A more powerful bow

Question

What methods are there to make more powerful bows, besides simply upscaling it? Just for definition, I will take more powerful to mean that it has more draw strength and longer range. The tech level is medieval, but absolutely devoid of gunpowder.

One methods I can think of would be to use pulleys like those found in compound bows, which can increase the range and accuracy, though it makes the weapon harder to maintain.

Another would be to give the bow four arms, ala the Dwarven Windlance from the Hobbit movies, but I'm not sure about how realistic the physics of that would be.

If it helps, the people using the weapons are the giants as described in my previous question How to make a realistic 'giant', but I am looking for some other methods to further enhance their bows besides the fact that they are simply bigger.

Answer 1

Does it really have to be bows?

Think of your giants as walking trebuchets. A trebuchet is essentially a giant mechanized sling. Slings have numerous advantages over bows: simple to construct and maintain, so your giants' awkwardly large hands don't prevent them from building it themselves, and unlike composite bows, slings don't disintegrate in the first heavy rain or whilst crossing a river. Your giants could use slings to break or weaken castle gates from afar, while likely still staying out of range of most man-powered bows. Plus the kind of nasty, brutal blunt damage it causes would make any self-respecting giant happy.

So it has to be bows

Ok, so bows are too cool to abandon. Fine. Your giants are still clumsy with making small flimsy things like wooden bows, so they'll naturally go for the largest, most in-your-face weapon they can design, given their ridiculously superior weight carrying capacity. Solution? Steel bows. While they weight a lot, they are capable of storing a lot more energy. For this reason steel bows (or crossbows) can easily cast bolts/arrows at similar or higher velocities than wooden bows, if properly designed. The spring-steel-like material must be quite uniform in quality, requiring a little skill in making the bow, but it's virtually indestructible. As a plus, it's pretty much a giant-only bow, in that no one else is likely strong enough to carry, never mind draw, such a puppy. Essentially giant-portable ballistas.

Answer 2

If you're talking about giants, you are looking at one very simple consequence: giants have long arms, therefore the arrows will be notably longer and heavier - as long as you're assuming archery of a similar style to ordinary medieval short bowmen. Those longer, heavier arrows would fly further and certainly hit harder, as long as the aerodynamics were not neglected. Like the heavy clothyard shafts of English longbowmen, only more so.

One thing the giants would probably not have much success with is a scaled-up longbow as such. The longbow design, extended to giantish proportions, would be vulnerable to progressive mechanical inefficiencies that would sap some of the draw's power; and such larger bows would be harder to build, if only because of the lack of availability of good wood in such lengths.

However, the giants could accommodate their longer draws with bows of lesser length. You would definitely want to consider the compound bows you mention, which give you a longer draw for the size. The giants themselves might have a tougher time crafting, as well as maintaining, the pulleys - an opportunity for some inter-species commerce, perhaps.

There is one questionable characteristic of compound bows in a medieval world, though: the pulleys are not circular, but eccentric in order to get the maximum advantage. This is a pretty subtle piece of geometry - compound bows were not invented until 1966.

As far as materials and construction goes, your giants would probably find it necessary to resort to composite construction (which, like compound design, gives equivalent draw and power in a shorter bow) rather than all-wood self bows. Once again, the greater requirements of craftsmanship and the complexity of construction would argue for bows built by someone else...

Finally, you are quite right to be skeptical of the physics in any of Peter Jackson's movies. Jackson is far more devoted to Hollywood tropes than to physical realism. :-)

Answer 3

There are a few issues that need to be faced when upsizing bows

Firstly, we consider why the bow is so effective (or was, back in the day). This is more or less easily answered: the arrows were downright sharp. Whether it was to pierce armour (which it usually wasn't) or take down a few horses (hehe, Agincourt), the bow and arrow was effective because sharp things are annoying^[1].

Secondly, we consider how this affects our giants using bows. Ok, so somehow, we manage to construct a really-long long bow™ (RLLB). That means we need pretty massive arrows, right? I guarantee firing a correctly scaled arrow from our RLLB will be like launching a battering ram - it will still be devastating but we might as well set it on fire^[2], make it bigger, make it faster, make it stronger, scrap the useless tip that isn't really a tip any more, and overall, make people fear it. Then you call it the fiery ram from hell™ (FRFH).

Thirdly, we consider how our FRFH will be launched by a mere RLLB. Frankly, it won't. It would be like launching a land-to-air missile with a spoon. So we need a new launch method, but still a bow. The RLLB gets an upgrade! Of course, we make it out of steel, because that makes it shiny and shiny things are better. We still have some pretty out of date string here, so we'll change that to... more pieces of string^[3] (a few hundred should be good) that rest parallel to the original. Because more stuff means more power, right?

