On Mon, 10 Nov 2008 09:04:23 -0800 (PST), rb608
wrote:

On Nov 10, 6:22*am, wrote:
Some considerations on casting and rod loading.

A simple calculation for casting in air is;

Frt = Fi * Fa * Ff * Flt

Where Frt = the force on the rod tip in kg.m/s², Fi = inertia (mass)
in grams, Ff = the coefficient of fluid kinetic friction µk ( air
resistance), Fa = the acceleration of the line in ms², and Flt = line
tension in kg.m/s²


Now, I admittedly can't haul worth a ****, but I do know my physics
(maybe that's my problem.) I'm having a bit of difficulty reconciling
your theory above with that of Mr. Newton who opined a much simpler
equation, F=ma.

Force equals mass times acceleration. That's it.

The extra terms you included (Ff and Flt) are misplaced IMO. Under no
circumstances would they be multiplication terms in the equation. The
line tension is just another Force that would be part of the net force
on the tip of the rod, not a separate term.

The air resistance term (what units are you thinking for that one?)
also does not belong there. Any resisting forces due to fluid
friction would similarly be a part of the net value of the Force at
the rod tip. It does not belong in the equation as a multiplicative
term.

As I said, I can't haul; but I fear the inaccuracies of your
mathematical equation may be detracting from your practical
instruction.

Um, what about differential in air density (altitude) and the
aerodynamics of the fly, lure, whiff, plug? IOW, how is the fact that
a #20 whatever is different than a bass bug, and when both are cast in
Gunnison or Val Thorens versus New Orleans or Venice, addressed...or not
addressed, as the case may be...? And I thought you couldn't
"calculate" air resistance in something like this - IOW, assuming no
other flaws in the formula, it would only work at one precise altitude
with an absolutely fixed-in-physical-characteristics fly. On top of
which, since all this **** is proportional to the square of this or
logarithmic to the inverse of that and all sorts of other scientifical
crap, maybe the manufacturing variations in lines are going to vary
enough in stuff like cross-sectional presentation of forward surface
area to get things all complicated-like instead of simplicity itself...

Yeah, yeah, yeah, I know...

"Hello, FBI, how can I direct your call?"

"GET ME AGENT VLASIC NOW, YOU MOTHER****ER!!!"

HTH,
R