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Throughout this little project I have had conversations with people from various camps of interest.  It started out back in the day when Firefly was just a pup.  Many hunters who saw her seemed concerned with whether that “thing” could kill a deer.  Or equally, “Why don’t you put some wheels on the limbs and make it into a compound bow, because, you know, the Romans  had wheels and everything.”

…Well okay then…    Perhaps they all went to sleep the moment I uttered the words “history project”.  However, these folks were generally kind and I tried not to let their suggestions bother me overmuch.

Most of the pestiferous comments  came from reenactors.  One chap took exception to the style of washers that appear on Firefly.  (“Modioli” to the truly erudite.)   Clearly they are not typical of anything that has been dug up.  They were made that way to increase the stability of the crossbars during certain spring tensioning experiments.  With Phoenix the historical shortcomings of Firefly’s washers will be addressed with more authentic full collar versions.  Rome wasn’t built in a day, nor are effective reconstructions of her torsion artillery.

If you are a reenactor and reading this blog with your eagle eye ready to pounce on something that can be shown as “inauthentic”, here are a few caveats to help guide you in your criticism.

(1)   Whatever you are thinking of criticising, it is very likely I have agonized over it to a certain degree.  While I am fully committed to the idea of ultimately achieving parsimony in the designs that are pursued in these reconstructions, I do not consider myself a slave to it during the development process.  This is because a large part of my work is to conduct experiments to see what made these machines function  as effectively as the record suggests.  At times these experiments may require adding components that, in all likelihood, would not have been seen on the originals.  Like the doppler chronograph hanging on the front of Firefly, or the Vernier plates   counter washers that are used to produce finely grained rotational adjustments for the washers.  Eventually I hope to be able to remove any complexities that were added for testing purposes.

Take this design for a cable backed limb.  It proved successful after nine previous attempts did not.  Some of the draw weights I was experimenting with topped 5500 lbs.  A couple of limbs outright broke.  Albeit without much fanfare thanks to a Kevlar safety strap.

cable limb

Certain highly engaged fellows have suggested that this type of limb is not at all “authentic”.   …..Epoxy soaked Dacron yacht braid not authentic?  Who’d have thought? However, as a stepping stone to a more historically correct steel tension rod, this way of going about limb development has many advantages for the tests we are doing.  Little things like safety come to mind. Or selecting the size and grade of steel rod, now knowing 11,000 lb. test yacht braid is sufficient to back the limb.  Or developing the attachment techniques to anchor an advanced version of Kevlar safety strap down the relatively stress-free  middle of the limb.

My approach is to first develop authentic performance within as plausible a platform as possible, take note of those places where authenticity in the build may have been breached, and then do the reworks needed to bring questionable areas more into historical compliance, all without harming the performance overmuch   (Notice I said “more into historical compliance”, there are no absolutes of perfection possible here.)  The safety strap will always be with us though, and the authenticity police will just have to lump it.

I do not believe I have ever suggested that our work here was geared towards making a “perfect” show-and-tell replica of how these machines must have appeared.  No one really knows, nor will they unless a complete specimen is found.  Even then, there were in all likelihood any number of variations on the basic design.  Iron frame ballistas appear to have spanned at least three centuries, perhaps more.  Variations are inevitable. The unknowns are vast.  Similarly, using Heron’s description of a small Cherioballista to validate interpretations of much larger machines, like the Orsova, is fairly presumptuous.  There are just too many imponderables for narrow windows of textual evidence of this sort to be relied upon.  Soft evidence vs. hard evidence?  Clearly I favor the latter, and even then I’m quite happy to admit I’ve probably got parts of it wrong.  It’s just the nature of the beast.

This is an experimental game we are playing, based strictly on replicas of certain artifacts,  just like the name of the discipline suggests.  Inevitably anyone working in experimental archeology will mix and match the evidence to suit their particular viewpoint.  I admit to this tendency myself, with perhaps one important difference.  For me, performance is the great common denominator. It is also the one key area where EA has failed to show any great insights into how these machines probably worked. Unless you consider all the negative attempts that show what doesn’t work.  There are plenty of them around.  Large parts of my own project are filled with such failures.

