I'm an author and illustrator in the fantasy genre, and I am working on a book series currently that requires some designs for repeating crossbows with a simple and effective lever or crank action that could be mounted on the back of a very large animal, say the size of a rhino, that could be operated by a single rider.

That was a mouthful...

I've done rudimentary first sketches which led me to understand that I didn't know enough about crossbows to fake it reliably, started doing research, and began to love crossbows.

But I realized that I need to find some crossbow enthusiasts to help me out a bit with terminology and the dynamics of such a thing; I want it believable, since I will be illustrating it in the books. Then I stumbled across this site while doing research.

It's a long-term project, so I promise I won't be a pest on the site. javascript:emoticonp('')

You can see some of my artwork here: http://www.toddlockwood.com/

Anyone interested in corresponding with me on designs would have my gratitude, and might be challenged to help invent something fun.

Many thanks in advance.

Take a look at Ralph Payne-Gallwey's "The Crossbow, Medieval and Modern" also published as "The Book of the Crossbow" There's a pattern for a Chinese lever-action repeating crossbow. These date back several hundred years at the least. Most weren't terribly powerful, but they were generally fitted with 10 or 20 shot box magazines on top. I have made several. They're not terribly accurate, but will reliably deliver one shot a second. Geezer

And I did find drawings of that machine just today. They're impressive in their simplicity.

Here's the question, then: if you had an unlimited budget and could design that bow to be murderous, how would you change it? What if it needed to pierce the hide of a rhino, say, and still be easy to reload/loose? What would be your first considerations?

The Chinese repeater has the advantages of being simple, robust and Really Fast Shooting. What would make it better? A more efficient lock/release would mean less string-wear and more accurate shooting... fitting the slider with roller-bearings to keep it tight, yet running smoothly on the lower stock would improve accuracy.
If you want more power, you'll need a longer lever-arm, or some sort of more efficient coupling, say like the Spanish 'gafa' cocking lever, that should afford improved mechanical advantage without too much increase in weight and complexity. A more efficient bow-stave (prod) would be helpful... perhaps a horn-sinew composite... either Eastern or European, would give you more punch than either a wooden self-bow or even a steel bow. Steel bows can be made stronger, but the composite bows will give more power for the weight of draw. Of course if your alien culture has some sort of naturally occurring carbon-fiber (like the N'avi of Pandora) that could help a lot.
A longer draw-length would increase power as well, though that will make your repeater wider, hence a bit unwieldy.
The fact is, you only get as much energy OUT of a bow as you put into it. Any quick-loading repeater will require substantial energy to span. Perhaps if you had a lever-action lock that could be pumped back several times to bring it to full-draw.... rather like a car-jack, that would give you more power (at the cost of slower loading). At some point, the whole concept of repeating crossbow becomes moot, as your 'repeater' gets heavier and more complex. It might be easier to simply have a strong crossbow that your Bantha-rider could rest in a swivel of some sort, without the auto-loading. Or have a loader riding behind, to hand you ready bows as the situation demands.
As far as shooting at Rhinos.... you would need a portable ballista to get the sort of energy you'd need to reliably take down a rhino. Renaissance armies went over to gunpowder for a reason. You can get ooodles more power from expanding gasses in a tight-bore than you can conveniently do with any sort of bow, or even bundles of sinew/hair twisted into a catapult skein.
If you want a light artillery piece... admittedly not a quick-loader, for shooting from Bantha-back, I recommend you look at the Roman 'Cheiroballista' light field artillery piece.
Heron's 'Bellopoeica' (Greek treatise on catapults) featured a crank-operated catapult with some sort of gravity-fed magazine for city walls. It wouldn't be very portable, but might load a bit faster than a standard machine. For more info on Greek/Roman artillery, look for "Greek and Roman Artillery" by Marsden. Either Oxford or Cambridge University press, I don't recall which, @ 1968. Payne-Gallwey has some stuff on Catapults as well, but Marsden is MUCH more authoritative.
Geezer

Hello ToLo,

Interesting site and your artwork ... well ... Fantastic!

I agree with Geezer, you might need a pretty powerful crossbow to take on animals of this size....though modern crossbows/bows already shoot "through" animals and they aren't really big(see Excalibur's Equinox, Exomax crossbows; Hunting elephants with crossbows, etc)

Unless of course you want to use shovels instead of arrows then you are looking at a two man team cranking things to load it....hey if it's a tank you want, it's a tank you're gona to get.

....fantasy wise > I'd make it a really overbuilt compound system...perhaps even reverse draw like Scorpyd



or even better - a REB(Reverse Energy Bow).



Pop four of these around the rider's seat and have him perform a rowing boat motion - spanning and unloading the weapons in groups...top row ...bottom row...top... bottom.....or build the animals anatomy around this system and have it do the same by performing sort of a "yoga move" - shifting series of protruding bones/thorns to span/shoot etc... while the rider is just chilling in the lawn chair on it's back and pulling on the leash to correct the trajectory.

***

Of course if you wish for a fast "cheetah" or "bat" like creature with a shady rider like a ninja or a wraith(J. R. R. Tolkien could have made them so much sicker if he gave them crossbows )...well if that is so then this topic is all yours >>>Link <<< I've missed one really nice lever-action crossbow and also found one new one, so I'll be adding them to the list a little later in the day.

