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Old 08-22-2010, 11:22 PM   #1
Big Texas Rock
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Default Curtiss JN-3 Prop?

I took this propeller to an Air Force Historian about ten years ago. He looked up the serial number and told me it was manufactured in 1917. It was made for an OX-5 engine and most likely was to be used on a JN-3. I'm not looking to sell it, but would like a value for insurance purposes.
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Old 08-24-2010, 12:26 PM   #2
Dave
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What are the numbers on the hub? I'm curious how it was determined that it was a JN3 and not another model using an OX5 or a Hall Scott engine.

The first thing to do is measure the diameter of the bolt hole circle. You can do that by measuring the distance precisely from, say, the left hand side of one bolt hole across the hub to the left hand side of the bolt hole that's furthest away from the reference hole. That should give you the distance between centers of those two holes. Is it 5 1/4" or 6"?

More information would be needed to guess at a value, including the above. It looks as if it has been refinished, which is also important to know.
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Old 08-30-2010, 05:25 PM   #3
Big Texas Rock
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Default JN-3 Prop

The numbers on the prop are as follows:

1
OX5
8' x 5' 3'
S.C 41785

The bolt hole diameter is 5 1/4 inches.

My father refinished it while I was stationed overseas. We know now that was the wrong thing to do.
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Old 08-30-2010, 06:14 PM   #4
Dave
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Quote:
Originally Posted by Big Texas Rock View Post
The numbers on the prop are as follows:

1
OX5
8' x 5' 3'
S.C 41785

The bolt hole diameter is 5 1/4 inches.

My father refinished it while I was stationed overseas. We know now that was the wrong thing to do.
Thanks. That always helps. Certainly the OX5 and the diameter and pitch could are consistent with a JN aircraft, but the high "SC" number implies that it was manufactured much later than the brief life span of the JN3, although I'm not sure there is any way to be certain about that.

I wonder what it is about it that he thought made it fit a JN3 instead of the later model JN4.
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Old 08-31-2010, 06:10 PM   #5
Big Texas Rock
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Default JN3 Prop

He said according to the serial number it was manufactured in 1917 and, if I recall correctly, the S.C. stood for Signal Corps. I'm not sure where or how he got his information, but he was the base historian.

Further info: It has no marks around the hub to indicate it was ever mounted on an aircraft. The leading edges and brass plates are immaculate.

Thank you for all the help and information.
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