Ok. guys..I have a "blonde" question..(mind you...I AM blonde!!!)

I am about to purchase the O.S. Surpass II an .50SX engine. I would love to equip them with aluminum spinners. I found out that the crankshaft is 1/4-28 size, but...do I buy a 2" diameter size spinner or 2 1/4" size??I assume this depends on the propeller size right??
Can you guys educate me here please

Thaaaaannnkkkk you very much !!!

I am not sure but I understand it has to do more with the cowl of your plane, whichever diameter fits it better.

dutchalltheway,
The size of the spinner is more often then not dictated by the plane that it is mounted on, not the size of the motor or the prop used. You'll need too look at the instructions for the plane you are planning on and get the spinner size that is recommended there.

Hope this helps

Ken

1/4x28 is a very commom propeller shaft nut size and a wide variety of spinner sizes will work. It depends on what looks right on your plane. You can even leave the spinner off completely if you are flying something like a scale Piper Cub, which just looks wrong when it has a spinner. Just make sure that the no part of the prop blade makes contact with the spinner. Cut the blade openings bigger if you have to.