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Jean Thibodeau




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PostPosted: Mon 01 Jul, 2013 11:51 pm    Post subject:         Reply with quote

X Zang, thank you for your replies and the very interesting information in them, very much appreciated.


For shooting a series of bolts up a wall maybe some very robust steel or iron bolts would work to be able to support the weight of soldiers using them as steps to climb up a wall ..... well maybe it only need to have a strong metal head and socket that will leave a few inches of very solid metal protruding from the wall even if the wooden shaft of the bolts breaks off ?

Just speculation, but very athletic soldiers would only need a short but solid piece to stick out of the stone walls to climb up.

Probably good to support them with covering fire from smaller crossbows of the same type plus other archers to force the defenders to keep their head down as the soldiers climb up the wall.

These triple bow crossbows seem to have been invented very early but still used over more than a thousand years or two as they must have continued to be seen as useful and effective.

Congratulations to the unknown ( Or I assume unknown ) genius who came up with the idea of multiplying the force and effectiveness of one crossbow prod in this manner.

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X Zhang





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PostPosted: Tue 02 Jul, 2013 1:11 am    Post subject:         Reply with quote

Jean Thibodeau wrote:
X Zang, thank you for your replies and the very interesting information in them, very much appreciated.


For shooting a series of bolts up a wall maybe some very robust steel or iron bolts would work to be able to support the weight of soldiers using them as steps to climb up a wall ..... well maybe it only need to have a strong metal head and socket that will leave a few inches of very solid metal protruding from the wall even if the wooden shaft of the bolts breaks off ?

Just speculation, but very athletic soldiers would only need a short but solid piece to stick out of the stone walls to climb up.

Probably good to support them with covering fire from smaller crossbows of the same type plus other archers to force the defenders to keep their head down as the soldiers climb up the wall.

These triple bow crossbows seem to have been invented very early but still used over more than a thousand years or two as they must have continued to be seen as useful and effective.

Congratulations to the unknown ( Or I assume unknown ) genius who came up with the idea of multiplying the force and effectiveness of one crossbow prod in this manner.

in my mind, this crossbow was always used for defensive warfare or field operations rather than siege. after all, shooting siege towers and chariots by it are more effective than shooting stone castles……

And……in fact……this crossbow is a large category of weapons. Chinese name is "床弩", means about……Perhaps……“large fixed crossbow” . And it is not always have three bows. some crossbows have only two bows, so it makes to be lighter and smaller and easy to quickly deploy.

like this

for 4-person team

Certainly, there is big one for 70 operators also……like this one
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X Zhang





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PostPosted: Tue 02 Jul, 2013 2:25 am    Post subject:         Reply with quote

And, look at the bolt in first picture.

"錾头箭" means “chisel head bolt”. This is a very common about chinese large crossbow……it is designed to attack armored unit
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Daniel Wallace




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PostPosted: Tue 02 Jul, 2013 8:21 am    Post subject:         Reply with quote

i was recently looking through one of my reference books on an unrelated note - there was an artists concept of a European example that was described as a 'arcubalista' it looked as if it was built up of one horizontal bow, and two other vertical bows. described similarly to sling heavy bolts or 'shot' (I'm guessing a fist size iron ball).



by the description your able to give X Zhang, the advantage this triple crossbow seems to be penetrative power. Idea i wounder, if the bows in this configuration somehow amplifies the draw length of the shot without over drawing the bows. in other words if the draw length on each bow would be 28 inches, is the triple bow still pulling the equivalent of that, or does can it draw each bow back 28inches but the total draw be more than that? Confused

i feel like that may be a physics question there. WTF?!
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T. Kew




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PostPosted: Tue 02 Jul, 2013 11:27 am    Post subject:         Reply with quote

Looking at the double bow with its single continuous string, you'll get equal draw on each of the two bows (roughly speaking). Consequently if you make one with e.g. two bows each of which is drawn about 5", your overall draw will then be 10" or so. I'm fairly sure this only works if they're of equal draw weight, though. You'll also presumably get the draw weight being added together - so at 10" a double-bow will have the draw weight of each individual bow at 5".
HEMA fencer and coach, New Cross Historical Fencing
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X Zhang





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PostPosted: Tue 02 Jul, 2013 5:48 pm    Post subject:         Reply with quote

And……FORGET 1000 yards range

i scoured 《武经总要》pages, the Max range is 300 double-paces in it, 600paces, about 450 meters.

