeup of 24ST ALCLAD (since 1954 known as 2024 ALCLAD).

Can Alcoa suggest any processing changes we could look for on 2-2-V-1, such as flat plate rolling process marks, heat treatment, rockwell hardness, anodizing chemicals, coefficent of expansion specifications, chemical properties i.e. tin, lead, aluminium content, etc., tensile/shear strength or other physical properties we might be able to test in order to get a date range on 2-2-V-1?

I don't know.  We'd have to start over with ALCOA.  I doubt that any of our contacts from 18 years ago are still around.

Can we chemically compare 2-2-V-1 to a known original Lockheed 10E sheet metal fragment?

We already know that it's the right stuff in the sense that it's 24ST ALCLAD.  A technique known as Neutron Activation Analysis could identify trace minerals in the alloy which, if compared to a known sample of metal from NR16020, could tell us that the two samples came from the same "batch" of aluminum.  But even then we run into a couple of problems:
• How big was a "batch"of aluminum in 1936/37?  Big enough for metal from the same batch to be sold to several manufacturers?
• According to ALCOA, the labeling on 2-2-V-1 indicates it is "reserve stock."  The only known surviving example of metal from NR16020 are souvenir scraps from the Luke Field accident and, therefore, from the original construction, not the repair.  Was the "reserve stock" used in the repair from the same batch of aluminum as the metal used in the original construction a year earlier?
• Neither of the individuals who own fragments of metal from NR16020 is TIGHAR-friendly.

Bottom line: Neutron Activation Analysis wouldn't reliably narrow the field.

[Ric Gillespie]

Just got off the phone. The Air Force Museum front office is being very supportive and cooperative.  They're still working out the procedures and details but I fully expect we'll be able to have a private tour of the restoration shop and meet with the shop foreman on Friday, March 28.  We'll need to hold it down to around a dozen people more or less and I'll need everybody's name to finalize everything.
The restoration shop is about a mile from museum and, unlike the museum, it is on the Air Force Base proper so we have to go through base security.  Everyone will need photo ID and it will simplify things greatly if everyone is an American citizen.

[John Ousterhout]

Will you be bringing 2-2-V-1 to show them?

[Ric Gillespie]

Will you be bringing 2-2-V-1 to show them?

You betcha.

[JNev]

I've been thinking about the rivet inspection conundrum - that being:  the head of a 3/32" AN455 brazier rivet is indistinguishable from the head of a 1/8" AN456 modified brazier. That would seem to mean that - as we stalk the hangars of the National Museum of the United States Air Force, micrometers at the ready, we won't be able to test our hypothesis that the scale of materials used in 2-2-V-1 (3/32" AN455 brazier rivets in a .032 skin) is not found on WWII aircraft that served in the Pacific UNLESS we are unable to find any rivet heads of the "right" style and diameter. 

If we do find rivets that could be 3/32" AN455s or 1/8" AN456s, we might be able to judge the thickness of the surrounding skin by a simple "thunk" test.  A .032 skin "thunks" very differently from, say, a .040 skin.  Not high science but what we're looking for is a sense of scale in how aircraft of a given time and size were constructed. 

Of course, we're also looking for more than rivet type and size.  We're looking for patterns that might match the artifact.  If we find a location on an aircraft that might match the artifact we can dig deeper and find out whether the materials actually do match.

Actually I believe you will find that an AD455 and AD456 are distinguishable due to height vs. diameter of the head - the AD456 has a more sharply radiused head (smaller diameter to similar height for a given size).  Hence while a #4 AD456 head may be similar in diameter to a #3 AD455, the head height would be noticeably higher.

As an 'inspection tool', it might be useful to prepare coupons with samples of #3 and #4 rivets of both types for comparison to what might be observed on the museum floor.  It would be nice to also have #3 and #4 AD470 types thereon.  #5 as well - all types - though advisible to double the coupon thickness to allow for normal tail development, etc.

I would be happy to help with preparing such coupons, if useful for this idea of visual comparison.  I do not possess any AD455 or AD456 rivets or the rivet sets for them but I'm sure I can get them.

[JNev]

The same online source for the Douglas C-47 manual posted on Feb. 25th also has the repair manual for the Consolidated PBY-5.  It's a bit of a surprise to learn that virtually all the skin plating above the chine on the PBY-5 hull was .030" Alcad, or thinner material than might be expected.  That's not the same as 2-2-V-1 and .032 I realize, but the manual does call for repairs to damaged .030 hull skin to be made with .032 material [...and AN456-4 rivets- the 1/8" shank rivets with the same head as the AN455-3 rivet.  See page 94 of 182.]

Look under "Other Airframes"

http://miravim.org/avimlibrary/Manuals/Airframe%20Manuals/

Consolidated 01-5M-3 (PBY-5 , 5A, 6A - Handbook of Structural Repair Manual)

That is an interesting find and I am a bit surprised at such light skins for the belly of a seaplane, even in the after hull.

Considering this and having looked at the Coronado example and considering the wreck of one of those in the region, I believe we should consider the Coronado carefully.  What was described by way of that accident was violent and might have produced something like we see in 2-2-V-1.  But to be sure, the Coronado would have to be shown to have used #3 rivets in those 'similar' areas, and if that were to bear out, it would really help to know more about the wrecked bird: had it been subjected to some previous repair?  No mistaking - 2-2-V-1 is a repair/alteration piece of metal, that is not factory stock stuff - the altered rivet pattern / sizing is evident and persuasive of that.

[Monty Fowler]

Thinking about the artifact (dangerous, I know), and the pending Dayton Expedition - Is there a way we can make a reasonably accurate, flexible template of the part? For comparison purposes with every aircraft we can crawl over, under or through? Something flexible and tough like Mylar, Tyvek, something like that?

That, and having good tape measures handy!

LTM, who flunked sewing class,
Monty Fowler, TIGHAR No. 2189 CER

[Mark Pearce]

That is an interesting find and I am a bit surprised at such light skins for the belly of a seaplane, even in the after hull.

Considering this and having looked at the Coronado example and considering the wreck of one of those in the region, I believe we should consider the Coronado carefully....

Agreed.  Following that reasoning, the PBM wreck on Howland Island should also be carefully considered. 
A large wing panel can be seen in the background of this photo

http://tighar.org/aw/mediawiki/images/c/c1/Plane_wreckage.jpg

Here's another surprise- WW2 wreckage found in 2006 in the Marshall Islands and alleged to be from a PB2Y Coronado.  Take a look at those rivets surrounding the inspection plate-  what do you think?   Could they be 3/32" or 1/8"?  AN455 or AN456??

http://pacaeropress.websitetoolbox.com/post/unidentified-wing-section-RoiNamur-6162613?trail

[Ric Gillespie]

Following that reasoning, the PBM wreck on Howland Island should also be carefully considered. 
A large wing panel can be seen in the background of this photo

That's a wingtip float, not part of the wing.

Here's another surprise- WW2 wreckage found in 2006 in the Marshall Islands and alleged to be from a PB2Y Coronado.  Take a look at those rivets surrounding the inspection plate-  what do you think?   Could they be 3/32" or 1/8"?  AN455 or AN456??

No way to tell scale, but I don;lt think those are braziers or modified braziers.

FWIW, I'm aware of no traffic either during or after the war between Howland or the Marshals and the settlement on Nikumaroro.

[Mark Pearce]

That's a wingtip float, not part of the wing.

A wing panel [with skin sections missing] is in the background- closer to the beach.  Click the image for a larger view.