Measuring stored energy is kind of a pain. But if you are interested in knowing where your energy is going it really is a necessity to get a fairly accurate reading of how much energy your bow stores. I am going to propose a simplified method for fairly accurate assessments. One person doesn't really make enough bows to supply enough data so I am asking the community here to help us out and see what we can come up with in a short amount of time. The method I am proposing involves taking one simple draw weight measurement at exactly one-half your draw stroke. Example: bow draws 50# @ 28", bow has a 6" brace height. So the power stroke is 22". So we measure 1/2 of the draw stroke plus brace height equals 17". This is where we measure the weight.
If someone here knows excel they can track this for us and give us the data. Before I go into detail, I want to show what I am thinking it will produce.
Measurement @ 1/2 draw, Stored SEPDF Backset style Bow Length
50# bow, 28" draw Energy
22# 40.3# 80.6% -1" straight 65"
23# 42.06 84.1% -5" straight 64"
24# 44.00 88.0% 0 R/D 65"
25# 45.80 91.6% .5" R/d 67"
26# 47.6 95.5% 1" recurve 64"
27# 49.5 99% 2" R/D 67"
28# 51.3 102% 3" recurve 66"
29# 53.1 106.2% 3" R/d 74"
30# 55# 110% 6" recurve 65"
These are just theoretical examples of what I think it will look like. If we can get in about 100 samples from the crew here we could establish a credable data base to figure where we were at and what the different numbers might mean to an everyday bow maker.
The info I will need is . Draw weight, #" at 1/2 draw. bow length, style and back set. I will probably add some optional rows just for reference.