500 yards range……more than English long bow and less than Turkish bow……
Sounds reasonable
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Daniel Wallace




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PostPosted: Wed 03 Jul, 2013 9:31 am    Post subject:         Reply with quote

X Zhang wrote:
And……FORGET 1000 yards range

i scoured 《武经总要》pages, the Max range is 300 double-paces in it, 600paces, about 450 meters.

500 yards range……more than English long bow and less than Turkish bow……
Sounds reasonable



i wondered how that show came up with 1000 yards? 1000 yards just seems like something out of this world, its not that if this were true i wouldn't believe it, but the application of such range is just improbable - it may as well be artillery.
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Jean Thibodeau




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PostPosted: Thu 04 Jul, 2013 3:19 am    Post subject:         Reply with quote

Daniel Wallace wrote:
X Zhang wrote:
And……FORGET 1000 yards range

i scoured 《武经总要》pages, the Max range is 300 double-paces in it, 600paces, about 450 meters.

500 yards range……more than English long bow and less than Turkish bow……
Sounds reasonable



i wondered how that show came up with 1000 yards? 1000 yards just seems like something out of this world, its not that if this were true i wouldn't believe it, but the application of such range is just improbable - it may as well be artillery.


Maybe they spoke too fast and meant 1000 feet instead of yards ?

Or, they spoke from being impressed at seeing the bolt fly so fast and disappeared into the distance ? A 1000 yards being poetic license rather than a measure distance ?

In any case 450 metres is very impressive and would have been very effective if hundreds of these where used all at the same time.

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X Zhang





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PostPosted: Thu 04 Jul, 2013 8:08 am    Post subject:         Reply with quote

Jean Thibodeau wrote:
Daniel Wallace wrote:
X Zhang wrote:
And……FORGET 1000 yards range

i scoured 《武经总要》pages, the Max range is 300 double-paces in it, 600paces, about 450 meters.

500 yards range……more than English long bow and less than Turkish bow……
Sounds reasonable



i wondered how that show came up with 1000 yards? 1000 yards just seems like something out of this world, its not that if this were true i wouldn't believe it, but the application of such range is just improbable - it may as well be artillery.


Maybe they spoke too fast and meant 1000 feet instead of yards ?

Or, they spoke from being impressed at seeing the bolt fly so fast and disappeared into the distance ? A 1000 yards being poetic license rather than a measure distance ?

In any case 450 metres is very impressive and would have been very effective if hundreds of these where used all at the same time.


er……you know…………there are Extreme Range, Effective Range and Average Engagement Range…………
The Turkish bow could send a light arrow acoss the distant of 600 yards, but in the actual war……

And the case of 450m, it used a kind of small steel arrow what looks like a big dart. And this ammunition is just used for Anti-personnel.
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Jean Thibodeau




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PostPosted: Fri 05 Jul, 2013 11:25 am    Post subject:         Reply with quote

X Zhang wrote:


er……you know…………there are Extreme Range, Effective Range and Average Engagement Range…………
The Turkish bow could send a light arrow acoss the distant of 600 yards, but in the actual war……

And the case of 450m, it used a kind of small steel arrow what looks like a big dart. And this ammunition is just used for Anti-personnel.


Yes I do realize that there is a difference, but effective range can vary depending on what one is trying to do: If aiming at one small target effective range will be a lot lower than maximum possible range.

If aiming at a large formation of closely grouped soldiers the effective range become where one has a reasonable expectation of hitting a target but not a specific target.

