| Author |
Message |
Benjamin H. Abbott
|
 Posted: Wed 25 Sep, 2013 8:30 am Post subject: |
 |
|
|
Just because an armor can resist the thrust of a sword doesn't necessarily mean it'll be proof against heavy arrows at long range. This is all speculation, of course, but single-handed thrusts with heavy knives don't exceed 72 J in modern testing. Assuming many sword thrusts would fall in the 50-70 J range, eyelet-holed doublets might well resist these while still failing against a heavy arrow delivering 80-90 J at 240 yards.
|
|
  |
 |
|
Matt Lentzner
|
| Posted: Wed 25 Sep, 2013 5:02 pm Post subject: |
|
|
Benjamin,
Do you have all this penetration data tabulated somewhere? I'd really be interested in seeing all of it.
Matt
|
|
 |
|
|
Neal Matheson
|
| Posted: Wed 25 Sep, 2013 10:56 pm Post subject: |
|
|
|
I suppose a difference between a sword thrust and an arrow is that an arrow is decelerating immediatley on encountering the target where a sword thrust isn't. Isn't the point of a heavy arrow to decrease the speed at which it decelerates? Maybe the Joule is not a good measurement to use in isolation.
|
|
 |
|
|
Timo Nieminen
|
| Posted: Thu 26 Sep, 2013 3:19 pm Post subject: |
|
|
| Neal Matheson wrote: | | I suppose a difference between a sword thrust and an arrow is that an arrow is decelerating immediatley on encountering the target where a sword thrust isn't. [...] Maybe the Joule is not a good measurement to use in isolation. |
This will matter for soft targets. Less so for metal armour. Not for plate, unless you can push the sword through with a push after putting the point on the armour.
To repeat what has been said upthread: energy is the most important thing determining whether or not rigid metal armour (i.e., plate) can be penetrated. (The energy depends on the penetrator geometry, so it's harder to compare different types of weapons, but easy to compare arrows with identical heads.) For other cases, things other than energy will have more effect, or other things will matter more than energy.
| Neal Matheson wrote: | | Isn't the point of a heavy arrow to decrease the speed at which it decelerates? |
Not when facing metal armour. The most important point of a heavy arrow is to increase the efficiency of the bow - to get more energy in the arrow as it leaves the bow. A secondary point is that it will lose less energy as it travels to long distances; this is because the arrow is slower, and loses less energy to drag (air resistance) due to this lower speed.
For a rigid plate, within the range of speeds seen in relevant arrows, the only things that matter are the size and shape of the arrowhead, and the energy of the arrow.
For flexible metal armours (e.g., brigandine, mail), you want a faster arrow. Energy matters most, but you want that energy delivered as quickly as possible, before the flexible armour can move much - energy that goes into moving the armour is energy that doesn't go into penetrating the armour. In this case, you want the arrow to decelerate as quickly as possible.
"In addition to being efficient, all pole arms were quite nice to look at." - Cherney Berg, A hideous history of weapons, Collier 1963.
|
|
|
|
|
Alistair Paul
|
| Posted: Sat 22 Feb, 2014 5:24 pm Post subject: |
|
|
Sorry for Necro-ing the thread. 
I shoot a modern compound bow at 60# @30" draw length, with correctly spined carbon shafted arrows of about 343grains (7.4gpi) and that gives me an initial arrow speed of about 302fps, I also use aluminium shafted 2314 (10.8gpi) arrows of 516grains with feather flights instead of plastic vanes and those arrows initially fly at 210fps, with vanes they fly at 240fps.
Does any of the tests take into account the type of fletching used as fletching makes a huge difference to the drag of the arrow.
We use Flu-Flu style fletched arrows for high lofted shooting in a confined space, my bow will hardly shoot a Flu-Flu arrow 60 meters. where as my bow is still shooting fairly flat out to about 50meters with the 343grain carbons
|
|
|
|
|
|
Timo Nieminen
|
| Posted: Sun 23 Feb, 2014 12:14 pm Post subject: |
|
|
A lot of the lab testing doesn't use arrows, but a point on a dropped weight. That way, they know exactly what the energy is, without worrying about a chronograph.
The tests using bows and arrows are usually less controlled. Whether this matters depends on what is being tested. If the test is to see if "arrows from longbow of XX lbs draw weight can penetrate mail at 100m", then fletching matters. The test should use fletching as used on historical arrows, on arrows of historical weight. No vanes. Usually, the biggest problem will be the target not being properly representative. (This can be a fatal flaw in the test, or not so bad. If you think the arrow will penetrate, the target should be tougher than the real armour. Then, when/if penetration occurs, you can say that the real armour would have been penetrated. If weaker armour resists penetration, then the real armour would have resisted penetration. There's little value in penetrating weaker-than-historical armour, or resisting penetration with stronger armour.)
If you want to measure energy required for penetration, just weigh the arrows, and put a chronograph in front of the target. Then fletching doesn't matter.
"In addition to being efficient, all pole arms were quite nice to look at." - Cherney Berg, A hideous history of weapons, Collier 1963.
|
|
|
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
All contents © Copyright 2003-2024 myArmoury.com — All rights reserved
Discussion forums powered by phpBB © The phpBB Group
Switch to the Basic Low-bandwidth Version of the forum
|
This is a standard topic