[MR] Heavy Helms and inertia

[Towey, Brian]

I don't know of any crash test dummy experiments to measure "protection."
It might be fun to try, though.  

Here's a thought experiment:

Roll a billiard ball across the table and squarely into another ball just
like it.  The first ball stops and the second rolls on.  Momentum is
conserved, as always, but it's transferred from one ball to the other.  

Now, roll the same billiard ball into a bowling ball.  It bounces off.  The
bowling ball may roll slowly, or it may just rock a bit, depending on the
table surface.

I want the sword to bounce off my helm instead of stopping while my head
rolls across the field.

Failing that, I want the sword to expend its energy crushing something
besides my head.  Like rolling the billiard ball into a feather pillow, to
continue the analogy.

I used the example of equal sized billiard balls, but the equality isn't
necessary for momentum transfer.  Compare, for example, the effects of
swinging a golf club against a golf ball compared with swinging the same
club against a keg of beer.  Or, crashing your car into a bicycle vs.
crashing your car into a cement mixer.  The biggest mass always wins.

-Charles Fleming
12 ga. great helm over steel cervelliere and coif.