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Message started by mgreenfield on Dec 23rd, 2003 at 5:09pm

Title: Projectile Shape
Post by mgreenfield on Dec 23rd, 2003 at 5:09pm
Almost all glandes and other special sling ammo pictured or described are roughly football or double cone shaped.    Why not spherical?

One theory is that air resistance causes the "football" to orient itself point-first in the flight path.    Bad football punts dont straighten out in flight, so I have doubts about this theory.    Any ideas???     Thanks!        mgreenfield

Title: Re: Projectile Shape
Post by Yurek on Dec 23rd, 2003 at 7:58pm
mgreenfield,

Some discussion about glandes shapes you can find here:

http://www.slinging.org/forum2/yabb/YaBB.cgi?board=1;action=display;num=1060740218;start=10

I don't think a somersaulted lead projectile can point itself, even though, it will be too late for a good range. So a spherical one seems to be safer. But if you release an elongated projectile right, then it will go further. I suppose elongated projectiles give a greater chanse to get a very good range, however it is more random and require a bigger skill.

Jurek


Title: Re: Projectile Shape
Post by Chris on Jan 6th, 2004 at 4:52pm
I have similar concerns as well.  It's really hard to say how a football-shaped projectile is actually flying without seeing it clearly in flight.  When I tested spherical and football shaped glandes, I found they were similar in range, but that the spherical ones were more consistent.  I don't doubt the football like ones are more accurate or deadly, otherwise the romans wouldn't have used them.

Chris

Title: Re: Projectile Shape
Post by Gaius_Cornelius on Jan 8th, 2004 at 2:26pm
Writing as a non-slinger who is mainly interested in the History of these weapons, I'd like to venture the opinion that Greco-Roman Glandes were almond shaped for the prosaic reason that they will sit in a small flat sling cradle without rolling out. After all, a soldier might have to wait a while for just the right time to let loose. He may even be expected to move with his sling at the ready while on the battlefield or while hunting. To the ancients, this may have been a consideration that overrode aerodynamics etc.

Of course, some ancient glandes were at least approximately spherical. Is it possible that the ancients understood that for that extra long range, a sphere was the best shape?

By-the-way, ancient glandes are actually generally oval in cross section whereas an American football (or a Rugby football) is circular in cross section. I think "almond shaped" is a better description of the general form of glandes.

Title: Re: Projectile Shape
Post by Chris on Jan 8th, 2004 at 3:40pm
Interesting.  Anyone have any ideas why such a shape (with an ovular cross-section) would be beneficial, other than making it less likely to roll out of the pouch.  Any aerodynamic reasons?

Title: Re: Projectile Shape
Post by Whipartist on Jan 8th, 2004 at 4:07pm
Gaius Cornelius has a compelling point.  An oval cross section doesn't seem at all right to me for aerodynamic efficiency.  I won't throw it out, but it seems they maybe had other considerations in mind.  Manufacturing or speed of throw, or who knows?

Title: Re: Projectile Shape
Post by WalkingBird on Jan 8th, 2004 at 9:13pm
Seems to me that everything exiting from a sling pocket has a spin imparted to it by the unfolding action of the sling. This appears to be the reason for the hum observed when throwing flat shaped stones. Because the glandes would be placed cross ways in the pocket and  perpendicular to the sling, the spin would imparted around the long axis of the glandes, (this would not be the case with a punted football). This spin would have a stabilizing effect on this type of projectile, If indeed they end up flying point first, it would not take place until the apparent wind had time to take effect and slowly turn the glande into a position of least resistance. In short, It ain't no short range thang. The further the glandes goes the more likely it is to be flying point first.  But perfectly matched cone shaped ends would receive the same effect from the apparent wind making it difficult for a glande exiting a sling to "choose" which end points first, that is to say no "weather vain" effect. So my guess is that if one end were bigger, left with a casting seam, flater, or what ever, may help to cause the glande to smooth out to point on flight.  Having said all that, I could be wrong, but that's the view from here.

WalkingBird

Me thinks I like this place.

Title: Re: Projectile Shape
Post by Chris on Jan 9th, 2004 at 3:07am
But if it were to leave the pouch spinning, like a bullet or good football throw, the ovular cross-section would cause drag (because it's no longer circular) and cause it to slow down.  It would be like riding in a car with square tires.  If they really are not circular in cross section, the whole theory of point first, spinning, bullet-like projectiles seems out of the question.  

