I know it's not a crossbow...(Ballistas, Catapults, etc.)

..but has anyone thought about making a scorpio or a full sized ballista? http://www.legionxxiv.org/catapulta/
I think I am going to start making a mini model of one for fun, hopefully leading to a larger one. It would be cool to design one based on modern materials just to see how much it could be improved upon.

Yeah, I have. I was looking to make it like quarter scale. Make it small enough that I could carry it by myself and that they wouldn't have huge issues with it at the range. I was also trying to convince some friends to build other small scale siege weapons and create a target siege weapon competition. But of course first I have to get off my lazy but and build one.

I really like the scorpio, I am thinking of starting with two large copper pipe sections and making twisting ratchet caps to tension the string.

Scorpions, catapultae, ballistas, Oh-my! Having had some long conversations with Darius the catapult guy and another old friend who regularly participates in the national-championship pumpkin-chucking competition, I will offer this warning. A catapult built correctly is an awesome machine, with LOTS of stored energy. As one experienced builder said: "It's easy enough to make a machine that will shoot a two-pound stone a hundred yards. The trick is to make one that will do it repeatedly without exploding.'
So if you're gonna make a catapult, do a LOT of research first and spend the money to buy the best materials. Junkyard catapults thrown together with nails and glue are liable to fly apart!
Otherwise: Go for it! Geezer

My drawings so far for the first model are for an all metal, mini scorpio made of commercially available hardware and nylon rope. It will shoot slingshot balls so you have an idea of the size.

I s doing some research on Roman crossbows today and changed my mind on making a mini ballista. Going to try and make a manuballista instead.
http://www.romanhideout.com/news/2005/20050224.asp
They are basically a shoulder fired ballista, or a torsion bow.

That link wasn't working but I googled it. Looks similar in size to the scorpio which is probably heavier due to brass construction. Looks like fun, keep us posted!

Ok corrected the link. Little copy and paste error which added an extra letter to the end.
Jake- You mentioned using nylon rope but it is my understanding that natural material rope is a better choice. Nylon rope stretches under tension and will permently deform all of which results in lost energy. From my limit experiance making rope and comments from others who have experiemented with this (and rope making) natural fiber rope can take and hold a considerable amount of torsion energy with out deforming. In fact during the rope making process the rope builds up a lot of stored energy.

basilisk120 wrote:Ok corrected the link. Little copy and paste error which added an extra letter to the end.
Jake- You mentioned using nylon rope but it is my understanding that natural material rope is a better choice. Nylon rope stretches under tension and will permently deform all of which results in lost energy. From my limit experiance making rope and comments from others who have experiemented with this (and rope making) natural fiber rope can take and hold a considerable amount of torsion energy with out deforming. In fact during the rope making process the rope builds up a lot of stored energy.

Most of the modern ballista remakes I have seen were with nylon. I am sure you are right but where am I going to get a bunch of sinew? I have hemp and I could use that but I was hoping to add modern material strength to the design....maybe steel cable?

For modern materials 550 paracord might be a good choice. I believe that is what is used by the SCA combat seige weapon ballistas. Its strong but has a bit of stretch that is going to have to be dealt with but I don't think it will take much of a set. Just make sure to get the real 550 paracord, there are several different types and imitations but mil-spec 550 paracord is the strongest. I know of a few people that play around with seige weapons so I'll ask them, If i can find there contact information again.

As for natural rope I was thinking of a hemp or jute rope. the type that you can pick up at a hardware store. That should be more than strong enought and have less stretch that the 550 paracord. I'm wasn't thinking of anything crazy like sinew. I have heard of sinew being used for this sort of thing and for ropes but not sure how how well it would really work. (may work great just need to research it, I heard about it from a History channel show so I take that with a grain of salt without further research)
Depending on what I need, making a simple rope is easy so I may go that route.

I am pretty sure a simpler version of a skein could be done in steel but then other problems arise, limb material, steel, rubber bumpers for stops....I really think it can be done with junkyard parts and exceed the original. It may take a few rebuilds but when I will have the means to get it all together...who knows?

I better set my sights a little lower for the first one, say, wood, glue, screws , some metal straps and round stock and twine?

1/2 scale of this.

Check this guy out, read the part about the direction of the arms.
http://stormthewalls.kicks-ass.net/Siege/Aitor/Aitor%20Iriarte.htm

Storm the Walls is our friend Darius' web-site. He checks in here occasionally. And now for tonight's caution-message from the old Geezer.
I will repeat myself just this once. You can store an amazing amount of energery in the rope-skeins of a catapulta. For this reason, recreational builders should be careful to do careful research about catapult construction. The originals were made of the strongest woods... ash, oak, rock maple and the like, and all joints were very strong mortise/tenon joints, reinforced with powerful pegs and iron strapping. Why do you suppose they went to all that trouble? Because they were gluttons for punishment? No, i'ts because otherwise, their machines would fly apart and hurt people. A catapult is a wonderful project, by all means go to it, but don't try to go cheap and slap something together unless you've got really good health insurance.
Years ago, One of my buddies broke one of the arms on his catapult... a dinky little thing that drew about 1200 lb at 30 inches. The broken bit flew through a 3/4 inch thick 90 year old yellow-pine wall. If it had hit someone, they would have been badly injured or dead. So take heed, and do it right the first time. Okay? Nuff sed? So get to it. Geezer

Yeah, thanks for that. I am not one to take safety lightly and I never underbuild. I HAVE been researching carefully and plan to have a bulletproof design and assembly method before the build even starts. This part of the reasoning behind the model.

