View Full Version : Questions on SC #'s and marks.

02-01-2016, 12:44 PM
Hi all,

A couple of questions regarding SC numbers and marks.

I recently came across a prop remnant on ebay that looks similar to mine. (Photos below)

1) Has anyone ever seen Signal Corps. numbers listed in an inventory sheet? If so, were they attached to anything like, manufacturer, model #, engine, or such?

2) Just a thought, but seeing how the stampings are the same on the mfg's # in the hub area and the SC# and square on the blade root, I'm thinking these were both done at the same time and by the mfg. This seems to be the same on a number of different props I have seen photos of. The mfg. stamps are the same type style as the SC#. Can one put forth the idea that SC#'s were assigned with the contract to the mfg. Say, a company got a contract for 100 units and were assigned SC 1 through SC 100 and it was the mfg's job to stamp the props?

3) The sharp knife-like stamps on these two seem to be an exact match. If the above is a possible scenario, then one could think that these two were manufactured by the same company and were only 112 pieces apart ( SC9876 and SC9988 ) I'm assuming the same mfg because of the same stamp profile and placement.

3) Does anyone know if that square below the SC# was an inspection mark, and if so, if there was anything inside it. I can't make out anything on either my prop or the other in the photo.


02-01-2016, 06:28 PM
I can't answer your question. I haven't ever found a correlation between Signal Corps numbers and any relationship to its application, but that's not to say that one doesn't exist. They always seemed more like a serial number than a design number, but whether they were assigned in clusters is a mystery to me as well.

Most of the other small stampings seem to be inspection related. Even the Navy anchor found commonly on their props may have simply been a final approval, but more often I think the stamp belonged to a specific inspector and would have either initials or a number included. The British had "A.I.D." inspection stamps. France had "S.F.A." stamped on their props (and other items).

02-02-2016, 11:05 PM
Thanks Dave,

I just figured I'd throw that out there. I saw your airfield inventory pages that showed design number to specific engines and aircraft. That was interesting to see.

Thanks again