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New Pictures--Range Boost (Read 18725 times)
Yurek
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Re: New Pictures--Range Boost
Reply #45 - Jul 31st, 2004 at 5:57pm
 
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Yurek, how long are your projectiles in flight?


Chris,

Welcome you back!

I didn't make exact time measurments. But today, during slinging into the lake with my long thin sling I was calculating the times of flying of stones. They were a bit different: from 6 to 8 (seems even 9 seconds). These times were mainly dependent on angles of throws (how high were trajectories). Of course, quality of the used stones and each throw, were significant factors too. So, the longer time of fly, not always means the grater range.

My problem with glandes is that I usually have a limited amount of them, so I concentrate on making good throws and don't  measure the times. During one of my first tries I counted one throw at ca. 10 s. Next time I will ask somebody for measuring with a stopwatch and let you know more exact results.

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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Chris
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Re: New Pictures--Range Boost
Reply #46 - Aug 3rd, 2004 at 7:20pm
 
If you could cut the drag in half for a ten second flight, you are looking at perhaps dozens of gained meters in range.  Any physics buffs care to give us an explanation?  I'm no expert by far. 

Chris
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Matthias
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Re: New Pictures--Range Boost
Reply #47 - Aug 3rd, 2004 at 8:43pm
 
I really need to clean up that spreadsheet and migrate it to a nice sling-specific web-app. How is your Java Chris?

Not having access to it at the moment, I'd hazard that Jurek is probably slinging to around 90% of max (no drag) range already. If it was possible to reduce the drag (shape, surface trickery or higher density ammo) even further, say by half, it stands to reason that he could pick up an extra 25m or so. Slinging lead is obviously the easiest way to pick up distance, as it does tend to minimise the aerodynamic effects...

It would be very valuable validation if we could try to compile some caparative range data. We need common projectiles across a range of shape/density efficiencies. Golf balls and tennis balls are good candidates for "standards". I was thinking about maybe water filled tennis balls as well. What is important is not so much how far a given contributor can throw these, but how what the range difference is. Anyone have any ideas for a "standard" set of sling ammo that is consistent among different locations? If we stick to spheres for now, it will keep things manageable. There is going to be some pretty big spread due to different people hitting different limits with different style/physiologies, but the more data the better...
  • Golf ball
  • Tennis ball
  • "orange" street hockey (nice and smooth)
  • Baseball
  • Squash ball
  • Baseball
  • A bucket of snooker balls would be ideal... lol


If anyone has ammo that is fully describeable we should add those off the top of my head I can think of concrete tennis balls and really pretty 1" lead spheres (hint hint)

Matthias
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David_T
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Re: New Pictures--Range Boost
Reply #48 - Aug 3rd, 2004 at 10:18pm
 
We need to have a few people experiment with pouch design related to the orientation of the gland at release.

I am thinking that purhaps a tilted or angled pouch would put the gland in the optimal point fist position at the snap of release--I don't know but I would think that that would make a very big difference. If the gland is having to orient itself in the first few seconds of flight, it is wasting much energy as compared to a perfect orientation at launch---just a thought??

What do you think?
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Matthias
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Re: New Pictures--Range Boost
Reply #49 - Aug 3rd, 2004 at 11:40pm
 
For sure glans orientation and throw mechanics are going to have a big impact with non-spherical ammo. As you noted in the other thread, just the spin orientation has a big effect on lighter projectiles due to the lift generated. A badly slung golfball is pretty depressing to watch as it dives into the sand rather than soaring out over the beach!

I would be quite surprised if an ovoid that leaves the sling with anything other than perfect orientation and spin will change significantly during the throw. If a spun-on-axis glans takes off pointing 40 degrees nose up (direction of throw) it is almost certain to land in the same attitude. Luckily, the benefits of lowered drag are most significant during the initial half of the flight anyway, so it doens't matter _too_ much that it ends up crosswise. This will be another argument for lower than "perfect" aspect ratios. My sim should be able to be modified to allow for changing attitude throughout the flight... if we can get it refined to the point that the difference made is outside the error I'll add it.

I used to have access to a 500 frames per second camera... what a blast it would have been to be playing with these ideas then!

