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General >> Project Goliath - The History of The Sling >> Excavation in Scotland article on NatGeo https://slinging.org/forum/YaBB.pl?num=1495730220 Message started by WojtekimbieR on May 25th, 2017 at 12:37pm |
Title: Excavation in Scotland article on NatGeo Post by WojtekimbieR on 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-scotland (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. |
Title: Re: Excavation in Scotland article on NatGeo Post by Curious Aardvark on 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. |
Title: Re: Excavation in Scotland article on NatGeo Post by WojtekimbieR on 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) |
Title: Re: Excavation in Scotland article on NatGeo Post by JudoP on 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. |
Title: Re: Excavation in Scotland article on NatGeo Post by wanderer on 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. |
Title: Re: Excavation in Scotland article on NatGeo Post by Parmenion on 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 |
Title: Re: Excavation in Scotland article on NatGeo Post by Curious Aardvark on 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. |
Title: Re: Excavation in Scotland article on NatGeo Post by wanderer on May 27th, 2017 at 1:38pm Quote:
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:
Yes. Apologies for Anglicizing his name. But according to the Daily Mail - so it must be true - the comparisons are down to Joerg. ;D Quote:
Daily Mail |
Title: Re: Excavation in Scotland article on NatGeo Post by Parmenion on May 27th, 2017 at 4:54pm
https://en.wikipedia.org/wiki/Stopping_power
Quote:
sling loses everywhere. the only thing at which it can reach or surpass a firearm is momentum and even that goes for trained slingers |
Title: Re: Excavation in Scotland article on NatGeo Post by WojtekimbieR on May 28th, 2017 at 8:54am
Didn't see there was a thread about the Burnswark archaeological site already.
|
Title: Re: Excavation in Scotland article on NatGeo Post by Curious Aardvark on May 29th, 2017 at 8:05am
yep, thread should be under 'whistling sling bullets'. Or a derivation thereof :-)
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. |
Title: Re: Excavation in Scotland article on NatGeo Post by Parmenion on May 29th, 2017 at 12:11pm
another example of irrelevant comparisons
https://www.youtube.com/watch?v=cK5lqNhk3bI Quote:
force and impact are related but not equivalent. how stable/heavy is a target defines energy and momentum exchange |
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