Excellent post matt! Exactly what I was looking for in this thread.
Maybe I’m missing something here. I’ve used a ratchet system to lift a car rapidly using just muscle power…and a car weighs significantly more than even the 750lb draw you mentioned (I’m also not exactly Arnold here with massive thews of steel). Granted, most of the rapid systems I’ve seen are hydrolic…but it should be possible to do the same thing with a series of differential gears, perhaps with some pulleys as well. No? Using a modern understanding of how mechanical advantage works, surely its possible to get 750lbs of draw by someone who can do 125lbs…thats less than 7 to 1 which doesn’t seem unreasonable to me.
According to Michael Bellesiles’ controversial book Arming America, the great range and penetrating power of the longbow (not the crossbow) did, in fact, relegate personal firearms to a marginal role, until somebody invented a fairly simple and reliable muzzle-loading flintlock musket (the earlier arquebuses having been more complex and more difficult to handle in a combat situation).
Here’s the thing: as you increase mechanical advantage, you also increase the input movement length. Take two hydraulic jacks, a one ton jack and a ten ton jack. For the same amount of work I do pumping the handle, the ten ton jack will only move 1/10 as far as the one ton jack. A hydraulic jack (or any other mechanical advantage device) doesn’t amplify your physical effort; it merely concentrates it.
If you increase the mechanical advantage on your crossbow crank by a factor of three, you now need to move the crank three times as far to pull the string back the same distance. The only way to increase the mechanical advantage of a crank without increasing the number of turns it has to make would be to increase the length of the crank arm itself, thereby providing greater leverage, but I would imagine that longer crank arms on a crossbow very rapidly become impracticable.
In the accounts of medieval battles, most crossbowmen seemed to be mercenary soldiers (Genoese, Swiss, Florentines). Being hired, most would probably not have fought with such elan as the English longbowmen. In an account of the Battle of Crecy, these hired crossbowmwn actually sized up the situation and left the battle early. I suspect that the crossbow was a good weapon for siege warfare, but not so good in open battle (a longbowman could get of several arrows while the hapless crossbowman was winding his crank. In any event the crossbow disappeared very rapidly, once the musket was developed.
Now, though, you’re starting to get not only into complexity, but also weight and dimensionality issues. Machines can get you the most out of yoiur muscles, but the upper limit is still reached far, far below what a relatively primitive chemically powered device can do. And there’s a limit as to what gears can do for you unless you start getting into some pretty large and/or heavy gears, and there’s a limit to the tension that a machine of a given structural strength can take. You don’t want your soldiers carrying frickin’ bicycles around.
Machinery’s great but the conversion from muscle-powered to chemical-powered devices is invariably a huge, huge revolution in warfare, whether it’s the propelling of projectiles or the movement of soldiers and material.
…and yet they were *still using them *at the end of the 19th C. So clearly it had some utility for them, even when they also had composite bows, foot bows, firearms, flamethrowers… bandit said he couldn’t see what possible use such a weapon could have. Maybe the high rate of fire is all it takes to make it useful in certain situations.
Perfectly correct. It’s just that your 7 to 1 mechanical advantage also means you have to move the cranking device through 7 times the distance of the straight pull. Another factor here is how you use a crank or windlass, compared with a straight pull. Compare the two images near the top of this page. It’s quite a different way of using your arms! The sorts of mechanical advantages I’ve been reading about are between 40-1 and 100-1 for a cranequin, depending on the gearing. Whether you actually need such high mechanical advantages to crank, I’ve no idea without actually trying the things.
My ballpark guesstimate is that a 3-turn crank gives a roughly 19-1 advantage (I assumed crank arm is twice the draw length) which on simple considerations should be more than enough, but is nowhere near the advantage of historic cranequins. Truth is, unless we build the things and play with them, we’re just not going to be able to know how easy or hard they were to use. I can’t even find out how many cranks the historic cranks take to draw a bow, youtube and google video have let me down…
“the windlass, was introduced in the 14th century. This used pulleys, attached at the butt end of the stock to a winding device that, when hooked onto the bowstring and wound, drew it to the trigger. The windlass could draw the string in only 12 seconds, even though it had a pull of 545 kilograms (1,200 lb).”
“The cranequin required very little strength to draw the crossbow string, but it was slower than the windlass, requiring 35 seconds for loading.”
So it looks like the cranequin was like a scissors-type car jack, not requiring much force but taking a lot of winding.
Not quite. The matchlock musket was a very successful weapon for a very long time. While it isn’t particularly suited to use a personal defense weapon or hunting weapon, due to the smoldering match which ignites the powder charge, matchlocks worked reasonably well as military weapons. The matchlock musket could be fired more quickly than a crowwbow that required a cocking mechanism, too. Wikipedia has a decent article about matchlocks.
Alright, I should have been more specific. On a battlefield, these things were not as useful, and the Chinese did not use them on the battlefield very much. They did use them for guarding, and were popular on the Great Wall. You could send out a nice volume of fire. But volumes of ineffective fire wasn’t that useful unless the enemy tried human wave tactics. Anyone with seige weapons could easily defeat a city defended by Chu-Ko-Nu.
On the other hand, note that the Chinese didn’t use them all that much on the batllefield, and that virtually none of their enemies wore serious armor. In addition, they’re not known as particularly great weapons, and no accounts of Chinese wars or battles I’ve read give so much as a mention of them, whereas they sometimes go into considerable detail about force composition, training, and armament. The best late Chinese generals, even against light forces (where you’d expect the things to be most useful), used wholly different weapons.
This site has the sole description of the things being used in battle I’ve ever heard of.
However, there’s rather some doubt as to whether or not this story is likely. It’s highly implausible that a force of 1000 crossbowman could even get their hands on that many bolts. Likewise, if they had to fire that many, the enemy either had about a million men or were not particularly hurt by it. And given that the Chinese eventually had to bribe the Huns, it aparently wasn’t a devastating weapon.
One innovation used in crossbows was a mechanism that varied the force of the bow through the range of it’s draw. It was referred to as “the Virgin”, since “it offered little resistance when slack and much resistance when taut”.
I still appreciate your and others posts in this thread. Its given me a lot to chew on here. I’ve always wondered why anyone bothered with gunpowder in the early days when it seemed you could get more battle field effect from the more convention weapons of the day (long bow and cross bow). I understood why the long bow was eventually eclipsed…it took a lot of training and practice to make an effective long bowman (or horsebowman). Years in fact. While training some mope to stand in a line and fire even the early matchlock weapons was really just a matter of a few weeks training to load and fire…and the much harder training to get them to actually stand there and do it when under fire. But I always wondered about the crossbow. It doesn’t take much training to teach someone to load and fire, and if you used it in the same kind of line formation and if you could get it to reload relatively rapidly…well, a lot of what ifs there, no doubt.
