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[Ric Gillespie]

2-2-V-1 exhibits remnants of the original labeling inked onto the sheet when it was manufactured by ALCOA.  The style of the lettering (the font) and the wording of the label are different from that seen on Electras.  Specifically, the font seen on the artifact is a slanted sans-serif type known as "Franklin Italic' while the font on seen on Electras under construction is an unslanted serifed type known as "Stymie Bold."  The letters and figures legible on the artifact are "AD  24" - without doubt originally ALCLAD 24ST.  The wording seen on aircraft under construction at Lockheed is "ALC24ST"

The lettering style and wording on the artifact is similar to that seen on examples of WWII aircraft, causing critics to conclude the aluminum in 2-2-V-1 must be of WWII vintage - the assumption being the style of lettering and wording ALCOA used changed over time.  That assumption turns out to be incorrect.

As shown in the attached document, ALCOA used different fonts to identify product from different plants.  We've had this "Plant Identification Marking For Sheet and Plate" since 1992 but only recently realized its significance.  It dates from 1947 and, according to the ALCOA executive who gave it us, it was the first time the company published such a guide, but there is no reason think it represents a change from long practice.  Based on this document, it seems safe to conclude that the aluminum used at the Lockheed factory came from the Edgewater, NJ plant.  The aluminum in 2-2-V-1 was made at the Alcoa, TN plant. (Alcoa was the name of the town.)

As to the use of ALCLAD 24ST versus ALC24ST, the attached photo of Consolidated PB2Y "Coronados" under construction in 1943 shows that both were in use simultaneously - in this case on sheet from the Tennessee plant.
Based on this documentation, there appears to be no reason to think the aluminum in 2-2-V-1 could not have been made at the Alcoa, TN plant in 1937.

[Randy Conrad]

Ric...Nice interesting find! Hey question for you...what does the ana .032 mean above the alcoa print in the metal?

[Friend Weller]

If I may, recalling from my aircraft design days, ANA is for ANodized Aluminum (a bright clad finish).  The .032 is the material thickness.

[Ric Gillespie]

If I may, recalling from my aircraft design days, ANA is for ANodized Aluminum (a bright clad finish).  The .032 is the material thickness.

That's right. Thirty-two thousandths (.032) was a common thickness for aircraft skins.  Anodizing was a corrosion inhibiting treatment used primarily on U.S. Navy aircraft subject to salt water environments - hence its use on PB2Y flying boats.

[Ric Gillespie]

CORRECTION

The "AN" in ANA stands for Army/Navy.  All products approved for use in military aircraft had an AN number.  The "A" means the sheet was produced at the Alcoa, TN plant.  A similar sheet produced at the New Kensington, PA  plant would be labeled ANK.  The Edgewater, NJ plant would be ANE.

See attached screenshot from Aircraft Sheet Metal Work, 1941.


Edit: fixed url tag.

[Ric Gillespie]

A few years ago, an anonymous TIGHAR critic compiled a collection of photos and references describing ALCOA labeling on aircraft aluminum. It's at https://aluminummarkings.wordpress.com.
In all cases prior to 1941, the labeling was "ALC24ST" other than "ALCLAD 24ST" as seen on 2-2-V-1.  His/her conclusion was that the aluminum in the artifact was manufactured not earlier than 1941. (The current site begins  "...precisely as the aluminum markings predicted. The artifact’s unique rivet pattern matches exactly the top of the wing of a surviving Douglas C-47B Skytrain built in the 1940s."  We checked the wing in question in 2017.  Not even close.)

Although the conclusion is bogus, it's an excellent collection of images  What does it really tell us?
•  The vast majority of photos date from after 1939.  Why?  Because aluminum aircraft manufacture prior to the outbreak of war in Europe was minuscule compared to wartime, beginning with British Lend-Lease contracts and the ramp-up in American military aircraft production. Pre-war photos of aluminum aircraft under construction are hard to find because there weren't many being built.
•  With a single exception, all of the photos show labeling in the Stymie Bold serifed font. Boeing, Douglas, and Lockheed seem to have used aluminum manufactured at the Edgewater, NJ plant.  2-2-V-1 was made at the Alcoa, Tennessee plant.
•  One photo (attached), taken some time between December 1942 and  September 1945, shows female riveters working in an unidentified aircraft with aluminum labeled "ALCOA,"  the skin thickness, and "ANK" on one line, and "24S-T" on a separate line. The font is Gothic Title Medium. This appears to confirm two facts - 1. The New Kensington plant was using the Gothic Title Medium font prior to 1947, and 2.  The New Kensington plant used wording different from the "ALC24ST" used by the Edgewater plant. Different plants sometimes used different wording.
•  There are no photos inn the collection showing aluminum labeled with the Tennessee plant's Franklin Italic font seen on 2-2-V-1 and yet the plant's sheet aluminum mill had been in operation since 1919. The one photo we have of wartime production using Tennessee aluminum is the 1943 Consolidated PB2Y shown earlier in this thread. In 1943, Consolidated was using aluminum from the Alcoa, TN plant.  The photo shows both the "ALC24ST"  and "ALCLAD 24S-T" wording. Again, different plants sometimes used different wording.

