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LibraryOgre
2010-02-05, 03:31 PM
So, a hand crossbow is cocked by hand, a light crossbow uses a lever, and a heavy crossbow uses a crannequin.

Why couldn't a higher-strength character make use of a higher-strength crossbow? It seems to me that someone with an 18 strength should be able to **** a heavier bow than someone with an 8, using the mechanical aid of a lever, and what they can accomplish with a cranked crossbow should be limited pretty much by material strength... but someone with an 18 strength is limited to the same crossbows as everyone else.

Any else though of these? How would you handle it?

Seatbelt
2010-02-05, 03:33 PM
The actual act of firing the crossbow is mechanical. Thats like suggesting that a higher strength score should grant more damage on a flintlock rifle. Yeah you gotta ram it in there, but all do to fire is squeeze.

Starbuck_II
2010-02-05, 03:34 PM
So similar to composite bow: to use the lever you must be stronger?

That seems fine. But the Str bonus of the crossbow would depend on it not you except for reloading.

What name would you call these hard to load + stronger bolts?

CTLC
2010-02-05, 03:35 PM
i understand the idea of being able to store more potential energy by having a tauter Xbow and more strength. itd be very hard, and require a lot of strength. i dont know much about xbows, but i doubt the difference would be so great. and the bow might break.

Riffington
2010-02-05, 03:35 PM
Right. What he wants is a powerful crossbow that can't be loaded without a Str 16.

Or a flintlock handcannon that would knock your sorcerer flat on his back if he tried to fire it.

Overshee
2010-02-05, 03:35 PM
So, a hand crossbow is cocked by hand, a light crossbow uses a lever, and a heavy crossbow uses a crannequin.

Why couldn't a higher-strength character make use of a higher-strength crossbow? It seems to me that someone with an 18 strength should be able to **** a heavier bow than someone with an 8, using the mechanical aid of a lever, and what they can accomplish with a cranked crossbow should be limited pretty much by material strength... but someone with an 18 strength is limited to the same crossbows as everyone else.

Any else though of these? How would you handle it?

Because what's bendier than wood and rope/twine yet can resist higher tension and has a chance of being made for market (and exists in DnD)? The point of a crossbow is that it's 1 handed, "easy" to load and ready, and can be kept drawn. I don't know all my DnD materials but besides "magic" stuff like super strong uber-spider web, and the magic tree of high-tensile strength and low plasticity point, I can't think of what you could use.

faceroll
2010-02-05, 03:37 PM
The actual act of firing the crossbow is mechanical. Thats like suggesting that a higher strength score should grant more damage on a flintlock rifle. Yeah you gotta ram it in there, but all do to fire is squeeze.

No, it's not like that at all. A crossbow allows you to apply mechanical advantage to store a great deal more potential energy than if you were to just pull on the bow itself. A lever is a strength multiplier. If you have 10 strength, a lever can treat you as having 20 str. If you have 20 str, why can you make a lever that gives you 40 str?

Using your example, you'd be using your int score to damage, since you crafted a better shaped bullet or better powder.


Because what's bendier than wood and rope/twine yet can resist higher tension and has a chance of being made for market (and exists in DnD)? The point of a crossbow is that it's 1 handed, "easy" to load and ready, and can be kept drawn. I don't know all my DnD materials but besides "magic" stuff like super strong uber-spider web, and the magic tree of high-tensile strength and low plasticity point, I can't think of what you could use.

Well, it looks like you already thought of some (there's also demon horn and dragon bone and glassteel and...). The fact that the cost goes up by 100 gp per point of str mod you want to add suggests that you are using some super special material, given that 100 gold represents like a decade of peasant labor.

Mando Knight
2010-02-05, 03:52 PM
Because what's bendier than wood and rope/twine yet can resist higher tension and has a chance of being made for market (and exists in DnD)? The point of a crossbow is that it's 1 handed, "easy" to load and ready, and can be kept drawn. I don't know all my DnD materials but besides "magic" stuff like super strong uber-spider web, and the magic tree of high-tensile strength and low plasticity point, I can't think of what you could use.

