AWAY / Casting mechanics, cont'd 3

Walter & Group....

I'LL BE AWAY FOR THE NEXT 4 DAYS.     GORDY

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From Troy Miller :

Ally is EXACTLY right ? we first have to decide what we?re studying the acceleration of, before we can have any hope of reaching agreement.  It?s like asking what RPM a car is at when you?re going down the highway.  What RPM are you talking about?  There are a number of things rotating ? crankshaft, camshaft, gears in the transmission, drive shaft, gears in the differential, wheel hubs?  we can?t arrive at an answer of significance until we agree what is the most important ?acceleration? to pay attention to.

 When I did the video studies (what, almost 15 years ago now?), I was studying the acceleration and path of the rod tip itself.  I learned a LOT about which types of acceleration resulted in the best SLP and most perfect loops.  I didn?t use any equations other than the general linear motion concept that acceleration = change in instantaneous velocity per unit time.  Down to earth, indeed? J

Regards,
Troy Miller

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From Aitor Coteron in answer to Al Buhr's statements :

Gordy,

I don't really understand what Al does mean with his statement.

IMHO the difference between two lines in its ability for turning over a long leader lies in their respective capacity of overcoming air drag with the minimum loss in their momentum.

An example taken form the daily life will illustrate my idea about this issue:

Two cars of the same make and model begin a 700 km trip with their tanks full. One driver likes to speed more than the other so he reaches his destination earlier. This car which has gone faster will have less fuel left in his tank at the end of the trip.

Between two lines of the same mass and cast with the same initial speed, that whose mass profile makes it travel faster (that is, that with the longer and thinner front taper) will reach the connection with the leader with its "tank" more depleted, so this faster line will have less capacity to turn over a long leader.

The problem lies in the fact that air drag increases proportionally to the square of the velocity, so the faster the line goes the higher the loss in its momentum.

In vacuum two lines of the same mass travelling at he same initial speed will turn over the leader the same, whatever its mass profile.

I could be wrong but this is how I see this issue until proved wrong.

Regards,

Aitor

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Aitor...

Wind resistance does make a major difference.  We must consider, too, that a line with greater mass will also be traveling with greater momentum.  The ideal line for casting in high winds would have minimal diameter and highest mass, as I see it. 

You are, I think, correct with you statement that the faster the line goes the higher the loss in momentum... However, if you have much more momentum to begin with you have a lot more to lose before collapse.

For most presentations, we'd like to have complete dissipation of energy at the very conclusion of the leader turnover.  If we have lots of energy left, we could look at that as wasted (unless we were trying for a forceful splash down as with a bass bug.)

Gordy

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From Walter Simberski :

Hi Gordy,

 

Ally is correct. I have used force and acceleration where torque and moment of inertia are the correct terms.

 

I'm off to do some fishing for a couple of days. Will get back to you on some of the other details.

 

Walter

 

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