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J.W. Salyards
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 Posted: Tue 11 Aug, 2009 7:13 am Post subject: Crossbow query |
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What is the minimum draw weight of a mid- to late- 14th c. crossbow with a composite prod that would be considered "military" as opposed to hunting or sport? I've done some searches here and elsewhere, but while I've turned up some info, but I'm hoping to find greater clarity here. 200#? 250#? 300#? Is there any agreement?
And along those lines, what is the maximum that could be spanned by hand or belt hook, as opposed to a mechanism like a goat's-foot, windlass or cranequin? I've heard 150 and 200 tossed around. Is that about right?
Many thanks!
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C. Gadda
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| Posted: Tue 11 Aug, 2009 8:59 am Post subject: Re: Crossbow query |
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| J.W. Salyards wrote: | What is the minimum draw weight of a mid- to late- 14th c. crossbow with a composite prod that would be considered "military" as opposed to hunting or sport? I've done some searches here and elsewhere, but while I've turned up some info, but I'm hoping to find greater clarity here. 200#? 250#? 300#? Is there any agreement?
And along those lines, what is the maximum that could be spanned by hand or belt hook, as opposed to a mechanism like a goat's-foot, windlass or cranequin? I've heard 150 and 200 tossed around. Is that about right?
Many thanks! |
150-200 lbs. sounds about right. Actually, with a belt and hook 250 lbs or even more is possible. I think around 300 is where a goat's foot becomes necessary.
Military crossbows in this period probably had draw weights in the several hundred pound range, actually, even over 1000 lbs. They were not weak, by any stretch.
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J.W. Salyards
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| Posted: Tue 11 Aug, 2009 9:29 am Post subject: Re: Crossbow query |
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| C. Gadda wrote: |
150-200 lbs. sounds about right. Actually, with a belt and hook 250 lbs or even more is possible. I think around 300 is where a goat's foot becomes necessary.
Military crossbows in this period probably had draw weights in the several hundred pound range, actually, even over 1000 lbs. They were not weak, by any stretch. |
Thanks for the reply. I'm sure there weren't hard rules for this sort of thing, but am I right in assuming then that only those that used a goat's foot, windlass or cranequin were considered military bows in the 14th c.? Or were there instances in the early part of the century when some that were hand-spanned or used a belt hook were employed in battle.
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C. Gadda
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| Posted: Tue 11 Aug, 2009 10:47 am Post subject: Re: Crossbow query |
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| J.W. Salyards wrote: | | C. Gadda wrote: |
150-200 lbs. sounds about right. Actually, with a belt and hook 250 lbs or even more is possible. I think around 300 is where a goat's foot becomes necessary.
Military crossbows in this period probably had draw weights in the several hundred pound range, actually, even over 1000 lbs. They were not weak, by any stretch. |
Thanks for the reply. I'm sure there weren't hard rules for this sort of thing, but am I right in assuming then that only those that used a goat's foot, windlass or cranequin were considered military bows in the 14th c.? Or were there instances in the early part of the century when some that were hand-spanned or used a belt hook were employed in battle. |
Note that I'm going from memory on the above, but my source (not handy whilst I'm at work) is Josef Alm's "European Crossbows: A Survey". In there it quantifies the mechanical advantages for each loading process. If memory serves, the windlass is the most powerful method, followed by the cranequin.
I *think* (and more informed myArmoury members can correct me if I err) that crossbows weak enough to be spanned by hand or belt hook would have been quite obsolete by the 14th century.
Keep in mind that, as a very rough rule, a crossbow has 1/4 the power of a longbow of the same draw weight, due mostly to the much shorter power stroke and other inefficiencies. Thus, to get the punching power of even a rather low ball 100 lbs long bow requires very roughly a 400 lbs draw weight for the crossbow. Even then there is an upper limit to the bolt's velocity, dependent on the limb speed of the prod. Steel prods are particularly inefficient in that regard. In practice, though, I suspect that bolts were purposely made heavier so that you'd still get a fair amount of K.E. behind them.
Not a lot of hard data on heavy crossbows out there that I know of. This is because the originals of course are priceless and probably not up to the stress of firing again, and that modern reproductions above 150-200 lbs are fantastically rare. I've heard of a few being built, but none have been tested from a physics standpoint to determine they're performance (again, that I know of). Would love to see a serious crossbow (say, in the 800-1200 lbs range) go through some modern performance testing.
