[Jean Thibodeau]

Just been reading an interesting discussion on the range of crossbows on Netsword site.
http://netsword.com/ubb/Forum8/HTML/000234.html

Here is a link to a crossbow maker who made some very interesting comments towards the end of the Netsword topic thread:
Seem worth having a look, LINK REMOVED BY ADMINISTRATORS

Very interesting data on comparative power of goat foot crossbows and heavy siege crossbows.

Have a look and have a read of the above and them we can have some good discussions about power and range and maybe also get confused about the physics of the whole thing.

I would think that one can do all sorts of math about acceleration curves and length of draw but to me the only thing the arrow or bolt reacts to is the speed of string as it leaves the bow or crossbow: The arrow or bolt only moves as fast as the string was moving and if the acceleration was over a short or long distance the arrow doesn't care. After it leave the string the arrow or bolt can only loose speed ! ( Unless one is shooting from a high place to a lower target. )

Oh, this one looks good: LINK REMOVED BY ADMINISTRATORS

[Jean Thibodeau]

Oh, just one little bump up and if you read the linked topic there is some interesting info I will just give a few highlights of, info I haven't easily found elsewhere: The goat's foot crossbows having a draw weight of around 450 pounds, the cranequin around 750 pounds and some heavy siege crossbows 1200 / 1500 pounds.

There is a post about a crossbow being tested that was left cocked for 500 years and still having a draw weight of 1500 pounds with an " unproved to me " statement that it is estimated that the draw weight was originally around 3000 pounds.

Anyway, this is the information I found most interesting.

[David Ruff]

Thanks for the comments.

The 380/450lb goatsfoot bow is alive and strong. Currently for sale now too. Tis the problem with building crossbows. Build one - like it, sell it, rinse and repeat.

We are forging some 1200 to 1700lb prods at the forge and will be doing some windlass and crank bows soon, will start posting results on those when we get done

[Jean Thibodeau]

[David Ruff]

Belt hooks are interesting things, They attahed via a ring to the stock below the trigger (for anyone whom is not familure with one) on a post like an "L" hook and then looped around the string (via a metal hook) and back up to a loop or hook that attached to the belt. This set up was a very effective - but crude - 50% let off.

In my belthooks i have cocked upto about 400lbs with moderate effort, i have maxed a 700lb bow, but let me tell you - just becuase you can "squat it" doesn't mean do it heheheh. You have to remember that you were gonna do this loading for awhile and it takes its toll on the back, legs and waist in a hurry.


Most medieval crossbows spanned only 4 to 6 inches, so the actual lift of the hook with the legs was very short and fast, Most modern target crossbows in medieval form pull 7 to 8", this is due to the low poundage - need to make power so a longer stroke is needed. In a high poundage you can use a short stroke with a lot of weight. Also they made prods that were hit and miss, so you didn't want to bend them a lot. Where now a days we can bend steel 8" of stroke and be safe doing it due to exacting specs in the steels we use.

It is true that it is easy to cock a belthook bow in the 400 to 500lb range, and people then were pretty stout and could handle it. However........

The belt hooks back then cocked from one side of the string, it made the bow off center, once you get the string cocked you could NOT move the string over to center it - so the cocking method was very inaccurate and no consistancy in it. Even modern day rope cockers (same thing as a belt hook) cock the bow off center, however even at the max power bows that are sold today you can center the string with a tug.

Belthooks were ONLY used for poor mans cocking devices and for a way to send a kid onto the field to kill knights and not be out several silver when the kid died.

Windlass and cranks on the other hand were a way to keep the string centered AND also cock high power bows (some say to 3000lbs by the mid 1600's). My guess is these bows of that power were VERY rare to see or face. They were heavy, took forever to load and took some SERIOUS skills to make and maintain. I would say a common siege bow of 1200 to 1500lbs was common. These cocking devices were for nobles and for bows used for siege. They required heavy bows to blow thru pavices and mortar and in a siege gave time to load these monsters.


Goatsfoots on the other hand are 4:1 levers and offer a way to cock by hand the same weight as a belthook does. They are more expensive and bulky then a belthook however and were reserved really for commissioned bows for the nobles.

On an off note.

If i remember payne galwey's statement he said the heavy he tested was 1200lbs and cocked for hundreds of years. My mentor Robin Allen at http://www.thecrossbowmansden.com/Home.html met payne galweys sister when he was a boy and handled the bows in his book. i'm here to tell you from experiance the prod he explains in his book makes a prod that pulls 1500 to 1900lbs. It is my belief that if the prod remained cocked that long would have lost some tension, but still would have been very usable. Im just not sure of his method of measuring the bows pull weight was accurate or valid.



I know in my testing i consistantly out range heavy (110+lb lonbows war arrow to war quarrel). Not by much, but outranged is outranged. However, a longbows rate of fire i would NEVER keep up with.


I will be traveling to england, scotland and germany at the end of this year for an all access pass to the displays. This includes after hours pass' and the ability to open the cases and handle the weapons. I will also be spending 3 days with war and weapon historians during this visit. I will learn a lot and it is my hope to clear up some of my errors in these weapons i have yet to discover.


Thanks again for the invite and i will keep you posted on the heavy bows coming out and what they can and can not do.

[Gordon Frye]

David;

Welcome to the site, and thank you for the informative posts! Crossbows are of interest to me, but it's difficult to find much good, solid information on them, so thank you for coming to the rescue. Do keep us informed as to the results of your research trip to Europe!

