As well as the Balearic slingers were considered the best ones of the world because they could shoot with accuracy farther and greater stones than anybody, the Achaeans were reputed to even have better accuracy than the Balearics. It was due, aside their ability, to the use of a special sling that allowed the glandes to remain fixed in the pouch and always come out in a  precise way, “like the arrow shot by a bow” (Livius)..... Did he means point-first ? ::)

I have not practiced much with glandes, but  I have observed what follows with stone projectiles and mainly with clay projectiles, of controlled shape.

If we turn around the sling with a certain separation between the two cords -the retention end in the middle finger by example- and we imagined the position of the pouch throughout a complete horizontal turn, we observed that when it is at our right the projectile is oriented with the point to the front. Therefore, if we let go the cord now, the projectil come out tangent to the circular trajectory, oriented point forward. This is one of the techniques of point-first launching, that nevertheless does not allow us to reach the maximun power as it is developed in a quarter of turn. The maximun power is obtained, as we know, with pitch type baseball launching, prolonging the arm forwards, which has a greater duration and effectiveness of transference of the momentum. Unfortunately then, the position of the pouch makes the projectile to leave crossed forwards. The technique can be varied using for example a vertical turn around and also modifying the position of the hand when releasing so that the projectile come out the best oriented forwards, but always this is obtained at the cost of a lost of power. For that reason we must adopt one or another technique according to the purpose of the shot. If we want to obtain a great penetration at a medium distance, we will use the point-first technique, but if we want to obtain the maximum distance we will forget it.

On the other hand, point-first flight considerably reduces the air resistance, like all we agree, and we would have  to consider if this effect compensates the lost of power of a launching point-first. The best thing will be probably a launching tecnique little forced, that provides to the projectile an inclination of about 30 degrees for example. This could be obtained without an appreciable lost of power and the diminution of the air resistance would be interesting. The launching technique would consist then of a turn around inclined 45 degrees and taking some care of the position of the hand in the release.

The shape of the projectile is the other decisive aspect. In my opinion glandes do not orientate  by themselves  as someones think, I´m sorry. On the contrary, due to the gyroscopic effect they acquire when shot, they roughly  conserve the inclination with which they start off, because beeing symmetrical and been their frontal surface symmetrical too in any position in which they fly, the force of the air is applied on the same direction of the center of inertia of his mass. Nevertheless, an asimetrical frontal section is put under a nonbalanced push of the air that rotates the projectile until it is oriented in a position in which this push is balanced. In a projectile with droplet shape which axis is not oriented on the flight direction, the center of the air push on the frontal section is placed towards the tail with respect to the center of inertia and, as I´ve said, a pair of forces takes place that rotates the projectile until both centers are aligned when orienting the projectile with the tail backwards. This effect was already used by the Romans, who reduced lightly the half of the glans.

However, this optimal assymetrical projectile, involves the problem of its lodging in the pouch. In a conventional pouch it would be left some inclined, and in the release it could oscillate and fly in a chaotic way. This takes us to another delicate subject: the design of the pouch. Conventional glandes even can leave oriented in an unpredictable way due to small variations of its position into the pouch when launched. For this reason the achaeans, masters of accuracy, took care so much of the design of the sling, so that the projectile was fitted well in the pouch and it was freed of precise way. I seems to me that the design of the pouch to lodge a type drop projectile placed trasversely, so that it takes spin, would have to offer equal support throughout its logitudinal axis. The transversal section of the pouch wouldl have somehow reproduce the longitudinal profile of the projectile, making the pouch of several sewn parts or by means of splits or holes. This is a good field of experimentation....

What do you think about all this stuff? The subject is very intrincate although exciting, but I think my message has been too long, almost an article, and maybe some confusing or sometimes  unntelligible due to my (and altavista) english  :-/

Hondero
I've read the same from Livy.
Did you say that the glandes were placed transverse(pointy ends facing the thongs)? Is this correct?
Your English is great!
Johnny

Hondero, ....read every word & loved it!  Keep these mini-articles coming.    I believe that in the next year or so, we will figure out a lot of our present "slinging puzzles".    Some slo-mo video work will be a BIG contribution.   Pretty exciting.     mgreenfield

And I'm still waiting on photos/video of the Cestrosphendon!!
Don't leave us in suspense!!
Johnny

The stone I threw for the record in 1981 is roughly football shaped and spun on its long axis when in flight.  It is about 1.75 inches long and 1.125 inches in diameter.  Projectiles of this shape fly much farther than round projectiles.  I am sure the throwers technique and release dictates the rotation or lack thereof.  I throw with an overhand motion best described by David Engvall as resembling a tennis serve.

