ORIGINAL: Sylvan
I'd love to see how you calculated it, but it matches what I have seen elsewhere
Actually it's pretty straight forward. If the bow is a 30" draw and an 8" brace height then the power stroke is 20 1/4 inches or 1.69 ft. If you pull 70# over the entire power stroke which gives the absolute maximum stored energy possible
Ahh, there's the key "over the entire power stroke" which means the force/draw curve is a flat line, no build up, no let off. So in this model the only way to raise energy is to increase the power stroke, so DECREASE the brace height. Like I said, "unshootable" [&:]
I've read about designs in arrows to increase penetration, basically a small weight in the shaft that when the shaft hit the target, the weight would slam forward giving it a secondary kick into the target.
Personally I think the biggest detraction to getting into bowhunting today is the cost, hard to find a bow for under $250-$300. Very easy to find a "not top of the line" bow for $700-$800.