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Forum Index > Historical Arms Talk > Heavy arbalest testing Reply to topic
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William P




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PostPosted: Thu 01 Mar, 2012 10:48 pm    Post subject:         Reply with quote

according to a booklet on the collection of the graz armoury, and the evolution of weapons and Armour from the late 15th to th middle of the 17th century, if it could not be proofed, according to the conditions set by the armorers guild, it was deemed 'good and sufficient' but im pretty certain that at least breastplates would be proof. and i think the best armours were proofed against muskets.

and we have ample evidence that japanese tosei gusoku armour, the breastplates were tested against arquebus rounds.
one of the members, eric S has a wikipedia archive of lost of weapons and armour.

this is conjecture on the part of my friend
but he reckoned that a modern hollowpoint handgun rounds of medium power, i.e .45 calibur or less,. could be resisted by late medieval, or renaissance breastplates, based mostly on the fact that hollow-points performs best against soft tissue and perform poorly against body armours, due to the fact that the bullet heads fragment fairly easily, likening it to a broad-head arrow.

and as for armour piercing heads this was an explanation of armour piercing 'plate cutter' heads, there werearrowheads i.e for a english warbow, not a crossbow, but i get the feeling a crossbow bolt against armour might perform similarly


Quote:
A plate cutter has a short, 4-sided, almost pyramidal shaped front which creates the initial hole, the 4 sides of the massive lozenge head then create small cuts enabling the metal to split & curl back out of the way. The head is thick to stop it bending or curling like a needle bodkin. The head is wider than the shaft to allow the shaft to slip through the hole without further friction. The Towton head was just one type found at the site. I imagine it was a general purpose head.
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Jean Henri Chandler




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PostPosted: Fri 02 Mar, 2012 6:50 am    Post subject:         Reply with quote

I'm also interested in your experiments on the Bremsen bolts. I've been working on a book on the Medieval Baltic and these played an important an important tactical role there. I'd love to see you get one working and hear what it sounds like...

On a related note, one Baltic researcher working out of the UK told me they have been able to follow the course of Medieval battles there by finding bolt-heads embedded in trees and the ground with metal detectors. How cool is that? Happy

J

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William P




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PostPosted: Tue 06 Mar, 2012 10:09 pm    Post subject:         Reply with quote

pretty cool, and while i already asked a varient of this question before.

its been noted that thpse windlass operated, steel prod based crossbows has poundages of up to 1000 or so,

based on 'stopping power against armour or whatever other factor, what kind of crossbow poundage would be the rough equivelent of a 100lb longbow?
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Leo Todeschini




PostPosted: Wed 07 Mar, 2012 12:24 am    Post subject:         Reply with quote

William P wrote
Quote:
based on 'stopping power against armour or whatever other factor, what kind of crossbow poundage would be the rough equivelent of a 100lb longbow?


I am working on this at the moment with a friend and I would estimate about 400- 500lb

Tod

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Randall Moffett




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PostPosted: Wed 07 Mar, 2012 5:30 am    Post subject:         Reply with quote

I think Liebel puts it around 340lb crossbow for 160 longbow. I have misplaced my copy of the book so I cannot say for sure.

RPM
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William P




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PostPosted: Wed 07 Mar, 2012 8:49 pm    Post subject:         Reply with quote

Leo Todeschini wrote:
William P wrote
Quote:
based on 'stopping power against armour or whatever other factor, what kind of crossbow poundage would be the rough equivelent of a 100lb longbow?


I am working on this at the moment with a friend and I would estimate about 400- 500lb

Tod

oh, so these 1000lb crossbows are well above and beyond the damage abilities of the warbows used by soldiers,
purely in terms of the fact that you can put more energy, potentially, into the projectile.

i see,
though i understand these 1000 lb crossbows were relatively rare items i items, and would probably be time consuming to reload, and pretty bulky to handle.
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Leo Todeschini




PostPosted: Wed 07 Mar, 2012 11:57 pm    Post subject:         Reply with quote

Randall Moffet Wrote
Quote:
I think Liebel puts it around 340lb crossbow for 160 longbow. I have misplaced my copy of the book so I cannot say for sure.


I will get back to you in due course, but I am absolutely certain this is not the case. From my experience I would put a 350lb crossbow at about 75lb longbow and that it is the 1000lb crossbows that are around the energy delivery equivalent of 160lb longbows.


William P wrote
Quote:
oh, so these 1000lb crossbows are well above and beyond the damage abilities of the warbows used by soldiers,
purely in terms of the fact that you can put more energy, potentially, into the projectile.

i see,
though i understand these 1000 lb crossbows were relatively rare items i items, and would probably be time consuming to reload, and pretty bulky to handle.