And so, when it comes to experimenting with catapults, for me the bottom line is all about performance.  Otherwise, what is it you have built? You might as well have made a nice drawing or computer graphic to illustrate your point.  High energy catapults are not for everyone.  There is always risk in such endeavors and it is best to be realistic about your capabilities.  For those of us working on the extreme sport aspect of these machines, the dangers to life and limb are very real.  Which, of course, is part of the appeal. So in short, there are substantial differences between  catapults built for educational and display purposes and those few machines that concentrate on shooting projectiles with authentic levels of power and range.  There is certainly nothing wrong with the former.  Let’s just not confuse the two.

That being said, appearances are important.  On one level we are creating a test bed for experimentation, and on another we are attempting an artistic creation.  Without this latter, the project would be a flat and soulless entity, and I make no apology for any authentic sensibilities that are offended by the aesthetics of what I am building.  For example, I like the curvy bits on Firefly’s stock profile.  They should be easily contained inside any reasonable parameter of how these machines may have looked.  After all, no one really knows do they?  If you are a rectilinearist and the curvy bits don’t work for you, so be it.  Think of them as a reminder of the enormity of what we don’t actually know about these machines.  The closed mind seems strong only to it’s occupant.

(2)  At times our work will show designs that may, at first glance,  seem needlessly complex.  If they are not the result of the aforementioned experimental aspects, they may be a form of thematic extension played out from well founded features that are apparent in the artifacts.  For example, it is indisputable that all the kambestrions that have been found (other than one that was mis-cast)  are equipped with four loops attached to their upright stanchions.  These loops are a clear indication that the machines were able to be disassembled with a minimum of fuss (i.e. they are modular, take-aparts).

If we respect this modular premise properly, it doesn’t make much sense to have only the kamarion and kambestrion be equipped with a take apart feature, when clearly other parts of the machine would also need a take-apart feature to make this design strategy a practical benefit.  Ergo, other parts of our reconstruction should follow suit and be easy to disassemble.  Now, does this mean we are over-engineering?  Not so much, by my reckoning.  Not if there are good reasons to include them.  It is just a matter of honoring the intent apparent in the artifacts themselves.

(3)  A couple of actual catapult scholars have suggested that if modern reconstructions are not equipped with sinew springs, then pretty much, the whole exercise is worthless as we will never know how the originals performed.    I consider this a fairly shallow objection.   It is true in a certain absolutist way, but fairly uncomprehending of what it takes to get these mechanisms working at a high level.  For example, take the subject of shooting accuracy.  There is no reason to suppose that the ancients would not have made high quality sinew springs that were, at least when dry, stable and reliable power generators.  This is not strictly provable as yet, but is a pretty sure bet for those of us that have actually worked successfully with nylon spring cord and dabbled with sinew a bit.  And so, if we can suspend our disbelief for a moment, and take as a given that Roman springs, however they were made, were up to the task of consistently powering their machines, we might well ask, “what other myriad factors are there in making a ballista shoot accurately?”.  And this, of course, is something we can test for very well.

(4)  I could go on, but let me just conclude with this: if you feel an objection rising in your throat, please make sure you understand where this project is coming from.  While  performance founded on parsimony is our ultimate goal, we have to be pragmatic about it.  So to repeat myself: I believe it is more productive to utilize the minimum innovation necessary to generate authentic performance, and then after thorough testing, come back with reworks to make everything as historically plausible as possible without losing all that hard won performance.  Your concerns over “authenticity” will be addressed eventually. The quickest way between two points is not always a straight line.

This behemoth of a machine is without a doubt the king of all minimally-working, display ballistas.

bbc ballista 3

It was made for the BBC program “Building the impossible”.  The scholarship that directed the project is generally considered as impeccable, and clearly the effort was very well funded. As I recall the range was  about 120 yards, and only a few shots were managed before it became irreparable.

