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Sling Speed???????????????????? (Read 37837 times)
HurlinThom
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Re: Sling Speed????????????????????
Reply #15 - Jul 9th, 2008 at 7:46pm
 
[quote author=IronGoober link=1215377301/0#13 date=1215610770]
This is assuming that there is no air resistance

I'd be willing to bet that very little slinging takes place where there is no air resistance. Sorry if I sound nit-picky, but I'm hyper-aware of what effect air resistance can have on a hurled object. Said objects can lose so much forward velocity that they seem to fall straight down. (They don't, but it seems that way.) Ruins that nice parabolic path.
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Thomas
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Re: Sling Speed????????????????????
Reply #16 - Jul 10th, 2008 at 12:40am
 
I used the Audacity program to speed check the following film clip of Yurek hitting a tire. An allowance was made for the speed of sound at the slinging distance of 20m. The camera to slinger distance was not used for the sound adjustment. This sound recording was complicated with all the various events, but the key peaks are discernible.

The adjusted interval is .336 sec. and average speed over 20m is 59.5m/s. (133mph).
Compare this to Yurek’s film analysis on his post #6.

http://www.kajakowe.com.pl/sling/hit1.avi

http://slinging.org/forum/YaBB.pl?num=1124289190/0#0


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Re: Sling Speed????????????????????
Reply #17 - Apr 15th, 2009 at 6:09pm
 
Working my way through removing that blasted spam but at least it's brought this thread to the top. In light of some of the speed questions of late, very timely Grin

Click on the link in the previous post and see one of the best of our slingers getting a genuine 60 m/s, and that is average over the distance, release velocity would be considerably higher.
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Thearos
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Re: Sling Speed????????????????????
Reply #18 - Apr 20th, 2009 at 7:25pm
 
On sound measurement: I've seen some vids on YouTube-- but wouldn't the 'crack' of the sling tassel come after the stone has already left the pouch ?

What's the muzzle velocity of a black powder rifle ? I ask this, because of T. Rihll's claim that slung lead really can't go fast enough to penetrate human skin-- and hence that lead bullets in ancient med. literature isn't from hand slings, but small catapults. Can slung lead go as fast and hard as a bullet fired from e.g. an arquebus or a wheellock pistol or a flintlock /fusil/ or musket ?

On a completely different matter, a friend has just returned from her Easter vacation on Ibiza-- and I just heard that she's bringing me a woven esparto grass sling that she bought (+video on the making of it). I hope it's not a tourist knock off, but a working balearic sling. Will report on Wed. !


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Re: Sling Speed????????????????????
Reply #19 - Apr 20th, 2009 at 8:19pm
 
Thearos wrote on Apr 20th, 2009 at 7:25pm:
On sound measurement: I've seen some vids on YouTube-- but wouldn't the 'crack' of the sling tassel come after the stone has already left the pouch ?

What's the muzzle velocity of a black powder rifle ? I ask this, because of T. Rihll's claim that slung lead really can't go fast enough to penetrate human skin-- and hence that lead bullets in ancient med. literature isn't from hand slings, but small catapults. Can slung lead go as fast and hard as a bullet fired from e.g. an arquebus or a wheellock pistol or a flintlock /fusil/ or musket ?

On a completely different matter, a friend has just returned from her Easter vacation on Ibiza-- and I just heard that she's bringing me a woven esparto grass sling that she bought (+video on the making of it). I hope it's not a tourist knock off, but a working balearic sling. Will report on Wed. !



A quick look around the internet seems to suggest muzzle velocities of the order of 800fps upwards for these firearms. I would not be at all surprised that these greatly exceed the velocities for the sling.

I'm currently reading Rihil's book, and her selectivity with respect to her sources strikes me as a little troubling. To quote her book (p100):
"To penetrate human skin, a blunt projectile must hit at 49 metres per second or more (111mph, or 163fps). To break bone it must hit at 65m/s or more (145mph,213fps)."  I think these numbers are probably about right, although lead glandes are decidedly 'pointy'!

On the next page she writes
"..a good slinger can consistently reach a velocity of 30-31m/s (about 68mph or 100fps), with best performance of 32m/s, and worst of 29m/s."

This is quite ludicrous, despite being in the academic literature. Such velocities are entirely inconsistent with observed ranges (ancient and modern!). I would guess many of the experienced slingers here exceed 50m/s without recourse to ultra-long slings etc. She does reference this web site, but somewhat selectively.

She asserts that Baatz's work must refer to catapults rather than hand slings simply because his figures are significantly higher than the 30m/s or so. Note that such velocities imply a maximum projectile range of less than 100m. This is not rocket science, it's basic physics.

I agree with you about the crack of the sling. This does occur significantly after the departure of the sling from the pocket. The projectile can be of the order of 1m downrange at the time of the whip crack.

Perhaps it is about time to get some realistic measurements from hand slinging into the 'respectable' academic literature before this gets too silly. Any suggestions about how to go about doing this?!