I think it is pretty established that warbows were significantly heavier than 100lb and were more likely up in the 140+ and I think were pretty comparable in energy delivery to the big bows. But some tests will tell.

The big war bows that you find in museums are all up at the 800lb+ area and most I would say over 1000lb. Windlass bows are a bit of a handful to handle but take maybe 10 seconds to load or so, but it is resetting the windlass that takes the rest of the time, so that the total cycle time is about 40-50 seconds.

Tod

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Randall Moffett




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PostPosted: Thu 08 Mar, 2012 6:07 am    Post subject:         Reply with quote

I think this might be in part Liebels using 350lb composite to the bow here not steel. I think one will find steel is much more inefficient than composite bows so maybe true a 350lb steel prod is equal to a 75lb bow (I'd be surprised though but I'd take like to see the test conclusions). The issue seemingly was making composite bows of sufficient power to larger steel ones meant a rather long prod. which seems to have been done on siege versions but not so useful for field use. In Liebels testing he uses joules upon initial delievery and impact and that is what he states for the given crossbows in his testing. Whether it is right I could not say. How are you gauging effectiveness?

RPM
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Jean Henri Chandler




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PostPosted: Thu 08 Mar, 2012 2:58 pm    Post subject:         Reply with quote

Some context on the types of crossbows, though I've covered this before:

From the records of the Teutonic Order, the Hussites, and the Poles, who were all very reliant on crossbows, it was not the windlass type which they called an "English Winder" but the cranequin type (known as the "German winder', also referred to as the statchel or stechel ("stinger") which they preferred for the open field. These were considered as powerful as the English winders but were smaller and much easier to handle. The former were mostly only used for siege combat, but I think this get's confused a lot because the windlass type were more popular in England which is much more influential on our understanding of Medieval history in the US.

I have sources for the Czechs, the Order, and the Poles on this. You can also read a summary paper at deremilitari.org which covers this stuff, called Horses and Crossbows: Two Important Warfare Advantages of the Teutonic Order in Prussia. by Sven Ekdahl. But their site appears to be under a malware attack right now.

The most powerful arbalests of this class were less common than the less powerful stegelarmbruste, 'sturrup crossbows' (I haven't been able to determine if these were steel or organic prod weapons, maybe both) and the knottelarmbruste which were of solid yew construction. The Order left records indicating purchases of prods specifically for all of these kinds of weapons, so did the city of Krakow. The ratio of the statchel to the other types is something like 1-10. Also the knottelarmbruste seem to mainly be used by peasant militia from the Abbeys and Monasteries land, whereas the other types were used by urban militias and foreign (mostly Czech and German) mercenaries. The regular crossbowmen (or ballistiarii as they were usually called in the German records) were often footsoldiers, whereas the elite with the more powerful (and more dangerous to use) statchels fought mounted, and were paid about half of what a lancer was paid, in one Polish source it was listed that it costs 11 grivna to equip a mounted arbalestier (which is about 10 or 11 marks, or very roughly 120 ounces of silver), compared to 22 grivna for a lancer. They also said in records from Krakow (15th C) a crossbow (type unspecified) cost 1 mark while a sword (type unspecified) cost 1/2 a mark. The various types of spanners, goats-foot, wippe, the belt-hook, the winch and the cranequin also cost money, the cranequin in particular was described as expensive though I've been unable to find the exact cost listed anywhere.

Some lower paid crossbowmen also fought mounted especially in the 15th and 16th Centuries, as scouts. This was documented as early as 1420 when Jan Ziska gave some horses to Hussite crossbowmen and trained them to be scouts. These were the guys in particular who made heavy use of those bremsen bolts, both for signalling and for demoralizing the enemy as they closed from long range to close / killing range. Sven Ekdahl gives some rough figures for the ranges for harassing shots, direct shots and killing shots but I don't remember off hand what they were.

My source for these costs is Uzbrojenie w Polsce średniowiecznej 1350-1450, “Armaments in Medieval Poland 1350-1450” Andrzej Nadolski, Polska Akademia Nauk, Instytut Historii Kultury Materialnej, (1990) The author of that book also claims they found two helmets, one 14th C one 15th C, which had been pierced by crossbow bolts, both in the face-plate. He didn't say what kind of helmets or how thick.

J

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Leo Todeschini




PostPosted: Sat 10 Mar, 2012 7:15 am    Post subject:         Reply with quote

I just remembered I have to reshaft these for a customer, so while they are here I thought I would get some measurements.

The story as I remember it .............They were found outside a castle with thousands of others, so presumably after a protracted siege. The castle was in Slovakia or Slovenia, but I can't remember which, but may be able to find out next week.

I have included pictures and there are two normal looking plate cutters and a curious leaf blade that looks like a mini lance.

