ORIGINAL: MJD
As to an increase in rpm, yeah that might be true with a good, small aluminum spinner on a 1/2A, but I bet you dollars to donuts (whatever that means but people say it) that with a plastic spinner you'll see zero gain to a loss on one. Just my call, others feel free to prove me otherwise.
I haven't weighed a spinner and compared it to the weight of a 1/2A prop, but I'm guessing it would add 40 to 60% to the rotating mass. While this might help smooth out the engine at idle, it will retard acceleration and require power to keep the spinner rotating. If mass were good, we wouldn't be using small aluminum prop washers, we would be hanging fat fender washers on there anticipating that additional rpm gain.
Don't you big engine car guys dump those steel flywheels and replace them with the lightest aluminum flywheels that will work? With the size engines we run, any power robbing addition has an impact -- I'm not sure that drag reduction will be enough to compensate.
Just my call, others feel free to prove me otherwise. BTW, I don't have any donuts.