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C. Gadda
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| Posted: Tue 11 Aug, 2009 10:59 am Post subject: Re: Crossbow query |
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| C. Gadda wrote: |
Not a lot of hard data on heavy crossbows out there that I know of. This is because the originals of course are priceless and probably not up to the stress of firing again, and that modern reproductions above 150-200 lbs are fantastically rare. I've heard of a few being built, but none have been tested from a physics standpoint to determine they're performance (again, that I know of). Would love to see a serious crossbow (say, in the 800-1200 lbs range) go through some modern performance testing. |
An addendum to this. The reason you don't find a lot of truly heavy crossbows is because they are difficult to make and not as much fun. I remember a friend of mine, Kurt Suleski, trying to build a crossbow in the 350-400 lbs range many years ago, and having a devil of a time finding someone that could do it. He even approached the Amish at one point, due to their experience with making leaf springs for their various conveyances. When it was finally built the heat treating was a bit off and it took a bit of a set, reducing its power to around 200-250 lbs, if I recall. There was at one point one fellow who would make the higher power prods, but he seems to have gone out of business. Todd of "Todd's Stuff" actually might make heavier crossbows, but you'd have to inquire with him.
As for "fun" keep in mind that really powerful crossbows require something akin to a dedicated rifle range for safety reasons, have long reload times, and can be dangerous to the user. (having said that, I'd love to own a crossbow in the 600-800 lbs range)
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J.W. Salyards
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| Posted: Tue 11 Aug, 2009 11:08 am Post subject: Re: Crossbow query |
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[quote="C. Gadda"] | C. Gadda wrote: |
An addendum to this. The reason you don't find a lot of truly heavy crossbows is because they are difficult to make and not as much fun. I remember a friend of mine, Kurt Suleski, trying to build a crossbow in the 350-400 lbs range many years ago, and having a devil of a time finding someone that could do it. He even approached the Amish at one point, due to their experience with making leaf springs for their various conveyances. When it was finally built the heat treating was a bit off and it took a bit of a set, reducing its power to around 200-250 lbs, if I recall. There was at one point one fellow who would make the higher power prods, but he seems to have gone out of business. Todd of "Todd's Stuff" actually might make heavier crossbows, but you'd have to inquire with him.
As for "fun" keep in mind that really powerful crossbows require something akin to a dedicated rifle range for safety reasons, have long reload times, and can be dangerous to the user. (having said that, I'd love to own a crossbow in the 600-800 lbs range) |
You mentioned 300 lbs as requiring a goat's foot. How high can you go with a goat's foot before it become necessary to have cranqequin or a windlass? 400 lbs? 500 lbs? Assuming you could do 400 lbs with the goat, I've heard that reloading with one of those is fairly fast (not the rate of fire of a longbow or composite bow, but faster than a cranequin/windlass by a large margin).
This isn't the high-end wall or siege bow, of course, but I'd be happy just seing or using a 400 lbs crossbow. But from what you're saying, finding anyone to even make that might prove difficult.
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J.W. Salyards
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| Posted: Tue 11 Aug, 2009 11:25 am Post subject: Re: Crossbow query |
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| C. Gadda wrote: | [
I *think* (and more informed myArmoury members can correct me if I err) that crossbows weak enough to be spanned by hand or belt hook would have been quite obsolete by the 14th century.
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There is a 15th century painting that shows a crossbow being drawn by a belt hook.
http://upload.wikimedia.org/wikipedia/commons...lo_023.jpg
Now, this doesn't necessarily prove that such bows were still in use, but it is interesting, especially given the level of detail in the rest of the panel.
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J.W. Salyards
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| Posted: Tue 11 Aug, 2009 11:51 am Post subject: Re: Crossbow query |
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| C. Gadda wrote: |
Keep in mind that, as a very rough rule, a crossbow has 1/4 the power of a longbow of the same draw weight, due mostly to the much shorter power stroke and other inefficiencies. Thus, to get the punching power of even a rather low ball 100 lbs long bow requires very roughly a 400 lbs draw weight for the crossbow. . |
I'm not disagreeing, because I'm just parroting here, but I've also heard that a crossbow had closer to 1/2 the power of a longbow. I've seen a lot of physics formulas tossed around, and given that I am greatly out of my depth in that area, I'm curious if there is a consensus as to what is definitive?
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C. Gadda
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| Posted: Tue 11 Aug, 2009 1:22 pm Post subject: Re: Crossbow query |
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| J.W. Salyards wrote: | | C. Gadda wrote: | [
I *think* (and more informed myArmoury members can correct me if I err) that crossbows weak enough to be spanned by hand or belt hook would have been quite obsolete by the 14th century.
. |
There is a 15th century painting that shows a crossbow being drawn by a belt hook.
http://upload.wikimedia.org/wikipedia/commons...lo_023.jpg
Now, this doesn't necessarily prove that such bows were still in use, but it is interesting, especially given the level of detail in the rest of the panel. |
Well, there you go! I would actually consider that pretty definitive proof that they were in regular use.