Matthias
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Hondero
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Re: New Pictures--Range Boost
Reply #50 - Aug 4th, 2004 at 2:23am
 
Quote:
I am thinking that purhaps a tilted or angled pouch would put the gland in the optimal point fist position at the snap of release--I don't know but I would think that that would make a very big difference.
What do you think?


Yes, David, I had the same idea, a special pouch design for glandes, maybe with a lateral hole or little loop that put jus a bit of retention at the release on and end of the glans, or an inclined and splited pouch than can throw the glans point-first but that prevent its release when spinning.
I´d like to have the time to experiment throwing  against a wall and see the impacts on the glandes.
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David_T
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Re: New Pictures--Range Boost
Reply #51 - Aug 4th, 2004 at 5:12am
 
Ahh yes, to have the time to pursue such things!

A loop Grin That is an idea. An angled loop on the trailing end that would still allow spin as it rolls out of the pouch.

Yes, and still stay in the pouch at all points during the spin.
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Re: New Pictures--Range Boost
Reply #52 - Aug 4th, 2004 at 9:37am
 
Friends, friends, friends!   I launch elliptical glandes point-first all day long with a plain "standard" sling, ...no special pockets, etc.   Many of these (not quite all) have no wobble.  The secrets are just 2:

1/  Use a "wide grip".  I put the retained cord on my ring finger to keep it far away from the release cord.  I let the retained cord hang free outside my fist.

2/ Be sure your palm is pointed forward at the moment of release, ....and I suppose as long before that moment as you can manage.   If you use a underhand delivery this makes it feel a little like bowling.

Glandes launched point first, and in stable flight, look like little high speed rockets.   They're very pretty to watch, ....and it's easy to do.

mgreenfield
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Re: New Pictures--Range Boost
Reply #53 - Aug 4th, 2004 at 10:03am
 
Yes!  The centrifugal force acting on the widened grip imparts more corrective torque on the cords assuring a correct orientation at release.  This must've been how the Romans learned it!  I have had midlevel results with obloid ammo using my normal grip, with both cords eminating from between thumb and forefinger and have used a bit of fletching attatched to the bottom of the pocket via thin carbon rod to effect the same results.  This allows me to keep my the style with which I have become most accustomed, with negligible loss in speed while getting rock solid perfect spiral releases every time.  

For those who wish to try it:

http://www.nyblimp.com/superior/carbon-rods.htm

has reasonable pricing.
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THOMAS
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Re: New Pictures--Range Boost
Reply #54 - Aug 4th, 2004 at 12:54pm
 
For more range with heavier ammo try a bead or ball on the end of the release cord. 
I don’t have very strong hands so I use a 1” dia. wood ball drilled through and counter sunk for the knot.  These can be found at most craft stores. 

This increased my 5 oz. hardball range by at least 30%.
The release cord and its end ball have never interfered with the shot.

THOMAS
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Re: New Pictures--Range Boost
Reply #55 - Aug 4th, 2004 at 6:28pm
 
Quote:
Friends, friends, friends!   I launch elliptical glandes point-first all day long with a plain "standard" sling, ...no special pockets, etc.   Many of these (not quite all) have no wobble.  The secrets are just 2:

1/  Use a "wide grip".  I put the retained cord on my ring finger to keep it far away from the release cord.  I let the retained cord hang free outside my fist.

2/ Be sure your palm is pointed forward at the moment of release, ....and I suppose as long before that moment as you can manage.   If you use a underhand delivery this makes it feel a little like bowling.

mgreenfield



Yes, yes, mgreenfield, you are right in the two points  Smiley With sidearm throw, and almost any inclination, you can also get the point first flight, but with all these styles the little problem is that you have to release just when the hand is at the level of the body and not more advanced, so that the palm point forward, and so you lose the last part of the snap, not developing the maximum momentum. But if one don´t look for max. range but penetration, the style is right.
You are the number one vertical thrower  Cheesy
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David_T
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Re: New Pictures--Range Boost
Reply #56 - Aug 4th, 2004 at 8:36pm
 
Oh yes Mike I agree that spirals are had with the regular pouch. I was just curious as to the "absolute opimum orientation" for record slings. I would love to see a high speed camera capture the sling motion to show the exact angle of the gland at release.

From this film, one could either change the rotation angle of the spin or the shape of the pouch to make it fit with the most powerful arm movement of the individual doing the slinging.
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