How did you make your sling? Did you braid it out of string fiber or leather thongs? Are you the one that threw over a quarter of a mile?
Thanks

Ibray,

How would you know? ;D  You only threw one a quarter mile!!  ;D

Overhand Huh. Wow

Lbray, welcome¡¡¡... it´s nice to see you here, not all days a world champion come here to talk with us. I´ve found the stone you throwed much heavy (10 ounces I think). Don´t you think a lighter stone would reach greater distance... You make me remember the old Balearic people.

jesús

Lbray, Welcome!  I would have loved to have seen that stone disappear over the horizon!

So you know David Engyall, the current champion? What can you tell us about the non-classical equipment he used? Have you considered claiming the record again?  

I think lbray answered that questions a bit under the thread: World´s records holders.
But there is maybe more to tell?

/Ulrica

Thanks, I just saw that.  Very interesting, too.  :)

Hondero,

Thanks for the interesting article. It is really interesting problem, the optimal puch for the "droplets". Maybe, the pouch made of soft and flexible leather would be a good way. Although, I'm afraid that that one may be not too good due to redudant adhesion to the projectile durring the release. I mean that too soft pouch slows down the escape of the release cord and keeps the projectile too long. Maybe the middle schould be soft but the endings gradually stiffer? The smart splits should be a good way too.

Jurek

I would not be surprised if this Achaean sling had something like a feather or a tail at one side of the slingpouch, to keep a certain orientation through the cast.

Hmmm... ::)

During the winter cold I made some 80gram plaster of paris eggs.  Each of these I painted half red and half white.  The color was divided along the long axis of each egg.

The idea was to be able to determine exact motion of the egg as it left the sling pocket and flew, ...especially if photographed in slo-motion video

The snow is gone, and I launched an egg today.  No need for slo-mo video.  It flew with long axis in the direction of flight, and with a perfect NFL quarterback pass spiral.

I now consider answered the question of whether or not Roman glandes flew point-first.  Of course they did!

mgreenfield

M Greenfield

    I have to agree with you on this. Last time I had opertunity to sling at the lake I took a rather long sling to be able to throw for range, and went out of my way to find and sling as many elongated stones as possible. Each of the stones, because of my style of throwing, left the sling with the long axis perpendicular to flight. In a fairly short distance one could see the stones take on a wobble effect as they began to orient themselves along the axis of flight. Further out all wobble was no longer apparent and they became a dot. The whole process taking on average of one half to two thirds of the flight depending on the length of the stone and overall shape.
    In my mind at least point first is an evident fact.

    Now for a glande mold.  8)


WalkingBird

Yes Siry,

They certainly do fly point first. No doubt at all in my mind either!! Some better than others, but they stablize and spin nice if they have enough air time.

I am returning to this thread, too, with renewed interest.

I am sure oscillations diminish during flight, but at the expense of velocity since the energy for dampening the oscillations comes from the kinetic energy of the glandes. It would be best to throw without oscillations.

I am still looking for a high-speed digital camera. I want to understand what I am calling the transitional period between the glandes in the pouch and glandes in flight.

I tried using my digital camera, but its slow shutter and frame speed I got blurred still pictures instead of sharp, motion pictures. Still it was enough to whet my appetite.

I think Hondero is right, the pouch may have to be shaped to fit the glandes to keep orientation correct during the toss and to induce the maximum spin on the glandes.  For starters, use a high-friction material.

Dan

  I have to agree with you on the fact that the "weather-vaining" of a glande must produce more drag on the projectile. At least until the gland is oriented long axis in line with the line of flight.
  So... glandes launched from a sling will experience more drag at first and less later in flight. The only question, I think left to settle, is weather the effect over the whole flight is more or less drag, and hence more or less distance. In other words, is the average overall drag increased or decressed. And that answer is beyond me, and what little testing I've done so far.
  Still I think there are some things we can conclude. First, that glandes were used extensively by the roman army necessitates some advantage to the slinger, if not they would not be used. Secondly if glandes of the same weight did not fly at least as far as a sphear then no matter how effective they are they would not be used, as the advantage on the battle field would shift to whoever could throw the furthest. So the glande must be capable of at least the same range as the sphear. Two things are evident, one the glande is more stable in the pouch for loading and slinging, two that the glande has more penitrating power for a given weight if thrown from sufficent distance. This still does not answer our question, but in my mind at least, I'm satisfied that on the battle field they are much more effective as ammo.
   My hat is off to who ever can settle the matter of overall efficency of the glande verses the sphear for flight distance.
   