Title: Re: Projectile Shape
Post by Gaius_Cornelius on Jan 9th, 2004 at 8:52am
It would be interesting to know if anybody has actually experimented with hunting (or simulated hunting) using an sling and glandes of ancient form. i.e. a sling with a flat diamond shaped cradle and almond shaped lead bullets.

In which case, is the shape of the glandes convenient for holding in the cradle without falling out? Or is this simply not how it is done?

Title: Re: Projectile Shape
Post by WalkingBird on Jan 9th, 2004 at 11:26pm
Chris, if I'm reading your reply right, what you are saying is that when the glande first leaves the sling it will be cross ways to the direction of flight? And due to this orientation would present more surface area to the apparent wind, thus causing a greater amount of drag.

If that is what you mean, I would agree the initial drag would be greater even if later it becomes less. But the reason for making glandes in the shape they are may not be for greater range, but greater effectiveness. That is, if indeed they do end up flying point first, the cross sectional density would go up for the same weight of projectile. As you know pointy things do a better job of bashing through shields, armor, flesh and bone better than blunty things. So to throw pointy things may just plain be more effective on impact even though the range may not be increased at all. Any way that would be my guess.
I've literaly got enough lead to throw away and one of these days when theres time I'll make up a couple of molds, make some pointy things and see how they work. Make some blunty things to compare to. I'll try and see what difference shape makes.
It ain't science but it is fun!  :D

WalkingBird

Me thinks I like this place

Title: Re: Projectile Shape
Post by Whipartist on Jan 13th, 2004 at 4:45am
So far, with clay glandes, I've noticed they tend to hit my target on the sides, not the points.  This is close range, but shows approx how release is.  

They spin on the axis.  My glandes are watermelon, not almond.  I think that the almond shape could be because they are easier to load and fire.  However, round shouldn't be a lot harder, so who knows.  It could be that ancient casting techniques made almonds easier to make than footballs.  Who knows?  I'm not sure how aware the Romans were of aerodynamics.  But if they were, there are other considerations.

A backspin on an appropriately shaped gland, would produce a lift.  I'm sure every slinger here has observed that effect in their slinging.  Depending on your stone, and your style, and your release, you've had sling stones curve up, down, right.  Probably not often to the left.  But maybe left too.  Well if you're left handed......  

In airsoft guns, they produce a backspin on the bb's called "hop-up" to keep them flying level over a great distance.  And it works.  My 250fps, airsoft pistol shoots a flatter tragectory over 30 yards, than my 400fps pellet pistol.  Backspin on smooth bb's.

If a gland was made right, and the slinger released right, the backspin would effectively increase range.  The glandes would be literally "flying."  Normal projectiles don't fly, they fall.

I don't know if anyone on our forum uses the underhanded "baleric" slinging technique, but I've found it puts a bottomspin on the stones, and they curve into the ground.  Overarm should do the opposite with shorter slings.  Longer slings need a horizontal throw.  

So we need to consider what types of slings we are talking about and so on.  In a hoard of other slingers, and other various battle conditions, long slings may not be too practical.  But short, over the top slings, could be.  And almond glandes in over the top throws, could be really nice.

Having said all that, the explanation is probably just manufacture, or speed of loading and some other utilitarian thing.   :)

This forum is pretty cool.  It's amazing how much of a resource it's become, so quickly!  And new members every week!  Who would have ever known slinging was so popular!  You've started a revolution Chris!  That's a pun btw  ;)

                                         Ben    


Title: Re: Projectile Shape
Post by Hondero on Jan 13th, 2004 at 2:04pm
Hi Ben... The famous design in almond that so many doubts raises... As you say, the projectile takes a certain effect according the launching technique.This effect takes place when rolling the projectile on pouch, and have a fundamental utility that it is to maintain the stability of the position of the projectile in the fly (gyroscopic effect). Also it can be used to obtain more range by elevating the trajectory, like in golf, but the fundamental thing in slinging is the is first, that it can be used with the suitable technique to send projectiles point forward. Then, like glandes are small and smooth, the effect that they takes when throwing is small, because they slip on the pouch  instead of rolling. For it, almond shape was the solution, that used to have even two edges marked in the widest section, so that when rolling on the pouch got more clench and didn´t slip, taking the projectile better spin. That is the secret of the famous Roman almonds of plumb. Those guys were very clever  :).

