Spinner size ?
 

How do you know what size spinner to get? I picked up several spinners at the Perry GA swap, but none of them fit with my prop (even though they appear to be the "right" diameter)

Thanks</p>

RE: Spinner size ?
 

Typically you choose a spinner diameter that fits the front of the cowl on a cowled plane.
Also it used to be a performance "rule" that you don't exceed 25% of the prop diameter for the spinner diameter. Otherwise you would be covering-up the part of the prop that makes the power. For example on a 10" prop you would want a 2.5" or less diameter spinner.
As far as fitting the spinner cap/top to the prop, it depends what type of prop you are using. Some props fit in the stock cut-outs while others need the cuts-outs enlarged to fit around the blades.

RE: Spinner size ?
 

With a cowl, the spinner size needs to flow into the lines of the cowl. Without a cowl, use whatever looks good to you.
Since a certain size spinner may be used with a little prop or a big prop, they make the slots pretty small and you may need to open them up.

RE: Spinner size ?
 

Other then ordering a pre cut spinner for the size prop I'm going to use I have never had a spinner I didn't have to open the slots myself. Takes about 15 or 20 minutes with a moto tool.

RE: Spinner size ?
 

Spinners are cut to fit the smallest possible prop; or not even that. You have to open out the holes to fit your prop.</p>

RE: Spinner size ?
 

You can get big bird spinners. In other words same diameter spinner but the slots are cut bigger for the prop

RE: Spinner size ?
 

Don't worry about spinner size versus the prop size. As long as you have at least 2/3 of the propeller exposed, you'll be OK. The inner third of the prop is mostly there for the ride, and to support the outer two-thirds, which do the actual work.