# The Golf Ball Slingshot Challenge



## JoergS (Dec 17, 2009)

OK, golf balls may be very big ands heavy for a slingshot, but they are still in the range of projectiles I have successfully used.

46 Gramms, that is about half of my 23 mm lead balls, and my bone crushers weigh 70 Gramms.

43 mm diameter is really big. But doable, with a slightly larger pouch than usual.

The theoretical advantage: Golf balls have grooves that are - supposedly - reducing the air resistance so they fly three times more far than regular, non grooved balls.

I would like to test this with a slingshot.

It is said that the grooves only work with a spin, so that the ball rotates in flight. How do we get the ball to rotate? My idea is to attach a rubber strip to the slingshot frame from ABOVE, so that the golf ball will hit it and push against it. Hopefully the friction will give the golf ball an upward spin.

What do you think of that? Any ideas?

Jörg


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## Fork Hunter (Apr 19, 2010)

Hi Jorg,
It is my understanding , as explained to me by a few of my sports fanatic friends, that the reason for the groves is for the golf club to engage the golf ball to impart the spin and it is the spin that not only makes the ball fly further but also makes it fly faster than a golf ball that flys with no spin imparted to it and dependind on the spin the ball has can control the flight , to some degree, of the golf ball ..

Hope this helps,
- Fork Hunter-


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## Marbles (Jan 23, 2010)

As kids we used to go to a golf course and collect balls that we flung with a David and Goliath sling a pouch and two leather straps, it was amazing how far they would go!!


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## NightKnight (Dec 16, 2009)

Sounds good! Did you see my post on golf balls before?

http://slingshotforum.com/topic/71-golf-ball-style-dimples/


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## sanjay (Feb 26, 2010)

Joerg- sounds like a fun challenge. I think the secret to spin is in the pouch and not post-firing impediments. Try using a convex rubber bulge in the pouch, or a wedge shape. The strike from an uneven surface onto the golf ball should impart spin. It will of course impact the aim, but hopefully you are not going to try to shoot targets at 150 yds







A wedge shape might even give you upward lift which should help with distance just like it does in golf. I think that if you focus on making your pouch more like a club strike- you will have the makings for yet another wonderful series of videos!


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## Fork Hunter (Apr 19, 2010)

Try a few ideas and set up your slow motion video camera . then watch to see if and what kind of spin is being applied to the golf ball. Heres another idea, instead of griping the pouch by the sides to draw the pouch back try putting a finger cott on you thumb or perhaps your forfinger and grasp the golf ball when drawing it back. Then release in a fashion to let the ball release slowly, where the finger with the finger cott on it will grip that side of the ball and impart the spin ....just an idea, maybe then you'll not need anything additional on your forks to make the ball spin . Kind of like how a baseball pitcher changes his grip on the ball to throw a slider ball or a sinker ball or curve ball....


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## TruckeeLocal (Dec 23, 2009)

The slingshot should naturally put an under spin on the projectile. So the question might be how to make the golf ball not spin.


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## Rayshot (Feb 1, 2010)

I agree with the idea of the spin being initiated at the moment of release. Tricky but maybe this is a beginning.....

A pouch made of a stiff but flexible enough material that;

1) is more or less shaped like a hand with knuckles down on a table with fingers curled

2) the force of the bands pulling on the stiff material makes the j shaped pouch want to straighten out

3) as the pouch is straightening out it is starting the turn of the ball

4) the j pouch has to have enough stickiness (friction) to have grab on the ball to be sure it initiates the spin

Just the beginnings of and idea.

The hard part is finding the stiffness and flexibility to not flatten out and yet not too stiff because if the ball stops turning before it loses contact with pouch it seems like we are back to no spin at all. And stiffness/flexible corresponding to the power of the bands.

Jorg you will probably thrill with figuring this calculation/combination.


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## christopher (Jan 8, 2010)

Do you not need to induce backspin to test the theory. dimpled golf balls imparts a turbulence layer separating or enlarging the buffer from the laminar flow. This allows the viscosity of air smoothly go around the ball as the buffer of turbulent air surrounds the ball. This will give you a faster projectile in comparison to an equally sized and weighted non-dimpled ball.

Backspin aids in creating lift as it forces the laminar flow into a low and high pressure zones, thus further reducing what is called leech drag force behind the ball. So with backspin you get further travel.

Also from personal experiences, inducing a backspin on a ball when imparting a lateral force requires a skid plate / surface to induce a backspin. The longer the skid plate and surface area for the ball to travel along the more backspin you gain, but you loose momentum too due to friction and change in angular forces.

Good luck and have fun!


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## Bugar (Dec 24, 2009)

I find quite a few golfballs on my property, seems a golfer used my woods as a target area or backstop for his golf stuff for many years, well whenever i'm taking a walk in the woods or just shooting at THINGS I usually pick up a golf ball abd shoot it away from my property, NOW when using my pocket shooters or ergo, don't get much distance, but can get some whopping big fork hits, seems the are quite short on distance, mebbe i'll make a golfball shooter and see how it turns out, pocket shooters and Dankungs don't work very well


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## ZDP-189 (Mar 14, 2010)

I have experimented a lot with smaller ammo with dimples - I used beads. I was going to cast them in lead, but danny said they are commercially available in China.


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