Need help with ID of this beauty!!!

[Collectionaire]

Please help identify my propeller

Stamped Not Airworthy

86 1/4
8 holes
Leading edge metal
6 plys
Stamped "8529"

Thanks so much everyone I LOVE this prop. So beautiful!

[Collectionaire]

Hub diameter 3 1/4
Hub thickness 4 inches
Bolt diameter just under 3/16ths

[Mtskull]

Firstly, a disclaimer: I am by no means a wooden propeller expert but I have some knowledge of the subject and I am happy to compare the specifications of your propeller with information that is in the public domain, on this forum and elsewhere.

Regarding your propeller, it has obviously been rejected at some stage in the production process and, as such, may be missing some markings which it might otherwise have received. It is also difficult to be certain as to whether dimensions such as the centre bore diameter and the bolt size etc. can be relied upon because we can’t be certain if these were made during the production process or added later for display purposes.
That said, the centre bore appears to be factory standard, so I will work on the assumption that the propeller is in the condition in which it left the production line.

Your measurements and photographs are very helpful, especially the last photo which includes all the bolt holes and a tape measure. From these we can tell that:

-The propeller is Right handed; i.e. it turns clockwise when viewed from the cockpit.
-The centre bore diameter appears to be slightly under 3 inches (this is the dimension which you give as hub diameter. I am not including the chamfer at the opening).
-The bolt circle diameter (distance between centres of opposite bolt holes) appears to be between 5 and 5 1/2 inches. (If you could measure this it would help).
-The hub thickness is 4 inches
-The bolt hole size is c. 3/16”.

I am going to disregard the bolt hole size, as it is clearly far too small to be the final size; most likely the propeller was rejected at a stage of production after the “pilot holes” of the bolt circle had been drilled but before they had been drilled to the correct size. This does not affect the bolt circle diameter measurement.

All of the information available is consistent with your propeller having been intended for fitment to a Curtiss OX-5 engine, in a tractor, rather than pusher, configuration. This does not narrow down the possibilities very far as to which aircraft it might have been intended for, as it was a widely used engine. A search of Wikipedia should provide you with a list of possibilities.

I hope this helps

Andy

[Dbahnson]

I agree that it was most likely rejected at the factory, carrying a production number of 8529 but never being stamped with any certification data as to engine or aircraft make and model or propeller model number.

I think its diameter is too short for an OX5 engine and was designed to operate at a higher RPM. I also think the center bore is larger than used for an OX5 hub. The style, the length and the method of metal sheathing are all consistent in my opinion with a "modern" propeller manufactured by any one of the many companies making them in the 30s and beyond.

I believe it will be impossible to determine a specific aircraft model although some might be eliminated with accurate hub dimensions, which I haven't tried to track down with the rough information given.

Just as an example, the OP should review this page and view all of the models with the prefix of "86" just to get an idea of possibilities from just one manufacturer, then realize that other manufacturers may have had similar sized props for additional aircraft.

[Dbahnson]

Here is a section of the Sensenich data that includes props with 86 inch diameter. Note that some of them have hub sizes that are similar to the OX 5 yet are entirely different application, namely 5 1/4 bolt circle and 4 inch hub thickness. Other manufacturers list similar dimensions. So I think this is most likely a "modern" style propeller, not an OX5 prop.

[Collectionaire]

Could anyone please give me an approximate value of this propeller?

[Dbahnson]

Approximately $300 to $600, but nearly worthless to a collector.

If you love it, you should just keep it.