Post your sketches mate! Don't worry about functionality...it will come.

"build the animals anatomy around this system and have it do the same by performing sort of a "yoga move""

Why I didn't think of that is beyond me. I already have the animals participating in the utilization of lances. Brilliant! A+ for you today!

I'll post sketches when I can. For the moment I have to get back to the paying work ...

The reverse draw and reverse energy bows are sick! And I mean that in the good way.

Awesome Awesome Art. I really like the dark feeling it has .

Yes: I found that link Googling "lever-action crossbow," and I devoured every word, picture and video of it. It's what led me to this site.

Great stuff!

I'm becoming a crossbow fan, big-time.

And thanks, KiwiJim! I joke with a friend of mine about Thomas Kinkaide, who calls himself the "painter of light," doing these saccharine landscapes full of flowers and retarded houses and such. (Oops ... did I just cross a threshold regarding terms of use of the website?)

Anyway, the joke is that i aspire to be the "painter of dark."

Carpe Noctum!

ToLo wrote:

(Oops ...)

ToLo wrote: I'm becoming a crossbow fan, big-time.

Now if you're ready... Please step into my Office.




I used to doodle back in high school a bit too ...only now I have much less time. What you see above is a basic concept of what I mentioned earlier(rider spans a set of bows with a rowing motion)...It certainly "looks" like it works, now if we were to build a prototype, this could in fact be a real cool toy.




fantasy wise > the levers were drawn very basic and only to show how they would function...now when I say "ars est celare artem" I really mean it ...these levers can be so much more, they can be used to house bladed weapons which in their turn can be combination weapons > gun blades, sword rifles, axe shotguns, compressed gas daggers, etc.



Another example of "hidden art" that could be difficult to illustrate without making a comic book goes hand in hand with compressed gas daggers , picture the same thing only this time -------> with arrows.

ToLo wrote:

... I want it believable,...

Crossbow don't really need to be HUGE, they can be quite compact and still deliver kinetic energy equal to KE of a bullet fired from a handgun...small powerful limbs(preferably parallel), efficient cams, and long draw length are some of the key features...then again it's up to you mate.

Guess that's it for today. Want more...let us know more about this project of yours.

Okay: I have to spill a little bit here: space for rider and machinery is limited by the real estate left over after considering the native movements of the animal in flight. Yes, in flight, because it is a dragon, as you might have suspected. So the area available to the rider and machinery is limited to a space in front of the rider and above, a long, narrow space behind (along the spine of the mount) and little else. I can easily imagine a crossbow that is cocked quickly and easily by a "shrug" or trained forearm movement of the mount, freeing the rider to simply choose targets and loose. That does, however, render a "rowing" motion problematic.

Sketches will come, I promise. But probably not suddenly. Right now I'm doing the work that pays the bills, while I shop the story around in search of a publisher ...

Could the dragon load it ? I'm thinking with a simple pulley and stirrup system.

I'm thinking the rider is responsible for shooting and for swapping out multi-shot magazines, but the dragon cocking the bow solves a lot of problems (and makes the machinery that much cooler!). The only trouble with having the mount do the cocking is that he will engage in dragon-on-dragon combat occasionally, and then he's going to need his claws. But if the same system can be backed up by the rider's legs, it's not terribly more complicated. The rider is strapped in anyway, on general principals. With a tall back on the saddle he could brace and push with his legs.

Well wings change everything ...I was still working on the ground unit...much much easier If we consider the few factors listed below and take advantage of the twin levers the ground unit is pretty much complete with the only change probably in the riders positioning putting him slightly lower and thus making the levers more comfortable to use...and well making better use of the levers, by adding a few more features.

I currently don't own any dragons, so I pictured this weapon mounted on "my" back instead (well I was born in the year of the dragon, so it's as good as it gets )

One important thing that I've come to understand is that there "has" to be at least two weapons, one on each side. This is the top most priority because getting shot in the back of the head is the last thing on the list. Long neck is also a problem as accidentally placing a shot in the cheek is not a selling factor, especially when we want it to be compatible with as many models of "dragon" as possible.

With the animal spanning the crossbows it would certainly look cooler, but it would still most likely be a simple "lever" or as kiwijim has suggested "pulley" system...just bigger and if fixed permanently - limiting animals motion > Imagine permanently being attached to an exoskeleton suit that was used to compress a powerful spring on your back and you would be required to perform series of complex motions in it...it's going to be a real work out. When I suggested it(animal spanning the bows) I was thinking of a practically stationary ground unit for artillery like applications that would either have protruding spikes for levers or a free(or extra) set of limbs to swing/pull these huge levers/ropes. A solution most likely lies in a system that would be permanently attached, but would have to be joined at a certain point to complete and ready the mechanism for spanning.

Still I like the simplicity of crossbows mounted on shoulders/shoulder blades and rider spanning them with the pivoting twin levers at his sides which he would also use to control the animal(yeh...no magic in my head ) as well as aim and shoot the crossbows...we'll see what else we can come up with in the next few days...should have some more pics soon.

PS: Here is a little theory...

Did you think about putting the rider some place else...say, the animals chest - hang gliding position? Guess it wouldn't go too well with the riders safety during the collision of animals in flight or ground fighting. Thought I'd mention it ... might just spring some more ideas.

Also just came to my mind...

An extra weapon mounted backwards right behind the rider to protect the rear.