Propeller ID. Sensich?

[cwspilot]

[I] have a prop off my dads old Stinson 10A. It was in a Sensich box. Its wood and painted.
The numbers I found:
A20066Y
72 KA 49
TC 802
PC 406
What do I have here? Year made? Pitch? Etc?

Thanks

[MWP_Lamar]

Unfortunately I don't have documentation on this exact prop. What we can know is that the "A" prefix serial indicates it was made between 1932 and 1942.

Sensenich props are stamped with a number known as a drawing or design number. The logic of the design number sequence is the first number is the diameter (length) in inches, the middle letter(s) designate the engine and perhaps the hub design, and the final digits are the pitch. There are a few exceptions to this logic but I seriously doubt this is an exception.

From this we know that your 72 KA 49 is a 72 inch prop for a Lycoming O 360/180 engine (the letter "K") and has a pitch of 49 inches. The "A" hub design was used on Stinson aircraft but as I said I cannot document this exact case. Hope this helps.

Lamar

[cwspilot]

Awesome

This is more information than I had (zero).
Thanks for your reply Lamar.
Based on the pitch, would this be a climb or cruise prop?

[Dave]

Actually, that's not a typical Sensenich serial number, and the Type Certificate (TC802) is listed under the Flottorp directory, although that particular type certificate includes several other models of various lengths and pitch. Since the pitch range for those type certicates range from 39" to 57" your pitch of 49" is more or less in the middle, but very slightly towards the "cruise" end of the scale.

I don't think you can rely on the serial number as indicating the date of manufacture, as those records only apply to Sensenich numbers, but it looks as if the type certificate expired in 1948, meaning that ones manufactured after that date could no longer be used on certified aircraft.

P.S.

I just noticed that the model is listed on the Flottorp page under "Armour Coated" propellers.

[MWP_Lamar]

Dave is absolutely right as usual. If it's not a Sensenich prop then the info I gave you is 100% dead wrong! That info only applies to Sensenich props. I proved again the old axiom concerning assumptions; I assumed the "wood" and "painted" referred to the box rather than the prop.

Lamar

[cwspilot]

Thanks for the info

The reason I thought it was Sensenich Prop was the box it was in. I remember my dad replaced the prop on the 10A for a more cruise efficient prop. Maybe that was the Sensenich.
Thanks for all your help

[Dave]

Sensenich also reconditioned many props from other manufacturers. They moved a lot of boxes around in doing so.