Just want to leave this here just in case any other owners have any input regarding my on going research on this rare watch.
I would love to hear from anyone who has one of these watches which was invoiced to Wittnauer (USA) on the dates 2nd of May 1930 and the 10th of April 1931.
I recently bought this watch after seeing it on eBay, I immediately thought it was something quite special even though it had a few issues like the obvious condition issues and the mismatched numbers. These issues did not bother me as I could see it needed just the lightest restoration which I really enjoyed doing.
The mismatched numbers did not deter me as I could see the rare SC 18.69 movement could only really belong in one of these watches. Condition ( not dressed up for sale) and the word SOLAR on the dial also told me that this was indeed a proper rare and very cool tool watch and like many military or tool watches mismatched numbers are the norm due to mass servicing by the military.

So the good news from Longines was that both case and movement are from the exact same batch (April 10th 1931) I have been in contact with three other owners who have SOLAR dial watches and two others also have mismatched numbers and all are from the same batch or the earlier batch in 1930.

What all watches have in common apart from the word SOLAR on the dial and the invoice dates is a number scratched inside the case back in the exact same place. My number is 20 the highest number is in the late 40s.
So I believe there were at least 50 of these watches invoiced to Wittnauer USA in 1930 and 31 the watch from the earlier batch also has AC 45 engraved on the outer case back which I believe stands for Air Corps (pre USAF) Who else in this era would require so many of these aviation watches?
So there is not one reason for me to believe any other at the moment but would love to hear from other owners.
Below are random photos of the light restoration.
Cheers, Michael

 

I think @Seiji could shed some light on these models due to his investigations of similar watches used by Japanese Naval pilots.

 

Hi Jim,
@Seiji has already seen this one

I am particularly interested in the Wittnauer invoiced watches from the 2nd of May 1930 and the 10th of April 1931 to see if any more of these watches have numbers scratched on the inner case back and maybe some more information regarding the provenance and to see if I can pin these watches down the the US Air Corps 100%.
Thanks, Michael

 

I think I have only seen three of these. First one was on Krantz Estate Jewelry and this is the second one I have seen.

 

@Seiji
Thank you!
This is one of the watches I have seen and have been in contact with the owner. the number is scratched (40) into the inner case back on this one and is from the 2nd of May 1930 batch.
Thanks, Michael

 

Sorry, not much help. From memory, the Krantz Estate one also had the same handwriting as Totaro's watch. Yours in all caps is a little different, not that it matters since they all have the unusual stamp on the backs of them. And I am of the opinion that the watches got regular service at the military depots at the same time so the movements often got mixed up with different cases so it is not a big issue with these watches.

I still find your restoration amazing [unless you are a watchmaker in which case nice job ]

 

Thank you!
No watchmaker but just a very careful and interested tinkerer really. I get more enjoyment out of the watches that way.
Thanks, Michael

 

Have you already tried MWR ? Air corps was founded in the mid 1920's, as far as I know. My understanding is, that they did mostly Maintenance and Training of Pilots. Which makes sense here, Navigation was essential . Are there small numbers on the outer rims of the middle case, bezel as well ? Great buy, Michael ! You became a Guardian of history....

 

Nothing constructive to add, but I saw this watch on eBay and I am glad that it has been sympathetically restored. Thanks for sharing photos of the movement and dial!

 

The problem is that the watches were being tested at North Island for the USAAC. The records are not on line. My friends in Washington DC can't find them.

 

Herés the North Island base and pictures of a watch they used. Also another Solar. The nav kit used at North Island View attachment 1573208

All the evaluations are at North Island at this time period because...that's right. P.V.H. Weems and Harold Gatty are in San Diego. It's more than just testing watches, it's the computers, the almanacs, star charts, refining the techniques, and the teaching classes.

 

Very interesting timepiece. Thank you for sharing pictures and info

 

Hi Achim!
Yes, a member on MWR spotted this watch on eBay too and started a thread on there which I gladly joined. Will check for numbers when I get a sec.
Cheers, Michael

 

This is great info!
It’s the first photo I have seen with someone actually wearing one of these watches also.
Thanks, Michael

 

It's actually a recruiter documentary from 1930s. Made at North Island. Details complete Army Celestial Training course outline. Harold Gatty appears in it.

 

That is the main reason you never see an Army soldier with the watch. Don't think the Army bought many of them since the A-11 came quickly afterwards

 

Have you seen this thread?

https://www.mwrforum.net/forums/sho...nes-Weems-Sidereal-Time/page4&highlight=weems

 

Wow, no not seen that thread, epic knowledge shared there
I had a skim through on my phone but will get a coffee and my laptop on tonight and have a good read.
Thank you!

 

I don't know if you came across the Army Avigation film at Rockwell Field North Island San Diego
I posted it in another thread. Might be interesting, might not. I think it could be related to your watch
if it is indeed Army Air Corps. Shameless self promotion of my own watch too

https://omegaforums.net/threads/anyone-have-a-historical-watch.145564/page-18#post-2148186