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Point-first flight (Read 10482 times)
Hondero
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Point-first flight
Feb 19th, 2004 at 2:32pm
 
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 ? Roll Eyes

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  Undecided

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« Last Edit: Mar 10th, 2004 at 2:04pm by Hondero »  

He brought a conquering sword..., a shield..., a spear... , a sling from which no erring shot was discharged.&&
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Johnny
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Re: Point-first flight
Reply #1 - Feb 19th, 2004 at 3:27pm
 
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
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mgreenfield
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Re: Point-first flight
Reply #2 - Feb 19th, 2004 at 4:25pm
 
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
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« Last Edit: Feb 19th, 2004 at 7:04pm by mgreenfield »  
 
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Johnny
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Re: Point-first flight
Reply #3 - Feb 19th, 2004 at 4:32pm
 
And I'm still waiting on photos/video of the Cestrosphendon!!
Don't leave us in suspense!!
Johnny
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LBray500
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Re: Point-first flight
Reply #4 - Feb 19th, 2004 at 5:58pm
 
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.
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Johnny
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Re: Point-first flight
Reply #5 - Feb 19th, 2004 at 6:50pm
 
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
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David_T
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Re: Point-first flight
Reply #6 - Feb 19th, 2004 at 9:23pm
 
Ibray,

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

Overhand Huh. Wow
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Hondero
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Re: Point-first flight
Reply #7 - Feb 20th, 2004 at 3:39am
 
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
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Dan_Bollinger
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Re: Point-first flight
Reply #8 - Feb 20th, 2004 at 9:24am
 
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?
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Ulrica
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Re: Point-first flight
Reply #9 - Feb 20th, 2004 at 9:55am
 
I think lbray answered that questions a bit under the thread: World´s records holders.
But there is maybe more to tell?

/Ulrica
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May the stones go your way&&&&//Ulrica
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Dan_Bollinger
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Re: Point-first flight
Reply #10 - Feb 20th, 2004 at 11:19am
 
Thanks, I just saw that.  Very interesting, too.  Smiley
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Yurek
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Re: Point-first flight
Reply #11 - Feb 20th, 2004 at 8:32pm
 
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

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In the shape, structure and position of each stone, there is recorded a small piece of history. So, slinging them, we add a bit of our history to them.
 
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Douglas
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Re: Point-first flight
Reply #12 - Mar 1st, 2004 at 4:47pm
 
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... Roll Eyes
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mgreenfield
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Re: Point-first flight
Reply #13 - Mar 8th, 2004 at 11:13pm
 
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
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WalkingBird
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Re: Point-first flight
Reply #14 - Mar 8th, 2004 at 11:47pm
 
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
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