Nononononono. You don't want something bendier than wood, you want something that has a higher tensile strength, so it'll spring back better. Something that bends more easily than wood would be something like a rubber band, which is actually horrible for this sort of thing.

Gee, is there any such material that has good compressive and tensile strength? Sounds like a really handy material. We could build all kinds of things out of it. If the engineers of the Middle Ages had that kind of material, they'd probably jump all over the chance to make a bow out of it.

The answer? Yes. You use it (http://en.wikipedia.org/wiki/Metal) all the time. And there are crossbows (http://en.wikipedia.org/wiki/Arbalest) with a prod made of one of the better examples of that material (http://en.wikipedia.org/wiki/Steel).

LibraryOgre
2010-02-05, 03:56 PM
Because what's bendier than wood and rope/twine yet can resist higher tension and has a chance of being made for market (and exists in DnD)? The point of a crossbow is that it's 1 handed, "easy" to load and ready, and can be kept drawn. I don't know all my DnD materials but besides "magic" stuff like super strong uber-spider web, and the magic tree of high-tensile strength and low plasticity point, I can't think of what you could use.

A human fighter, in 3.5, can have a strength of ~35 (18 +6 inherent +5 level + 6 enhancement). He can, for the low-low-cost of 975 gp, have a composite short bow which lets him take full advantage of his +12 to strength; there is no implication that he cannot have such a bow, and I think a number of players would be offended if you said "No, man, a short bow can't handle that."

Note that the 975 for the 1d6+12 is considerably cheaper than: a +1 magic crossbow (1d8+1; 2000+ gp) or a crossbow made of adamantine (1d8; 3000+ gp).

Signmaker
2010-02-05, 03:56 PM
Gee, is there any such material that has good compressive and tensile strength? Sounds like a really handy material. We could build all kinds of things out of it. If the engineers of the Middle Ages had that kind of material, they'd probably jump all over the chance to make a bow out of it

As an undergrad in engineering, I must inform you that you've made my day. Kudos, good sir.

faceroll
2010-02-05, 04:01 PM
A human fighter, in 3.5, can have a strength of ~35 (18 +6 inherent +5 level + 6 enhancement). He can, for the low-low-cost of 975 gp, have a composite short bow which lets him take full advantage of his +12 to strength; there is no implication that he cannot have such a bow, and I think a number of players would be offended if you said "No, man, a short bow can't handle that."

Note that the 975 for the 1d6+12 is considerably cheaper than: a +1 magic crossbow (1d8+1; 2000+ gp) or a crossbow made of adamantine (1d8; 3000+ gp).

It's worth mentioning that str rating is only cheap if you start with max str. If you got a new str rated bow everytime your str went up, the cost increases dramatically.

ericgrau
2010-02-05, 04:06 PM
Historically if you had high strength you just grabbed a composite bow, even when others were fighting with a crossbow. The only advantage of the crossbow is that it's easy to use. Once you start training people in arm strength there's little point to not teaching them technique as well.

In an interesting historical battle a commander noticed that none of the enemy had armor, on account of guns making armor virtually obsolete. He realized that the faster firing longbow would now be superior to guns against armorless opponents. So he asked for a large number of archers only to find out that there were no longer anywhere near that many people alive who knew how to use a bow well as it took practically a lifetime of arm training.

Seatbelt
2010-02-05, 05:42 PM
I'm not sure how much I believe that. It was my understanding that longbows were really good at punching through plate. I'm probably wrong though. :(

Artanis
2010-02-05, 05:49 PM
I'm not sure how much I believe that. It was my understanding that longbows were really good at punching through plate. I'm probably wrong though. :(

No matter how good they were at punching through plate, they were even better at punching through a shirt :smalltongue:

Aldizog
2010-02-05, 06:00 PM
In the BECMI Companion Set, a character with 18 Str could fire a heavy crossbow every round, whereas most characters could fire it every other round.
"Winch? Don't need one."