Thanks for the heads up Geezer. Its easy to forget how much energy these devices can store and how little warning it can give before things can turn bad.
I was thinking of building something in the 150 to 200 lb range, depending on how effecent the thing is. While not 1200lb it will still have plenty of poptential for damage.

Random thought on these different types of ballistas. I was wondering if making the ballista stronger doesn't add speed but makes it possible to shoot a heavier object at the same speed.
Which of course brings up the question of what is the max speed of a projectile from a ballista and if a lighter draw weigh ballista could give a higher flight speed because the limbs could be made lighter?
So based on the projectile weight is there an ideal draw weight? of course that would depend on several factors so not sure it would be possible to create an "Ideal Weight" Table or something.

Yeah, you have to imagine that the projectile could not go faster than the string of the launcher. Then add weight to your projectile and power becomes important. String speeds being equal on a 200 lb draw device and a 1200 lb draw launcher, obviously you still can't get above string speed but you can put more power into the flight of a projectile.

I am really interested in the inswinging arm designs. Longer power stroke but the power increases right at the release, like all great bows.

That inward swinging limb design looks really neat. with the smaller manuballista that might move the "spring box" (I really couldn't think of a better name for that part) toward the user which could make it more comfortable to shoot and balance the bow better.

Just another random thought. As I was thinking about it a bit more the rotation speed of the limbs may be related to the tension in the rope more than the total draw weight. But high tension systems need to be treated with respect. nothing like having your bow collapse in mid draw

Hi guys,

Please check out the Wiki I founded mostly for my own manuballista (in Greek cheiroballistra) project:

• http://ballista.wikia.com
  

Currently all of the content in that Wiki is written by me, but I'm hoping that'll change eventually. Unfortunately the lack of any decent communication channels (e.g. proper forums or mailing lists) within the Wiki project makes collaboration very difficult. I may end up moving the Wiki to another host just because of this.

You are probably most interested in these articles, which I hope will eventually end up into "real" articles in scientific publications:

• http://ballista.wikia.com/wiki/Cheiroballistra
  
• http://ballista.wikia.com/wiki/Inswinger_and_outswinger_controversy
  
• http://ballista.wikia.com/wiki/Personal_torsion_weapons
  

The problem I've noted with academic research related to the manuballista (and ancient artillery in general) is that the academics tend to be, well, academics, meaning they're fluent in ancient Greek and Latin, but lack experience in practical issues. For example, their reconstructions may be perfectly doable with modern machinery, but not with tools of the era (antiquity). This tends to lead to unrealistic reconstructions. Second thing thing the academics seem to struggle with is performance of these machines, which is so poor that nobody in the antiquity would have used them. Anyways, I'm hoping that my work as an academic and as a craftsman/hobbyist will eventually help fill the voids I've described.

Now, fortunately some non-academics have managed to get impressive results from these machines:

• http://wattsunique.com/blog/
  

Actually Nick's blog was the reason I again (after a pause) became interested of the torsion weapons. As an example, his machine has spit out war-weight bolts at 400fps.

As you can see, I'm pretty deep in this manuballista stuff, so feel free to ask anything .

-basileus

Wow Basileus, that is a nice, and informative Wikia site. I hope that I will be able to add some more information to that at some time.

You have lots of information on one type of Cheiroballistra but do you have pics and information on other types? I believe that there were a few different types of small shoulder fired torsion bows but then again I could be wrong about that.

I made a ballista, one of only four I know of in the world. I sold it to Ron Toms in Texas. In ancient Greece, the ballista threw rocks and the catapulta threw large arrows. Details are on my website:

Knight's Armoury

One word...BEAST!!!

I work and study all the time, but the last few night's I slept only a few hours thanks to you guys and your infinite potential to amaze. Now it seems this night will also be sleep free...it just blows my mind what you guys put up!!!