The weights are leaf 40grams
larger plate cutter 54 grams
smaller plate cutter 45 grams (which is handy because I have just received some 45gram ones in the post from Hector Cole this morning)

The sockets in the same order are 10.8mm
11.5mm
13.5mm

They are pretty well preserved so I don't think they will have lost that much mass

Tod



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Jean Henri Chandler




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PostPosted: Sat 10 Mar, 2012 11:49 pm    Post subject:         Reply with quote

Fascinating Leo, thanks for posting. Any idea if these are hardened?

And can you give us the weights after they are re-mounted?

J

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Leo Todeschini




PostPosted: Sun 11 Mar, 2012 12:41 am    Post subject:         Reply with quote

I tested for this and they are plain wrought (or are now anyway)

The client wants them mounted on 12" shafts so the finished weight will not be representative, but I will be mounting my new heads on 15" which is a bit better and as I know the weight of these, this will give us the finished weights of what these bolts once were - give or take.

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Benjamin H. Abbott




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PostPosted: Sun 11 Mar, 2012 8:00 am    Post subject:         Reply with quote

As far as English warbow to crossbow comparisons go, the 1200lb crossbow Ralph Payne-Gallwey used to a shoot a three-ounce bolt 460 yards would have delivered around 200 J at close range. (Sending a three-ounce bolt that distance would require 171 J in a vacuum. Air resistance brings that up to 190-210 J based on the ratios I've seen for heavy English warbow arrows). The heaviest English longbow known - 180lbs - with the heaviest English arrow known - four ounces - would only manage about 160 J, so that crossbow performs significantly better with a lighter projectile. An average 150lb English bow with a lighter arrow would only deliver 110-120 J, while 110lb composite Turkish bow would manage 80-100 J with the light arrows the Turks apparently favored. Thus the aforementioned steel crossbow hit dramatically harder than other contemporary missile weapons. Only the 240lb composite Manchu bows - probably never used in war - combined with a heavy Machu war arrow would exceed the power the 1200lb steel crossbow.
Read my historically inspired fantasy fiction in here. I walk along a winding path set by Ludovico Ariosto, William Morris, J. R. R. Tolkien, and Ursula Le Guin.

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Timo Nieminen




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PostPosted: Mon 12 Mar, 2012 2:24 am    Post subject:         Reply with quote

A mere 180lb Manchu bow might be sufficient to exceed 200J. Should be sufficient. Depending on brace height and draw length, that would be somewhere in the vicinity of 250-300J stored. For Japanese bows, you only need about 140lb to exceed 250J stored. Long draw length helps for East Asian bows.

Koreans bows would be good candidates, too - long draw, and efficient.

"In addition to being efficient, all pole arms were quite nice to look at." - Cherney Berg, A hideous history of weapons, Collier 1963.
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Randall Moffett




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PostPosted: Mon 12 Mar, 2012 6:39 am    Post subject:         Reply with quote

Timo are those initial or impact joules? I think Ben is giving impact energy delivered. I would never have assumed a 180lb draw dow could have 300J of initial energy though. Sounds super high. Where does this info come from? I'd love to have it though for my own nefarious uses.

RPM
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Benjamin H. Abbott




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PostPosted: Mon 12 Mar, 2012 10:16 am    Post subject:         Reply with quote

I was referring to energy imparted rather than energy stored - two very different things. A 180lb Manchu bow would need a really heavy arrow and performance equivalent to a Turkish composite to deliver 200 J at close range. I'm skeptical. Have any actual tests with heavy Manchu bows and those 100-gram arrows even been done? In any case, we've still got a steel crossbow that hits harder than any bow with the possible exception of a few extraordinarily strong archers from the other side of the world - and that's with a mere three-ounce bolt.
Read my historically inspired fantasy fiction in here. I walk along a winding path set by Ludovico Ariosto, William Morris, J. R. R. Tolkien, and Ursula Le Guin.

Out of doubt, out of dark to the day's rising
I came singing in the sun, sword unsheathing.
To hope's end I rode and to heart's breaking:
Now for wrath, now for ruin and a red nightfall!
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Timo Nieminen




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PostPosted: Mon 12 Mar, 2012 5:01 pm    Post subject:         Reply with quote

Randall & Ben,

Yes, my numbers are stored energy, and the initial energy of the arrow when shot will be lower, and the impact energy after going some distance will be lower still. But if we assume an efficiency of about 80%, 250J stored will give us 200J at point blank range, so a 180lb Manchu looks good.

I don't know of any quantitative tests. Force-draw curves have been measured, so the stored energy can be known, rather than guessed (mine is guessed; more below), but AFAIK, the only source is the Archer-Antiquaries journal c. 1966.