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C. Gadda
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| Posted: Tue 11 Aug, 2009 1:25 pm Post subject: Re: Crossbow query |
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| J.W. Salyards wrote: |
I'm not disagreeing, because I'm just parroting here, but I've also heard that a crossbow had closer to 1/2 the power of a longbow. I've seen a lot of physics formulas tossed around, and given that I am greatly out of my depth in that area, I'm curious if there is a consensus as to what is definitive? |
I'd like to see your sources. I'm gauging my statement based on the fact that most long bows will have a draw length of around 28" or so and most crossbows perhaps 6-8" at most. Haven't really seen much else on the subject, though I know other factors are the prod material, the drag of the string on the tiller, among others.
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C. Gadda
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| Posted: Tue 11 Aug, 2009 1:31 pm Post subject: Re: Crossbow query |
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| J.W. Salyards wrote: | You mentioned 300 lbs as requiring a goat's foot. How high can you go with a goat's foot before it become necessary to have cranqequin or a windlass? 400 lbs? 500 lbs? Assuming you could do 400 lbs with the goat, I've heard that reloading with one of those is fairly fast (not the rate of fire of a longbow or composite bow, but faster than a cranequin/windlass by a large margin).
This isn't the high-end wall or siege bow, of course, but I'd be happy just seing or using a 400 lbs crossbow. But from what you're saying, finding anyone to even make that might prove difficult. |
Got access to some of my notes from Alm. Here's what he says:
Hand/Stirrup: draw weight limit ~150 lbs
Hook & Pulley: 2:1 mechanical advantage
Goat’s Foot or Built in lever: 5:1 mechanical advantage with about 300 lbs draw weight limit
Windlass 45:1 mechanical advantage
Cranequin 145:1 mechanical advantage
Note that I flip flopped when I said the windlass was more powerful. So much for memory. So now you know everything I know on this...
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J.W. Salyards
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| Posted: Tue 11 Aug, 2009 2:52 pm Post subject: Re: Crossbow query |
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| C. Gadda wrote: | | J.W. Salyards wrote: |
I'm not disagreeing, because I'm just parroting here, but I've also heard that a crossbow had closer to 1/2 the power of a longbow. I've seen a lot of physics formulas tossed around, and given that I am greatly out of my depth in that area, I'm curious if there is a consensus as to what is definitive? |
I'd like to see your sources. I'm gauging my statement based on the fact that most long bows will have a draw length of around 28" or so and most crossbows perhaps 6-8" at most. Haven't really seen much else on the subject, though I know other factors are the prod material, the drag of the string on the tiller, among others. |
Nothing terribley academic. Anecdotal, mostly, which can surely be suspect. There were a couple of archers on other sites (Netsword being one) who had done some testing of bows v. crossbows, based on medieval replicas and range tested with bows/bolts based on the weights of musuem examples apparenlty. One mentioned he had a 450 lbs crossbow that he spanned with a goat's foot. Given extensive testing, that particular archer gave the 1/2 estimate, as did another doing similar tests.
Of course, this is hardly scientific. or conclusive, which is why I was asking. It seems like arguments crop up, formulas fly, and nothing is settled when it comes to bows v. crossbows or arrows v bolts or either v. armor. Very confusing.
Does Ralph Payne-Gallwey have anything to say about this?
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Leo Todeschini
Industry Professional
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| Posted: Tue 11 Aug, 2009 4:02 pm Post subject: |
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Hi All,
What follows is general.
An average man can hand span a stirrup bow upto about 220lb a strong man upto maybe 300lb but not many times.
A belt hook will get you upto about 350 and a belt hook with pulley logic tells you should therefore do 700 which would be a respectable and very fast spanning for a war bow. They didn't seem to run that high so there must be a reason for that and one I will have to have a look at at some point. Not sure about that.
A goats foot will go to about 450lb and cranequins generally stopped at about 700lb and windlass after that. Not sure why there should be a limit on the cranequin so I guess it was just convention. For the record I can span a 270lb bow using a goats foot with my index finger only.
I built a cranequin a while back and the ratio was not as high as 140:1 but cant remeber without going through my pictures. So not sure about Josef Alms numbers and the same goes for my windlass bow. it is a 3 pulley bow so 8:1 on the pulleys and then the winding axle is 20mm and the arms about 150 so there is a 15:1 here, so 8 x 15 =120 ie my windlass is 120:1. That draws 750lb and can be loaded by a 10 year old.