At the absolute maximum range of these triple bow crossbows, a single one would do very little, but hundreds of them could still rain down a more or less effective very long range suppressive fire.

Now, this might be a waste of ammunition better used at much closer range.

At extreme range all of the bolts might miss, but they would make being on the receiving side a bit dangerous and scary.

All, this said, I understand the point you where making about the different ranges being distinct in their possible usefulness or futility. Big Grin Cool

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David J.





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PostPosted: Sat 06 Jul, 2013 8:43 am    Post subject: Triple Crossbow         Reply with quote

Quote:
Consequently if you make one with e.g. two bows each of which is drawn about 5", your overall draw will then be 10" or so. I'm fairly sure this only works if they're of equal draw weight, though


That would be correct if, and only if, the angle of the of the string bow would be improbably acute (i.e. 0 degrees). In fact a bow that is drawn 5" adds more 5" inches of draw when the string angle is more obtuse. A bow limb may only be drawn 5", but it can yield a20" draw .

Hypothetically, a single bow crossbow may provide 20" of draw when the limbs are displaced 5" inches. The addition of a second prod, also displaced 5 inches, utilizing a pulley system may add another 10" of draw, but it will never double the draw unless the string has no discernible angle throughout the entire power stroke. The addition of a third bow at the front of weapon will not add any draw length as it is not leveraged.

Quote:
it would seem true, but why not just build it into one big limb?


That does not work very well due to the relationship between surface area and volume. Surface area goes up squared, volume goes up cubed. If you had a bow and doubled the dimensions (length, width and height), would would end up with a bow 8 times as heavy, but only 4 times as much working surface area. A giant, single bow would be lethargic, barely able to move its own limbs, let alone a projectile. The dry fire speed (Maximum velocity) would be extremely low. The Chinese understood this, as did the Greeks (more on that later). A triple bow crossbow would have three times the mass (for the bows), but also three times the surface area. Theoretically, it would be able to launch a projectile three times as heavy at the same velocity. The pulley system would also assist in higher dry fire speed. However, unlike modern compound bows, the draw force curve would not be improved in such a system.

Is there any documentation on how the back and middle bow were connected? A pulley system like this?:

http://www.youtube.com/watch?v=86Nv1Yz9x1g

Or connected by just wrapping the string around the limb?:

http://0.tqn.com/d/asianhistory/1/0/M/B/-/-/crossbow.jpg

Quote:
1000 yard range is impressive and I wonder at what velocity the missile leaves the crossbow ? ( one could say muzzle velocity but technically there isn't a muzzle. Wink Laughing Out Loud ).


That is easy to determine in vacuum. The formula is range is: Range= ((V^2) * Sin (2 * Angle))/Gravity. So V= Sqrt (Range * Gravity/Sin(2 * Angle)). In order to reach 1,000 yards in vacuum, you need 311 fps at a 45degree angle. Realistically, you would need more speed when you factor in aerodynamic drag. Less aerodynamic projectiles will need substantially more velocity. Torsion powered catapults can launch 4 kg pumpkins at over 700 fps, but the horrible aerodynamic characteristics of pumpkins yields ranges of only 1,200 yards or so. In vacuum, those pumpkins would go over 5 kilometers, or over 3 miles.

Quote:
I am no expert but as I understand it the long bow style of limb tends to be suited better to shooting heavy missile while the faster limb action of the recurve suits lighter higher velocity arrows.


Longer limbed bows will provide more favorable draw force curves, all else equal, thus storing more energy. However, that energy is worthless if it can't be transferred to the arrow. A longer limbed bow will shoot an arrow with more kinetic energy if the arrow is heavy enough (say 15 grains/pound), but will have trouble casting light arrows, as much of the energy will be utilizing to accelerate the heavy limbs.

Quote:
The Turkish bow could send a light arrow acoss the distant of 600 yards, but in the actual war……


I think the record is +/-930 yards. The Turkish flight bows were short, highly reflexed and had a high draw weight. They utilized short, aerodynamic arrows that were shot using an overdraw device (Siper):

http://www.youtube.com/watch?v=nXs8voBJbJk

Koreans also had an overdraw device like this one:

http://www.youtube.com/watch?v=e2Fnb2c5f98

800+ yards is claimed for the Korean, though not verified, is possible.

