[Jean Henri Chandler]

Has anyone done any kind of test or academic study with an antique or replica of a military grade Renaissance arbalest? I know a couple of the very heavy prods (circa 1000 lb draw strength) have been made, at least one in the US and one in Europe, but I never heard about any tests actually being done. Anybody know about any?



J

[Leo Todeschini]

Jean Henri Chandler wrote

[Jean Henri Chandler]

I would really appreciate that, thanks Todd.

You are one of the people who makes prods of this strength, correct? Do you know how many others there are around the world? I seem to remember there was one guy in Texas and another guy in Eastern Europe somewhere...?

J

[Leo Todeschini]

Well here is some very unscientific info.

The bow is 850lb and shoots a 65g bolt. The steel is .2-.25% carbon and was shot at 15 yds with the steel directly on a straw boss as a backing.

The steel was only 1.6mm thick but as they were the clients bolts I did not want to risk any damage to them.

I did not shoot the bow for distance but I would expect about 230-250 yds with this bolt and a lighter bolt maybe another 30-50yds.

The strings on my bows are very heavily waxed to cut down on string wear, but this will add considerably to their weight and so reduce efficiency considerably. We may replace the string on this bow with a lightly waxed one for testing.

I have handed the bow over now and so what the client does with it as regards testing is out of my hands, but if I find out anything I will either post it up or ask if he could.

On another note, it does seem that we do not know definitively if arrow/bolt heads were hardened or not, however case hardening was known about and easy to do in volume batches, so I am pretty sure they would have done this and so with this in mind I will sooner or later make some bolts up with about .8% carbon heads at near full hard and properly sharp and see what difference this makes.

Tod

[Bartek Strojek]

Cool photos, Leo!

Great that someone spends some time, effort and money to do some experiments, even "unscientific" ones.

[Randall Moffett]

Man Leo wish I were around to see that one! Some day when I have a little money I want to have you make me a crossbow.

Do keep us posted on how things go. I'd be interested to hear what the unhardened verse hardened heads do.

RPM

[Steven H]

Thanks so much for sharing this Tod.

I'll note that while the plate was penetrated the bolt didn't get far enough through to badly injure someone wearing that plate.

I was thinking about how to set up a better test and I figure you could use several layers to test both penetration and damage to the hypothetical person underneath.

First layer armour of various types.
Next padding and clothing type textiles as appropriate.
Then tatami to simulate muscle and flesh.
Last wooded board to simulate bone.

My thought is that a test like this would demonstrate how difficult/unlikely it is to severely damage the flesh or bone underneath the armour, padding and clothes.

Keep up the good work.

Cheers,
Steven

[Gabriele A. Pini]

Good idea, but between the "meat" and the padding I would like to see some device to measure the force of the impact. Or its possibile to calculate it?

[Jean Thibodeau]

[Craig Johnson]

I seem to remember an article from about 10 or 15 years ago where they compared some period crossbows and firearms to modern firearms as far as muzzle velocity and such. No Idea how scientific it was. My guess is it was in one of the gun mags.


Best
Craig

[Jean Henri Chandler]

Leo,

Thanks so much for posting. Very interesting.

Did you have any other observations from your informal tests? How would you compare the power of this 850 lb draw weapon with a modern hunting crossbow? Or a longbow?

If your client shares his test results with you, can you share them with us? Id like to know the speed and 'muzzle energy' of this weapon.

J

[Leo Todeschini]

Jean Thibodeau wrote

[Jean Henri Chandler]

Todd, do you make any high draw weight bows designed for use with a cranequin instead of a windlass?

Something like one of these?

http://www.wga.hu/art/h/holbein/hans_e/sebastia.jpg

http://www.artfinding.com/images/lot/_240/pet...443492.jpg

J

[Jean Thibodeau]

[Jerzy Miklaszewski]

Just a thought - why using? tatami or the straw - there is an easy way to simulate flesh - with real flesh and bones. I mean to use a dead animal, like swine or pig (it has moreless the same density and construction as human muscle).
The most important would be to have it fattened and wet, so that the muscles wouldn't tighten too much.

The other thing is the way of attaching the steel and cloth to the meat - I mean the way how would the entire armour behave on that animal while being hit by the bolt.

Another thought is how to reproduce the momentum caused by the movement and mass of a knight (or soldier) that is approaching the shooter by foot or by the horse. With such mass (especially with the horse) the hit is empowered many times, causing the hit to be much more efficient.

what do you think?

[Leo Todeschini]

Hi All,

Well following up on my offer to Jean, I have something to report.

I made a steel 'bolt' from a 350mm long x 12mm (14" x 1/2") diameter four face sharp at the point with a taper behind the head and thinned down at the back to fit into the nut.

I shot from a 700lb bow into the same steel as I shot from the 850lb but at about half a meter as the bolt was likely to tumble so the further away I was the less likely I was to get a clean hit.

The steel bolt faces were slightly smaller than the normal bolt but the penetration was far less, with the steel bolt bouncing out without full penetration.

So it is fair to say that there were some differences between the bows, 150lb weight for one, but the difference in performance of the bolts was drastic so in a crude way we can conclude that Jeans musings on the effectiveness of a very heavy bolt has an answer. If you want high impact energies you need the classically weighted/proportioned bolt and that a very heavy bolt in fact has lower impact energy.

The pictures show the same steel from the shots at the beginning of this thread, the larger hole being the hole created with the wood/steel bolt and the smaller hole being from the all steel bolt. The bow used was my own rather than a customers and is pretty similar to the bow at the beginning.

Jerzy Miklaszewski suggested various tests and mediums for testing and much as I am interested in pursuing testing properly, until I can secure a nice grant to cover my time and costs I now have to pop off to the workshop and earn some money.


Tod

[Aleksei Sosnovski]

Heavier bolt SHOULD have more energy. But there is one big BUT. Heavy bolt moves slower which means that padding is more effective. Imagine having your bolt attached to a heavy truck moving at 5 mph. It has an enormous amount of energy, but it will knock the target down without penetrating it. On the contrary, a rifle bullet, which has less energy, will punch a hole in the steel even if you hang it without anything behind it.

[Jean Thibodeau]

Thanks for the test and it does seem to show that heavier is not necessarily better but there might still be a few questions to answer " eventually " ( I don't expect Leo to spend all his time doing extensive tests. ).

A few issues:

A) The heavy bolt seems to be very unstable and I guess a real bolt meant for serious use would have to be heavy and balance sufficiently to fly true to a reasonable range.

B) This was a test of an extreme weight and may have crossed over way past the crossover point where the extra weight reduced velocity to such a degree as to result in maybe a lot of momentum but too little velocity ? ( Aleksei's example of extreme momentum but very low speed means more of a heavy push than penetration ).

C) Where a bolt would be optimized for effect on target might mean that the bolt could be heavier than the original bolts made by Leo but the weight might be optimum at only 5% - 10% - 20% ................ XX% more. ( Or already optimum ).

A test in the other direction of an extremely light bolt would also give a result showing an inefficient bolt I assume.

So, I'm not completely abandoning the idea that " maybe " our reproduction of period bolts are a bit too light but I am now convinced that a 2X - 3X - 4X or more weight bolt is way beyond the optimum weight.

Leo thanks very much for the test as it does at least show the effects of really overdoing it in one direction that show a loss of effectiveness.

[Benjamin H. Abbott]

Testing with a 150lb longbow showed that the kinetic energy increased the heavier the arrow got. The maximum in this case was four ounces. Lighter bows show even higher efficiencies with more grains per pound of draw weight. If crossbows perform differently, I would be interested in knowing why.

[Glennan Carnie]