Then again, that system didn't have 35-Str fighters nor Strength-rated bows. The heavy crossbow was flat-out the most damaging bow there was.

herrhauptmann
2010-02-05, 06:17 PM
I'm not sure how much I believe that. It was my understanding that longbows were really good at punching through plate. I'm probably wrong though. :(

Depends, are you using the TV show Manswers as your basis? On one of those shows, they took a high strength compound (compound != composite) bow, gave him some super duper arrows tipped with heads that were like 50$ a piece. (What you'd use to go bear hunting. Hardened steel, sharp as anything)
-Took an archer off the US national team, and had him fire arrows at first a chain shirt made of butted non hardened steel links (they bought from museumreplicas.com). Arrows went straight through, because the heads were strong enough that the rings would give before the arrowhead. meanwhile there was enough force behind that arrow that it'd go straight through anything weaker than the arrow head.
-Then they took a piece of 20 gauge steel, I forget which blend of steel it was, but it was not an especially high grade (weaker than the head again), and fired at that. Also went straight through.

Historical armor: Chainmail was riveted. And I believe once they understood the hardening process for it what it was, the links would be hardened before riveting. (Heated, whacked with a hammer.)
Plate armor, would get massively hardened from all the hammer blows necessary to shape it. I think the producers also assumed a metal thickness on the basis that if it were any heavier, your armor would weigh over 50 pounds and you wouldn't be able to move in it.
By the 16th century, plate armor was proof against pretty much any 1 handed slashing weapon, and did well against even 2 handed slashing weapons. It was also proof against 1 and 2 handed piercing weapons (spears, sword points) everywhere except joints, (and if you could cram the dagger point into it), the visor.

Fhaolan
2010-02-05, 08:13 PM
Hey Mark, howya doin'?

Here's my breakdown. The 'weight' of the crossbow is built-in to the crossbow. Meaning a light crossbow has x strength on it's own. A heavy crossbow has x+y strength. Using some silly, half-arbitrary math...

Let's compare the crossbow damage to the bow damage. I'm going to use the damage by dice/crit calcs from http://www.highprogrammer.com/alan/gaming/dnd/statistics/weapondamage/ because it's there.

A shortbow arrow fired from an average strength (10) bow does 1d6, with a x3 crit. This is average dam of 3.658.
A longbow arrow fired from an average strength (10) bow does 1d8, with a x3 crit. This is average dam of 4.702.

Okay, a crossbow 'bow' is even smaller than a shortbow, really. Arbitrarily, I'm going to say it's a category smaller, so the a bow the same size as a crossbow's bow would probably do 1d4, with a x3 crit. This is average dam of 2.612.

Now, on to the game stats for crossbows
A hand crossbow bolt does 1d4, with a 19-20/x2 crit. This is average dam of 2.612. Basically, this is like the bow is a Str 10 bow. It can be drawn by one hand (requiring the other hand to hold the bow itself of course) by a Str 10 person. Yeah, that maps pretty well.

A light crossbow bolt does 1d8, with a 19-20/x2 crit. This is average dam of 4.702. This is basically like my arbitrary mini-bow but at Str 14 (+2). I can see a Str 10 person needing a lever to pull this.

A heavy crossbow bolt does 1d10, with a 19-20/x2 crit. This is average dam of 5.747. Progressively, this therefore is a Str 16 (+3) crossbow. Personally, from my RL collection of bows and crossbows... I think this is a little understated for even the smallest crannequin crossbow I've got. If I was restating damage, I'd put the heavy crossbow at a Str 18 (+4), with a 1d12 - 19-20/x2 crit... also it would give the d12 something else to do.

So a Str 10 person would need one hand to draw a hand crossbow, a lever to pull a light crossbow, and a crannequin to pull the new heavy crossbow. The question is, should a Str 18 person be able to treat the heavy crossbow as if it was a hand crossbow for a Str 10 person... It feels a bit Action Movie-ish to me, but would it really break the system? I doubt it.

