How to Test A Scutum

[Marcus Mummius]

Interesting stuff, Nerva.

Are you saying you didn't repair the scuta during the period you used them. Because I think that if the backbracing came loose for example they would have repaired this.

Vale,

[Hibernicus]

I know the durability of luan scutums. Used them for years in the SCA

Some scutums we were using until recently had been retired SCA shields and are now back in SCA circulation. Tough.

I do not believe that a 3 ply replica is as durable as luan. The replica is more resistant to penetration by pilum. I've stabbed right through a luan scutum with a gladius. It barely nicks the replica. An edge cut does not go as deep on a replica but based on observations will cause a replica to fail and probably sooner than a luan scutum.

I also think that as tough as the replicas are that crushing blows will weaken them too... accumulative blows from repeated shield charges, being crushed under a pile of bodies and gear, being fallen on..

It is my suspicion that the repicas will weaken and completely fail sooner than luan. While a pilum might penetrate a luan scutum to the wood haft leaving a small square hole, I suspect that repeated blows by pilum will eventually weaken the structure of the scutum because in our tests the inner lath layer starts to crack and split.

This part of my motivation to test replicas and see them torn apart. Each replica costs $250- $275 in materials and takes 40-50 hours to make. Having someone pay for it is even better! Putting 2-3 replicas through the paces is expensive! Compared to labor the materials are cheap!!

But this is something we were committed to do before the opportunity to test them by "experts" presented itself.

Maybe we can learn something.

[Postumus]

Just some thoughts on testing.
Make the tests repeatable. An example would be swinging a weight on the end of a cable a measured distance would provide a suitable blunt impact test. A gladius could be mounted on a pivot with a weight attached and dropped allowing for a repeatable test. The advantage here is that you could compare results of similar impacts on different scuta designs.


Testing provides insight into not just what worked, but more importantly why it worked. That in turn can lead to understanding how the original designers went about solving problems.

Good Luck and more power to you for making this kind of inquiry.

[sulla felix]

Maybe that's the way you'd steer, by rocking one way or the other on the umbo?

Well, I have given that a lot of thought and think that the umbo would catch on every stair tread? Might work with a flat shield face up, the umbo being used to hang on to?

[Hibernicus]

One of the things we've decided to do, are going to do, is completely delaminate a tested scutum.. soak it until we can peel it apart and examine the damage to each layer.

Another thing that will be part of the testing will be repeated blows to the same area of the scutum from a variety of weapons.

[Robert]

I do believe Postumus has a very valid point. His first laude from me for a levelheaded approach to the discussion.
The amount of force should controlled, as to be able to repeat the experiment on different types and different makes of scuta. I envision a sort of spring loaded mechanical arm, calibrated to a force and momentum similar to a shoulder high strike downwards and a solid thrust forward, both of course by a typical human and not some cyberspace golliath. The scutum should be mounted in such a way that it is not a ridgid mount, but will give under impact (as would one held by a miles) and allow some pivoting.
I would be interested in the protection against ranged weapons, particulary different shapes of arrowheads, all fired under controlled conditions. The observation of the metal shieldrims failing is an interesting one, as we "know" these were later replaced by rawhide stitched on, as was common amongst aux. Could this be battlewise redesign?

[Magnus]

I still don't see the point to this though...we already have accurate and detailed accounts of damage done to scuta by both foreign and domestic ancient weaponry. And that is under battlefield conditions...a far cry from a controlled environment.

[Hibernicus]

All good ideas... and thanks!

We've talked about using an air gun to propel missiles after doing human tests to see how much force a thrown javelin or pilum imparts.. (also arrows, glandes etc) .

We also talked about using a machine loaded with a sword to strike the scutums

They suggested a ballistcs gel dummy with human skeleton inside for some of the testing.

[Nerva]

Ha!, we lost another scutum at the week-end. Same as all the others, split right down the center from top to bottom. When I get home at the week-end I'll post up some pictures of 'retired' scuta, I think you'll find them entertaning.

There's no real point in trying to test a scutum under 'lab' conditions. All of ours were destroyed by battlefield events that would be difficult to simulate properly. Our first was destroyed by a sarissa. Punched a hole right through, it was open season on that scutum after that.

