Pat, they used two woods at most and that is ash and poplar. Poplar does seem to be lighter, though if you weigh two shafts of the same measurements you get only about 5-10 grams of difference, which does not seem to be that much. I think that poplar main advantage is very low hysteresis, which causes it vibrate different than ash and thus fly better. The same reason makes oak very muggy shaft.
Anyway - they did not spined arrows even until post 1900´ or some as proper understanding of spine came in pre WW2 era, but they judged stiffness of arrows empirically by the weight of the shaft (and eventually diameter).
With warbows spine is not much of concern, the main problem is to have an arrow stiff enough - which does somehow just about work with the diameters of preserved arrows, give or take.
A 3/8´´ shaft works well from some 75# up to 100# where I think starts to be somehow weak, unless you sellect harder wood specifically, then tapered 1/2´´ is needed for bows up to 120# or 130# with rather long taper to nock and the heavier bow above that weight the less of the taper to nock (means longer mid portion of the bow is paralel).
I had some 12 mm (which is not yet 1/2´´) from very dense ash, which was from core and somehow green in collor and both Mark and Joe thought it was enough stiff for 150# and more. I have noticed that in soft materials they penetrate better than full 1/2´´ because of smaller diameter.
I think that decent penetrator for 100# would be around 12 mm in 2/3´´ of the lenght to front, 10 cm of paralel shaft there , and tapered down to 3/8´´ nock (or rather 9 mm) and tapered to 10 mm where the arrowhead is fitted. This way it wont need to cut so big hole to go through.
I would only make them around 75-80 gr for 100#.
This is what I m now making for Berkelley for myself.
Jaro
