All I can say about it is that if you dig deep enough int the earlier Ashby studies, he determines that the ME, or overall mechanical efficiency (basically, everything that goes into a strong, deep-penetrating broadhead design) is highest for straight-edges blades. My own personal problem with convex edges is that after several sharpenings they tend to flatten out and I worry that the two edges will become slightly different in convexity which would affect weight/balance and could affect flight accuracy. That said, I really like the new Eclipse Werewolf and with a Rockwell hardness of 52-54, they’ll be a lot slower to grind down and change shape. dp

I suspect this is one of those things that makes more of a difference on paper than in the real world. If the broadhead is shaped like a spoon, perhaps it may make a real difference. But a profile like an Ace Standard or zwickey Eskimo? Non-issue.

If the mechanics is the same as a knife blade the radiused edge carries more strength at the nose, as the head’s width is carried forward a bit more. In practice most heads of the Zwickey style (Zwickey, Magnus, Stos, etc.) have a tripled nose which gives way more strength than the radius alone. Then you look at other successful designs like the Hill and Simmons that have a negative radius. There is likely a practical trade-off between penetration, cutting, ease of manufacture and plain ‘ol “this looks good”. There is no question that the Eclipse and Journeyman broadheads just plain look good.

I like the straight edges for the ease of setting the initial angles on a S-24 Tru-Angle jig with files. And thereafter it’s easy to “field sharpen” a used head with a file I keep on my quiver. You can also hone a straight edge without the need to rotate the head as it is drawn along the stone. I find the Stos to be “self-jigging” if I lay them on a dummy credit card (the banks send me these regularly).

I’ve got a modest collection of glue-on heads and it’s a good mental exercise to look through them and wonder “why was this designed so?”

Unfortunately, the answer in many cases seems to give a nod to the old bass lure philosophy: a lure that sells well is more often designed to catch fishermen, not fish.