Demented
2010-02-05, 09:10 PM
Crossbow, Strengthened Heavy: You draw a strengthened heavy crossbow back by turning a small winch. Loading a strengthened heavy crossbow is a full-round action that provokes attacks of opportunity. Normally, operating a heavy crossbow requires two hands. However, you can shoot, but not load, a heavy crossbow with one hand at a –4 penalty on attack rolls. You can shoot a heavy crossbow with each hand, but you take a penalty on attack rolls as if attacking with two one-handed weapons. This penalty is cumulative with the penalty for one-handed firing.
If your Strength bonus is less than the strength rating of the strengthened heavy crossbow, you can't reload it. However, you can shoot a loaded strengthened heavy crossbow regardless of your Strength bonus. The default strengthened heavy crossbow requires a Strength modifier of +0 or higher to reload with proficiency. A strengthened heavy crossbow can be made with a high strength rating to take advantage of an above-average Strength score; this feature adds the crossbow's strength rating as a Strength bonus to damage. Each point of Strength bonus granted by the crossbow adds 100 gp to its cost.
For purposes of weapon proficiency and similar feats, a strengthened heavy crossbow is treated as if it were a heavy crossbow.

Something like that?

Problem: An (arbitrarily high)-strength strengthened crossbow that is self-loading or loaded magically. Being dependent indirectly on strength is not enough, but being dependent directly on strength is not logically applicable to crossbows.

Overshee
2010-02-05, 09:14 PM
Nononononono. You don't want something bendier than wood, you want something that has a higher tensile strength, so it'll spring back better. Something that bends more easily than wood would be something like a rubber band, which is actually horrible for this sort of thing.

Gee, is there any such material that has good compressive and tensile strength? Sounds like a really handy material. We could build all kinds of things out of it. If the engineers of the Middle Ages had that kind of material, they'd probably jump all over the chance to make a bow out of it.

The answer? Yes. You use it (http://en.wikipedia.org/wiki/Metal) all the time. And there are crossbows (http://en.wikipedia.org/wiki/Arbalest) with a prod made of one of the better examples of that material (http://en.wikipedia.org/wiki/Steel).

I am not by any means an engineer, but I would have thought that metal deforms too easily...

KurtKatze
2010-02-05, 09:15 PM
Just make it a martial weapon and make a houserule for it. Still you are better off with a bow because you will need the rapid reload feat to make loading a crossbow a free action.

I think that the composite bow covers this quite well though. Most classes which are "forced" to take the crossbow due to proficiencies won't have the str. score to make good use of a composite variant anyway.

And technically from a realism point i agree with the others. All you do is load it, you dont really have to pull it with your own strength because you will usually have a lever or handle or something. For the bow you need your own full strength.

I'd suggest you just use a bow (I have a manshu-composite shortbow it is really funny to shoot with it^^)

Mando Knight
2010-02-05, 09:38 PM
I am not by any means an engineer, but I would have thought that metal deforms too easily...As compared to wood? I... it... d... just... what?

...
...
...Sir Patrick Stewart handles this situation (http://www.google.com/images?hl=en&q=facepalm&sourceid=navclient-ff&rlz=1B3GGGL_enUS310US310&ie=UTF-8) a lot better than I can.

DragoonWraith
2010-02-05, 09:38 PM
I am not by any means an engineer, but I would have thought that metal deforms too easily...
Depends on the metal. One of the really nice things about metal, steel in particular, is that you can have very particular control over its properties.

Sstoopidtallkid
2010-02-05, 09:40 PM
Just make it a martial weapon and make a houserule for it. Still you are better off with a bow because you will need the rapid reload feat to make loading a crossbow a free action.

I think that the composite bow covers this quite well though. Most classes which are "forced" to take the crossbow due to proficiencies won't have the str. score to make good use of a composite variant anyway.

And technically from a realism point i agree with the others. All you do is load it, you dont really have to pull it with your own strength because you will usually have a lever or handle or something. For the bow you need your own full strength.

