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Holes on the back of Propeller hub

kjelle69

Active Member
See attached file, I have a Pacesetter propeller which have two holes on the back of the hub, anyone who knows what the purpose of these holes is? Balancing?

One is filled with resin and the otther one partly filled with a grey-ish glue.
 

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I have an aluminum prop with a spacer. There are two locating dowels, on opposite sides, but not exactly between the adjacent holes.

Aerodon
 
If the holes are for balancing then I wonder why are they not symetrically opposite each other? Wouldn't it be more efficient for the prop manufacturer to sand off a teeny bit from the blade rather than drill a hole that is so close to the hub.
I don't know the answer and probably it doesn't really matter other than for curiosity, but I thought that perhaps the holes are tooling holes from the manufacturing process.
 
If the holes are for balancing then I wonder why are they not symetrically opposite each other? Wouldn't it be more efficient for the prop manufacturer to sand off a teeny bit from the blade rather than drill a hole that is so close to the hub.
I don't know the answer and probably it doesn't really matter other than for curiosity, but I thought that perhaps the holes are tooling holes from the manufacturing process.

You cannot balance the prop until it is complete, including the finish. If you sand after finish, then you have to refinish. Now you have to balance again.

See the vicious circle that has started?
 
Wood Props

Ever flown behind a Catto?

I have and flown behind a metal FP as well as a variety of wood props. Warnke’s both Bernie and Margy, Pacesetter, Sterba and Performance Propellers both Clark and Frank’s versions. I can say that they all have there +’s and -‘s but a properly built wood prop has a special feel to them, hands down smoother than all of the others. Don’t knockem till you try’em !😁
 
I think Catto props are made using a wood core(?) so they probably fall into the same category, but I agree with your comment.

I was the first RV-6(A) builder to put one of Clark's Performance Propellers 3 blade props on my 6A in the early 90's. Every other RV owner that ever flew in it with me always mentioned how it felt turbine smooth (and we didn't even know what dynamic balancing was back then)
 
My props are balanced during construction, before paint, in-between clear coats, and after final finish. There is no real need to drill a hole in the hub, and create a point for the hub to start cracking. It's a good idea to inspect that hub for cracks propagating from those spots during your condition inspection.
 
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