Saludos

Title: Re: Projectile Shape
Post by Yurek on Jan 13th, 2004 at 9:26pm
I have observed two extreme kinds of a fly of the flat stones:

The first one, when the stone is rotating like a throwed up coin. Then it flies making a loud hum, and the trajectory is crooked due to the strong Mangus' effect and a lift of a flat profile. Such shots are short and inaccurate, of course.

The second one, when the stone is rotating like a disc or a boomerang.  Very probably it slips itself off from the pouch flat, and get the flat rotation by cathing the pouch edge. This kind of a fly can be very far and stable, sometimes. The rotation stabilises the stone which gets a lift just like a disc or a wing. It happends rather seldom.

How the flat stone will start depend on how it is situated in the pouch and what is an angle of the pouch relative to the trajectory durring the release.

Such effects sure aren't so very apparent for the flat shaped lead glandes, but they could appear however. Then maybe the ancient warriors would like to get the loud hum which had the psyhological working durring a mass volley. Or maybe just the "disc" fly of the glandes? Well, it only my free reflections. I dont't know how flat is the cross section of the Roman glandes.  

Maybe it is worth the consideration.

Jurek




Title: Re: Projectile Shape
Post by justbarak on Jan 13th, 2004 at 10:18pm
I was wondering the same thing about the almond shape - that it might possibly provid grip in the sling to increase spin when it is released.  The same thing is done to the drill in a bow drill for making fire without matches.  The drill is given an oval shape or edges in order to provide a gripping surface for the bow string to grab and rotate the drill.  Otherwise the string just slides without spinning the drill.

The various techniques for throwing are mentioned throughout this thread.  Can someone describe them: overhand, underhand, etc?  I'm assuming that a clockwise rotation (relative  is the most universal ,and in that, a vertical rotation or a horizontal rotation, and then something around 45 plane of axis (the blue, green, and red circles on my little photoshop stick man slinger - the starred arrows being the rough point of release). Then there is a counter clockwise rotation as well, which I imagine is only used in a vertical spin.  What purpose is a cc throw?  Is it accurate at all (I only use it for spelunking frogs in the pond out back ;D)



Just imagining the throws, it seems like the clockwise 45 degree rotation would release the projectile in a more pointed position rather than totally broadside.  But I'm not sure.  I need to make another sling and try it out.  In PNG (Papua New Guinea) down in the Sepik flood basin where there are no rocks but lots of clay the village kids made clay shot which they dried in the sun.  It was round.  Not that they are as advanced as the Romans were  :)

Barak

Title: Re: Projectile Shape
Post by JeffH on Jan 14th, 2004 at 1:12am
Barak,

Great illustration!  I think the release points are a bit late in the circuit, but otherwise seem accurate.

I can't get anything but distance from the underhanded sling style.  So I use a one-circuit (wind-up) style.

It starts with the stone hanging.  I sling the stone up and around my head and let go in an elevated side release.  Stand and point your right hand at the ground.  Then raise your arm until it is about 30 degrees above horizontal.  This is the change in angle of the stone, but it occurs in a full rotation.

This is probably not a very good style, but I have no one to teach me better.  I find multiple rotations to be very difficult to master, though sometimes more accurate if I limit it to two.

jeff <><

Title: Re: Projectile Shape
Post by justbarak on Jan 14th, 2004 at 3:12am
Yeah, I realized after I posted the picture that the release points were a bit late.  Ok, so the "underhand" throw is the vertical rotation clockwise.  Is that correct?  What is considered overhand?  

I find the vertical rotation gives me good accuracy in a vertical plane - i can hit trees and fence posts with it.  But hitting anything on the X axis (horz), regardless of how I swing it, is completely random.  Judging the arc is definitely more difficult.  I find I aim best with one or two rotations and then release.  There is definitely a timing in the throw that provides the greatest power.  When I have access to my brother's video camera I want to video slinging some rocks and then slow it down and try and quantify the movements involved.  Maybe we could generate some discussion on throwing techniques and see what theories we come up with.  

