More on Acceleration

To Gordy and all,

Having been a navy pilot most of my life I think I understand a little about accelerations. ( Aterburner takeoffs and catapult shots for example.) I also understand deceleration as in an arrested landing on the carrier.

I think part of our problem here is just getting on the same page in defining acceleration. From the dictionary accelerate is simply defined as "to speed up". Acceleration also has one definition that says "the rate of such change".

If we start with a desired final speed of the rod tip we can get there through constant acceleration which by definition is a continual increasing speed.

We can aslo get there by increasing the rate of acceleration which would imply starting with a slower acceleration.

Perhaps Bruce and Neil could weigh in and let us know which of these two options produces the best loop and would be easiest to repeat on a regular basis.

I guess my bottom line is that all the discussions have been correct but I think we sometimes throw around this term acceleration correctly applying to the situation.

Just my thoughts!

Phil Gay

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Phil ...

Good suggestion. I bounced this by forwarding your message to Bruce. I highlighted your specific question. I'll value his answer.

Gordy

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From David Lambert, MCCI :-

Gordy:

Bruce's article in The Loop is exceptional work; we've come to expect

that.

Two observations regarding his and Noel Perkins' theory of constant

acceleration:

1) I think most of us agree that a smooth increase in rod tip speed is

the desired goal. Seems to me that Bruce and the group could agree on

some term other than 'constant acceleration' to describe this action.

Here's why: Most of us were taught in high school that 'constant' means

unchanging. That remains the perceived definition and, in fact,

'unchanging' is the 1st definition in Websters. (Unchanging acceleration

would /seem/ a contradiction in terms.)

As instructors we strive for clarity. If we have to define the

definition to students, we do them a disservice by interrupting the flow

of information -- especially if other perfectly acceptable words are

available. How about 'even' acceleration? Or simply 'smooth'

acceleration. Those are the terms to which we default when we try to

explain 'constant.' Both of those words work, even when unaccompanied

by graphs and charts.

2) Dermon and others have stated that a 'surge of acceleration' at the

end of the cast will likely result in a tailing loop. I'd be more

comfortable saying "could end in a tailing loop," since in real-world

casting, we throw plenty of casts that end in a surge of power but don't

tail. Evidence: tuck casts and other forced curves, aerial rolls, etc.

And, if a caster drops the rod tip far from the line of the cast coupled

with a late burst of acceleration, he or she can throw a large,

irregularly shaped loop downward.

Thanks for the intellectual challenges. All of us are better

instructors for them.

David

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David .... Good thoughts. One way I can purposely place a tailing loop way out near or at the leader is to produce a burst of power near the end of the cast. It won't do that if I can MAINTAIN that acceleration right to the rapid negative acceleration we call the, "stop".

Gordy

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From Walter Simberski (CCI and mathematician) :-

Gordy - I expect that the near linear acceleration provides a similar purpose to always adding a bit of

drift to your backcast. As long as you are drifting you can't creep and drifting doesn't hurt your cast.

You also can't creep if you come to a rock solid stop but even the slightest waver could result in a

tiny bit of creep. Eventually this would become part of your muscle memory and would become a

hard habit to break.

Now for the constant acceleration thing. If we had dedicated use of a casting analyzer some

of us could eventually get to the point where our acceleration was 100% constant, even as different

muscle groups came into play during the stroke, but this would take a lot of practice. If our goal

was to have constant acceleration that would mean those of us who couldn't get to perfectly constant

acceleration would have little bumps and valleys in our acceleration graph in our attempt to be constant.

Each bump represents an accelerated acceleration followed by a decceleration. Valleys would be

a decrease in acceleration followed by increase in acceleration. Each decceleration represents a slight

unloading of the rod as well as a change in the path of the rod tip. Each time this happens we are

causing bad things to happen to our cast.

The easiest way to avoid the bumps and valleys is to go for an increasing acceleration. As long as the

increase is smooth and relatively small it does nothing to hurt our cast because we learn to compensate

for the change in the effective length of the rod with our hand path to maintain slp.

If the acceleration of the acceleration is too great the caster will lose control of the cast and this will

manifest in bad loop formation and/or waves in the rod leg.

The happy medium is somewhere in between constant acceleration and losing control of the cast.

For the long rod question - I will assume that we aren't talking about a two handed rod. Since the

rod is slow action it will negate the advantage of extra leverage somewhat so the primary advantage

is reach rather than longer casts. The rod would be well suited for dapping, also Polish nymphing.

It could also be used on small creeks where foliage makes it impossible to cast even with a shorter

rod.

Cheers

Walter

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Walter ......

As usual, you are very informative. Nice to have the opinion of a mathematician !

Gordy

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From Steve Jacobs on the Huffnagle knot :

Gordy,

A while ago you said that you were working on a modified Huffnagle.

Did you ever put anything out to the study group on your research? I

can't find anything although I may have missed it.

The way I tie the knot is to make a figure 8 in the shock and tie the

class tippet through the figure 8, put in 6 1/2 hitches, and finish

with a 4 turn bimini type finish.

Thanks

Steve

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Steve....

Yes. I, now, pass the class tippet (often the double line loop out of the Bimini twist) through the fig-8 knot in the shock tippet, as you described. I AVOID A SINGLE HALF HITCH AROUND THE SHOCK TIPPET OR AN, "S-KNOT" (AS SHOWN IN, "BILL'S KNOTS"), BECAUSE I FOUND THAT WAS THE STRESS RISER WHICH WAS THE ACHILLES HEEL OF THAT KNOT AS OFTEN TIED. Instead, I go right to an 8-times through half hitch. I back-wind the half hitch loop very tightly from the fig-8 knot in the shock tippet making sure to keep the turns right neatly against one another.....then pull it tight.

I, then, over-lay the bitter end by winding it back the other way over the tightened 8 X half hitch until I get just beyond it and finish with the same 4X finish knot that you use.

This eliminated this knot as the weak link in the system in big game leaders (when tested AFTER at least a one hour battle.)

The one disadvantage of this revised knot is that while it is tight when first rigged, after a long battle about 1/4" of the double class tippet slips through ..... so you have to take that into account if you are rigging for an IGFA record, since the rules state that you can only have 12" of shock tippet, including the entire knot .

Gordy