Walter....
I've been thinking about that.....quite a task for you, however.
Gordy
From: WALTER/SUE SIMBIRSKI <simbirsw@xxxxxxx>
To: Gordon Hill <hillshead@xxxxxxx>
Subject: Re: High Speed Data for Straight Rod Tip Trajectory Cast
Date: Wed, 29 Mar 2006 10:09:02 -0700
Gordy - the email limiting could be an artifact of the hurricane season you experienced
in the fall. I'm still a month or two away from getting my web site up and running but
the offer to host a discussion group, or groups, still stands.
Cheers
Walter
From: Gordon Hill <hillshead@xxxxxxx>
To: simbirsw@xxxxxxx
Subject: Re: High Speed Data for Straight Rod Tip Trajectory Cast
Date: Wed, 29 Mar 2006 07:11:46 -0500
Walter:
Good analysis.
There is a second reason for there being a lower incidence of tailing loops on the back cast, and that is that is more difficult for casters to generate a spike of power during the back cast stroke.
If you have the Group address book, go ahead and send this string of messages to the Group.
My server has been limiting the number of e-mail messages per 24 hrs....I guess they are looking at my messages as spam or something. That's one reason for the dramatic drop in my Group messages, lately. You see, they are added to the voluminous list of messages I send as I perform on several FFF, CBOG committees. I'll spend over an hour a day just on the deliberations of our Glossary Committee which I now chair.
Gordy
From: WALTER/SUE SIMBIRSKI <simbirsw@xxxxxxx>
To: Gordon Hill <hillshead@xxxxxxx>
Subject: Re: High Speed Data for Straight Rod Tip Trajectory Cast
Date: Tue, 28 Mar 2006 17:41:43 -0700
Gordy - I took his reference to torque as the rotational form of force, or r x F, where
r is the vector from the axis of rotation to the point the force is acting on, and the
rotary motion of the elbow/wrist as the angle the torque rotates through. THis is based
on Server's description of work being the integral of torque and amount of rotation.
When we look at the rod we are dealing with two opposing forces - the force
applied by the hand in a rotary fashion and the resistance at the tip of the rod
due to momentum of the line and rod. This is what causes the bend in the rod. If the
rod was rigid then the force applied to the line at the rod tip would be at right
angles to the rod at any instant in time. Since the rod is flexible the direction of
the force applied to the line is at right angles to the point of impact rather than
the rod tip which why we can have tailing loops. In a rigid scenario the force on
the line is slightly upwards at the start of the cast, horizontal to the ground at
mid cast, and slightly downwards at the end of the cast and we get a wide loop as
a result. Since the rod is flexible we can actually reverse the order and have the force
applied slightly downward at the start of the stroke, horizontally at midcast and then
slightly upward at the end of the cast resulting in a tailing loop. This is one of the
reasons why Mac Brown says that it is very difficult to have a tailing loop on the
tailing loop if the back cast is downwards.
Cheers
Walter
From: Gordon Hill <hillshead@xxxxxxx>
To: simbirsw@xxxxxxx
Subject: Re: High Speed Data for Straight Rod Tip Trajectory Cast
Date: Tue, 28 Mar 2006 14:59:39 -0500
Walter...
I think Server is referring to the rotatory motion of the elbow/wrist when he talks about, "torque".
Gordy
From: WALTER/SUE SIMBIRSKI <simbirsw@xxxxxxx>
To: Gordon Hill <hillshead@xxxxxxx>
Subject: Re: High Speed Data for Straight Rod Tip Trajectory Cast
Date: Tue, 28 Mar 2006 11:28:27 -0700
Gordy - I agree with the majority of what Server says except for the concept of
maintaining maximum torque throughout the casting stroke. The issue is that torque
and force are vector quantities. What you want to do is maximize the amount of
force in the direction you want the line to travel. This direction is determined
by the point of impact (as defined in Joan Wulff's book). This brings up two points - applying maximum force throughout the cast will result in a tailing loop, and the
stiffer the rod the greater the amount of force that can be applied while maintaining
the optimal point of impact.
The idea that a fast stop vs a slow stop is one we have discussed in the past.
The main reason for the fast stop is because, as Server says, we simply run out
of arm.
I wouldn't classify myself as an excellent caster but I have been spending some
time developing a "feel" for when to reverse the direction of the casting stroke. There
is a very fine line in this respect. If you wait just a fraction too long the line
begins to fall and results in slack - this in turn results in shock waves in the
reverse cast. If you rush things just a bit you are rewarded with a nice whip crack
sound (and another $2.00 fly goes missing). If you wait until you feel maximum load in
the rod you are already too late - by the time you react the line will have started
to fall. I've seen/heard of several "tricks" to set cadence - counting, singing
Born Free, metronomes, waiting for the rebound, observing the line for wave or sags,
listening to line movement - all of which tells me that there are many different
sensual clues so this should be an interesting survey.
