Short staves- draw length and draw weight trade off

[jameswoodmot]

Having had no interest in short draw bows, Native American bows, arrows and quivers turned up today, now I want to make a short bow!

I’ve got quite a few short elm staves that should be ideal for this but it’s lead me to wonder about the trade off between draw length and draw weight.

If I’ve got 50 something inches of wood I can either tiller to a low poundage at a longer draw length or a higher poundage at a shorter draw, how do I know which is going to give me the best arrow speed for that stave? Somewhere there is a sweet spot in the middle but is there any way of getting a rough calculation? I suspect there are too many factors for it to be viable to work out.
I have only ever got a bow to my draw length before and just let it turn out at the poundage it wants to be.
Is it know what sort of poundage and/or draw length any of these bows were historically?

[sleek]

Short bows... my favorite 😍

Im decently studied up on them and have made a few over the years. A couple are pretty fast. Ill tell you a few bullet points on short bows.

Short bows are not limited in their draw length and weight by nature of their length alone. Their width and amount of recurve at the tips make up for the rest of the equation.

A 50 inch bow can pull all the way to 26, even as a stiff handled bow if the handle is its smallest size,  the tiller is good, and the tips have enough recurve to keep the string angle down from stacking.

It can have any draw weight you desire as long as there is enough wood in the bending section to absorb the bending stresses. This is controlled by how wide the bow is made to be. By nature of how things work, a 50 pounder will need to be twice as wide as a 25 pounder with all things equal, because two 25s equal a 50.

So, your stave width will be your primary limiting factor.

[jameswoodmot]

Fantastic, thanks Sleek


So with the bows in the book, the length and width are listed. Lots of them are only just over an inch wide.
If I wanted to make a replica of one with very similar dimensions, the higher the poundage I make it the shorter the draw length will have to be to prevent it taking loads of set or snapping.
If I were to set the limiting factors to those dimensions, I can vary the draw length and weight within reason. Is a lower poundage at a longer draw going to give more arrow speed than a higher poundage at a shorter draw?

[sleek]

Set only happens when a bow has too much draw weight for its working limb volume. Its not related to its draw length, even though thats what is commonly blamed for set.