I'd suggest you just use a bow (I have a manshu-composite shortbow it is really funny to shoot with it^^)The real issue is, though, auto-loading crossbows. There are a lot of ways to do that, they're generally considered necessary to make a crossbow viable, and that would allow a Str-10 mage to shoot a str-40 bow.

Splendor
2010-02-05, 09:41 PM
The problem stems from D&D crossbows. The medieval cross bow was a very simple weapon that almost anyone could use. You could keep them cocked for a very long time to allow better aiming. You could even preload them in advance before combat started (bolts don't fall out).
Realistically Bow and Crossbows had about the same range, and penetration power (Bolts had a higher initial velocity, but they weighed less).
Since Crossbows were easier to use at point-blank range armor was thickened to help protect knights from them (infact crossbows were outlawed, but most people ignored that rule). So we think they were "better" when infact they were just easier to use.
The crossbow's only back draw was that they took forever to load. The average crossbowmen in the medieval ages could fire about 2 bolts per minute. That's 30 seconds (5 rounds) of reloading before you can fire. Those 30 seconds are filled with you attaching a crank, winding the string back, then loading the bolt before you take aim.

Could a really strong person reach down and just pull the string back and lock it in place? Maybe. Keep in mind your average long bow back then had a draw strength of 68lbs while your average crossbow had a draw strength of 740lbs.... But bonus damage for being strong? Nope. Just maybe a faster loading time.

Tehnar
2010-02-05, 09:47 PM
I see no reason why crossbows should not be able to be modified to benefit from a higher STR rating of the wielder. Actually Im pretty sure, that as the crank and lever mechanism was developed and upgraded that is what happened. I also see no problem in it from a mechanical balance point of view.

As for historic bows, you have to consider the fact they estimate most historic longbows had about 650-700 lbs of pull, some of the stronger ones probably nearing 800 or more. Modern bows top out at around 300 lbs. The fact that England also imported wood for making longbows at high prices (and had a law that traders had to bring wood for making longbows as a part of their shiphold), makes it pretty clear that longbows were a very good weapon.

Grumman
2010-02-05, 09:47 PM
I am not by any means an engineer, but I would have thought that metal deforms too easily...
Based on what, exactly?


And technically from a realism point i agree with the others. All you do is load it, you dont really have to pull it with your own strength because you will usually have a lever or handle or something. For the bow you need your own full strength.
No. You are still pulling it with your own strength, even if you're using the lever for greater mechanical advantage.

Overshee
2010-02-05, 10:25 PM
As compared to wood? I... it... d... just... what?

...
...
...Sir Patrick Stewart handles this situation (http://www.google.com/images?hl=en&q=facepalm&sourceid=navclient-ff&rlz=1B3GGGL_enUS310US310&ie=UTF-8) a lot better than I can.


Unless wood is wet, it will either break or bend back to what it was before. Metal bends and doesn't bend back.

Demented
2010-02-05, 10:34 PM
That depends entirely on the metal, and there are plenty of metals that can bend as flexibly as wood (and more) without permanent damage. By the time you reach the point that even those metals are bent permanently, wood was broken long ago.

Tyndmyr
2010-02-05, 10:39 PM
If they can make ballistas, they can make powerful crossbows. They may be heavier, they may be more expensive, but neither of these are an issue to your high strength warrior.

I see no overwhelming fluff issue here, a composite crossbow would be no worse than a composite long/sortbw. Likewise, I see no balance issues. It simply makes crossbow build less sucky.

Draz74
2010-02-05, 10:40 PM
No matter how good they were at punching through plate, they were even better at punching through a shirt :smalltongue:

This is my favorite post in this thread. Have a cookie.

CyMage
2010-02-05, 11:01 PM
Interesting thread but I think I can explain the discrepancy. I'll refer to this image of a crossbow. (http://www.thebeckoning.com/medieval/crossbow/xbow-diagram.gif)

The key to why a stronger character can't get more out of the crossbow is the 'nut or catch' or part 'H' on the diagram. The crannequin might be able to pull the string further back with a STR 20 Fighter, but he still can't set it any further back to get more tension. He will probably have an easier time getting the string set but the STR 10 character has to crank it just as far to get it ready.