Brace height about 6-7", draw to perhaps 35", assume linear force-draw curve, and one gets about 250-300J for a reasonable range of draw lengths. The long draw length comes from both the hand being drawn back to in front of the rear shoulder, and the thumb draw putting the string closer to the wrist. (And the Manchu thumbring puts the string 1" further back than a tabbed thumb ring!) A longer draw than 35" is plausible, too, but starts to need a tall (or at least long-armed) archer.

A Manchu bow is much bigger than a Turkish bow, but given that the Manchu arrows are much heavier, perhaps 80% efficiency is plausible? Doesn't change too much if we assume 70%, but then we want to start with closer to 300J stored.

"In addition to being efficient, all pole arms were quite nice to look at." - Cherney Berg, A hideous history of weapons, Collier 1963.
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Randall Moffett




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PostPosted: Mon 12 Mar, 2012 6:40 pm    Post subject:         Reply with quote

Timo,

OK. How was this measured? Seems very high but I guess it could be. I do not know enough about these types of bows really. That woudl be truly an awesome amount of energy though. Liebel puts a 750lb crossbow with composite prod at 331J initial energy (which I think it not stored but right upon loosing the bolt but he is unclear). At impact, (which I can only assume is the 180 meters-once again he is unclear, but this is the only specific distance he mentions) is 126J. Cleary a bow and crossbow are different but 200J of initial energy ondce released would be immense.

Was this part of a larger test or experiment that was done?

RPM
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Benjamin H. Abbott




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PostPosted: Mon 12 Mar, 2012 9:29 pm    Post subject:         Reply with quote

I'd call it informed speculation. We have solid data on English and Turkish bows. Scholars have weighed surviving arrows, calculated the draw weights of surviving bows, and taken performance tests of replica bows. By combing this information with understanding the physics involved as well as surviving arrows and historical draw weights, we can guess the power of Manchu bows.

As Liebel's numbers go, I have a lot of trouble believing any personal crossbow delivered more than 300 J. Get much past 300 J and you're punching through high-quality breastplates. The evidence suggests even windlass-drawn crossbows couldn't do that; they tested armor against heavy crossbows. For a 750lb crossbow to do deliver 331 J, it would have to have a power stroke outside the range of any European crossbow I've ever encountered and/or be extremely efficient. An actual 616lb crossbow with a 9-inch power stroke managed only 95 J with a 90-gram bolt. I think something must be off with that crossbow, but probably not by a factor of three.

Read my historically inspired fantasy fiction in here. I walk along a winding path set by Ludovico Ariosto, William Morris, J. R. R. Tolkien, and Ursula Le Guin.

Out of doubt, out of dark to the day's rising
I came singing in the sun, sword unsheathing.
To hope's end I rode and to heart's breaking:
Now for wrath, now for ruin and a red nightfall!
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Timo Nieminen




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PostPosted: Mon 12 Mar, 2012 11:41 pm    Post subject:         Reply with quote

I've seen measured force-draw curves for modern replica Manchu bows. Convex early in the draw, a little concave near the end of the draw as the bow stacks. There replicas are short draw length compared to originals (and lower draw weight, too), and significantly less reflexed. An original bow should give a more convex force-draw curve, and stack less, so should be better. So, to assume a linear force-draw curve is probably an under-estimate for a good original, and is a good approximation for a modern replica (as long as it doesn't stack too much).

Given a linear force draw curve, the stored energy is just (1/2) * F * (DL - BH), where F is the force at full draw, DL is the draw length, and BH is the brace height (that is, DL - BH is the distance the string is drawn back). F in newtons (pounds/2.2*9.8) and DL, BH in metres and you get the energy in joules. A convex force-draw curve, such as you should have with a good recurve-reflex bow, will give more stored energy, a concave force-draw curve (like a typical straight bow) will give less.

Draw weights we can get from literature (especially military examination rules and other military regulations); a whole bunch of this information is in Stephen Selby's "Chinese Archery".

That part is straightforward if we're prepared to make such simple assumptions about the force-draw curve. What the efficiency will be is a much more open question, but we know that a heavy bow like the Manchu bow will need a heavy arrow to obtain a reasonable efficiency. My estimates for efficiency are just guesses based on what is typical for decent bows (70%-80% looks OK, for heavy arrows). Given that the efficiency depends on the arrow weight, and making too-light arrows heavier gives you a lot more energy and costs little speed, my working assumption is that the typical 100g Manchu arrow gives reasonable performance.

Needham gives average range of modern Chinese/Manchu bows (156lb) as 200 yards, extreme range as 250 (so less than half that of Turkish bows). Don't know what weight arrows were used for this.

"In addition to being efficient, all pole arms were quite nice to look at." - Cherney Berg, A hideous history of weapons, Collier 1963.
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