Slo-bo

Good question, BobCo, I was just talking about this with a friend this past weekend. I had a number of different arrows of different weights and speeds, all with field tips, and shot them all several times into several different target mediums, in unshot areas of the targets. Not any kind of scientific test, obviously, but I was curious how speed and weight factored into penetration. I assumed that the arrows that had the most KE, according to the charts, would have the deepest penetration. I found in fact, that the lightest, fastest arrows penetrated evenly, or sometimes a bit deeper than the heavier arrows. Now granted, there wasn't a huge difference in calculated KE, but enough that I assumed there would be more of a difference. I also realize that shooting into a dense target is different than shooting into a live animal, and that there are factors such as larger arrow diameter equaling more drag in the target,(this is just an assumption on my part, I shouldn't be surprised if I'm corrected on this!), and of course, actual penetration in/through an animal will rely heavily on the type and sharpness of the broadhead used. In my opinion, in most cases, once you have reached a certain speed/KE, it becomes somewhat of a mute point, it's more a matter of how deep in the ground the arrow will stick on the other side of a pass-through shot.
As far as factors in actual penetration, much will affect this. A perfectly tuned bow, with the correctly spined arrow, and a super sharp head, would certainly give better penetration than a poor set up. If I remember correctly, you shoot traditional also,(or exclusively?), so I would be interested in knowing about KE=ing penetration in slower arrows. I look forward to the replies from this post, good one!