The projectile weight also seems to factor into efficiency as much as the throwing technique and shape.  At least it does for me.  Too light and I nearly whip my shoulder sockets out and air friction stops the stone too soon.   Too heavy and I can barely manage the rotations and the throw.  Something slightly smaller than a golf ball has about the right weight for me.  

Any thoughts on the subject of weight as it relates to distance and accuracy?  

Barak


Title: Re: Projectile Shape
Post by Hondero on Jan 14th, 2004 at 12:59pm
Yurek,
the cross section of the glandes is only a little flat, just to have a good grip into the pouch. Flat spinning missils are not aerodynamics besides humming. Here is an almond glans, point forward,  between my fingers




Barak,
the 45º turning in your drawing is the best for a point forward launching, and if you throw from the low position better. You can get the technique and see how
the missil fly launching elongated stones type hot-dog (if not available such stones, can be made in dried clay).
What a nice bull-roarers there are in Papua New Guinea. Did you get some old ones?

Title: Re: Projectile Shape
Post by Yurek on Jan 14th, 2004 at 4:41pm
Hondero,

In our climate zone the "almonds" appear mainly as the seeds (stones) in the markets, hence my first image of the word "almond" was the flat "seed of almond",  despite I had seen the pictures of the Roman glandes before :) They are really simillar shaped to the almond fruits. There was the small incomprehension :)

Saludos

Jurek








Title: Re: Projectile Shape
Post by Whipartist on Jan 14th, 2004 at 7:00pm
Great picture Hondero!  

I'd say that if this whole theory on the spin effect for added lift, is correct, then the shape of the glands isn't just for added grip on the pocket, but primarily for it's qualities in flight.  A perfectly smooth gland won't produce as much lift as an almond shaped one.  I know this is part of the point already stated, but I think it's the primary one.  I've seen experiments done on baseballs and other types of balls in regard to how much lift is generated by a backspin, etc....  The shape and quality of the surface has effect.

Title: Re: Projectile Shape
Post by mgreenfield on Jan 14th, 2004 at 7:12pm
I'd really-really! like to see slooo-mo film of some good glande launches.   Do they go point-first like NFL football, or sideways with back spin to "fly" like golf ball, or something else altogether?   What slinging hero will come up with the film for us first?   mgreenfield

Title: Re: Projectile Shape
Post by justbarak on Jan 14th, 2004 at 7:45pm
So what if the surface of the gland was pitted like a golf ball?  And just in a cartoonish curiosity - I wonder what would happen if you put a super short shaft with fletching (tail fins) on it so that the overall shape is similar to the steriotypical World War II bomb.  I have one of those nerf footballs that whistles when you throw it and has the tail fins on it.  If they were really short, close to gland (like one centimeter max), and flexible like on arrows so it wouldn't catch on a sling, I wonder if the initial drag before the gland straightened out would be to great, or if it would help it fly.

It would be amusing anyway.  

Hondero,
I never encountered bull roarer's in PNG.  We lived in the highlands, and perhaps they were native to the coast where there was more Australian aboriginal influence.  I have one though - a tourist item from Sydney.  They are great fun.

Barak

Title: Re: Projectile Shape
Post by Yurek on Jan 14th, 2004 at 9:37pm
Ben, mgreenfield,

If that glans is throwed corectly by the "point first" style it rotates rather around the axis which is approx parallel to the fly direction (probably it gets a bit precession often). So that kind of a fly is similar to a fly of the rifle bullet. Then the rotation doesn't produce the lift bat only helps to keep the direction of the projectile due to the giroscopic effect (as Hondero mentioned once). There is no lift when the axis of the rotation is parallel to the apparent wind direction. In this situation the oval shape is a negative factor because it brakes the rotation. The biggest lift is produced when the axis of the rotation is perpendicular to the apparent wind direction, when the projectile flies crosswise. And if the axis is vertical and the rotation is clockwise then the trajectory turns left. But if the rotation axis is horizontal  and the projectile has the back spin, then lift is directed to up and is beneficial, because prolongates the fly. This fenomenon is known as the  Mangus' Effect. This one is stronger when the suface of the projectile isn't very smooth and regular. I don't think that aventage of Mangus' lift (the crosswise fly) bigger than adventage of the "point first" fly for mentioned glandes.

