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Re: Arfon's Aerodynamics, a thought.

To: "DrMayf" <drmayf@teknett.com>, <land-speed@autox.team.net>
Subject: Re: Arfon's Aerodynamics, a thought.
From: Ken Bond <kmb2@humboldt.edu>
Date: Thu, 16 Jan 2003 16:09:28 -0800
Golfballs, dimples, ridges, and turbulence:

Since I get paid to confuse students... I just got to jump into this
discussion with a bit of info.

*****

First, Callaway just recently came out with a golf ball WITHOUT dimples but
with ridges.  320 Hexagons and 12 pentagons 8.3-thousandths of an inch high.

*****

Second, from an old article on dimples on golf balls, I quote the following:

"The key, Mr. Thurman explains, is to create a dimple with enough depth to
produce air turbulence around the ball as it rotates in flight.  That helps
the ball penetrate what engineeers call 'the force barrier' - the
resistance that builds up as the ball moves through the air.  But too much
turbulence increases the drag on the ball, causing it to drop too fast.
        Most dimpled balls crack the force barrier when they reach a speed of
about 80 feet a second.  Once they get through, air resistance drops by
half, and the ball goes farther.  (Mr. Thurman estimates the same ball,
undimpled, would have to travel more than 200 feet a second before breaking
the 'force barrier'."  WSJ, 7 Nov. '97, Pg. B1+

*****

KEN

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