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Velocity and Penetration (Read 31205 times)
M. Demetrius
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Re: Velocity and Penetration
Reply #30 - Oct 7th, 2007 at 7:45pm
 
>>>To bad we can't get a chronograph and actually time some of the people
Anybody [not me] want to stand close enough to a slung bullet zipping by to chrono it?  Huh

So where do we get the stickers?  I'll let my van wear one!
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Dravonk
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Re: Velocity and Penetration
Reply #31 - Oct 8th, 2007 at 3:41am
 
M. Demetrius wrote on Oct 7th, 2007 at 7:45pm:
Anybody [not me] want to stand close enough to a slung bullet zipping by to chrono it?  Huh

Psst, not so loud or Aardvark will really do it. Wink
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loh_kah_hoe
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Re: Velocity and Penetration
Reply #32 - Oct 9th, 2007 at 1:05am
 
Quote:
Quote:
Finally, there are tales of shooters' slings cracking like whips when they shot.
 I have noticed that this happens with some slings when I sling powerfully.  I remember techstuf saying that the crack is a miniature sonic boom.  Does anyone else get this effect?  I have known release-node knots on the release cord to come undone due to this (I know it is due to this and not the stone because I was swinging and practising with no stone in the pouch and it happened).  If you swing very violently, powerfully, then this effect happens.  I am sure it is not unknown for everyone else.


It did happen when I performed the figure-8 correctly. The crack is quite loud and.......cool. The sling is just a normal sling, nothing fancy designed for the crack. So, those tales are true.
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Curious Aardvark
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Re: Velocity and Penetration
Reply #33 - Oct 11th, 2007 at 11:25am
 
[quote]Psst, not so loud or Aardvark will really do it.  [/quote]
has already done it. :-)
Well I had to stand pretty close to video the penetration tests we did :-)

Maybe next year we'll get a radar gun setup as well :-)
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Dravonk
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Re: Velocity and Penetration
Reply #34 - Oct 12th, 2007 at 1:08am
 
[quote author=curious_aardvark link=1146852045/30#33 date=1192116345]Well I had to stand pretty close to video the penetration tests we did :-) [/quote]
Isn't a tripod cheaper than a human? ;-)
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Monkeywjcr
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Re: Velocity and Penetration
Reply #35 - Mar 15th, 2008 at 8:19pm
 
A sling can have the same killing power as a 45. cal pistol. Anyone who does not belive me can eat math:(mv^2)/2= KE   75g=typical sling projectile weight   111m/s=accepted sling projectile velocity   1/2(.075kg)(111m/s)^2=460J   .22 caliber long rifle=190J, .45 caliber Automatic Colt Pistol=450J
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Aussie
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Re: Velocity and Penetration
Reply #36 - Mar 16th, 2008 at 3:27am
 
111 m/s is quite on the high side for the average slinger, but attainable by some, definitely not me.
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Curious Aardvark
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Re: Velocity and Penetration
Reply #37 - Mar 16th, 2008 at 9:53am
 
hmm, well the typical weight for a sling glande was 1 1/2 - 2 ounces. so nearer 50 grams than 75. And yes it makes a difference as to the reachable velocity of the slung missile.
Not arguing that  a slung missile is lethal.

But you just don't get the penetration you get with a firearm. So while a lucky head shot might kill someone, you are far more likely to cause broken bones or deep internal bruising.

That said at short range I've seen a 3/4 inch ball bearing go straight through a 3/4 inch sheet of plywood. Dunno what that equates to but you wouldn't get me standing in front of larry bray with a ball bearing and a sling - no matter what body armour you had on hand :-)  (unless someone else tested it first lol)
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Do All things with Honour and Generosity: Regret Nothing, Envy None, Apologise Seldom and Bow your head to No One  - works for me Smiley
 
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wanderer
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Re: Velocity and Penetration
Reply #38 - Mar 16th, 2008 at 11:54am
 
'Stopping power' or 'killing power' as far as I know has no definition in terms of an equation. So, I'm not clear why kinetic energy as a means of comparison is any more appropriate than, say momentum.

