Please help with prop info!

[Junglemike]

Greetings to all,

Thank you for your interesting site-I love WWI aviation but knew nothing about this subject-appreciate everybody sharing their expertise.
I curate a small museum and recently acquired a cut-down (unfortunately) prop.
I will share the anecdotal info provided by donor. I'm doubtful of the literal accuracy however it may add something of use.

"...prop was off the first US Air Mail plane. My grandfather was in charge of demolishing the plane and decided to keep the prop to someday put a clock in it for a wall decoration."
More likely it was a first or early TYPE of mail plane. anyway here is more concrete info

Manufacturer-Buffalo Aeroplane Corporation, Buffalo NY.
length (cut down) - 4ft-9ins
width at manufacturers decal- 9ins
Hub bolt holes-8.
7 layer laminate

markings:-
first blade- numeral "1", underneath it alphanumeric code "86X522.
second blade-numeral "2", underneath it "H" and "S" separated by a "dumb bell" looking symbol. underneath that an alphanumeric "SC 61646". A cloverleaf acceptance stamp is underneath that.
Hub-one side number "1327" and other side "301".

Hoping it was a US military plane before becoming a letter carrier. either way, any help is greatly appreciated.

Thanks.

[Dbahnson]

Not enough there to narrow it down very far.

"86X522" is the diameter and pitch in inches. It was originally 86 inches long.

Buffalo Aero ("BUFFAIRO") produced a number of props for the Curtiss Aircraft Company.

"SC 61646" is a "Signal Corps" number, which doesn't help much in identification.

"H.S." may refer to "Hispano Suiza" or "Hisso" engine, although Curtiss also made a variety of "HS" seaplanes.

The other numbers are likely production numbers, of little use in identification.

You should see if the hub dimensions match any of the common early engines, which could eliminate some of the possibilities.

[Junglemike]

Thanks for your time and quick reply. I'll do more work on the hub dimensions. Is it safe to say that it IS a military prop given the signal corps serial and acceptance stamp?

[Dbahnson]

Thanks for your time and quick reply. I'll do more work on the hub dimensions. Is it safe to say that it IS a military prop given the signal corps serial and acceptance stamp?

Yes, it was manufactured for the Signal Corps, although that doesn't necessarily mean that it was used by them, but it's a good bet. Some props showed up as surplus and were used in non-military operations, just as some of the aircraft were.

Since it's already stamped A7A the hub dimensions should match for that and matching won't do much except confirm that it's not mis-stamped.

[Junglemike]

Sir, thank you so much for your help and expertise. I deeply appreciate it. By the way, this prop WILL gone on immediate display!