Enjoy your new sling!
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Thearos
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Re: Sling Speed????????????????????
Reply #20 - Apr 20th, 2009 at 8:34pm
 
Yes, you're right about the surprising "pointiness" of lead bullets (which I posted about in the Goliath forum)-- so that the figures about blunt penetration are not relevant-- we must be dealing with lower penetration thresholds !

If you want to get the figure into academic literature: you have to write a short note, with good evidence (not YouTube measurements, etc), but real measured experimental evidence, and clear argument-- and send it off to a refereed ancient history journal. The piece will be sent anonymously to two specialists (military historians of the ancient world), who read it and make a recommendation.

The catch here is real experimental (not "speed gun by the side of the road") + referenced (not "I read somewhere on the internet") evidence-- not because of academic snootiness, but just so that the results are checkable...

For what it's worth.
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Thearos
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Re: Sling Speed????????????????????
Reply #21 - Apr 20th, 2009 at 8:35pm
 
PS If you post it here, I'll read it first.
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Thearos
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Re: Sling Speed????????????????????
Reply #22 - Apr 21st, 2009 at 8:46am
 
One possible outlet would be the Journal of Roman Military Equipment Studies (they had a good piece on sling bullets from Frisia a while back, and are very receptive to experimental archaeology)-- but I have no idea if they're still going.

Ancient History Bulletin might be a good bet. Military History Quarterly ?

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Thearos
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Re: Sling Speed????????????????????
Reply #23 - Apr 21st, 2009 at 9:01am
 
Aussie: I mean no offence by what I wrote, and take none at what you wrote. But whoever Wanderer is, he asked a question; as one who has sat on the readers committee for several peer reviewed Classics and ancient history journals, and as one who's had peer reviewed papers accepted, and rejected, I thought I had the expertise to offer a reaction.


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Re: Sling Speed????????????????????
Reply #24 - Apr 21st, 2009 at 2:58pm
 
Thearos wrote on Apr 21st, 2009 at 9:01am:
Aussie: I mean no offence by what I wrote, and take none at what you wrote. But whoever Wanderer is, he asked a question; as one who has sat on the readers committee for several peer reviewed Classics and ancient history journals, and as one who's had peer reviewed papers accepted, and rejected, I thought I had the expertise to offer a reaction.




Thearos, no problem. I did ask! I'm quite familiar with academic practise. There also seems to be a journal which had 'scientific archaeology' in the title - the work of Brown-Vega which we discussed here a few weeks ago was published there.

At any rate, it seems to me that a clear up of these figures is long overdue. I'll think about it - bearing in mind that I am well past my 'sell by' date I'm not convinced I'm a good experimental subject.
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Re: Sling Speed????????????????????
Reply #25 - Apr 21st, 2009 at 5:24pm
 
Wanderer: I guess I can hear a dry chuckle, and I deserve it. But my suggestion still holds: organize a real bit of  experimental archaeo, and publish it in a journal. Journal of Roman Military Equipment Studies had plenty of those in the day (e.g. guys timing how long it took to make a Dacian-war scythe, then photographing the impac of the war-scythe on reconstructed Roman armour, etc).

What's the guy's name, who does a lot of Roman experimental archaeology ? Not Baatz-- Marcus junkermann, who reconstructed a Roman cav unit. It might interest him.


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Re: Sling Speed????????????????????
Reply #26 - Apr 22nd, 2009 at 4:14am
 
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Re: Sling Speed????????????????????
Reply #27 - Apr 22nd, 2009 at 8:08am
 
Thearos wrote on Apr 22nd, 2009 at 4:14am:

Thearos,
Thanks for the suggestions and the above link. I will have to spare some time to trawl a little in the current archaeology literature and get a sense for the style. Rihil's book quotes a number of sources to which I have no access. and I would like to read them if possible also.
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Re: Sling Speed????????????????????
Reply #28 - Apr 23rd, 2009 at 8:41am
 
Hallo,

I use the videocam with 25pics/sec, so each picture is 0,04sec. Today I sling a stone 225gramm, 10,5m ins 6 pictures (0,24s).

10,5m/0,24s = 43,7m/s  

E= 0,5 x m x V x V
E= 0,5 x 0,225kg x 43,7m/s x 43,7m/s = 215 Joule ore 161ftlbs

It is not so exact, but the rate of mistake is less 5%

Greetings Michel
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Thomas
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Re: Sling Speed????????????????????
Reply #29 - Apr 23rd, 2009 at 10:51am
 
Quote:
Fx 2000

     
Re: Weavers figure 8 videos
Reply #4 - Today at 9:06am Quote
A littel tipp for people like me, who have there problems with a right figure 8. When I tested it, I ever loos my tennisball. So I take a 3 feet long naylon rope, at the end I make a ball build of two old socks, tough guys can use a tennisball Grin Grin Grin. With this constuction I learn it verry fast.

Greetings Michel


Fx 2000

With 225 gr. you are with out doubt a tough guy! I don’t own a video cam. How do you determine the frame count?

tom                  
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