I'd also argue that even comparing the kinetic energies in the example quoted needs a truly exceptional 'muzzle velocity' and heavy projectile. I suspect that very few of us would exceed 60m/s.

As C_A writes, the results of being hit by a sling projectile are rather different from guns, but in neither case would I stand down range of someone using them. My suspicion is that comparing kinetic energies for slings and bullets may underestimate the effectiveness of the sling.
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Aussie
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Re: Velocity and Penetration
Reply #39 - Mar 16th, 2008 at 10:50pm
 
[quote author=curious_aardvark link=1146852045/30#37 date=1205675585]hmm, well the typical weight for a sling glande was 1 1/2 - 2 ounces. so nearer 50 grams than 75. And yes it makes a difference as to the reachable velocity of the slung missile.
Not arguing that  a slung missile is lethal.

But you just don't get the penetration you get with a firearm. So while a lucky head shot might kill someone, you are far more likely to cause broken bones or deep internal bruising.

That said at short range I've seen a 3/4 inch ball bearing go straight through a 3/4 inch sheet of plywood. Dunno what that equates to but you wouldn't get me standing in front of larry bray with a ball bearing and a sling - no matter what body armour you had on hand :-)  (unless someone else tested it first lol)

[/quote]

Interesting story by Saxton Pope, an American instrumental in reviving archery in the early part of last century.

An overconfident museum curator offered to allow Pope to shoot at him when he was wearing chain mail. They eventually thought better of it and draped the armour over a wooden dummy. The bodkin pointed arrow produced sparks as it penetrated the chainmail, both sides of the wooden dummy and produced a bump as it pushed on the rear side of the chainmail. The curator turned a sickly pale.
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« Last Edit: Mar 17th, 2008 at 6:36am by Aussie »  

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Thomas
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Re: Velocity and Penetration
Reply #40 - Mar 16th, 2008 at 11:01pm
 
If I slung 148 gr. baseballs to 57m/s (on radar) when I was 55yrs. And this was done under bad indoor conditions. What is the  problem with you strong young people slinging past 60m/s with stones of minimum frontal area? Of course you can and do, judging by the impact reports I read.

tom
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Aussie
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Re: Velocity and Penetration
Reply #41 - Mar 17th, 2008 at 6:59am
 
There is an easy way to measure your slinging velocity by recording the sound of the sling over a short measured distance. Using "Audacity" it is very easy to see the exact time interval and calculate velocity with a very high degree of cetainty. This was discussed in a thread started by Dork (Nov. 20, 07)

The program is called "Audacity". http://audacity.sourceforge.net/
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Thomas
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Re: Velocity and Penetration
Reply #42 - Mar 17th, 2008 at 12:17pm
 
Aussie

Thanks for reminding me, I did install that program when the link was first posted, however other duties, a hospital stay and winter here in Ohio,U.S. precludes any velocity testing or just plain slinging. I did come up with a feasible ballistic pendulum design prior to hearing about this more elegant sound method.

tom
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dork
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Re: Velocity and Penetration
Reply #43 - Mar 17th, 2008 at 9:31pm
 
I think the best way test all these theories is with high tech equipment. Equipment one might find on a documentary type show running tests on ancient weapons.

If only someone from the discovery channel would contact us looking for help. They could settle all bets.

Like that will ever happen
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Maximillion
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Re: Velocity and Penetration
Reply #44 - Mar 21st, 2008 at 10:02pm
 
I have tried throwing sharp objects, and if i use a football shaped object with pointed ends(I sharpened a section of a railroad spike) I found that as it comes out of a sling with the spin it flies smoothly and one of the spikes is facing my target.  I had this projectile(I'm not sure of the velocity but I'm sure it was in upwards of 120 mph and it went through both sides of a metal trash can
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