  WalkingBird

  Who is having fun on the forum!

I think we'll produce some formal research on this topic, as it is a good one and as far as I know, has never been explored.  I'm trying to get in touch with some aeronautical engineers and physicist.  

Chris

Chris

   Good luck with the research. I'm very interested in the outcome, as I'm sure many are.

WalkingBird

Reading this thread I remembered an article of Dietwulf Baatz about the ballistics of slinging of lead glandes.

Baatz (Schleudergeschosse aus Blei, page 59 pp., Saalburg Jahrbuch 1990) made some remarks on the physical characteristics of lead glandes. The sphere is an aerodynamcal disadvantageous form. For this reason modern bullets are long and pointed. For his ballistic formulas he defined a drag factor Cw which shows the air resistance of a shape of the projectile. The more disadvantageous a shape is the higher is its Cw. For the sphere Baatz estimated a drag factor of 0,48. Other shapes like unround, biconicle and looping projectiles or such with a rough surface are estimated with aunified Cw = 0,4. It is the interruption of air current at the edges of these projectiles that diminishes the drag of the air. Baatz believes that the ancient slingers got the optimal shape by practise. I think these shapes where already an old tradition when lead glandes became popular. Korfmann gave examples of shapes of neolithic clay projectiles in his doctor thesis. They are egg shaped or biconic.

funda iucunda  

Baatz knows probably not more about aerodynamics than I do and I do know very little about that. In fact I learned most about that here on slinging.org. So I rather recommend search here on slinging.org for air drag. The Achenbach curves you can find here are IMO very interesting. The form of these cd/speed curves are probably similar with glandes, i.e. there is probably a critical speed where the cd drops down, but the actual critical speed and cd values are different. Scientific research of knowledgable people would be interesting, but because of the asymmetry the rotation is even more important than on spheres[1] which makes it probably much more difficult to analyze.

Zwiebeltuete

[1] To calculate the range of golf balls you have to include the lift caused by rotation of the ball. It is pretty important there.

Logically, one may deduce that in our day at least, slinging hand made obloid glandes would only be of true benefit for long distance slinging.  That being the case, it is truly most suited only for occasional extreme distance practice or competition, and given that the record distance is still held by natural ammo....perhaps naturally obloid ammo is the true bargain.  Certainly, it was by observation of the increased distance gained by obloid stones, that lead glandes got their shape.

It is always fun to watch an enlongated stone come out of the pocket attempting a topspin dive to the dirt until it's spin axis precesses into a fixed position parallel with it's trajectory....at which point it squirts ahead with noticeably increased velocity.

Spheroid ammo is truly advantageous to the more challenging slinging exercise, accuracy sport.


TS

If the shape does matter what's about the direction in which the slinger puts the glans in the pouch. One might put it in the pouch with its length following the direction of the cords or crosswise. Is there a significant difference?

it depends on your slinging style.  there can be a signifigant differeance, if you sling to put spin on the ammo in a particular direction, but if you just whip it out it probably won't make much of a differnce

I pesonaly think wide grip point first spiral is the only way to go. I am of the thought that it improves your aim.
But just my humble thought

thanks, but I'm not sure whether I understand in detail the meaning of "wide grip point first spiral". Does  wide grip mean that I put the loop on  ring finger instead of indexfinger? And what's point first spiral exactly?

funda

Retention on little finger, release pinched 'tween thumb and index. Cords are a palm width appart ... throw with your palm facing target when release is made. 8)  Oh the glandes need to be oriented in the pouch pointed across the narrow dimension :)

It is when the glande spins American Football, or rifled bullet style as opposed to just wobbling or flipping through the air.

Many thanks for your quick answer. Just one question, for I'm not sure whether I understand right (I'm not a native speaker).  Does "pointed across the narrow dimension" mean that the longitudinal axis of the glans is parallel to the longitudinal axis of the sling?