Grumman
2010-02-05, 11:01 PM
Unless wood is wet, it will either break or bend back to what it was before. Metal bends and doesn't bend back.
Er... you have heard of these things called "springs", right? They're pieces of metal that bend and then bend back on their own.

Metal only undergoes plastic deformation if you bend it too much. If you're willing to ignore metal fatigue (or if you're using a metal that doesn't suffer from this problem), you can easily bend metal and have it bend back to its original shape.

Fhaolan
2010-02-06, 12:24 AM
Interesting thread but I think I can explain the discrepancy. I'll refer to this image of a crossbow. (http://www.thebeckoning.com/medieval/crossbow/xbow-diagram.gif)

The key to why a stronger character can't get more out of the crossbow is the 'nut or catch' or part 'H' on the diagram. The crannequin might be able to pull the string further back with a STR 20 Fighter, but he still can't set it any further back to get more tension. He will probably have an easier time getting the string set but the STR 10 character has to crank it just as far to get it ready.

The idea, at least my interpretation of the idea, is not that a specific crossbow fires harder if a stronger person uses it. Instead it's that if a person is strong enough, he could treat a heavy crossbow the same way a weaker person would use a light crossbow. Still does the damage as a heavy crossbow, but has the rate of fire of the light crossbow. Or, you could build a heavier crossbow to take advantage of the fact that the strong person could load it at all.

Of course, all those magic tricks used to make magic reloading crossbows would need a bit of fiddling, to set strength to caster level or some such thing. Not that it would make that big of a deal. By the time the caster can create an automatic crossbow of Str 30 (+10), which would be what? 1d24 damage, once a round? (Yes, d24 die do exist. Weird, but true.) The caster's probably doing ten times that with area damage spells.

Overshee
2010-02-06, 12:29 AM
Er... you have heard of these things called "springs", right? They're pieces of metal that bend and then bend back on their own.

Metal only undergoes plastic deformation if you bend it too much. If you're willing to ignore metal fatigue (or if you're using a metal that doesn't suffer from this problem), you can easily bend metal and have it bend back to its original shape.

Why yes I have, actually. I don't know much (anything) about metal strength, and I'm sure we could handwave it away in DnD, but it seems like stress would destroy the crossbow pretty quickly, leaving you weaponless till you bend it back...

Fhaolan
2010-02-06, 12:38 AM
Why yes I have, actually. I don't know much (anything) about metal strength, and I'm sure we could handwave it away in DnD, but it seems like stress would destroy the crossbow pretty quickly, leaving you weaponless till you bend it back...

Metal prods (technical term for the crossbow's 'bow') are, and have been in historical times, reasonably common. It's just spring steel, like the leaf springs on a car that can last 20 years of constant abuse. Yeah, it will fail eventually, but then so will wood or anything else.

Mind you, the really powerful crossbow-type things doesn't use bendy bows. They use torsion, storing that power in twisted ropes. The smallest of that style I've ever seen is mostly brass shod oak and hemp ropes. It weighed about 30 lbs, so it's not exactly what you call quick on the draw. The pull weight on it was I think about 500 lbs. Not sure what that would translate to damage-wise in D&D.

The Big Dice
2010-02-06, 12:30 PM
There's a lot of myths and misconceptions about bows and crossbows. The draw weight of a Welsh longbow could be anywhere from 100 to 140+ pounds. That's based on surviving samples brought up from the wreck of the Mary Rose, which was Henry VIII's flagship right up until it sank leaving the dock. Longbows were powerful but modern tests have shown they had little chance of piercing full plate armour at a distance greater than about 20 yards.

And yet the longbow isn't the most powerful design of bow. That is probably the Mongolian horse bow, which has a composite build and a sophisticated geometry that allows for a massive draw, smooth acceleration of the arrow and a surprising amount of force delivered.

