dory

[PMBardunias]

I think I would suggest that if I was to stand face to face to someone, largely covered in "copper-alloy", I would want a heavy short spear I would need to hold at the balance point.

I might wish for more length if fighting in a line with overlapping reach of spears and at least a second rank of possible impalers. Taken to its limit we end up with sarissa, but in such formations, reach can be an advantage with the right tactics- just as short weapons can with very different tactics.

I would explain I could give him a heavy, stiff parallel sided untapered shaft, but it would be as hard to make as a tapered shaft and would actually be lighter. If the gentleman insisted and said he had read that an untapered shaft was heavier, I would have to explain that if the spear head has an external diameter of 25mm, I could tamper the shaft to around 30mm towards the butt. The extra wood at the butt end would help the balance and add a little weight.

Two things are getting mixed up here I think that may confuse some readers. A tapered shaft is always lighter for any given strength along the long axis. That is why it is a tapered cone, distributing force back and not simply an abrupt change in diameter- like a pilum made of wood. Tapers suffer from lateral stress though. But the second reason for a taper is balance as you suggest above. Thus, given the same spearhead, your tapered shaft is heavier (the diameter starts out equal to the parallel shaft at the socket, then widens) but the balance point is moved rearward. In this function it is simply a proxy for rear weighting with a counterweight.