What's about the slinging style? I normally use the helicopter or over head style. Does that make a difference?

funda

The glans sits in the pocket with the long axis parallel with the fold, pointy ends sticking out. The natural way for it to sit, really.

When you throw, using any style, the idea is that you use your hand and wide grip to manoever the glans into the correct launch position. Releasing the thumb lets the projectile roll out of the pouch, which is where the spin comes from.

It is easier to get the right (and repeatable) orientation using throwing styles that don't twist around too much. The underhand/sidearm variants work well, as do the overhand/apache. Figure eights should be good, but depending on your windup, you may need to twist your wrist a little bit. Helicopter is tougher, since you have to roll you wrist to keep it spinning, and that sets the galns/pocket to wobbling...

Matthias

For those of us who rely on the narrow grip, I believe I am being objective in advancing the following pre-production model as perhaps the most advanced and reliable distance rig currently available on the planet.  Even wide grip distance fans can benefit from a satisfying release every time.

The user will experience ballistic spiral releases at every launch no matter the style.....never any ammo hang ups....and virtually no sling cord wear.  The rig shown has had 2,024 river rocks leave it's pocket thus far and shows nominal wear. I believe the fibrous components of this design should realize a 10,000 round service life before needing replacement, provided only smooth river rock commensurate to pocket size is used. (Nearly the only kind of natural ammo worthy of serious slingers.)

This system induces just enough spin to maintain stability for the duration of flight.....thereby translating more energy to increased velocity at the moment of release.

The steering vane is attatched via a carbon fiber shaft and held in place via pocket support cord and reactive centrifugal force.  It is easily removed as desired.

The production model is more streamlined for even greater mind blowing performance.....truly....I am stoked!  The official results, I trust, will be impressive.  I am currently waiting to hear back from Guiness regarding acceptance of my application.  If they should prove uninterested, I still plan to release my results on video.  


http://img78.imageshack.us/img78/9421/spiralglidereleasesystem4iy.jpg


Hope you like it.



8)


TS

Quote:

smooth river rock commensurate to pocket size is used. (Nearly the only kind of natural ammo worthy of serious slingers.)

Hey! Just because you're stuck in Nebraska doesn't mean that nice smooth beach granite won't outsling river pebbles any day! The ocean sorts then nicely by size for me too. 8)

LOL.....and yes...when I said 'nearly' I was thinking of you!  :P


;)


TS

TS that is a nice release mechanism  8).  I was considering an archers caliper style release  clipped to my retention cord.  :-/ I  may need to reconsider the archers caliper.

A bow release of the proper design can be useful. Back in the 80's I approached a bow release manufacturer to produce one of my designs.  Negotiations broke off due to 'Product Liability' concerns on the part of the manufacturer.  The product I invented at the time, made use of the same principles as a bow release.  I have found the Wynn Free Flight relax trigger and the Tru Fire X-Caliper Pro relax trigger releases to be most adaptable to our sport as manufactured.


http://img242.imageshack.us/img242/7664/supersling8xt.jpg


http://img242.imageshack.us/img242/9677/trufirexcaliperpro9td.jpg


I sometimes employ the TruFire release for heavy slinging.  Ammo such as heavy water balloons,
stones and such.


TS

Wow! :o

Thats pretty nice! How reliable is it? for release times compared to slinging without fancy devices? does it require earlier/later release than the normal sling?

TechStuf that is truely a very appropriate name for you!!!! I love the designs.

I love how the sling, probably one of mans most primitive ranged devices, can be advanced so much with all this technology! Its just that there is so much on it thats done by hand that can be taken and re-made into a more modern style without really taking away too much from the experience that is SLINGING!

Slingwolf, in answer to your questions....

Firstly, I don't know how fancy this rig is.....I mean, compared to some of my creations, it might be considered quite utilitarian in form and function.

Regarding reliability....I hope my statements earlier in the thread are meaningful enough.

As regards the timing of release, the difference is notable.  The release is much improved....it is cleaner and much more consistent than traditional slings. Therefore those who might experience this design will instantly, and to varying degree, notice the change in timing required.  I found myself learning to release a bit later with this system.  Of course, all being relative.....certainly those who are involved in 'extreme distance' exercises will experience the greatest gains.

The production model has some notable improvements over the one shown.  Improvements which, in my admittedly subjective opinion.....will add even more to the enjoyment of the 'slinging experience'.