Additionally, getting the back spin in the sideways fly, is very little probably due to the pouch position during the release in the typical ways of the slinging. So I think the oval cross section and and the edges aren't good for ranges and accuracy.

I suppose there is different kind of a lift which can be profitable. If the glans goes and rotates point-first and its nose is a little bit "snub" relative to the trajectory (apparent wind) then it should get a lift like a wing. But when the its nose is a bit lowered then lift pushes that one down and is unbeneficial.

Probably mantioned effects wasn't very significant on battlefields, for lead glandes due to their a big density.

Barak,

I think the tail fins should be rather big for quick stabilisation the short and massive glans, so they would probably cause the bigger wake (turbulences) and as result the bigger drag. Additionally the glans would lose quite a lot velocity yet before the its stabilisation.


Jurek, who hopes he is clear

Title: Re: Projectile Shape
Post by JeffH on Jan 14th, 2004 at 10:53pm
Barak,

Check out my post in the "other" section on bull roarers.

Easy to make and the fun never stops.

jeff <><

Title: Re: Projectile Shape
Post by justbarak on Jan 14th, 2004 at 11:32pm
yeah, the tail fins were a flight of wild imagination.  

Jeff, I actually saw your bull roarers earlier today and was quite inspired.  I promptly went to my little woodshop to see if i could find some suitable wood, but all I had was light weight narrow planks.  I think I'll make a run to woodcraft and see if they have some nice cocobolo planks.  I love wood grain.

Well, unfortunately I ran out of intelligent contributions to this thread several posts ago... lol, so I will go back to my shop and continue making more sawdust.

Barak

Title: projectile Shape
Post by Hondero on Jan 15th, 2004 at 4:20am
Yurek, Ben, mgreefield... etc,
Interesting the debate on glandes flying. I thing the Magnus effect in glandes, whatever was the position of them in the flight, is not meaningful due to high density of the missil, as we say about dimples in glandes. So neither loss of accuracy nor elevation by bakspin would be considerable in glandes. In my opinion the aerodynamic advantage is due to the stability of the position (more o less parallel to the advance), as the cross section (important in air drag) is less than the one of a spherical missil of the same weight and of the same glans in an erratic flying. Is the same principle of fire guns bullets.
The effect would be more importat if the pouch was striated as barrel rifles   :D    But here the striated is the missil. In fact there are anothers glandes that have four edges.

Title: Re: Projectile Shape
Post by Chris on Jan 15th, 2004 at 2:10pm
The idea of fetching might be a bit overkill and fragile, but what about a little length of sling attached to one of the points; maybe 5 inches worth.  It can be a thin piece of cotton or something.  It only would cause lots of drag when it's not oriented in the "dragging" position where it just stays in the projectiles wake.  It would be simple to add, and durable (attached with a little drop of super glue or something).  

I really have serious doubts about people consistently casting projectiles with perfect orientation and spin.  It just doesn't seem like an easy thing to do repeatedly, especially in a battle scenario, where time is limited and conditions may be less that ideal.  

Chris

Title: Re: Projectile Shape
Post by Gaius_Cornelius on Jan 15th, 2004 at 2:48pm
The orientation of a glans in flight is an interesting question that might be answered by having a target such as a block of plastercine. The impact marks might make it clear which way the projectile was orientated when it struck. Just a thought....

Title: Re: Projectile Shape
Post by Yurek on Jan 15th, 2004 at 5:09pm
Chris,

I think that consistent "point-first" throwing is possible but not easy. If you once find the way of geting it, you can copy this way next times. There are conditions however, the cords must be distant in the palm, and a minimum amout of rotations of the sling is necessary and the projectiles should be consistent too.


Cornelius,

Wouldn't be easier to beat into something big and hard (for example the conrete wall)? The lead glandes are soft so they should get the marks.


