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Excavation in Scotland article on NatGeo (Read 1879 times)
WojtekimbieR
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Excavation in Scotland article on NatGeo
May 25th, 2017 at 12:37pm
 
An interesting article sent to me by a friend

http://news.nationalgeographic.com/2017/05/ancient-slingshot-lethal-44-magnum-sc...

(Let's not mention the word "slingshot" because it's not even funny anymore)

How do you think they came up with the stopping power estimate? It can't be momentum because 44 Magnum has over twice as much, let alone kinetic energy (multiple times more), so either they're making it up entirely or use some other method of calculation more favorable to the slower sling projectile.
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Re: Excavation in Scotland article on NatGeo
Reply #1 - May 25th, 2017 at 12:58pm
 
Is that the excavation jaegoor is helping out with ?

In which case that's how they got the estimate. I believe jaegoor slung into ballistic jelly.

Failing that it's the one that joerg sprave was involved in. No actual slingers involved in that one. They rigged up a sort trebuchet and also used slingshots (joerg is probably the owrlds top expert on slingshots and rubber powered weapons in general)

Can't remember which of them is involved at burnswick.

Bear in mind that a 50gram sling bullet has significantly more mass than a magnum bullet. So doesn't have to hit at the same velocity to impart the same amount of energy.

As far as hitting a human sized target at 130 metres.

Hmm, i'll believe that one when i see it.

Yes if you sling enough missiles you will hit people.

But actual sniper style targeting at that distance - it's going to be a pretty low hit percentage. 


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Re: Excavation in Scotland article on NatGeo
Reply #2 - May 25th, 2017 at 3:45pm
 
Yes I did the calculations, the handgun bullet is three times lighter but impacts at 7 times the velocity (assuming sling speed 60m/s). So as I said, momentum is twice as much and energy is about 16 times more.

I'd be interested if anyone could replicate holes in lead glandes that produce sound when slung (or has it been done? Don't know what term I should search to find that)
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Re: Excavation in Scotland article on NatGeo
Reply #3 - May 25th, 2017 at 4:20pm
 
From back of the envelope calculations I did a while back- I put a very solid sling throw as around that of a .22 round (160J) and possibly approaching 9mm (520J) for the most powerful throws. 44 magnum is about 3x more energetic than 9mm (1400J) according to wiki though, so I don't buy that you could do that with a sling.

For reference a 100g stone slung at 50m/s has 125J of energy, I'd guess this is attainable for most well trained reasonably fit people using a long sling.

As you all may have guessed- a bullet fired from a gun is much faster but much lighter. 9mm only weighs 7.5g apparently.
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Re: Excavation in Scotland article on NatGeo
Reply #4 - May 26th, 2017 at 4:15am
 
The whistling business was discussed on this thread: http://slinging.org/forum/YaBB.pl?num=1470995579

There were some other related videos posted and linked to by George on his channel.

The 'stopping power comparable with a .44 magnum' keeps coming around. No idea who has most recently asserted that as true. Since no-one seems to have a formula for 'stopping power' that can be reasonably agreed upon, I have no idea how to argue with it.

Just catches the eye more than just remarking  that a sling can kill, etc. It doesn't need to be a pretend magnum to do that.
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Re: Excavation in Scotland article on NatGeo
Reply #5 - May 26th, 2017 at 9:04am
 
it's probably a momentum comparison
for example :https://www.youtube.com/watch?v=0a_IHHcw6do  time 2:00

the stones he is using seem 200g to me. he got  180km/h =50m/s
so P=m*u=0,2*50 (kg*m/s)= 10 (kg*m/s)

and from wikipedia a .44 (340 gr (22 g) LFN +P+ Buffalo Bore Heavy)
has 434m/s at 22g
so it's P'=434*0,022 (kg*m/s)=9,54 (kg*m/s)

P>P'

but the slingstone energy will be 0,25kJ
while the magnum is 2kJ



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Re: Excavation in Scotland article on NatGeo
Reply #6 - May 26th, 2017 at 2:56pm
 
They re not saying the same energy.

Lead sling bullets have as much a drilling aspect as a pure impact effect.
So while they might not hit as hard as a fired bullet. The actual stopping power of a larger missile drilling in could easily be just as catastrophic for the organism it impacts.

The whistling bullets experiments were done by Joerg.
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Re: Excavation in Scotland article on NatGeo
Reply #7 - May 27th, 2017 at 1:38pm
 
Quote:
They re not saying the same energy.


Isn't the trouble that it is never clear what they are saying? Stopping power is at best some presumed measure of effectiveness for a weapon. We're being told to believe it because someone has apparently some calculation with some formula that tells us so, but they won't give us the formula, so we are left going around in circles wondering whether maybe they meant kinetic energy, momentum, or whatever.

If you do a Google search on 'sling stopping power', see what you find.

As I remember now, Malcolm Gladwell repeated this notion in his book and TED talk, of which there is a transcript here, but since he reckons a sling throws rocks at about 35m/s and does not indicate how he is calculating ‘stopping power’, we are back where we started.

The relavent bit is at 6:30.

Threads on this were going strong on this forum long before his book, and I think there’s a good chance the claim actually originated in this forum. One of the previous threads here, but there were earlier ones with similar comparisons.

Quote:
The whistling bullets experiments were done by Joerg.


Yes. Apologies for Anglicizing his name. But according to the Daily Mail - so it must be true - the comparisons are  down to Joerg. Grin

Quote:
And German researcher and slingshot enthusiast Jörg Sprave has since analysed their kinetic energy to make the startling discovery.
He believes they would have had the same stopping power as a modern .44 Magnum handgun, which fires bullets at speeds of around 1,475 feet per second (450 metres per second) and imparts 1,160 foot-pound force (1,570 joules) of energy.


Daily Mail
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Re: Excavation in Scotland article on NatGeo
Reply #8 - May 27th, 2017 at 4:54pm
 
https://en.wikipedia.org/wiki/Stopping_power

Quote:
More immediate effects can result when a bullet damages parts of the central nervous system, such as the spine or brain, or when hydrostatic shock occurs.


sling loses everywhere.
the only thing at which it can reach or surpass a firearm is momentum and even that goes for trained slingers
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Re: Excavation in Scotland article on NatGeo
Reply #9 - May 28th, 2017 at 8:54am
 
Didn't see there was a thread about the Burnswark archaeological site already.
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Re: Excavation in Scotland article on NatGeo
Reply #10 - May 29th, 2017 at 8:05am
 
yep, thread should be under 'whistling sling bullets'. Or a derivation thereof Smiley

The problem is that 'stopping power' can mean something as simple as : it kills you, therefore you stop.
In which case a sling is the equal of a firearm.

It's only when you get the energy carried and imparted by a missile that it means a completely different thing.

And as far as I know  jorg, never used an actual experienced slinger. Just trebuchets and slingshots of one type or another.
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Re: Excavation in Scotland article on NatGeo
Reply #11 - May 29th, 2017 at 12:11pm
 
another example of irrelevant comparisons
https://www.youtube.com/watch?v=cK5lqNhk3bI
Quote:
how much force needs to be exerted in order to kill?If we are talking about how much force is neccessary to kill somebody by an impact to the brain anything over 3000 Newtons spread over an area of 30mm^2 is enough to kill a human being...   ....3000 Newtons is equivalent to the force neccessary to smash a concrete block in half


force and impact are related but not equivalent.
how stable/heavy is a target defines energy and momentum exchange


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