Wooden Propeller found in CA barn

[dmitchel]

Hi
I need help- this propeller was found in a barn. I have no idea what it is off of or who made it, or year of manufacture. Any help I can get would be appreciated.

[Dbahnson]

It might be a dirigible prop, but I can't identify it.

[dmitchel]

Thank you. Any idea what the numbers mean? And could the U.S.P. be a manufacture?

[Dbahnson]

One is probably a serial number and the other likely a design number, but I have no references that show anything that even resemble that nomenclature, which further makes me suspect that it is more likely a dirigible. (For whatever reason, some of the dirigible props I've seen have been painted silver.) The USP may be the manufacturer (U.S. Propellers, which made a lot of drone props, also made quite a few props for certificated aircraft) so that's a possibility although I suspect that the stamping is that of an inspector, perhaps inspector number 2 at whatever manufacturer he worked for.

[dmitchel]

What horsepower engine would this 12 foot propeller been used on? Thank you again.

[Dbahnson]

What's the diameter of the bolt hole circle? That might provide a clue.

[Bob Gardner]

Good Morning Dave,

Twelve feet is an enormous diameter, rarely used, except on a few airships and German giant aircraft of WW1. But none of them look like this one.

I wonder if this prop might not be helical in design? In other words, that it will not screw its way through the air?

If it comes from a drone aircraft, twelve feet diameter would suggest an enormous target drone. The British once used radio controlled DH Tiger Moth aircraft in this role (called Queen Bees). These aircraft had a prop with a diameter of around six feet. Perhaps American gunners needed larger targets than British gunners! (I meant to add a smiley here to indicate my joke but I've failed!)

If the prop came from a drone or from a farmers' mill used to pump water for irrigation it would probably not need brass sheathing on the blade leading edges. Similarly, nor would a prop from an airship or dirigible.

It is beautifully constructed from laminations which rules out any decorative function such as advertising or as a mock up for the film industry.

I remain baffled!

With kind regards,

Bob