Jurek

Title: Re: Projectile Shape
Post by mgreenfield on Jan 15th, 2004 at 7:02pm
Jurek, ....see post "Correctly Slinging Footballs" down the list a little.     I think there is a "standard" technique that will propel glandes consistently point first, and stable in that orientation.    Lots of what we know indicates this.  We just have to somehow reclaim this knowledge from the dust of ancient history.    mgreenfield

Title: Re: Projectile Shape
Post by Yurek on Jan 16th, 2004 at 7:01am
mgreenfield,

You have pointed all condition very well. I think it make sense.  One day I observed step by step my stone slinging on the "high speed shutter" video. The pouch positions were rather similar in the most releases, although I didn't try to control it at that time.

Jurek

Title: Re: Projectile Shape
Post by Gaius_Cornelius on Jan 16th, 2004 at 7:32am

wrote on Jan 15th, 2004 at 5:09pm:
Wouldn't be easier to beat into something big and hard (for example the conrete wall)? The lead glandes are soft so they should get the marks.


Good idea! Can anybody try that? Preferably reproducing ancient equipment and techniques as closely as possible and/or investigating how different techniques might affect the results.

Title: Re: Projectile Shape
Post by David_T on Jan 19th, 2004 at 9:37pm
Just an "off the top of the head guess" on the suject of the Almond shape. It has a point first travel and being somewhat flat with edges would definately add to the damage on impact. Sharper, more squared edges as seen in some of the photos, would "dig in" as compared to "slide off" a target that was not hit squarely.

To illustrate: think of a sqare block on a lathe spinning. What would happen if you stuck your  finger out and moved it forward to touch the block. It would bust the finger. But if the object spinning was spherical, you could not only touch it, but run your finger back and forth on the object without hurting it.

So, the flatter shape would do more damage even if hitting "side first"????

Title: Re: Projectile Shape
Post by Ulrica on Jan 26th, 2004 at 10:52am
How about sling coals of fire ??  :o
I got the idea when we light a fire outdoors yesterday.
( By the way I light it with Flint-stone and steel. It was a pretty nice feeling when I managed it that way!)

Ulrica

Title: Re: Projectile Shape
Post by David_T on Jan 26th, 2004 at 12:38pm
Coals of fire. Now that would be a way to cause trouble in a city with grass roofs!.

Title: Re: Projectile Shape
Post by Ulrica on Jan 26th, 2004 at 2:27pm
;D  Yeah!!!!

Just wonder how the sling would look like ....

Title: Re: Projectile Shape
Post by Yurek on Jan 26th, 2004 at 4:46pm
Ulrica,

The great idea for New Year! It would work like fireworks ;) I think the sling should be maded of acbestus (unhealthy) or of soft steel net.

Jurek

Title: Re: Projectile Shape
Post by Ulrica on Jan 27th, 2004 at 4:46am
Could also be an idea of lighning the olympic fire at the international Slingolympic ;-)


Title: Re: Projectile Shape
Post by Hondero on Jan 27th, 2004 at 1:29pm
Ajaaa¡ Ulrica, your idea is not new :D. Some years ago, the international University Olimpic Games took place in Mallorca (Baleric Is.) and at the oppening of the games some slingers from the island lit the olimpic fire throwing incendiaries missils from the distance. It was a fascinating show. I think copied the ceremony in video, I´ll look for it.

Title: Re: Projectile Shape
Post by Ulrica on Jan 27th, 2004 at 1:45pm
Hondero,
I didn´t knew that :D

And I also just learned that Baleric Is is called Mallorca.
I´ve been there once, many years ago.   :)

Tell me if you find the video.

Ulrica

Title: Re: Projectile Shape
Post by Chris on Jan 28th, 2004 at 12:54am
How about slinging Molotov cocktails?  For those who don't know what I'm on about, they are glass bottles filled with flammable liquid (could be alcohol or gasoline) with a rag stuffed in the opening.  You can light the rag on fire and throw the bottle.  The glass breaks on impact, and the liquid combusts.  Very similar devices were used in ancient times during sieges.  I'd imagine a sling would lend well, and provide better payload than a flaming arrow.  

Chris

Title: Re: Projectile Shape
Post by Hondero on Jan 28th, 2004 at 4:00am
Yes, the molotov- sling surely works well, and for great loads even could be used a staff-sling. Our beloved sling has been used of multiple ways throughout the time. Its last registered military use was in the Spanish civil war (1936-1939), in which it was used to send grenades. Can you  imagine a sling launching of grenades to 100 meters?  :o

Hondero


Title: Re: Projectile Shape
Post by Ulrica on Jan 28th, 2004 at 4:11am
Wow.
That is really something!!

