I.D. Help Requested

[Rampboss]

Wooden propeller – 83-1/4” long with the following data lightly stamped or burned into the area near the hub. The steel splined hub with 8 bolts is attached. No mfgr. name found. It has metal leading edges complete through the tips of the blades, red tips on the blades. Wood is a dark natural finish.

Model 83AA58 or 68 or maybe even 66 (very hard to decipher)
Ser #72869
HP185
RPM2550
ATC586 or 386

Any help you could provide would be appreciated. I have no provenance for this item whatsoever except that it sat for years on the floor of a motorcycle repair shop in Southern California. It is not in terrific shape but it is representative of ??? I acquired this prop in the mid-90's.

Rampboss
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[Dbahnson]

I think it's a Sensenich propeller, even though it doesn't show up on their model listing page, but I also think it's an oddball of sorts. Out of all of the Sensenich models only 2 of them are 83 inches. The "ATC586" is the Type Certificate number, which appears on quite a few of the Sensenich props, but does also appear on the only 83 inch model.

The suffix number (indicates pitch) must be 66 since the type certificate range begins with 67" and goes down to 58". A pitch of 66" would be considered "coarse" for that model and more likely used in a cruise (vs. climb) type of performance.

See the attached page at the bottom, where it shows an 83AA model. I notice that the hub dimensions are similar to the other TC586 models except that it is 5 1/4 inches thick. The #3 footnote indicates that the approval expired in 1956, but the serial number is consistent with a manufacture date between 1932 and 1942.

So my opinion is that it was manufactured by Sensenich but that it was made in very low numbers, perhaps for some special usage. I doubt that you can identify it further, but you might try contacting Sensenich directly.