For myself, the sensation is similar to what Server describes although the thought
process is a bit different. I always try to throw in a bit of follow through just
after the stop in order to make sure I don't creep. This would be similar to Server's
"well I did my best, but I see the wall coming so I'd better slow down, but the backpack on by back is moving so I'd better reverse the forces I've been applying and
things are finally at their conclusion" in that I am reducing then reversing forces
but not instantaneously. The tactile sensation is one of coasting to a stop even
though the elapsed time frame is very short.
Cheers
Walter
From: Gordon Hill <hillshead@xxxxxxx>
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Subject: Re: High Speed Data for Straight Rod Tip Trajectory Cast
Date: Tue, 28 Mar 2006 10:12:06 -0500
Server....
Remember the studies showing that the maximum speed of the rod tip lies between the stop (or rapid deceleration) of the hand and RSP. Even if you can show that the line has ceased to accelerate, it, perforce, is also moving at max. velocity. At RSP the line can and does overtake the rod tip as the loop starts to form.
You are correct in that I can't actually feel or sense that as I cast, and I doubt other casters can, either.
So your question as to just what the caster senses at the end of the stroke is a good one.
Before I send in my own answer:
LET'S HEAR FROM OTHERS IN THE GROUP AS TO JUST WHAT EACH CASTER "FEELS" OR, "SENSES" AT THE END OF HIS/HER CASTING STROKE. (no matter how wierd it might sound.)
Gordy
From: Ssadik1@xxxxxxx
To: hillshead@xxxxxxx
Subject: Re: High Speed Data for Straight Rod Tip Trajectory Cast
Date: Tue, 21 Mar 2006 23:56:10 EST
Gordy,I wanted to talk with you before your week long casting retreat but it didn't happen. The subject would have been to canvas excellent casters on what they think they are sensing near the end of the cast. I need to talk a little about the anatomy of a fly cast to get into this discussion. For purposes of brevity let's consider a baseline cast -- no hauling, no base motion (on some future discussion I'll go into the physics of energizing casts with base motion -- most casters trying for long distance do some form of this and my plots were a version of this style of cast). Also you can refer to casting analyzer plots to see some of what I am talking about here. A dominant constraint on rod angular motion is the range of rotation available from the wrist (60-70-80 degrees of motion). The mechanical work performed on the rod-line system for this baseline cast is predominately the integral (a calculus term) of applied torque versus the angle the torque rotates through. For maximum line speed you need to generate the maximum torque throughout your limited range of rotation (maximizes the integral) -- this maximizes the work done and maximizes the energy available to the line. So your goal in this type of casting (maximum line speed) is to apply as large a torque on the rod butt as you are physically able to do over the entire limited range of rotation available to you. Well, if you do this what choice do you have but to feel as if you must also stop rapidly -- you can only go so far (the degrees of motion mentioned earlier) and your wrist hits a wall. So maintaining a beneficial torque as long as possible necessitates stopping the wrist rapidly because you have only a few degrees until you are at the end of wrist travel available. To me this is like those tests of sport cars where they see how far a car has to travel to first accelerate to 100 mph and then decelerate to a stop. For casting the act of stopping the wrist is an artifact (a requirement) that is required by human anatomy. If improved performance is sought it comes about by generating larger and larger amounts of work over the limited range I mentioned earlier. Stopping harder has an insignificant effect on this. Another thing about the anatomy of a cast is that sometime before getting to RSP the line acceleration has ceased. (I estimate on my plots I had another 4-5 feet of travel before RSP and half of that would be after line acceleration ceased.) This is because while it is true the tip is moving the fastest at RSP the angles are poor and the line near the tip is being directed toward the ground excessively. Consequently the majority of the flyline is in free flight and that near the tip is traveling in a circular trajectory aimed as much toward the ground as it is forward. The caster probably has no sense of any of this except for the fact that his body knows the limit of his controlled wrist rotation. So, what can a caster sense?? Certainly one of the bigger feedbacks should be an awareness of when the torque on the rod butt reverses because the caster is the one supplying this torque. You can also think about what you sense when the peak counterflex//rebound occurs. I'm pretty sure I know what my body does but then I know what a strange instant this is -- you body intuitively knows that something has to change or you'll be trying to setup larger rod vibrations. Check your reaction and I think you'll find you perform hand manipulations which change the boundary conditions (structural dynamics speak) and disrupt the vibrations. So the sensations go something like -- well I did my best, but I see the wall coming so I'd better slow down, but the backpack on by back is moving so I'd better reverse the forces I've been applying and things are finally at their conclusion. I'd be curious to know what proficient casters think they are sensing -- it would probably reveal some confusion. What about you -- what do you think your're sensing at the end of a cast?Regards - Server