I have a CG skytiger, that originally didn't have a cowl, but I made a cowl for it. Goldberg recommends a 2-1/4" spinner, but my cowl's diameter at the front is about 2-1/2". I want to know if using a spinner that isn't the same diameter as my cowl makes it a lot less aerodynamic? I'm using a OS 46fx, can I use a 2-1/2" spinner on it so it's the same diameter as my cowl?

Thanks, Brian

Wether or not the spinner matches perfectly, the plane will always be aerodynamically cleaner with a cowl, than without one...

If the forward edges of the cowl are rounded into a sort of airfoil'ly shape it's going to be as good as any, spinner mismatch or no.

Using a larger cowl, won't negatively affect your aerodynamics. If anything - it'll decrease your parasite drag.

Sorry akpilot, but a larger cowling will give you more drag due to the increased frontal area and wetted area.

Hey Someone11, where do you fly? I live in Fresno also (Clovis actually) and I usually borrow Buchanen's fields for my gliders or a farmyard for my little electrostreak. Anyways, most spinners I've seen are smaller then the engine's cowling, so I wouldn't worry about it.

Dan Nelson

Someone, use whichever you think looks better. It won't make any difference aerodynamically that you can detect.
Good Luck.

I fly at the FRM airfield in Madera. Here's a link to their website: http://frmmember.freeyellow.com/


I flew my skytiger last weekend with a 2-1/4" spinner and it worked fine. The fact that I have a cowl there instead of the "cheeks" made a difference, so I don't believe I have to worry about the size of the spinner lining up with the cowl.

Thanks for your help guys!

-Brian