Back to the Greeks. While the Chinese solution to building larger, more powerful tension bows was ingeniously simplistic, the Greek's solution was complex marvel that would push the bounds of projectile velocity. Utilizing a torsion spring, the Greek ballista (later roman torsion powered variations in particular) allowed extremely high velocity to be achieved by concentrating the energy storing material (Sinew) near the fulcrum. Thus, the outside of the torsion spring would only have to move a fraction of an inch for every inch the tip of the limb moves. The result is very high dry fire speed.

http://alexisphoenix.org/ballista.php
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X Zhang





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PostPosted: Sat 06 Jul, 2013 11:29 pm    Post subject: Re: Triple Crossbow         Reply with quote

David J. wrote:
Quote:
Consequently if you make one with e.g. two bows each of which is drawn about 5", your overall draw will then be 10" or so. I'm fairly sure this only works if they're of equal draw weight, though


That would be correct if, and only if, the angle of the of the string bow would be improbably acute (i.e. 0 degrees). In fact a bow that is drawn 5" adds more 5" inches of draw when the string angle is more obtuse. A bow limb may only be drawn 5", but it can yield a20" draw .

Hypothetically, a single bow crossbow may provide 20" of draw when the limbs are displaced 5" inches. The addition of a second prod, also displaced 5 inches, utilizing a pulley system may add another 10" of draw, but it will never double the draw unless the string has no discernible angle throughout the entire power stroke. The addition of a third bow at the front of weapon will not add any draw length as it is not leveraged.

Quote:
it would seem true, but why not just build it into one big limb?


That does not work very well due to the relationship between surface area and volume. Surface area goes up squared, volume goes up cubed. If you had a bow and doubled the dimensions (length, width and height), would would end up with a bow 8 times as heavy, but only 4 times as much working surface area. A giant, single bow would be lethargic, barely able to move its own limbs, let alone a projectile. The dry fire speed (Maximum velocity) would be extremely low. The Chinese understood this, as did the Greeks (more on that later). A triple bow crossbow would have three times the mass (for the bows), but also three times the surface area. Theoretically, it would be able to launch a projectile three times as heavy at the same velocity. The pulley system would also assist in higher dry fire speed. However, unlike modern compound bows, the draw force curve would not be improved in such a system.

Is there any documentation on how the back and middle bow were connected? A pulley system like this?:

http://www.youtube.com/watch?v=86Nv1Yz9x1g

Or connected by just wrapping the string around the limb?:

http://0.tqn.com/d/asianhistory/1/0/M/B/-/-/crossbow.jpg

Quote:
1000 yard range is impressive and I wonder at what velocity the missile leaves the crossbow ? ( one could say muzzle velocity but technically there isn't a muzzle. Wink Laughing Out Loud ).


That is easy to determine in vacuum. The formula is range is: Range= ((V^2) * Sin (2 * Angle))/Gravity. So V= Sqrt (Range * Gravity/Sin(2 * Angle)). In order to reach 1,000 yards in vacuum, you need 311 fps at a 45degree angle. Realistically, you would need more speed when you factor in aerodynamic drag. Less aerodynamic projectiles will need substantially more velocity. Torsion powered catapults can launch 4 kg pumpkins at over 700 fps, but the horrible aerodynamic characteristics of pumpkins yields ranges of only 1,200 yards or so. In vacuum, those pumpkins would go over 5 kilometers, or over 3 miles.

Quote:
I am no expert but as I understand it the long bow style of limb tends to be suited better to shooting heavy missile while the faster limb action of the recurve suits lighter higher velocity arrows.