We need more data.  Consolidated built the PB2Y at its San Diego.  PBYs and B-24s built in San Diego should also have aluminum labeled in the Franklin Italic font.  The PBY-1 first flew in 1935. If we could find a photo showing labeling on an early PBY under construction, it might match the labeling we see on 2-2-V-1 and prove the artifact COULD date from 1937. It wouldn't prove the case, but it would eliminate a possible disqualifier.

[Matt Revington]

The web page for the Alcoa, TN plant (https://www.alcoa.com/global/en/who-we-are/history/default.asp) mentions that in 1937 their aluminum was used for the America's Cup winning yacht, Ranger, built for one of the Vanderbilts. 
It was assembled at the Bath iron works in Maine (http://america-scoop.com/index.php?option=com_content&view=article&id=830:ranger-s-story&catid=182:ranger&Itemid=394&lang=en). 
The ship itself was scrapped during the war but more information (possibly photos of the construction and alcoa aluminum labels)  might be found in these papers from W. Starling Burgess an Aeronautic and naval architect who worked for Alcoa at the bath iron works and designed the Ranger.  the collection is listed at this web site (https://research.mysticseaport.org/coll/coll193/) but it would take a visit to the Mystic Marine Museum in Mystic CT to go through the material.

 I originally thought the hull was aluminum but a closer reading states it was steel and aluminum was used for the non-hull construction

[Ric Gillespie]

The web page for the Alcoa, TN plant (https://www.alcoa.com/global/en/who-we-are/history/default.asp) mentions that in 1937 their aluminum washed for the America's Cup winning yacht, Ranger, built for one of the Vanderbilts. 

The ALCOA site says, "Key to its speed is the world's first mast, boom, and spinnaker pole made entirely of Alcoa aluminum."  Would those be made of ALCLAD 24 S-T sheet?  Probably a long shot, but any excuse to visit Mystic is a good excuse. It's a wonderful museum.

[John Balderston]

We need more data.  Consolidated built the PB2Y at its San Diego.  PBYs and B-24s built in San Diego should also have aluminum labeled in the Franklin Italic font.  The PBY-1 first flew in 1935. If we could find a photo showing labeling on an early PBY under construction, it might match the labeling we see on 2-2-V-1 and prove the artifact COULD date from 1937. It wouldn't prove the case, but it would eliminate a possible disqualifier.

The wonderful San Diego Air & Space Museum (http://sandiegoairandspace.org/) has archival holdings of Consolidated Aircraft, including photos.  Many of the photos have been scanned and are posted on Flickr (https://www.flickr.com/photos/sdasmarchives/).  Knowing we are focused on production in the mid-1930's, I did a search on "XP3Y" and "XPB2Y" hoping to get photos of building the PBY Catalina prototype, and PB2Y Coronado prototype.  Bingo, several good photos of unfinished aluminum.  However, alas, could not spot any ALCOA markings on the aluminum.  Perhaps another TIGHAR can do a more extensive search and have better luck than I.

[Don White]

In my father's collection of yachting books is ON THE WIND'S HIGHWAY, the book Harold Vanderbilt wrote about the building of Ranger. I have not looked at it in years, but I recall it contained many photos of the construction. I will have a look at it next time I visit my parents (late October). As I recall the aluminum alloy was always referred to in this book as Duralumin and was mainly used for the spars.

LTM,
Don White

[Ric Gillespie]

The "AN" in ANA stands for Army/Navy.  All products approved for use in military aircraft had an AN number.  The "A" means the sheet was produced at the Alcoa, TN plant.  A similar sheet produced at the New Kensington, PA  plant would be labeled ANK.  The Edgewater, NJ plant would be ANE.

Here's a new piece of information.  Marking aeronautical products with "AN" dates from specification AN-M-13 published on July 12, 1943 (first page attached), so any aluminum marked ANA, ANK, or ANE dates from after that date.

[Don White]

Happens that my parents' place in Niantic is not far from Mystic Seaport and it's a place we regularly visit. One of my first visits was in the 1960s when a friend of my father's was a curator there. Maybe I can put in some research time on my next trip up there (planned for 3rd weekend of October).

My father, Larry White, is also a retired Coast Guard officer (1943-79) with whom I have discussed the Niku hypothesis and asked questions about Coast Guard procedures at the time (I specifically asked if he ever met or heard of Warner Thompson, but he had no recollection of him). His final two assignments were Chief of Search and Rescue and then Chief of Operations at USCG HQ so he knows a bit about looking for lost people. There are some interesting parallels -- his first command was building a Loran station on Baffin Island. He had also given me David Binney Putnam's two books about going to the Arctic to read when I was about the age David had been when he made those trips. He is an experienced celestial navigator (published author on the subject), fluent in Morse code, and former private pilot. I wonder what light he might be able to shed on anything -- what questions TIGHARs might want to ask -- while he is still around to answer them. He is 92 and not in great health.

LTM,
Don

[Jeff Lange]

Bless your father for his years of service! My late father served aboard the USS Wakefield- the largest transport they had, from 45-46 when he mustered out. Coasties never get the credit they deserve for all they do! Semper Paratus!