Welcome BarneyRubble,

That sound from the pouch is due to it's odd aerodynamics.  During that snap of your wrist, the sling is attaining some pretty decent velocity, and the air vibrates as it tries to move out the way of the pouch, making a whooshing sound.  Some of my pouch designs produce it, and others don't.   You'll just have to experiment a bit to eliminate it.  I'd try smaller pouches and thinner cords first.

The sound projectiles make is different.  Odd shaped projectiles often tumble through the air, causing vibrations, which produces a whizzing sound.  You can eliminate this by using smoother and more spherical projectiles. 

I don't think adding weight to the pouch won't solve any of your sound problems.  What it will do is handicap your range.  When you snap your wrist, you transfer a certain amount of kinetic energy into your sling.  You want as much of that energy to be transfered to your projectile.  Adding more weight to the pouch means more energy is stored in the sling, and not the rock. 

Ideally, you'd want the lightest weight sling possible, and the heaviest payload that feels comfortable.  That gives you the most efficient energy transfer, and thus the longest range.  A couple of the members have made some super-slings made of steel wire or nylon (fishing line) and split pouches (aka lovelock pouch) for this exact reason and also reduced air resistance. 

Chris

Hey There!

You guys just brought up a thought that came to my mind a while back in an effort to help me kick Spencers butt in his "field goal challenge" Don't tell Spencer but, I was thinking of experimenting with a weighted pouch in order to achieve more pouch speed when trying to sling a very light tennis ball. The ball has no wieght and I am thinking that the added pouch weght may give me more speed. I agree that a weighted pouch would be counter productive for slinging stones but do you Physics dudes think it may help with light projectiles?  You know-- the concept of trying to sling with a parachute/tennis ball There is more air resistance to slow it down.??

Actually, I have only made one tempt at the Field Goal challenge and it was windy so I may still be able to beat his 70 yards. A weighted pouch would technically pass the rules since you are not adding weight to the ball.

Give me some feed back---and don't tell Spencer

Yes, adding wieght for a lighter projectile would probably increase the release velocity.  A light sling and a light projectile means that air resistance plays a big factor than with heavier projectiles, limiting the "muzzel" velocity.

Chris