I think I remember that part in the grail quest books. I have to say though that bitching about how good things were in the past is a peculiarly British pastime and I'm sure that Cornwell was using the scene to make a 'plus ca change' point. Another author who does the same is Julian Rathbone - especially in 'The Last English King' which is a great read which I can heartily recommend.
I've been wondering about something for a while which was restimulated by your post. What if they didn't put the heaviest heads on, but the lightest possible ones?
The thought goes like this. Drag is mostly produced by surface area of an object which is defined by radius squared. Mass is produced by volume which is defined by radius cubed. In some aquatic animals, for example, this produces a selection bias towards increased size because the extra volume you get contains a lot of muscle which is acquired for not that big an increase in surface area, and therefore drag. The result is that big aquatic animals are fast, and the blue whale, for example was only hunted from the 1930's onward for that reason.
As with aquatic animals, so with arrows. The increase in mass should come at the expense of smaller increases in surface area, and therefore drag if you make them bigger. The problem is that with a tip heavy arrow with a big head on it, eventually, the tip will drop and the drag then goes up markedly as the length of the shaft and fletches come 'face on' to the direction of travel.As Hardy pointed out, the calculations at the end of the book didn't allow for attidudinal changes in the arrow.
Now, to my mind, for a galling arrow, the head doesn't need to be heavy, just strong enough to withstand the impact and hard enough to concentrate all the force at a point without deforming so that it has a chance to go through. Ascham said that ash was the material of choice because it gives a hell of a whallop (fierce heavy stripe is how I think he put it), which to me indicates that the job of providing weight to the arrow belonged, perhaps predominantly, to the shaft. We also have an indication that fletches were 'long and low', from a welsh poem about a medieval chap saying what he'd need to shoot a really strong shot (yew bow, girlfriend nearby to impress and a few other bits and pieces). I'm not at all a fan of using art of the period as too much of a guide because those guys had some real problems with scale and perspective - but some depictions of arrows do look as if the fletches com a a long way down the shaft.
Where all this is going is that the trick might not be to add a heavy arrowhead- it'd be to use heavy wood and control the attitude of the thing in the air so it presents as little as possible of itself for as long as possible, as big aquatic animals do. What about taking the heaviest shaft you can find, put a bodkin head on which is strong enough to do withstand the impact without deforming, but no more, and experiment with 8.5inch fletches in terms both of height and position on the shaft? It'd still weigh in at over 1000grains and might travel a long way.
I'd be surprised if this hasn't been done - its just that I haven't heard about it and I'm curious.
C