Impact energy increases as a square to velocity and velocity falls through the floor if the bolt is over weight so the sim is to get a bolt that is a balance between higher weight to have the potential to deliver lots of KE and low weight to to have the velocity to deliver lots of KE bearing in mind the low return rates of a steel bow. Bolts seem to vary between about 40 and 65 grams.
In my experience I would say that a cross bow needs to be 2-3 times the weight of a longbow to be reasonably comparable in distance but I have not done any penetration tests so can't comment on that.
Fun is an interesting way to look at these things. A windlass bow is obviously impressive and we can all ooh and ahh as it is spanned and shot, but after you have spent the best part of a minute reloading and wondering how to stop your windlass going rusty after you keep putting it on the wet grass and watched your friend with a 300lb goats foot bow knock out 5-6 shots to each of yours you do hanker after a goats foot.
If you want fun don't go for a windlass or a cranequin.
Heavy bows are not really much harder to make than light ones, the real work comes in the spanning devices and with modern steels and heat treatment there is no reason not to make heavy bows - except for potential litigation.
Sorry for the lack of quotes and sources, it is late here..........................
Tod
www.todsworkshop.com
www.todcutler.com
www.instagram.com/todsworkshop
https://www.facebook.com/TodsWorkshop
www.youtube.com/user/todsstuff1
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J.W. Salyards
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| Posted: Tue 11 Aug, 2009 7:17 pm Post subject: |
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Thanks for the wonderful information, Tod. I have no practical experience with crossbows (yet--I'm working on the wife to free up the purse strings to get one!), so stuff like this is very helpful and illuminating. Thanks again.
C. Gadda--thanks as well for responding. I appreciate all the info.
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C. Gadda
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| Posted: Tue 11 Aug, 2009 8:07 pm Post subject: |
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Thanks, Tod - more than I knew a few minutes ago.
Actually, I think I got the figures above out of Paterson's "A Guide to the Crossbow", and they seem to refer to particular examples (the cranequin from the Met. Museum of Art and the windlass from the Royal Armouries) that were tested, and thus should not be taken as a blanket rule. Your figures, therefore, are probably much more accurate and practical.
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J.W. Salyards
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| Posted: Wed 12 Aug, 2009 6:45 am Post subject: |
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I PMed Tod, asking about the potential lethality of a crosbow spanned by hand, and got this response, which he suggested I share here in the even that anybody else might be interested:
| Leo Todeschini wrote: | A 270lb bow will barely go through 1mm mild steel so plate would be out of the question, put a needle bodkin on it though and it would sail through mail or thin leather armour.
I don't thik it would be considered military simply because a more powerful bow is easy to make so why make a weaker one? There is a cost difference but not that much of one.
But what power was considered military changes over time. If they were around at Hastings they would have been light at maybe no more than 150lb-200lb as they had no spanning devices.
By the early 14thC they were using heavy wooden prodds or composite and had and used both the belt hook and the pulley and hook so they could comfortably span upto say 450lb, by mid 14th the goats foot arrived and this is simply a more wieldly system than pulley and hook and probably comparable in spanning weights and certainly easier to use.
by the early 15th the windlass was established and this cheaply allowed a massive bow to be drawn and so massive bows were made.
By the mid to late 15th the cranequin arrived and allowed posh hunters and mounted troops to load heavy bows with a compact, if costly, device. The cranequin was really only around in larger numbers post decline of the bow as a weapon of war, when it had become a hunters tool.
I hope this helps and all dates are approximate.
If you wouldn't mind, could you post up your question and my response as we may as well keep it public for all.
Tod |
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Daniel W
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| Posted: Wed 12 Aug, 2009 7:35 am Post subject: |
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| J.W. Salyards wrote: | ...
| Leo Todeschini wrote: |
I don't thik it would be considered military simply because a more powerful bow is easy to make so why make a weaker one? There is a cost difference but not that much of one.
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Tod |
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from a hunting perspective, more powerful isn't always better. if a projectile hits a target with enough force to fly through and not stop, then it isn't imparting as much energy as it could. (seem to recall the smaller carbines in WW2 were more effective for this reason, actually, but I could be wrong) Bodkins get even worse.
I'm thinking people back then weren't entirely stupid, and would have at least noticed this, assuming they used crossbows all that often for hunting. now, on the heavier poundages, does the effective range for an *accurate* shot increase enough that it would justify the more expensive crossbow? and, wouldn't there likely be sanctions on just how heavy a bow a fella can have? (if were the local lord, they'd all be locked up. yeah. I know. I'm mean.)
| C. Gadda wrote: |
| J.W. Salyards wrote: |
I'm not disagreeing, because I'm just parroting here, but I've also heard that a crossbow had closer to 1/2 the power of a longbow. I've seen a lot of physics formulas tossed around, and given that I am greatly out of my depth in that area, I'm curious if there is a consensus as to what is definitive?