I do not doubt there was a certain amount of dissatisfaction with that range of shot and longevity of the machine.  Trying to balance authenticity in the build with authenticity in the performance is what makes this game tick.  I truly wish them better luck with their next endeavor.

Progress with catapult reconstructions is a process, not an event.  But try telling that to a TV producer.  Or, for that matter, a scholar trying to illustrate their pet interpretation of how these machines “must” have appeared.

Put another way, comes this email from fellow catapult maker and teacher from NZ,  Murray Hill:



With all that said, I would like to extend my thanks to Murray and the other reenactors and scholars that have appreciated what I am attempting to accomplish with these reconstructions and experiments.   I prefer not to mention names more than necessary, but you know who you are.

Back to my experiments now…


And here’s a plug for Murray’s book —


Codex catapulte


Murray brings enough humor to the subject of ancient catapults, I found it hard to tell the difference between laughing and learning. Definitely not for catapult prudes or folks that can’t stand a good belly laugh mixed in with their scholarship. Just my cup of tea.



And because this next book provided me with the inspirational backbone to keep going when the appeal of ancient torsion tech was at it’s lowest ebb, I highly recommend this modern classic by Dr. Tracey Rihll from Swansee University.  Consume this over a long weekend and you will have a firm grasp on the history of catapults, what they were likely capable of, and how they affected the ancient world.  Not many stones left unturned here.  A dedicated work of scholarship, kept lively by the prudent use of imagination to help guide the reader into an appreciation of how vast are all the things we do not know about ancient technology.  Not a snoozer like some.

Tracey Rihll



This little book by Duncan Campbell is a good primer on ancient catapults.   The author keeps a tight reign on any speculation regarding catapult theory and effectiveness.  Although, it must be said, some of the illustrations depict machines with idealized versions of resting torsion springs, all very straight and ticketyboo.  However, the book is well thought out in it’s presentation of the basic facts.  It was my first introduction to the Orsova artifacts and it’s photos are what spurred me to undertake the Firefly project.  I always keep it handy for quick reference.

Duncan Campbell



At this point in time (and on a Tuesday, no less) I’ve decided an assessment of our current lines of enquiry is in order.

(1)  Firefly is waiting for another set of matched bolts to be made and a definitive solution to all the bolt breakage that occurs when shooting at mid-range, that is 300-400 yards.  Our extreme range testing 0f 800-1000 yards did not have this problem because landing in a soft field is a viable option for bolts descending at a 55 degree angle.  Shallow angles that come from flat trajectory fire are more problematic.  At fifty yards it is easy enough to make a small rock free dirt backstop, and that works great.  However, at 300 and 400 yards the landing zone for my fragile beasties needs to be the size of a small bus.  And me, with my bad back and everything.  Boo-hoo!  Still looking for a rock free (or somewhat free) hillside.  The ground will no doubt freeze solid in the next couple of weeks.  More testing will probably have to wait till next season.

(2)  The Sinew Vs. Nylon question needs more work put into it.  ’nuff said.

(3)  Phoenix proceeds apace.  I work on her everyday. Soon, things will be seen to happen as several of her major components get hooked together with their permanent accoutrement.  All shivery with anticipation, I am.

I expect Phoenix to be able to delve into the following subject areas:

(a)  Is a flat-topped crossbar indicative of a wedge machine?  Is it’s flat-top a suitable foundation for a pair of counterpoised wedges to drive a spreader bar? (this latter, nicely radiused where it contacts the spring, of course) and by this method put our all-important linear pre-tension into the springs.  Because no crossbars were found for the Elenovo machine, I feel Phoenix is at liberty to explore the notion of a wedge machine based on the unique information concerning the crossbars obtained from the Lyon artifact.

(b)  The crank handle from the Elenovo horde will be duplicated and used in the winch design for Phoenix.

(c)  Similarly, ferrous tension rods for Phoenix’s limbs will be based on the artifact thought to be one, also from Elenovo horde.