On the other hand, those same tests have shown that it's possible to send an arrow 300 yards and hit an area about 10 yards across with surprising consistency. And that's the key to military archery. It was all about putting large numbers of arrows into a precise area, not picking out an individual target.

Crossbows were used in exactly the same way, though they tended to be made in a fashion that was based on bows encountered in the Middle East during the Crusades. That is, a composite design for the actual bow part. To help protect the crossbowmen during the vulnerable loading time, they also carried something called a pavise. Which was basically a shield that could be planted in the ground to provide cover.

Torsion style devices tend to be too bulky to use by troops on foot, though they were fairly effective as artillery. And to make the jump from crossbow to Chinese style repeating crossbow is quite a leap. Chinese crossbow development followed a very different path from European development.mIncluding some very advanced designes for large scale weapons that had a single string that used the force from two or even three sets of arms to launch a missile.

ericgrau
2010-02-06, 01:15 PM
(bow vs. armor tests)

I wouldn't be surprised if a longbow could punch through plate if fired straight at a range equal to half the width of a TV studio. But shots in battle aren't always so ideal. As said, shirts are still easier to pierce. Guns also took less training.

The arbalest looks like an interesting weapon but it seems more like another step or two in the direction of the heavy crossbow rather than a higher strength weapon. Instead it looks like it takes even longer to load. Not that I know for sure, but that's what the pictures and description seem to suggest.

elonin
2010-02-06, 01:38 PM
English Yewman were renowned at being able to put their arrows through plate, but this required years to train and lowered the effective range. Crossbows were easier to use requiring more training. In the real world materials etc metal doesn't have the flexibility that wood does. There would be a difference between cross bows and balista. The source of the balista's strength is in its scale.

Drogorn
2010-02-06, 01:48 PM
English Yewman were renowned at being able to put their arrows through plate, but this required years to train and lowered the effective range. Crossbows were easier to use requiring more training. In the real world materials etc metal doesn't have the flexibility that wood does. There would be a difference between cross bows and balista. The source of the balista's strength is in its scale.


Er... you have heard of these things called "springs", right? They're pieces of metal that bend and then bend back on their own.

Metal only undergoes plastic deformation if you bend it too much. If you're willing to ignore metal fatigue (or if you're using a metal that doesn't suffer from this problem), you can easily bend metal and have it bend back to its original shape.

Elonin, please read the thread and try to have some understanding of the properties of the materials we use every. single. day.

Mando Knight
2010-02-06, 03:13 PM
I don't know much (anything) about metal strength, and I'm sure we could handwave it away in DnD, but it seems like stress would destroy the crossbow pretty quickly, leaving you weaponless till you bend it back...

Quick primer on the strength of metal:
http://upload.wikimedia.org/wikipedia/commons/b/ba/Sears_Tower_ss.jpg

Steel.
http://upload.wikimedia.org/wikipedia/commons/0/01/Boeing_787first_flight.jpg
http://upload.wikimedia.org/wikipedia/commons/6/69/F-35_Lightning_II.jpg
http://upload.wikimedia.org/wikipedia/commons/6/6d/F-22A_Raptor_-03-4058.jpg

These bad babies have skeletons consisting almost entirely of aluminum and titanium alloys, softer and weaker (but lighter!) than steel.

In general, steel undergoes plastic deformation only at stresses that a similarly-sized piece of wood would break under.

LibraryOgre
2010-02-06, 03:51 PM
In general, steel undergoes plastic deformation only at stresses that a similarly-sized piece of wood would break under.

And by "plastic deformation" he means "when you change its shape, it stays in that shape."

For example, take a longbow, made out of wood. Unstrung, the bow is straight. When you string it, it keeps trying to get back to straight. When you pull it back to your cheek, then release it, it's force comes because the strong wood is trying to get back to straight VERY QUICKLY. To do "plastic deformation" with wood, you generally need a heated, steamy box; otherwise, it returns to its shape or shatters.