Longer limbed bows will provide more favorable draw force curves, all else equal, thus storing more energy. However, that energy is worthless if it can't be transferred to the arrow. A longer limbed bow will shoot an arrow with more kinetic energy if the arrow is heavy enough (say 15 grains/pound), but will have trouble casting light arrows, as much of the energy will be utilizing to accelerate the heavy limbs.

Quote:
The Turkish bow could send a light arrow acoss the distant of 600 yards, but in the actual war……


I think the record is +/-930 yards. The Turkish flight bows were short, highly reflexed and had a high draw weight. They utilized short, aerodynamic arrows that were shot using an overdraw device (Siper):

http://www.youtube.com/watch?v=nXs8voBJbJk

Koreans also had an overdraw device like this one:

http://www.youtube.com/watch?v=e2Fnb2c5f98

800+ yards is claimed for the Korean, though not verified, is possible.

Back to the Greeks. While the Chinese solution to building larger, more powerful tension bows was ingeniously simplistic, the Greek's solution was complex marvel that would push the bounds of projectile velocity. Utilizing a torsion spring, the Greek ballista (later roman torsion powered variations in particular) allowed extremely high velocity to be achieved by concentrating the energy storing material (Sinew) near the fulcrum. Thus, the outside of the torsion spring would only have to move a fraction of an inch for every inch the tip of the limb moves. The result is very high dry fire speed.

http://alexisphoenix.org/ballista.php


i'm afraid that the initial velocity and dispersion are not catapult's strongest suit. Perhaps catapult is better at high-torque.
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David J.





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PostPosted: Sun 07 Jul, 2013 7:07 am    Post subject:         Reply with quote

Quote:
i'm afraid that the initial velocity and dispersion are not catapult's strongest suit. Perhaps catapult is better at high-torque.


Torsion weapons (scorpions, onagers, ballistas, carroballistas, etc.) can achieve amazing velocity, and consequently long range. Did you check out the links I posted? From my posted link:

Quote:
Firefly smacking out a heavy one pound bolt (467 grams) at an estimated 360 feet per second, with the sharp tipped bolt being found protruding from Mother Earth at an approx. 45 degree angle, 845 yards downrange.


From here:

http://alexisphoenix.org/ballista.php

Also please check out:

http://wattsunique.com/blog/


And this:

http://en.wikipedia.org/wiki/Pumpkin_chunking

Torsion beats out all other machines except modern air cannons.

The sinew spring is concentrated at the fulcrum. This means that torque is reduced, but offers the advantage of high efficiency with light projectiles.
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Jean Thibodeau




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PostPosted: Tue 09 Jul, 2013 3:52 am    Post subject:         Reply with quote

David J. wrote:
Quote:
i'm afraid that the initial velocity and dispersion are not catapult's strongest suit. Perhaps catapult is better at high-torque.


Torsion weapons (scorpions, onagers, ballistas, carroballistas, etc.) can achieve amazing velocity, and consequently long range. Did you check out the links I posted? From my posted link:


Torsion beats out all other machines except modern air cannons.

The sinew spring is concentrated at the fulcrum. This means that torque is reduced, but offers the advantage of high efficiency with light projectiles.


Thanks for the links: Impressive information, the torsion weapons do seem to be more powerful as medium to heavy field artillery and/or for static sieges in the bigger versions of onager. Cool

The Triple Bow Crossbows, to me, seem to have two real advantages in being relatively light weight and can be taken down for storage and travel: I think they are a good choice as very light field artillery easy to move around on a light cart and needing very few men for each.

They are also more efficient and have more range than a European styles crossbow with a single prod, but the single prod crossbows are more practical as individual weapons at the cost of having to use very heavy draw weights that they use inefficiently.

The more powerful torsion machines look a lot heavier and would be less handy: Closer to 18th century canon in weight, maybe similar to a 3 or a 6 pounder canon, and needing a lot of muscle power in the form of draft horses to manoeuvre if we use an anachronistic tactical model of comparing their possible uses as field artillery in close support of infantry ..... maybe ?

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David J.





