Where i can buy a composite crossbow prod? I want something strong and accurate(about 800 pounds?). It's for my Swiss soldier form the canton of Uri, 1475.

François

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If you find out, please let us know. I know of nobody making these, and I had been told that the art may have been lost, needing us to reinvent it. Composite bows, while the same technology, weren't built up the same way.

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Thomas, this is the informations that I found in the book ''Medieval Military costume'' by Gerry Embleton;

''...this cross section of a composite crossbow stave shows that the inside or ''belly'' was assembled from irregular pieces of horn....They were meticulously grooved yo make tight joints and then glued together; we do not know what adhesive was used, but the method was clearly so effective that the final composite structure was symetrical, balanced, and could take the massive strain of repeated bending and releasing. The (upper) 'back' of the stave was made from sinew, the outer covering from parchment, birch bark, or -as here- heavy paper with densely printed pattern.''

[ 08-08-2005: Message edited by: larcheveque ]

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I'm making just a guess here, but I suspect that the adhesive had to have been hide/hoof glue based with something added so that it would bond with the horn and sinew but still have also been flexible enough to withstand the flex and shock of repeated firing.

Est 125lb prod x 6.5 inch draw. = 800 lbs.

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I want a 800 lbs prod x 7 inch draw = 5600 lbs.

Thomas, i think this mean on top of each other but i'm not a good reference for the composite prod construction.

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I think you might be entering the range of steel prod siege arbalasts at that draw weight - I am under the impression that the composite prods were more on the order of 350 lbs - still requiring a cranequin or other mechanical assistance. The sort of monster you are talking about would have a special cocking stand, or a large windlass, and sounds like a wall bow to me.

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quote:

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Originally posted by Thomas james hayman:
800lbs at 7", wow, thats pretty powerful. I think i'm going to leave laminated prods for now, too much on. Might be fun for the future though.

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I would be very careful Thomas - given the form of construction, and the power of it, if the thing were to give way when drawn you would have something aking to a small, low power grenade going off a short distance in front of your face - the 'shrapnel' of horn would be heading not directly toward you, but you might hurt someone 'but good' accidentally. One would think that the cover and glueing would keep flying debris to a minumum, but the potential for someone getting hurt is there.

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quote:

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Originally posted by larcheveque:
I want a 800 lbs prod x 7 inch draw = 5600 lbs...

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Francois, are you certain? 800 lb prod would create a ballista. I think this is beyond a windlass.

A 300 lbs prod x 7 inch draw can be used with a wood goat foot lever(I say that because I tried).

I have a crossbow with a steel prod of about 400 lbs(between 400 and 500 lbs) and I can easily use it with a windlass with only 2 pulleys on it. For this reason, I don't think a windlass with 4 or 6 pulleys is made for a prod of only 400 or 500 lbs.

I'm sure i can make a crannequin crossbow with a steel prod of about 800 lbs but the problem is the Swiss army seems to have mostly composite prods. For the composite prod of Swiss crossbows, I don't know the strenght of their prod but they use a crannequin. I think the crannequin is a sign of great power.

This is an interesting link about crossbows strenght:

http://www.period-crossbows.demon.co.uk/

[ 08-09-2005: Message edited by: larcheveque ]

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I am pretty sure the cranequin is more a sign of a moderately powerful bow that can be loaded on horseback - neither the windlass nor the goats prod work well (the windlass wouldn't work at all, being far too awkward) from horseback. The mechanical advantage of the canequin is not as great as a multiple paired pullied windlass.

The goats prod is more of a French/Italian solution to cocking a moderately powerful bow, the cranequin is the German invention for the same task. For extremely powerful bows (like wallbows), the Germans tended to use special cocking stands with levers, and windlasses.

Keep in mind the German penchant for mounting crossbowmwn, and using them mounted occasionally, and you can see why the cranequin was developed.

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You have a really good point. I agree with you about the moderately powerful bow for a horseman. This point make me think about another thing; I saw crannequin crossbows with stirrup and some without. Is it possible to separate crannequin crossbow in two classes; for horseman and for foot soldier? Logically, it's harder to load and hold a crossbow only with two hands instead of with your feet and your two hands. But if we look the mounted crossbowmen in ''The Swiss at War 1300-1500'' they all have stirrup on their crossbow...

[ 08-09-2005: Message edited by: larcheveque ]

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It is a good question, but one I do not know if we can ever have a certain answer for.

One thing we should keep in mind is that the steel bows were the latest technology, and were intodced because they were more powerful, just as the composite prods replaced the simple self bow prods of early European crossbows, as the technology was introduced from Outremare.

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Arma Bohemia(http://www.armabohemia.cz/) works on a prototype. In cca 3 months, composites prods will be probably available with a power of 120-150kg

François

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I think the point I was driving at is not that composite crossbows are more dangerous than guns or steel prods if they fail.

My point is they are more likely to fail than either of those two items, because we know how to make the steel prods and guns competantly, and the knowledge to reproduce a composite prod properly has been lost. Since you would be trying out an unkown technology from scratch, it would be more likely to fail because you have not done this before.

If we had a composite crossbow maker to show us how to manufacture a prod successfully, things would be much easier and less prone to failure - not so?

It would be safer to try to reproduce one in a lower poundage first, and perfect the technique before begining with a 350-400 lb draw prod.

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