What size spinner should I use for a Ryobi with a 18x8 prop ? Would a plastic spinner be ok or should I use aluminum ?


Thanks
Jim

3" plastic will do....lot's of carving tough...
Depends on the prop...some have a bigger hub, some smaller..

You need to size the spinner to the plane and not the propeller.
Why size backplate will work with your cowl?

The plane is a Dynaflite 1/4 scale Fly Baby


Thanks
Jim

Sounds like a 3" spinner is correct.

Big ol' spinner cone on a Fly Baby? I don't think so. A spinner nut would be much more appropriate on that plane. In any case, I try to use a spinner nut whenever I can. It's cheaper, lighter, tougher and much easier to change props. Best of all - no carving necessary.

JB: The hub nut made sense for me. Did one 3" plastic spinner for 16-8 MAS Classic and ended up having to notch 2 of the posts to get it to fit. It will probably be my last.

The hub nut I made from 1.5" dia G-10 1" length -drill and tap, put on mandrel (long bolt) put a taper on front .375" from 1.5" to .9375") ; true up exterior for any non-centering of bore.
Two .190" holes to take 3/16" music wire tightening bars offset.
drill press, die grinder w/cutoff wheel. tap set

Volfy nut is very nice and would do the same if I had the tools.