Our second was lost to a two handed heavy axe which broke it's spine right down the middle. Our third to a Norman 'clanky' trying to burst through our shield wall, he just ran at us and impacted at speed. The scutum broke right down the middle.

On the other hand, our flat auxiliary scuta survive much better. Edge damage from axe, falx and sword strikes being the most common damage inflicted. Arrows are all right, they just stick in the scutum, some penatrate through but have lost too much energy to cause us any real injury (Only joking, we use rubber tops to arrows!)

[Robert]

Salve Nerva!

The reason for a test in a controlled environment is to be able to test different kinds of scutum and clippea construction to see how they stand up to impact. In battlefield conditions, this data would not be available, as the circumstances of the damage inflicted differ. I am interested in the observation of the oval clippeus standing up to punishment better, could be why the curved rectangular scutum was fased out in later periods.

[Nerva]

Hi Robert

Don't for get the flat shield is also called a Scutum :wink: Anyway, I too find it interesting that the flat shield is stronger but I can tell you why that is in this case. Our flat Clippeus/Scuta are constructed from a single sheet of 9mm marine plywood. They are hardened with a twin pack hardening compound and covered with heavy linen.

Our curved scuta are hardened and covered with the same linen but, they are constructed from two single sheets of 4mm WPB plywood with Cascamite wood glue in between. Structurally this seems to be weaker than a single layer of flat ply.

Also, I've noticed that bending the ply places greater stress on the individual longitudinally grained ply sheets, this may possibly contribute to the failure of the shield over time.

Now I must point out something else. The shields that failed by vertical splitting we're all Deepeeka and to be fair I do not think they we're ever designed for combat. Our third shield was made from 'bendy' ply which is structurally very weak. The combat shield we now make ourselves have yet to be properly exposed to 'kicking and bashing', but it will be interesting to see how they fair out.

You may well be very right about the reason for the change in scutum design, and construction of a flat shield is also much easier but I can tell you this, in combat, the curved scutum is far superior in terms of protection offered and ease of use.

[Marcus Julius]

I would be interested in the protection against ranged weapons, particulary different shapes of arrowheads, all fired under controlled conditions.

You beat me to it robert. In addition to the various arrow styles, how about the different types of bow. Then again, if you're using an air cannon to launch projectiles, this would be moot. I would also like to see things like sling stones of varying materials. Maybe the difference between a bolt and stone fired from a ballista, and comparing the different varieties of ballistae, as well, from the large machines down to scorpio and smaller ballistae.

I, personally, would be interested in the results of a spear (contus and/or lancea) thrust from a cavalry charge. (Do a speed and force test on a couple of practiced horsemen, then put those figures into some form of thrusting mechanism?)

[garrelt]

We had arrows shatered when fired from 10meters with a 45pound non composit wooden bow.
Some stuck in the shield, as i recal none went through our 9mm thick flat linen covered plywood shields.

A sharp spear (contus and/or lancea) goes trough, even when the horse is passing by in a walking pace.
We tried this last year, on one of our shields, and the point went trough about 2cm.
The spear was used single handed.
This was not intended but just happened.
Imagine what will happen in a galop.

During LREII in Archeon in 2006 i have thrown, in a slow trot, an untipped broom stick at a shieldburg and caused some damage to the shield of Andreas or was it Robert?
Anyway if this would have been a sharp javelin it would have gone through and would have hit him.

Sorry no pictures

[Hibernicus]

The "air cannon" would be calibrated to shoot an arrow so that it strikes with the same force as one shot with a bow. The idea, I've been told, is to shoot arrows at a taret that can measure their impact/force etc and then adjust the air gun to deliver an arrow.

But then the use of an air gun might not happen. It's their budget, not mine.

We'll see. If this project does not get off the ground then we'll do our own testing as originaly planned.

[Robert]

Hib, you can rig a testbench for a bow as well. All you really need is a good griprelease and the means of mounting the bow. I recall a similar setup in Archers Bible a lot of years ago. So an airgun is not realy essential for that kind of test. For javelins and spears, perhaps a small cart on rails, propeled by compressed air or even bicycle inner tubes as springs. You can add more to get the right speed, mounting the spear non-ridgid to cancel out the momentum of the cart, it's just the spear when it hits.