Rome sweet Rome. A planned project and a question.

[gimzod]

Hey guys. ( Not sure if this is the right place. Will move if it not suppose to be here.)

Starting to draw up a plan for another project based on the internet hit Rome sweet Rome. Will be easy enough to get the marines and Romans, but have a very odd question that puzzling me. Could a roman ballista get through the front glass of a marine humvee?

Thanks for any help

[commissarmoody]

I am not so sure considering I have seen the ballistic glass stop bullets. But you could totally deflate a tire. And might even be able to get into the engine block.

[Modhail]

The answer may not be as simple as that... For example, tests have shown that modern bulletproof vests (without solid trauma plates) are quite adept at stopping a bullet, but not an arrow from a medieval bow. Something to do with the way the material responds to the differing speed and weight of these vastly different projectiles. Also, apparently, a flexible arrow shaft causes a sort of jackhammer effect at the point aiding penetration of the fabric layers.
A bullet causes a high energy impact through speed but has a relative low mass, dissipate the kinetic energy and most of the danger is averted. A ballista bolt is a significant amount of mass at slower speed. That sort of kinetic energy is harder to dissipate as you can't dissipate the projectile's mass or inertia.
I personally think a hummer window would stop the bolt at anything beyond point blank, but would worry how deep the projectile would penetrate before coming to a standstill. Even it was stopped a third of the way of the projectile length it could still injure the driver. We really should have someone with too much money run some live fire tests...

[zizi666]

Was thinking along the same lines as Modhail.
Some years ago there was a scare that terrorists would start using crossbows.
Tests showed that a bolt fired with 2-handed crossbow went through a torso when fired up to 90m. A small model (crossbow-pistol) could do it up to 10m.
So a large bolt fired from a ballista... (also take in account the speed of the vehicle: standing still or moving towards the firer at say 60 km/h would make quite a difference IMO)
As for the engine block.. Meh, don't see that happen.
It would be able to penetrate a radiator though and since this is the SF board, a tyre could prove very difficult :

[Elbows]

A ballista would very likely go through the windshield of a humvee.  Bullets, while exceptionally dangerous are extremely small and expend all of their energy suddenly.  A ballista round would have some serious momentum behind it.  Now if you're talking about heavily up-armored HUMVEE's...perhaps not.  I would argue it'd likely crack the windshield terribly regardless.

Mass times acceleration and all that.  A small 55-grain bullet may be travelling at 3000 fps, but a 4-5 lb. ballista at 100-150 mph would do serious damage. 

[gimzod]

got a link to the source material?

Rome sweet Rome?

Sure  https://docs.google.com/file/d/0Bx_wEpbf68sZNjY1OWI2ZTItNjAxMS00MTEwLWI5ZTgtYjk2MzdmNTU5NzJh/edit?hl=en_US

[mcfonz]

From what I remember in regards to my time doing archery, point blank range, as in, within a couple of feet of a bow, the arrows will be less potent.

I would also say it would be pretty darned hard to fire a ballista that accurately. It wasn't aimed in the same way as a bow and tended to be deployed against blocks of troops where it was guaranteed a hit.

As for glass - it's an interesting one. The angle of the glass would be as important as it's resistance, I also suspect it depends upon the materials used in the construction of the bolt. Are you talking modern compounds or Roman ones? If Roman, I suspect it wouldn't penetrate.

Arrows are funny things, I have shot one at a health tree trunk and watched as the head sheared off and the shaft shattered into splinters.

[YPU]

God I love this discusion! I don't believe anybody has mentioned the diference in material strenght of a bolt vs a bullet. I would argue a straight hardwood bolt shaft, let alone a metal tiped one, is much better for penetration then a lead bullet which smudges out pretty much instantly.

I'm curious if there is anything to find on the acuracy of balistas. Crosbows are pretty acurate as far as I am aware.

[mcfonz]

It's not a question of accuracy - more how it is aimed. And then you have to factor in range as well.

If you are shooting a bolt at a moving vehicle that is going across or oblique to the facing of the ballista I would question it's ability to follow the target or even lead it at all.

I think the bolt hitting the glass itself would represent very slim odds indeed. That's before discussing whether it would get through the glass.

[YPU]

Hypotetically, in a combat situation, in a relatively urban enviroment, say a fort where one might find a balista, the hummer would probably not travel that fast and the path would probably be predictable since a fort would have a single route designed for carts which the bummer might run into.