Throwing great spirals with every cast.....enhancing velocity, and not having to replace sling cords has renewed my vigor for our sport considerably.

After I get the go ahead from Guiness.....wait til you get a load of my personal custom distance rig, if you think this one is 'fancy'......

This potential 'world record wonder' is sooooo not fair!


Peace,


:)


TS

well tech its a nice looking rig
Its nice to know that nebraskan is going after the record
I hear your thoughts about cord wear. I don't seem to have those problems . But then I am a wide grip fanatic.
see if you can do me a favor head down to the "mighty Mo do around the Bellvue area in the old bell of brown veiw park and see if you can hit the far bank a couple of years ago i could only make it 3/4 of the way.
no looking for the narrowest point either lol
             A.C. Scott
                  out

I am currently slinging further than can usually be visually confirmed by naked eye and would likely have to rely on sound from a tree impact.  As it is now....I am occasionally slinging over the Elkhorn river from my back yard with natural ammo.  A distance of 1,440ft.

I have also been working with special glandes which exploit basic principles in order to decrease the drag co-efficient considerably.  It makes use of high RPMs in order to create a slight constant vacuum at the nose of the glans, while separating the skin of the glans from the immediate atmosphere via a thin envelope of compressed air.  The added volume serving to increase adhesion of laminar flow at the rear of the projectile, while at the same time increasing lateral inward pressure at the tail of the ammo.....in effect....nominally serving to 'squirt' the ammo forward.  Rudimentarily....it is kind of like a person pinching the back of a slippery grape.

The idea was inspired by the work of Viktor Schauberger, the Austrian naturalist.

Quite similar in principle, though appreciably simpler, to this concept:

Viktor Schauberger's Biological Submarine


TS

TechStuf, I wish you success with your world record. Over 432m is very impressive. Your design is also interesting, but ...

I will stay with the simple stuff. A point why I am so fascinated by the sling is it's simplicity. One rope and three knots and you're there.

Zwiebeltuete,
who is now tablet weaving a sling and is progressing faster thanks to Willeke

I appreciate your point of view.  It's one that you and I happen to share, relatively speaking.

Good luck with your tablet weaving project!

Woven slings are simply beautiful....even though, like my own slings, they are not so simple to make.

TS

The woven sling is one in my series of reconstructed ancient slinging equipment. 99% of my slinging I use a 2 EUR 3 knots PP rope sling. The remaining 1% is testing of my reconstructed equipment.

I would like to see you sling, but I am very sure, that I will not get to Nebraska the next 5 or 10 years. There are also very few slingers in Germany which would be available for meeting. So do we get a life video feed from your world record? :)

Btw. which sling length do you use? The current records have been with rather long slings AFAIR.

Zwiebeltuete

42".....it used to be 49"....but I don't move quite as fast as I did twenty years ago.  I am confident that an improved design will more than make up the difference.

I wish I could pull off a live feed.....but I will get video of the event either way.  I use a rather unique method of finding the projectile after impact, which should prove somewhat entertaining as well.

Regards,


TS

Did you get information about the record procedures? My impression from the news papers on how to do a record for the Guiness Book of Records is:

• Each try for that book costs money. I think around 500 EUR.
  
• There are rules on how to conduct the undertaking. Maybe to make it comparable to previous records.
  

The rules might state that the distance is measured up to ground impact. Just finding the projectile would the not be enough.

Zwiebeltuete

Go Techstuf Go!!! :D

Who cares about Guiness?  Just do it!

When do you plan to do this?  Want any of us to come over and witness? ;D

Zw,  I've already applied and am simply awating the yea or nea from Guiness.  The only reason I'd like to make it official is to stoke the home fires here at Slinging.org and as a bit of advertising for my products.


Tint, either way.....I'm going for it.  Rather than seeking to impose on any one here to incur travel expense to verify the new record,  I will most likely have a couple locals and a notary present.


8)


TS

I'll be cheering you on!  And one of your first customers. I'm sure! 8)

This summer I tried to sling point first. I managed it once with a irregularly shaped stone. It was a underhand throw with my flax sling (1m length). The stone flew about 130 m. I didn't realise any wobbling. As far as I could see the stone flew point first like a rocket. Using other styles I never reached more than 100 m. So I believe that the technique made the success. But it seems to take much training to gather skill. Until now I didn't repeat this style with satisfiying frequency.

funda iucunda