Slinging.org Forum - World´s record holders

Hondero

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World´s record holders
Feb 16^th, 2004 at 6:15pm

Yurek, good news¡¡. Finally I have made contact with the world´s record holders David P. Engvall and Larry Bray. I´ve told both you are writting them. Look at the instant messages for more details. I hope you´ll publish here the most interesting messages they send to you Wink

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To: Jesus Vega

I understand that you have a friend interested in sling distance
throwing.
As far as I know I still hold the record of 1565 ft. 4 in. set on
September 13, 1992
at Baldwin (dry) Lake, California.

I would be interested to hear of your progress.

I will be out of town this coming week. But I will be glad to offer
assistance when
I get back if you are interested.

Best Regards,
David P. Engvall

Hi Jesus,

I held the record through most of the 80's and early 90's. I threw a rock with a home made sling with a leather pouch. Fell free to get in touch with me if you would like.

Larry Bray

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He brought a conquering sword..., a shield..., a spear... , a sling from which no erring shot was discharged.&&

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Yurek Funditor Past Moderator Offline The best thing, is a good sling. Posts: 942 Poland Gender:	Re: World´s record holders Reply #1 - Feb 16^th, 2004 at 7:53pm Hondero, Thank you very much. I will inform you all if got to know something new, as so far. Jurek
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Dan_Bollinger Descens Offline Have Sling, Will Travel Posts: 136 West Lafayette, Indiana, USA Gender:	Re: World´s record holders Reply #2 - Feb 16^th, 2004 at 8:33pm Thanks, Hondero, for finding those guys! It looks like 1565 feet is the distance to beat. A dry lake, what a good idea. I wonder how they dealt with 'bounce?' I wish we could all get together and see one of us beat that record!
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David_T Funditor Past Moderator Offline Hooked on Sling'n Posts: 760 Greenville,SC Gender:	Re: World´s record holders Reply #3 - Feb 16^th, 2004 at 9:00pm I wonder if they have any restrictions? Could you spray the projectile with silicone to decrease friction? Go for it Yurek !!!
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Johnny Funditor Offline Posts: 620 Goodlettsville,TN Gender:	Re: World´s record holders Reply #4 - Feb 16^th, 2004 at 10:10pm Can you give a description of the slings and the size and weight of the stone?
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Hondero Senior Member Offline Posts: 463 Madrid-SPAIN Gender:	Re: World´s record holders Reply #5 - Feb 17^th, 2004 at 4:26am I hope these men send us information about all these aspects. I´m very interesting in sling details and throwing technique.
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Dan_Bollinger

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Re: World´s record holders
Reply #6 - Feb 17^th, 2004 at 8:54am

The resistance between air and silicone versus air and lead is nil. However, the resistance between air and air is slightly less. So, the trick is to make sure a little air remains attached to the glandes. One way is to rub the glandes with 400 grit sandpaper perpendicular to the throw axis. The fine grooves trap a layer of air improving performance.

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Yurek

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Re: World´s record holders
Reply #7 - Feb 17^th, 2004 at 10:07am

Dan,

I think you are right. First golf-balls were just very smooth. Once one guy had observed that old and scratched ones flew further than smooth ones. That "paradox" caused that people started using dimpled golf-balls afterwards. The dimples reduce the air boudary layer and as a result size of the wake is smaller.

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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David_T Funditor Past Moderator Offline Hooked on Sling'n Posts: 760 Greenville,SC Gender:	Re: World´s record holders Reply #8 - Feb 17^th, 2004 at 4:24pm Cool
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Dan_Bollinger

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Re: World´s record holders
Reply #9 - Feb 17^th, 2004 at 4:32pm

Yurek, I think we are talking about two distinct phenomenon. The microgrooves I was talking about only work in shapes already well shaped aerodynamically like an airfoil as a way of reducing a small amount of drag by improving boundary layer attachment.

What you are talking about is creating an intentional turbulent flow around a poorly formed shape like a sphere. Turbulent flow on the backside of the object has slightly less drag than a poorly attached one.

Ultralight builderse learned this. They taped a piece of string at 10 O'clock and 2 O'clock (with 12 O'clock the direction of travel) on round struts. It reduced drag and saved them the expensive of the more expensive, properly shaped struts. Dan

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mgreenfield Funditor Offline Posts: 509 Milwaukee Wisconsin Gender:	Re: World´s record holders Reply #10 - Feb 17^th, 2004 at 5:02pm And fast backspin on the golf ball creates a region of lowered air pressure on the top of the ball and a region of raised pressure on the bottom of the ball, making it actually fly aerodynamically. A properly hit golf ball is a thing of great (aerodynamic) beauty in flight. mgreenfield
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Dan_Bollinger Descens Offline Have Sling, Will Travel Posts: 136 West Lafayette, Indiana, USA Gender:	Re: World´s record holders Reply #11 - Feb 17^th, 2004 at 6:41pm I believe you. And, I don't see how it would be possible to put backspin on a slingstone to improve flight. Generally, pouches give the slingstones a 'roll' rotation, not a 'pitch' rotation. Dan
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Yurek

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Re: World´s record holders
Reply #12 - Feb 17^th, 2004 at 8:12pm

Quote:

Yurek, I think we are talking about two distinct phenomenon. The microgrooves I was talking about only work in shapes already well shaped aerodynamically like an airfoil as a way of reducing a small amount of drag by improving boundary layer attachment...

Dan,

I really mixed two those things, I didn't consider that the air should flow laminarly along of the almost whole perfect airfoil and just its shape causes a very narrow wake (turbulent air flow behind). So the dimples have nothing to do in that case. The microgrooves stop a very thin adjacent air layer, so the friction is only between the air layers but not between the projectile and air. I hope I have anderstood it corectly.

On golf-balls, as I know the dimples give two adventages, they reduce the air drag and intensify the Mangus effect (mentioned by mgreenfield). But for slingers, the Mangus effect is't friendly, really.

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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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Dan_Bollinger Descens Offline Have Sling, Will Travel Posts: 136 West Lafayette, Indiana, USA Gender:	Re: World´s record holders Reply #13 - Feb 17^th, 2004 at 8:50pm Yurek, You have accurately stated what I have heard to be true. One cannot escape friction or gravity on this planet!
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mgreenfield Funditor Offline Posts: 509 Milwaukee Wisconsin Gender:	Re: World´s record holders Reply #14 - Feb 17^th, 2004 at 10:27pm Friction?? Gravity?? At my age, I hate 'em both! mgreenfield
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