Over-achiever fin fillets?
I see a lot of high-power rocket build threads where the builder shows off the construction of ample-to-monstrous fin fillets. So far, I have refused to do this if I’m able to get ample epoxy inside between the motor mount and airframe.
So I don’t want to shed fins, either, but my meager understanding of aerodynamics says that fillets can actually have more drag than a 90-degree butt-joined airfoil on a round fuselage. Case-in-point, the F4U Corsair’s bent wings eliminated the need for fillets by joining at 90 degrees (while giving good prop clearance with short landing gear). I looked at pictures of the X-1 and X-15 and they appear to me to have tiny, if any fillets, too.
So what gives? Is this tribal knowledge gone out of control or do the standard rules not apply at smaller scales?
-Ron