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PostPosted: Sat 13 Jul, 2013 8:28 am    Post subject:         Reply with quote

Quote:
Thanks for the links: Impressive information, the torsion weapons do seem to be more powerful as medium to heavy field artillery and/or for static sieges in the bigger versions of onager.


The onager was a Roman invention that replaced the siege ballista. It was simpler than the ballista (1 torsion spring vs. 2) and there was no need to synchronize multiple torsion springs. It also appears that in the same foot print, the onager can have a more massive torsion spring. However, accuracy will be diminished with the onager compared to the ballista.

Quote:
The Triple Bow Crossbows, to me, seem to have two real advantages in being relatively light weight and can be taken down for storage and travel: I think they are a good choice as very light field artillery easy to move around on a light cart and needing very few men for each.


I agree, with a caveat. Multi-Bow Crossbows were of various sizes. X Zhang posted two pictures and notated that the double bow crossbow utilized 4 men and the triple bow crossbow required 70 men. The 70 men crossbow would be only practical in sieges. The triple bow-crossbows in the posted links were small and likely very portable.
Anti-personnel torsion weapons could also be compact. The Xanten Catapult, a wooden frame device, was certainly compact:

http://www.romanarmy.net/xanten.shtml

Here is a compact iron frame device:


http://torsionsfire.de/Shooting.html

200m with a 5400 grain projectile is not that impressive when compared to the larger Orsova ballista I posted links to earlier, but it still translates to about 300 ft. lbs. of energy. The carroballista was a cart mounted ballista moved by donkeys. There is some debate whether the ballista was shot from the cart or just transported to and from the battlefield by the cart.

Quote:
They are also more efficient and have more range than a European styles crossbow with a single prod, but the single prod crossbows are more practical as individual weapons at the cost of having to use very heavy draw weights that they use inefficiently.


I would like to see the a more reconstructions with period material to better understand the performance characteristics of multi-prod crossbows, or any antiquated crossbows for that matter. Here are is a link to some heavy weight composite crossbow testing:

http://www.historiavivens1300.at/biblio/beschuss/beschuss1-e.htm
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Benjamin H. Abbott




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PostPosted: Mon 02 Dec, 2013 1:22 pm    Post subject:         Reply with quote

Note that Firefly - mentioned here earlier - has shot 998 yards. I guess crossbows may not be able to produce the same velocity, but torsion can. Various torsion weapons saw use in medieval times until replace by gunpowder weaponry.

Oh, and apparently there are claims of 1,000+ yards for triple crossbows.
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Jean Thibodeau




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PostPosted: Mon 02 Dec, 2013 10:36 pm    Post subject:         Reply with quote

One big difference between the European single bow crossbows and the Chines triple bow crossbows seems to be that the power stroke and the bolt are much longer, so probably they get a lot more speed out of their crossbows because of better use of the stored energy in the bows.

Also the total draw weight can be equal or higher without making a single bow prod with very thick and heavy diminishing the efficiency of the weapon.

The return speed of materials become a case of diminishing return when the prods become very thick and heavy: With each bow on a triple bow Crossbow one can add the draw weight of each to the total draw, have a very long power stroke without overstraining the bows and each bow built lightly enough to be fast and responsive I think ?

This is my best guess that can make it credible that range on these can be very high: Velocity may top off at some point when the elastics and return speeds of the prods reach their optimum level of efficiency, but the same speed of limbs, but with more draw weight means that one can increase the mass of the missile for greater momentum and striking power without a significant reduction of missile speed.



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TBC01.JPG
My drawing interpretation of a tripple bow crossbow, some elements are just my ideas of how I would design one and not stylistically Chinese or historical.

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TBC02.JPG
Close up of crossbow string.

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TBC03.JPG
The other side.

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TBC05.JPG
My idea of scale for a man portable single user weapon as opposed to larger carriage or stripod mounted siege versions.

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TBC08.JPG
From an " Oaprey " book on Chinese siege weapons: This one being a double bow crossbow.

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TBC10.JPG
From the same book, and the drawing I based my fantasy version in my drawings.