Now, take a spring steel item; you can find those, conveniently, in binder clips and the like. When you compress a binder clip, the metal bends. When you release it, the metal springs back. If it was very strong metal, it would spring back even faster. That "springback" drags a line with it, which pushes a bolt... very, very fast.

ericgrau
2010-02-06, 03:58 PM
Elonin, please read the thread and try to have some understanding of the properties of the materials we use every. single. day.

I'm still trying to figure out how these two quotes are related.


Quick primer on the strength of metal:

[pics]

In general, steel undergoes plastic deformation only at stresses that a similarly-sized piece of wood would break under.

1. Titanium is stronger than steel. For that matter aircraft aluminum is as strong as mild steel, and that building is probably designed with cost and simplicity in mind. I bet it uses mild steel as it is cheap and easy to design with, assemble, etc.

2. Though it is completely unrelated to those pics, metal is stronger than wood, and can be made to be more springy. But it also tends to be a lot heavier without a complicated design structure. A complicated lighter weight, more springy metal bow could be made but a simple metal bar would have all the problems people are worried about here: either it would bend easily enough but it would permanently bend without springing back (thin) or it would be springy enough but way too rigid to bend much at all (thick). The 2nd case could be used for a very high force bow which is probably why the arbalest uses a steel bow.

EDIT: Btw, if anyone has a strange urge to make a steel bow that doesn't take a goliath to pull back, the structure I'm talking about would be very similar to a truck leaf spring: multiple seperate sheets for flexibility yet stacked for strength. But a truck spring is designed for 500+ lbs. and is biased to have a high compressive strength at the expense of a poor pull strength. Maybe if you found an ATV spring and annealed it to remove the bias it could be converted into a bow. Or I bet some bow maker out there already makes steel bows.

Roderick_BR
2010-02-06, 04:21 PM
The actual act of firing the crossbow is mechanical. Thats like suggesting that a higher strength score should grant more damage on a flintlock rifle. Yeah you gotta ram it in there, but all do to fire is squeeze.
A quote from Red Mage from 8bit theater on why high STR characters deal higher damage with firearms in eletronic RPGs:
"They throw the bullets"

Mando Knight
2010-02-06, 05:06 PM
1. Titanium is stronger than steel. For that matter aircraft aluminum is as strong as mild steel, and that building is probably designed with cost and simplicity in mind. I bet it uses mild steel as it is cheap and easy to design with, assemble, etc.

Common misconception. Titanium alloys have a similar specific tensile strength (MPa/kg) to steel, as do high-strength aluminum alloys. If weight isn't a factor (that is, only the cross-sectional area is taken into account), steel (especially 300 M steel or similar high-strength steels) trumps the other two alloy groups quite handily. The main limiting factors in using steel in aircraft are its corrosion resistance and its weight... I can guarantee that using steel is cheaper than using a similar-strength aluminum or titanium alloy in nearly all other applications.

As to the building? It's the famous 442 meter-tall Willis (formerly Sears) Tower in Chicago. Something that large and that expensive doesn't get second-rate material. You don't spend several hundred million (after date conversion) USD on something that could fall over because you used a "mild" steel.

Fhaolan
2010-02-06, 05:24 PM
Or I bet some bow maker out there already makes steel bows.

A friend of mine has one. I'm not sure where he got it, to tell the truth. It pulls at about 95lbs. Neither he nor I can use the monstrosity properly, because that draw is more than either of us can deal with at the moment. He has it more as a 'look, it's weird' kind of thing.

paddyfool
2010-02-06, 05:35 PM
On bows and armour penetration: I've always understood it as bows having sufficient power to punch right through plate at short range, but that arrows slow down a lot more as range increases than bullets, so this effect rapidly fades away (although arrows are still moving fast enough to easily punch through a shirt and muscle etc. beneath it at 200 yards from a powerful bow). And then there's the other issue of the sheer intensity of training involved to get to be good with a bow...