Ivo

Newsflash! Geezer makes nice.
Hey there crossbow and catapult guys: Geezer here with a few extra comments about balistas. I'm sure you're all tired of hearing my rants about safety-safety-safety (and this from the guy who shot himself in the eye with a stonebow) But Darius' latest post, with photos nicely makes my point. If you go to his site and read the stuff about getting the big balista working, you'll note the many-many unforseen problems he had to sort out in the teething process. Note also that he made a concerted effort to use the right materials and did all his joints in the approved ancient mortise and tenon fashion. Even so, there were plenty of failures and near-failures that could have been catastrophic. So my point is that you'll all save time and possible injury by putting a LOT of research into what was done on the ancient machines, and then follow-through.
I know it's lots more trouble making all those pesky mortise and tenon joints, and monolithic blocks of ash for framing or laminated maple limbs are more trouble to do, but they'll be less trouble in the long run than doing it over and over and over.
Still, I'm really-really looking forward to seeing some neato catapult projects in our group. So what are you waiting for? GEezer.
ps. for Ivo. Have you had anybody else encounter problems posting comments? At least on my machine, hitting 'tab' permanently disappears a post. Since I write professionally, I'm plenty accustomed to hitting tab at the beginning of a paragraph. I have inadvertantly deep-sixed a number of comments in this novel fashion. So is this something that can be fixed? Geezer

basilisk120 wrote:Wow Basileus, that is a nice, and informative Wikia site. I hope that I will be able to add some more information to that at some time.

You have lots of information on one type of Cheiroballistra but do you have pics and information on other types? I believe that there were a few different types of small shoulder fired torsion bows but then again I could be wrong about that.

Well, I'm myself only interested in the iron-framed Roman ballistas. The small (~8kg) cheiroballistra (manuballista) is the only one of those which has been described in ancient manuscripts. Archaeological excavations have provided us with quite a few parts from larger, but similar machines. Take a look here for a partial list:

• http://ballista.wikia.com/wiki/List_of_archaeological_finds
  

About shoulder firing... I assume you mean that the crescent-shaped piece at the end of the stock is place vertically and placed against the shoulder? I doubt any ballistas were shot like that, as all evidence points towards horizontal placement of the crescent-shaped piece instead. For little more details see this link:

• http://ballista.wikia.com/wiki/Cheiroballistra#Crescent-shaped_piece
  

I recommend taking a look at the bibliography page and downloading everything you can (see the links on the right):

• http://ballista.wikia.com/wiki/Bibliography
  

Iriarte's (2000) first article can also be found with little googling. I also strongly encourage you to buy Marsden's both books, as they include translations and analysis of everything Greeks and Romans wrote about artillery. In some areas his interpretations are obsolete (e.g. cheiroballistra), but most of his work is still usable.

I host Iriarte's info on a subpage on my website. Aitor is a friend of mine. Pay SPECIAL attention to his method of connecting the half-spring frames to the upper and lower transverse members. A few wooden wedges, and he solves a problem that other siege engine archaeologists could not. Pure genius... that which only can come from an Engineer, not and Academic. Without Academics, we would not have those nice Greek and Latin translations. Without us Engineers, no one would have a working siege engine replica.

Geezer (Iolo) is correct about my approach to the ballista reconstruction project. Top rate and CORRECT materials, CAREFUL planning and problem resolution, and carefully considered wood joinery. We who try to reconstruct the result of 400 years of refined engineering are mere amateurs, no matter how complicated our computers are. NEVER forget that! It would be at your peril.

Some construction axioms:

Never overbuild parts, PARTICULARLY moving ones, thinking that more mass is stronger and thus better.

If you do not have an INSTINCTIVE understanding of strength of materials, rooted in REAL experience, and how to orient grained materials like wood, and can properly estimate material dimensions required to resist forces, YOU SHALL FAIL to make a safe catapult. Being a math genius counts VERY VERY LITTLE.

Never contradict or disregard what the ancient engineers tell you when if comes to construction features, thinking that you know better. With the materials they used, YOU DON'T. PERIOD. You depart from what they say to do, and you SHALL ruin your machine and possible your skull.

If you don't understand what the ancient texts tell you, do NOT proceed in the of ignorance without UNDERSTANDING what they are talking about. Or, you SHALL ruin your machine and possible your skull. Talk to other catapult researchers (like me or Aitor) who HAVE figured out what those strangely translated Greek expressions mean.

Get the point? Building a machine like this is 2/3 planning and 1/3 actual construction. Shortcuts produce fast (and potentially dangerous) failures.

Oh, and Geezer? Master Iolo? Don't hit the TAB key.

Wow Darivs that is the nicest ballista I have seen. Granted the others were SCA combat siege weapons but still that is a top quality project.

Funny (at least to me) siege weapon story. I heard this story when in the SCA group as was part of in Minnesota. After one of the guys in the group builds a ballista he moves to a near by small town (Population approx 5,000). He has the ballista on the lawn of his house and the cops stop by and inform him that there is an existing town law against having "Medieval Siege Weapons" on your lawn.
Ok maybe the story isn't that great but what are the odds of moving to a town that already had a law prohibiting siege weapons on the books. Not sure which is odder that the town has the law or that it has been enforced, more than once it seems.

Ok I'll be really embarrassed if this story is about Darivs because I am probably butchering it