I would just be nervous, just have some few seconds to throw and what if it stuck into the cord ;-) or I throw it in the wrong direction. ::)
no no.. that is nothing for me.

Ulrica


Title: Re: Projectile Shape
Post by MrKipper on Jan 28th, 2004 at 9:53pm
Fascinating topic...

After trying my new sling out today, I have to say that it seems very unlikely that even on very long flights that air resistance will ever overcome the tumble imparted by leaving the pouch.  So, the almond shape must use the tumbling or be designed to create tumbling.  A rapid spin on a nearly spherical object would create gyroscopic stability in a plane perpendicular to the spin axis.  Myself, I throw vertically, over or underhand, the gyroscopic spin means my throws tend not to slide left or right, unless the stone has such an odd shape that the air resistance overcomes the gyrostabilization.  But maybe the shape is for psychological effect.  We've probably all noticed the hum created by rapidly spinning non-spherical stones.  Imagine being on the battlefield as a group (legion, battalion, whatever they're called) of slingers all release missles designed to hum.  It would be like being attacked by an angry horde of bees!  Mind you, bees that can break your bones!  Could be very effective against enemy morale

Title: Re: Projectile Shape
Post by Ulrica on Jan 31st, 2004 at 4:12am
Hello everybody!

My pink Concrete-Ammo is ready! I haven´t tried them yet, we do have too! much snow right now, and more is coming...

but here is two pic´s of them. Enjoy:






Ulrica

Title: Re: Projectile Shape
Post by Dan_Bollinger on Jan 31st, 2004 at 11:42am
One theory for the elongated 'almond' glandes shape is that they stay put in the pouch better than a sphere, making for faster spinup.

Pouch release does indeed spin the projectile, my observation shows.  And a flat shaped glandes will 'buzz' when thrown and spun.  

My theory for the flattened shape is that they wanted the 'buzzing' when they fly. Remember, glandes weren't for hunting or sports. 'Effectiveness' is more than accuracy and efficiency when talking about a military purpose.

Hannibal said his elephants were annoyed at the buzzing of slingstones.  The torrent of slings was used by generals more to break discipline and induce fear in the opposing troops than to do actual damage. It they heard the 'buzzing' of a near miss it would have as much, or more, effect as a hit. Very demoralizing, and very effective.

Title: Re: Projectile Shape
Post by mgreenfield on Jan 31st, 2004 at 12:39pm
Re the demoralizing buzz, .....yep, there's a lot to that.   I went to Jr. HighSchool in tuff town & for fun over lunch a cuple gangs would square off at opposite ends of the football practice field & throw rocks at each other.   Anyway, I had small sling even then & a lucky shot w a rough "buzzy" stone over the top of a charge from the other end would break up the charge instantly.    Kids knew how to have fun then, huh?   That was a long time ago.  A wonder none of us ever got killed!    mgreenfield

Title: Re: Projectile Shape
Post by Chris on Jan 31st, 2004 at 7:48pm
While I agree that the noise can be demoralizing (I've heard them whip past my head many times), I do believe the sling was an effective weapon as well.  For example, the romans developed tongs to remove slingstones from wounded soldiers.  I'm confident that a sling in the right hands with the right ammo could be very deadly.  

Chris

Title: Re: Projectile Shape
Post by Ulrica on Feb 1st, 2004 at 11:03am
I tested my pink concrete ammo today, but with my first hit, the ammo smasch into hunderds of pieces... So it´s more for long shots like my daughter slinged. They landed soft in the snow. And was pretty easy to find.

Stones work so far best for me.

Ulrica


Title: Re: Projectile Shape
Post by Yurek on Feb 1st, 2004 at 7:22pm
Urlica,

I'm sorry about your pink ammo :( It was so... so... beatiful :'( ;)

Last Saturday I tested the plaster-sand-balls. I fit a proportion of the sand and plaster and water this way that I was able to form the balls by the hands, without the molds. They hardened very quickly and were dense enough. I used minimum of the plaster, only for getting the good cohesion. They flew like a quite good stones, but some smashed up durring the release. Getting the good proportion require some tries but it is pretty quick and cheap way.

Jurek

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