It would be cool to be able to see the force of your arrow. However, I'm not sure using it to determine if your arrow has the force to kill a particular animal would be practical. Who and how do you determine that? I'm not being sarcastic about this. It's an honest question.
I wasn't suggesting that is would be some kind of computer capable of taking into account all variables. It would just be used as a guideline for a minimum.
For instance, NY state says to hunt big game, you must use at least at 35 lb bow. Well, as we all know, this may or may not be good enough. For instance, a 23" draw length is not going to do what a 30" draw length will out of that bow. Not by a long shot. We also know that a 250 grain arrow will not penetrate as well as a 600 grain arrow. These are just two variables that are completely left out of the minimum requirement, yet have great affect on the effectiveness of the 35 lb bow. Sure, there are other very important variables like broadhead sharpness, and FOC, but this device could give a good basic guideline on the force needed to at least think about hunting a particular size animal.
Ashby's main point had to do with what he considered penetration. To him, it was passing thru the medium. However, as long as you strike vitals you do not need to go thru the animal.
Well, the arrow has to go through at least one side of the animal. Ashby's tests had nothing to do with what was required to kill an animal. They have to do with arrow penetration and broadhead toughness. As far as I know, all measured results came from dead animals. Some animals probably had multiple shots put in them to bring them down. The shots that didn't even pass through a rib, probably had nothing to do with the death of the animal, but they were shots he could record if the animal was eventually killed.
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Yeah, it's a good device that shouldn't have been laid aside. But it was totally forgotten when the chronograph was invented. Companies that marketed the penduluum have already come and gone.
I think you're right about the "come and gone" part. I doubt many would buy it, in this day and age of "speed".