----- Original Message -----
Sent: Friday, December 15, 2006 4:07
PM
Subject: New information / casting
mechanics
Walter & Group...........
This is an important, "heads up" message on fly casting mechanics.
During the past few weeks we've been doing some FFF committee work which
has brought to the forefront some new information derived from the study of
findings using the Casting Analyzer by Bruce Richards and Noel Perkins
(Engineering Dept. U. of Mich.)
Before being enlightened by this along with information gained from
Server Sadiki & Walter Simberski of our Group and other engineers
and physicists with whom I've spoken, I and most others were teaching that
acceleration had to increase during the casting stroke for most efficient
casts and best loops. As you know, I even used the term, "accelerated
acceleration" to make the point. I was wrong.
We also taught that acceleration should be greatest near the end of the
stroke. Many, including me, had a sketchy understanding of the differences
betwen, "speed", "velocity" and "acceleration" often mixing up these terms
as we taught.
As I understand it, new information includes the fact that an efficient
cast with good loop control is best achieved with SMOOTH, CONSTANT ACCELERATION THROUGHOUT THE ENTIRE CASTING
STROKE.
This does not change the observation that rod tip speed increases near the conclusion of the stroke and
is maximal betwen the stop (or max deceleration) of the hand/rod butt and
the rod straight position (RSP) at which point the fly line can overtake the rod tip
yielding loop formation.
The acceleration of the rod tip during the rotational phase near the end
of the stroke is responsible for the greatest tip travel during the stroke
in a given period of time and so accounts for the increase in tip speed
during that interval.
Acceleration during this rotational phase can be considered as change in
angular velocity of the rod
despite the fact that the acceleration itself has been constant throughout
the stroke including the preceeding translational phase. Its
measurement would be that of rate of change of angular velocity.
One observation has been that the translational phase has as one major
objective, the taking up of slack thus making the rotational phase more
efficient.
As Bruce Richards has analyzed these elements, he's found that the best
loops for distance casting have been achieved with:
1.) Smooth, constant acceleration through the entire stroke.
2.) Longer translational phase to delay the rotational phase, thus
placing rotation closer to the end of the stroke.
From a practical teaching standpoint, he has found that the loops improve
quickly when he has taught to delay the rotational phase. Since
learning that, I've found the same thing.
All this, I feel, can dovetail very well with the simplistic concepts of,
"start slow and end fast" and, "loading move followed by power snap",
"Pop-stop", "speed-up-and-stop" which are easy for our students to
understand.
Bruce will probably write an article for the LOOP on this subject.
We'll also start to disseminate this information at our Continued Education
Courses the first of which will be at the Marlboro Mass. Fly Show in
January.
Gordy