I was talking to my cousin and he was saying that when shooting a 2blade broadhead cut on impact that you have to use a straight fletch and when using a 3blad broadhead you have to use helical. Is there any truth to this?

Not that I have seen. I shoot helical regardless. My arrows fly like darts with either broadhead.

Chad

I use helical on every arrow I make, irregardless of what tip it has.
I would think that a two blade's possibly greater tendancy to plane would mean that helical would be even more important.

Guy

In short - nope.

Helical always stabilizes anything better. Think about the spin put on a bullet by the rifling of a gun barrel. Now think about what that bullet would look like with no spin.

BS.

Helical is the way to go. You can vary the amount of offset, but stick with helical.