Just had a look at this very interesting video by Tod of Tod's Workshop comparing the very old windlass crossbow with a 950 pounds of draw weight and a modern compound crossbow of 150 pounds of draw weight and the effectiveness of the heavy bolt's momentum versus the much higher velocities of the light modern crossbow bolts

https://www.youtube.com/watch?v=ghoVmc12vEs

The heavy crossbow bolts have a lot more momentum even if they have less kinetic energy, the depth of penetration of the heavy bolts is impressive, and avoiding " spoilers " a completely blunt tip on one of the heavy bolts does something surprising.

Hi all and thanks Jean for posting this up.

I am currently having fun messing about with crossbows, partly as crossbows and partly under a series of films called “lockdown longbow”. That has a simple premise that I have a crossbow that shoots medieval weight arrows (not bolts!) at the same speed as a 160lbs longbow. But this film is not one of those...

These films did get me thinking though and I thought I would directly compare a modern and an old crossbow and see what there is to learn and talk about; and here we are.

I hope you enjoy it.

Tod

Hey Tod,

As you said in the video, you found a definite point where the velocity of the light bolt was limited by the inertia of the steel prod.

The obvious conclusion is that high strength steel prods should use heavier bolts to increase energy transfer efficiency and deliver higher momentum. But of course there is a point where the increased mass will be optimal and additional mass does not move fast enough to increase momentum.

An idea for you is to use your adjustable mass bolt and see if you can find the optimal mass for a particular bow. I‘d enjoy that video. Whatcha think? 80-90 grams for that big windlass bow?

Michael P Smith wrote

Quote:

An idea for you is to use your adjustable mass bolt and see if you can find the optimal mass for a particular bow. I‘d enjoy that video. Whatcha think? 80-90 grams for that big windlass bow?

I actually use exactly this in the video before this one. I use a variable weight bolt to work out what weight heads I need if a bolt is being problematic and so I have tested all the way up to 125g.

Tod