Allons!

Gordon

[Wolfgang Armbruster]

This is really great information!
I had no idea that such extremely strong crossbows existed. However I'm glad that I was right in my assumption that crossbows are stronger and outrange longbows *g*

I know people continued to use crossbows for a long time after firearms made their appearance, especially for hunting purposes. But for how long were they used on the battle-field? I was under the impression that people stopped using cross-bows in war in the early 16th century when harkebuses started getting better. Has anybody more detailed information on this? I guess my assumptions are at least partly wrong.

[David Ruff]

[George Hill]

[Jean Thibodeau]

David;

Thanks again for a long and informative post and please keep us informed and consider posting new topics about crossbows and maybe just participate in other topic threads that you find interesting.

I would suggest asking Nathan for status to post new topics on the " Makers and Manufacturers Talk " forum where product announcements and some marketing is allowed and encouraged. You might also consider writing one or more feature articles for this site about crossbows. ( Contact Nathan Robinson by P.M. or E-Mail should you wish to do this. Oh, no obligation to do so by the way and I don't want you to feel any pressure. )

Just looking at the shape of the goat's foot lever in pictures I've seen I assumed some variation in the amount of leverage as the lever pushes / pulls ? The amount of pressure applied by the hand might seem constant since the poundage would increase as the lever travels but the leverage advantage would also increase towards the end of the stroke ???

My assumptions may be completely wrong here and you did give a good explanation already about goat's foot crossbows, but I'm still unsure about my above question.

[David Ruff]

Heheeeh.

Something like this exists in show cases; I do not have a picture off hand of a period bow in this weight. I do know there is a company that makes one pulling 3300lbs. Roman ballista’s if I remember correctly pulled 1200 to?? in lbs and launched a 10lb spear out to 250+ yards. It is of my opinion they did the same thing I do in the forge I create my prods in.... Take a piece of steel, heat it, hit it, shape it and what it comes out to - it comes out to. A crank is a 45:1 advantage lever and it is VERY possible to crank up a 3000lb crossbow, it is very possible to have it hold together - these people were not dumb and they did what worked.

What I am saying is, I do not know of any specific examples of period crossbows pulling this weight, however I do know of experts that have guessed to what the weight could have been based on mass and material, and I do know of reproductions pulling to 3300lbs that are supposed to be copies of bows or copies of things that were used and put together free form.


Here is a link of a bow http://www.balestrantica.com/il_diavolo.asp that pulls 3300lbs, or so I have heard. I do not think they may the crank for it however due to legal reasons? Not sure, my translation is not that hot.

Robin Allen is finishing up a 2000lb crossbow based on a true build that existed

Me? That’s too heavy to attempt of even want to attempt.


Last thought; in England today they still pull bolts out of solid stone castle walls. What kind of power does it take to drive a bolt like these (copies of bolts used in and around London LINK REMOVED BY ADMINISTRATORS and drive it into solid stone?

Better yet, battlefield reports of crossbows being able to penetrate 12 inches of bound oak at 100+ paces. I know from my personal bows and from others that I have shot we have not been able to do it on bows upto 1100lbs.

[David Ruff]

[David Ruff]

Just a quick note:

I have attached a quick video of a goats foot bow cocking from about a month ago. The bow was still untested at this stage so it will not show the bow holding the prod back. The prod itself is rated at 650lbs at 8" of draw. This bow draws 5.5 to 6" with that prod so it should be in the area of 380 to 450 with 450lb being more likely. It topped out a 350lb scale so again - guessing.

It will show atleast how effortless a goatsfoot appears. Actual weight im feeling on the handle is about 90 to 120lbs.

LINK REMOVED BY ADMINISTRATORS

And here is a bow that has not officially gone up on the boards for viewing. It is a target build medieval - not really copying anything from history, just a look cool type bow.

LINK REMOVED BY ADMINISTRATORS

Enjoy

[George Hill]

[David Ruff]

[Benjamin H. Abbott]

[David Ruff]

[Florian H.]

[Jean Thibodeau]

As to ideal weight of a crossbow bolt to get the most power on impact one can increase the weight of the bolt to a great degree with a very heavy powerful crossbow: A small lost of velocity is negligible compared to the energy of a much greater mass moving just a little slower.

But how much is too much ? What would be the weight ideal for a bolt to get maximum velocity ( No point going so light that a lighter bolt has almost the same velocity. ) versus the maximum weight of bolt where any increase in weight would total less energy or momentum, momentum which might be more relevant to terminal effect than kinetic energy when dealing with the relatively low velocities of arrows and bolts compared to bullets were kinetic energy of a 3000 ft/sec projectile becomes relevant.

( Well, the whole subject of kinetic energy versus momentum is responsible for the death of many trees to make the paper of gun magazines over the years and maybe we should not go there ? )

What would the ratio between these bolt be ? If one gives the light bolt a value of 1 would the heaviest bolt be 1 1/2, 2 or more in weight ? Maybe figures in ounces would help visualize the weight of bolts easier on us who don't relate to weight in grains in a meaningful way: Number of bolts to the pound maybe ? Sort of like shotgun gauges maybe: 12 bolts to the pound or 24 bolts to the pound would be an easy scale to understand.

Would a siege crossbow in the 2000 pound range have a figure ( gauge ) of 4 to the pound ? Is a 1 pound bolt totally realistic or ridiculously heavy ? Now, with a large siege engine like the Romans used the bolts might get into the spear range in size and weight ?

[David Ruff]