BB for sure in terms of performance efficiency spinners make a difference however I have my doubts that with our models airplanes and the speeds we operate them at among other things, I doubt most of use could tell a real differance. They may acturally affect the sound but not sure how big a change that would be.

I like you actually prefer with many of my airplanes to use spinner nuts and reccommend them to most sport flyers.

There is one factor though where spinners can make a big difference and that is cooling. On any cowled and specifically a tightly cowled installation the spinner can be an important component of the cooling system.

Here is an example of one of mine that that I beleve the spinner is an important part of the cooling system:

John