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X Zhang





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PostPosted: Tue 03 Dec, 2013 7:09 pm    Post subject:         Reply with quote

Jean Thibodeau wrote:
One big difference between the European single bow crossbows and the Chines triple bow crossbows seems to be that the power stroke and the bolt are much longer, so probably they get a lot more speed out of their crossbows because of better use of the stored energy in the bows.

Also the total draw weight can be equal or higher without making a single bow prod with very thick and heavy diminishing the efficiency of the weapon.

The return speed of materials become a case of diminishing return when the prods become very thick and heavy: With each bow on a triple bow Crossbow one can add the draw weight of each to the total draw, have a very long power stroke without overstraining the bows and each bow built lightly enough to be fast and responsive I think ?

This is my best guess that can make it credible that range on these can be very high: Velocity may top off at some point when the elastics and return speeds of the prods reach their optimum level of efficiency, but the same speed of limbs, but with more draw weight means that one can increase the mass of the missile for greater momentum and striking power without a significant reduction of missile speed.


do you think about harm of friction?I still think that it should has a pulley system
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Jean Thibodeau




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PostPosted: Wed 04 Dec, 2013 1:49 am    Post subject:         Reply with quote

X Zhang wrote:
Jean Thibodeau wrote:
One big difference between the European single bow crossbows and the Chines triple bow crossbows seems to be that the power stroke and the bolt are much longer, so probably they get a lot more speed out of their crossbows because of better use of the stored energy in the bows.

Also the total draw weight can be equal or higher without making a single bow prod with very thick and heavy diminishing the efficiency of the weapon.

The return speed of materials become a case of diminishing return when the prods become very thick and heavy: With each bow on a triple bow Crossbow one can add the draw weight of each to the total draw, have a very long power stroke without overstraining the bows and each bow built lightly enough to be fast and responsive I think ?

This is my best guess that can make it credible that range on these can be very high: Velocity may top off at some point when the elastics and return speeds of the prods reach their optimum level of efficiency, but the same speed of limbs, but with more draw weight means that one can increase the mass of the missile for greater momentum and striking power without a significant reduction of missile speed.


do you think about harm of friction?I still think that it should has a pulley system


Keep in mind that my drawing is a fantasy design and if it was to be actually made it would need more attention to details like friction that could wear away the crossbow string and how it would be armed using a pulley system.

One thing I would do is that the parts of the bows where the sting slides against would have to be rounded rather than of rectangular section as in my drawing, and even better if wrapped in a very smooth and low friction material: This could be horn surfaces added over the ends of the prods ?

I added a cross-pin in the stock for a European styled cranequin cocking device that is removable for a smaller triple bow crossbow like this, but a pulley system might be integral to a larger siege piece serviced by a crew of loaders and a shooter.

http://www.todsstuff.co.uk/crossbows/spanning...ssbows.htm

http://www.todsstuff.co.uk/crossbows/hunting-crossbows.htm

The style of my drawing is a fantasy version of what a European Triple bow crossbow might have looked like if the Europeans had even had the same brilliant idea as the Chinese inventors of the triple crossbow,

Not historical, but might be interesting in a fiction novel or might be interesting as something to make ? Although, to have this made it would be expensive if one wanted a really well made one as it would take a lot of work to fine tune the design to function well, and also the size and ergonomics would also have to be carefully thought out for it to work as a hand portable crossbow.

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Kurt Scholz





Joined: 09 Dec 2008

Posts: 390

PostPosted: Wed 04 Dec, 2013 6:51 am    Post subject:         Reply with quote

The triple and double crossbow design is not limited to China, it was also employed in South East Asia.
A major technical challenge, that has not yet been discussed, is tuning the two to three bows in order to launch the arrow straight. If I'm correct, this tuning is a major challenge, experienced crossbowmasters such as the South Asian needed help for from Chinese specialists. It also explains, why even in China the multiple bow crossbows are always large artillery systems and never small handheld weapons.
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