Nice story 

The shape really does help over normal (irregular) rocks.  But I can't say that it's any better than spherical projectiles like golf balls.  What do you think?

My experiments with golf balls have been pretty positive.  What trouble did you experience with them?

Chris

Brent,

What was it that made your sling so peculiar to the golf ball.  Did it have some attributes that, in the design phase, seemed to be better suited to the the smooth surface or the size?

Any old sling should throw a golf ball quite well if released properly.  I have thrown many and they were much more acuurate than I could take advantage of.  The biggest problem I have with the golf ball is its light weight.  Not enough "feel" to the swing, and they tend to release late.

I have been doing some figuring on the weight issue.  My conclusion so far is this:  the projectile MUST have enough weight (and momentum) to force its way out of the pouch.  We all agree that the pouch is best shaped to cup and hold the stone a bit.  This means that the stone will be held by the pouch until is released.  The golf ball has to overcome the inertia of the release cord as it begins to move forward at release.  The ball remains in the pouch until its relationship to the pouch is such that its momentum can push it past the edge of the pouch.  This point comes when the release side of the pouch has opened enough.

We know that very heavy stones tend to release early and very light ones late.  I am guessing here, but it appears that every sling will have its prefered weight based on several things.  They include but are not limited to:

Stiffness of pouch and cords
Depth of pouch "cup" and how tightly it holds the stone
Weight of cord (release cord inertia is affected by this)
Angular velocity of stone at release
Release style
Release angle (maybe)
If your release cord is long and drags your hand

This is kind of like hand loading metallic rifle cartridges.  The projectile is the single biggest factor.  All the others have to be adjusted to the projectile to get the desired results.

Jeff ><> - Who thinks this point should be discussed further

Let me clarify my statement on the cupping qualities of a pouch.  I prefer a pouch which is literally flat, but which has just a little give to the leather to hold the stone.  When I mentioned that a cupped pouch is universally prefered, I should have been more specific.  I don't mean deeply cupped by any means.  In fact, I have seen some which were so cupped I had a hard time believing that they would throw well at all.   I suppose what I should have said is that we prefer pouches which hold the projectile, and cupping is the easiest way to achieve this.  High friction coefficient between pouch and projectile also work quite well.  The andean style slings use both methods: split pouch for slight cupping action and wool material for friction. (Whipartist wins again with his o-so-beautiful, hand made andean slings!)

The slings I have been making have a natural cupping aspect because the leather pouch is flexible and the strands of cord at their edges is not.  This causes the pouch to cup somewhat by virtue of design, but not much and in varying amounts depending on the stone weight.

I have one sling which is made of stiff leather; no natural cup whatsoever.  I have yet to use it because light projectiles like golf balls tend to perform escape routines as I do my wind-up.  And I only have access to light projectiles (mostly golf balls) for my general slinging.

By the way, Chris,  I have just made a new sling using #72 seine twine.  It is made the same as my others in all respects except that the pouch is slightly altered to accept the larger cord.  The cords are much stiffer and heavier than in my previous slings.   The pouch is supple, yet thick leather. This sling eagerly awaits a test trial to judge the nature of its releasing qualities.  Could I send a pic of this sling to post? (Preferably before I get it dirty.)

Jeff <>< - who wants to get to the bottom of the releasing delima

The Tomek's (guy from Poland) site with a few pictures about making the projectails with the tennis balls by himself. The nteresting idea. He also demonstrate his nice slings.

Tomek and his friends have conreated the special furnave for bakeing the clay glandes and dishes.

"proca" [protsaa] = sling in Polish

http://www.proca.jaremi.net

Jurek

Yes he is, just with water. This is no Molotov coctail or nitroglycerin

Jurek

Ben, my man, you have plaited one too many cords.  You are getting poetic.

A slightly prolate sphere may be the answer.  It would fit into the pouch nicely but be very close to spherical for aerodynamic efficiency.

jeff <><