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I'd like to see your sources. I'm gauging my statement based on the fact that most long bows will have a draw length of around 28" or so and most crossbows perhaps 6-8" at most. Haven't really seen much else on the subject, though I know other factors are the prod material, the drag of the string on the tiller, among others. |
It seems to me that going with the bigger-is-better mentality would fix the 'short' prods. at least, that would work in places you didn't much care about having heavy things to lug, equip and field. this heavier (in terms of actual weight not draw weights, to clarify) might be another reason for a lighter cross bow. I know when I go out fishing, I gripe about my five pounds of gear.
remember, the first cross bows were ultimately over sized bows stuck on a stock. As a side note, if steel is so poor for its energy returns, why was it used? because it was common and durable? what other materials for the prod could be found, if any? (not arguing, just curious.)
Edit: eated fa spellig erores.
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C. Gadda
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| Posted: Wed 12 Aug, 2009 8:35 am Post subject: |
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| Daniel W wrote: |
from a hunting perspective, more powerful isn't always better. if a projectile hits a target with enough force to fly through and not stop, then it isn't imparting as much energy as it could. (seem to recall the smaller carbines in WW2 were more effective for this reason, actually, but I could be wrong) Bodkins get even worse.
I'm thinking people back then weren't entirely stupid, and would have at least noticed this, assuming they used crossbows all that often for hunting. now, on the heavier poundages, does the effective range for an *accurate* shot increase enough that it would justify the more expensive crossbow? and, wouldn't there likely be sanctions on just how heavy a bow a fella can have? (if were the local lord, they'd all be locked up. yeah. I know. I'm mean.)
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I'd be cautious about regarding "imparting energy" as being vital to wounding. There is something to be said for "blow through" that causes the victim to bleed out of two holes rather than just one, and insufficient penetration is far less effective than over penetration. As for carbines, not sure where you picked that up. In a book on US small arms from WWII and Korea that related stories from veterans of those wars about the guns they used, I saw at best lukewarm "yeah, it was all right" to outright loathing of the carbine. Most preferred the Garand.
| Daniel W wrote: | It seems to me that going with the bigger-is-better mentality would fix the 'short' prods. at least, that would work in places you didn't much care about having heavy things to lug, equip and field. this heavier (in terms of actual weight not draw weights, to clarify) might be another reason for a lighter cross bow. I know when I go out fishing, I gripe about my five pounds of gear.
remember, the first cross bows were ultimately over sized bows stuck on a stock. As a side note, if steel is so poor for its energy returns, why was it used? because it was common and durable? what other materials for the prod could be found, if any? (not arguing, just curious.)
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Weight is always a factor - no argument there.
As for steel, it was used because it was quicker and much cheaper to make. Composite prods were MUCH more labour intensive and expensive. And your reading into what I was saying - I only said steel was less efficient, and it should not be construed as being "poor" or unusable in any way. You just have a lower maximum velocity limit is all.
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Leo Todeschini
Industry Professional
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| Posted: Wed 12 Aug, 2009 10:29 am Post subject: |
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| Quote: | Danile W wrote I'm thinking people back then weren't entirely stupid, and would have at least noticed this, assuming they used crossbows all that often for hunting. now, on the heavier poundages, does the effective range for an *accurate* shot increase enough that it would justify the more expensive crossbow? and, wouldn't there likely be sanctions on just how heavy a bow a fella can have? (if were the local lord, they'd all be locked up. yeah. I know. I'm mean.)
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Looking at the hunting treatises and a paintings etc hunting was done at realtively short range and was more about stalking or even having the game driven to you if you were posh enough rather than taking that 200yd shot. Basically a crossbow is a pretty noisy thing and the bolt doesn't travel that fast so most game would start on loose and a miss would result.
So higher power is not about longer shots or faster projectiles, it is about energy delivery and penetration. Small bows are fine for hunting small game, and would suffice with a good shot for most game but for large game bigger would on average be better.
Tod
www.todsworkshop.com
www.todcutler.com
www.instagram.com/todsworkshop
https://www.facebook.com/TodsWorkshop
www.youtube.com/user/todsstuff1
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J.W. Salyards
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| Posted: Wed 12 Aug, 2009 11:11 am Post subject: |
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I've heard tell of a crossbow with a goat's hook built into the stock/prod, as opposed to separate piece fo equipment. Is there any documentation for this?
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