(d)  Phoenix will make every attempt to balance herself using only a wedge based system, and then we can see if an equally imposed 180 degrees of washer rotation yields the high power we are looking for.  This would allow us to dispense with the vernier plates and make some sense of the coarse washer adjustments evident of the Lyon machine.  Power and simplicity is our signpost from the Romans.  Nothing else will do.

(4)  Although I haven’t mentioned it yet, plans are afoot to make a reconstruction of the Lyon machine.  To demonstrate the simple and forgiving nature of the iron frame design, this machine will be made with more rough and ready blacksmithing techniques.  An ugly machine, with much lower standards of fit and finish, yet undiminished in her power and accuracy.  At least, that would be the goal.  Deliberately making misshaped and unsymmetrical parts fit solidly together into something wierdly wholesome and impressive is a personal challenge I am looking forward to.  I believe that the basic Roman design was so good it could accommodate more ad-hoc forms of manufacture.  In other words,  iron frame ballistas were a reliable manufacturing concept that could be exported to all corners of the Empire and then made locally.  Crudity of manufacture does not necessarily belie reliable performance if the basic design is forgiving enough; witness the Kalashnikov.   The Ak-47 is rarely revered for the prettiness of it’s workmanship,  and yet as an effective and exportable concept it has become renown for it’s robust simplicity and ease of manufacture in third world conditions.  So, that will be our take on the Lyon machine.  An easily made inswinger, miles ahead of the competition when it came to long range precision work.

From this distant remove, 1700 years after their common usage, ancient ballistas are mechanisms that defy modern attempts to categorize them absolutely.  However, there are traces of the mechanically irrefutable about them, if we have the wit to know what to look for.




“Stacking” is what we call it when the draw weight hits a point during the draw back where it starts to increase very rapidly. Responding to a question about stacking by John Payne, I came up with this blurb about how it seems to work with inswingers.  At least, how it seems to work with Firefly.  With catapults, everything is a situation.


There are two types of stacking.  The usual archery type that has to do with the angle between the string and the limb at full draw, and another type that has to do with the spring saying “Oh! now I’ve hit a wall. My fibers are getting stubborn.  I’m not going to budge so easily anymore.”  (Not bad for a talking spring, huh?)

The first type is easy to understand.  Imagine an ordinary limb on a hand bow at full draw.  The more you pull it back the closer the limb and string get to forming a straight line.  In other words a straight line pull.  That’s like pulling on an anchored chain.  Not move so much.  Here’s a rough idea of how this type of stacking works on an inswinger.


The second type of stacking, the springs “hitting the wall” phenomenon, is only something you can judge by how much the draw weight goes up and at what point that happens during the draw back.  With an inswinger I don’t think the first stacking issue (the archery one) starts to take effect until we get beyond 100 degrees.   Therefore:  If your stacking is happening at 100 degrees or less then you are probably hearing the spring talking to you.  This sort of thing is more likely with a short fat spring, rather than a taller, skinny one.  It’s certainly something to be aware of if the draw weight skyrockets all of a sudden.  Back off.  Play with it.  At some point you will have to say, “That’s enough for this framework I’ve built.  I will not ever draw it back any further than this.”  Whatever that draw length happens to be.  That is what I did with Firefly.  Fortunately by the time I made the decision  to enforce a ban on further draw back, she was performing at the level we see today.  I would be pretty nervous about going any further.  Too many bends and breakages for one lifetime.

In her current configuration, Firefly clearly shows the spring type stacking.  That is why I’m keeping her at 45 degrees of limb rotation.  There are a lot of advantages here.  If it’s done right, little things like:  faster cocking times, more compact machines, and hopefully, the highest velocity Dura bolts possible out of authentic geometry.   With catapults, everything’s a situation. What a grand hobby! It’s all just tickety-boo when you find the right combo.

….or so you think, at least for a while….


