Primitive Archer

Bjrogg, You had me at tea pot. That's got to be the best title I've ever heard!

I love your short bows. Top notch stuff. Very inspirational.

   In southern Ca. we have a lot of Chinese elm. Great bow wood but hard to handle. It works easy enough once split but almost impossible to split. The wood looks very similar to the American varieties.

Nice bow BJ. I like it!

   Virtual mass is easy to calculate. It helps if you know the stored energy but if you don't you can usually get it by shooting a few different weight arrows.
Here is how to calculate it. His bow shot 256 fps with a 463 grain arrow. You go to a KE chart and look it up It shows 67.39 ft pounds. Lets say I estimate the bow is storing 93% of draw force. So it would be 93% X draw weight ( 98# )  That would give me 91# of stored energy. So now I simply add enough imaginary weight to the arrow that we know the speed of which is 256 fps to give me 100% efficincy. On the icase if I add 160 grains to the 463 grain arrow and then check the ke at 256 fps it will give me about 91 Ft#. So to check speeds of arrows I have not shot simply add 160 grains to the arrow I want to the know the speed of. So if I want to know how fast a 320 grain arrow would be I add 160 to 320 and see what speed gives me 91 ft#. So 320 + 160 + 480. How fast would a 480 grain arrow have to be to get 91.  The answer would be 292 fps.

   I am guessing at the stored energy in this case because I only hvae 1 arrow sample. If I had two samples I could be a lot closer. A 250 grain arrow should do about 316 fps.

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Bjrogg