Finally, we consider how this thing will work. Pretty much, these medieval missiles work best used in a siege, but hitting a warrior with a FRFH? More reliable than a measly arrow.

To sum up: We can't have little bows for big giants, and we can't have little arrows for big bows. And having a sharp tip on a large log doesn't do much, because tips are for piercing, and you threw piercing out the window the moment you said giant. So this new weapon is for crushing everything, but is probably ideal for destroying castle walls. And hitting anything that will make a big sound when it gets hit.

[1]: Being crushed is probably more annoying
[2]: Fire makes it go faster <<<< Joke <<<<
[3]: Couldn't think of anything better than more

Answer 4

Well the English long bow was an incredible weapon and could perform feats very few archers could duplicate today. Being able to shoot an arrow up to 400 yds, most bows today have a range of ~200 yards. These are also much lighter arrows with high end composite materials.

Something to think about is that the more powerful the bow the stronger the arrow has to be. One thing the long bows have is a more 'constant' acceleration. Even though they don't have the power of the old long bow, today's high powered bows are so fast that they will shatter wooden shafts. So, that is one of the reasons why the windlance was shooting an iron arrow, it needed to be strong enough to handle being shot. It wasn't just to penetrate the dragon hide. The Roman Ballista basically shot Javelins. Cross bows have much thicker (and also shorter) arrows than their cousins. Shorter arrows also help prevent shattering issues.

So you need to think about that as well, giants are going to have longer arms, which can pull longer arrows which will need to be much thicker, and will still probably fly farther if they are proportionally larger. It would be more like each giant was carrying around a ballista. That is frightful enough in my opinion.

Answer 5

Does it have to be a bow? Similar to the sling comment, a spear thrower or Atl-Atl would be a great option for a giant to deliver an arrow. It is a simple tool that could be sized up easily and quickly even for giants.

Answer 6

Firstly you want to look at different materials than wood. Due to the giants greater draw strength, looking at different materials for a bow there are a few requirements they should meet:

• elasticity, the bow would need to return to its original shape after the draw is released, this would rule out things like rock/steel (which would have some but not enough to last more than heavy use).

• how the force is distributed, a wooden bow works particularly well because is is not brittle, the grain enforces the structure by spreading the force equally over the bow. If a bow has a knot in it or twisted grain it is likely to snap when placed under the pressure it is used at.

These are the main requirements for a good bow to be made.

One form of current bow is a laminated bow, several layers of wood glued and pressured together. you could use this having the giants pounding a trunk so that it is thin enough to comfortably fit in the hand.

Recurve horn bows gained their reputation from the mongols, these were wooden bows tipped with horn, as a bow entirely made from horn would be to hard to draw and if there are giant animals the horn would be easier to get hold of. also bone or horns have a grain which would give it a similar structure to the wooden bows in terms of strength.

I would recommend a horn bow if it is possible to get the materials to make it.

Answer 7

Have you considered the idea more along the lines of a giant caber? (https://en.wikipedia.org/wiki/Caber_toss) As stated by another poster, the point of an arrow was pierce, at scale this useless. But if you consider what the trunk of a giant redwood for instance, would do an army of foot soldiers rolling down hill or across a plain, the damage potential would be terrifying.

Answer 8

I think you are operating under the misunderstanding that bows are somehow at a pinnacle of strength. That is not the case at all, it's not hard to make a bow that will shoot an arrow faster.

The limits are whether you can draw the bow and whether the arrow can survive the launch. After all, consider the crossbow--the same basic technology level but with a much stronger draw. Any creature that can build a crossbow can build a normal bow of the same strength, the point of a crossbow is to use mechanical advantage to draw it and then allow the shooter to relax while aiming.

Answer 9

With natural materials, a steel crossbow is probably the apex of "tension" devices like bows, and as noted the launch force wold require arrows (technically "quarrels") to be shorter and thicker proportionally to survive.

The ancient Greeks and Romans used "torsion" weapons, which used twisted bundles of fibre to provide the power to the throwing arms. By the end, there was a sophisticated body of science behind them, including methods of calculating things like how tight to twist the torsion skeins, the proper angles for the launch arms relative to the torsion skein and the body of the weapon and so on. These were very expensive and required a skilled team of ingeniares to build, although ordinary soldiers could operate them. These came in all sizes, from Roman "Scorpions" (essentially squad level weapons that were operated by two or three man teams) to giant siege engines. More can be found at this link: http://www.mlahanas.de/Greeks/war/Catapults.htm

Counterpoise weapons like Trebuchets are not really suitable as personal weapons due to their design (they use the power of gravity to "pull" the counterweight down and move the lever arm, so if they are not straight "up and down" they lose considerable power), so unless the giant is "so" giant they can pull one out of a pocket or backpack and put it on the ground, it isn't going to help in a battle.