There is no final verdict possible in this game of iron frame catapult reconstruction.  No matter how well done, there will always be contingents of armchair theorists ready to rip into any modern attempt at making an “authentic” machine.  It really is a fools game trying to hold up any one design as the preeminent candidate for scholarly acceptance, whatever that is. Might as well dump chum into a shark tank.   Agreement is no longer possible because there are so many careers and threads of opinion at stake.  Inswinger or outswinger? Barring a definitive archaeological find, there will never be a winner. The waters here are just too deeply muddied by all the thrashing around.

Going back to my hobby now.   Thankfully, very few people ever read this blog.  I like the quiet of not being judged by paper know-it-alls with limited shooting experience.


On the other hand, I’m in a mood.  Let’s smack back at the poor dears anyway.

If, by the slimmest of chances, there is a partisan from the outswinger camp reading this labyrinth of a blog, here is something you might want to consider:  if an idiot like me can make an iron frame inswinger perform at levels so much higher than any iron frame outswinger, are you really saying I have accomplished something the ingenious Romans could not have, all with the exact same artifact geometry? Do you really think the Romans did not see the same performance potential in their own parts, just as many of us have done? Of course, they weren’t exactly artifacts back then were they?  They were an integral part of an engineering triumph made by ancient craftsmen who put their reputation on the line trying to develop superior machines.   When it comes to catapults, superior is superior in any epoch.

It is no accident that a modern inswinger can be built so effectively around functional duplicates of a Kambestrion and Kamarion that have been lying dormant in the ground these many centuries.  To see this you just have to turn away from the view that history is solely an exercise in “interpreting” the textual evidence from dead languages. Arguments based only on appeals to authority just don’t cut it in this game.  These machines are deeper than that. Think CSI rather than Henry Higgins and you’ll have the jist of it.  If you are lost, always go back to the hard evidence.  The artifacts are the hard evidence.

Here is something undeniable for you to chew on, the sight and sound of an authentically powerful iron frame ballista going off.   Click for vid: canyon 3     As an inswinger, Firefly simply demonstrates the inherent mechanical logic of the artifacts themselves — the hard evidence given it’s most dynamic and compelling interpretation from a shooting standpoint.  In other words, the kind of performance success any weapons development program strives for.  Perhaps the outswinger faction of this teapot tempest undervalues the idea of superior ballistics.  It’s very doubtful that the Romans were similarly unambitious.


If you are interested in the difference between hard evidence and soft evidence, here is the definition I prefer. It is copied from this website:  htmhttp://www.av8n.com/physics/authority

The Value and Limitations of Soft Evidence

There is a huge difference between hard evidence and soft evidence. Reliance on authority, credentials, and reputation is near the top of the soft-evidence scale. If you don’t have any hard evidence, you ought to be guided by the best available soft evidence. However: remember that the top of the soft-evidence scale remains far below the bottom of the hard-evidence scale.

Hard evidence always outweighs soft evidence.


Not convinced? Perhaps a shooting contest  could settle the matter?


Well that worked a treat.  Clearly they are all won over.  Back to my machine now.


In the deepest parts of an investigation there is a theme we often fail to see, blinded as we are by disparate facts. When the underlying pattern finally emerges there is a breathless innocence — letting go of what we thought we knew.  Istina.

Happy birthday 63 year old me.




Unless, of course, you have enemies.  In which case, it might be a good idea to skip the middle bit.

And the hero of the hour is ….. fanfare please …….


Today, Oona warned us of a big fat rattlesnake coiled up under the couch. (No, they don’t always rattle.)  The pesky serpent would have been about a foot away from my leg when I sat down. That would have been a drag, to have his boorish little fangs stuck in my leg. I like that leg too, it’s the only good one I’ve got left.

So, kudos to Oona!  …….And ticker-tape parades, and dog cookies, and ball games, and swims in the lake, and fetching ballista bolts…….. What an uber hound!

Respect born of fear.

Blithering is what we do when dialog outruns the message it was meant to deliver.

Dithering is what we don’t do when we just wished we were doing something.

Is Sinew Vs. Nylon even a sane consideration?  I wonder sometimes.


I seemed to be a bit stalled on this sinew vs. nylon thing.  I think it is suffering from estivation.

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