Loop / fly line tension of each leg

Walter & Group.......

From Carl McNeil..........

G’day Gordy, with regard to Ally’s diagram:

 

The outline given confuses.  In the diagram a  point is highlighted that has ‘no tension’  and 'slack line' I assume we’re referring to the newly formed rod leg of the fly line and not tip counter-flex.

Either-way they are all under tension; with the rod leg remaining under tension for the remainder of the cast. The loop - front face, and top and bottom legs must all propagate forward under tension, as is later highlighted in the ‘cutting the line’ example.

 

That small embryonic loop in Ally’s diagram is most certainly under tension – if it were not, the loop could not form  –  fact is, you can’t push a flyline.

 

Remembering we’re talking line tension here and not mass or energy present in the system;

I believe Paul is correct in his statement regarding points of maximum tension being present and equal in both legs. …Can’t believe I said that ;-)

I’d also hazard a guess that the amount of tension present in either leg was in fact equal for the duration of the cast (after the stop and before the point at which the line fully straightens) – regardless of the length of line in the leg – but I could be wrong, certainly keen to find out!

Cheers

Carl McNeil

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 

Carl....

 

I think you and Paul may well be correct, but I'm quick to add that I'm not sure about that.  Seems to me that there must be some tension in each leg ..... but I know of no determination of their being equal or, if so, that relationship remains throughout the unrolling of the loop.   I call that into question because of the dynamic nature of the system.

 

Problem reduces to the fact that I have been unable to find a reference to any actual measurements which have been done to confirm any of this.

 

We are basing our opinions on logic and the old (but still probably valid) formulae of Ed Mosser, Graig Spolek and John Robson along with the more recent mathematical renditions of Noel Perkins and his staff ....... NOT actual physical determinations.

 

An unknown Guru once said:   " TO MEASURE IS TO KNOW".    (The reason I said, "unknown Guru" is that I have seen that statement credited to several different authors including Antoine de Saint-Exupery, French aviator and author who disappeared while on a mission over Europe in 1944. )

 

Gordy

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 

From Troy Miller:

 

I can’t agree with these statements:  “I have to agree the loop does not pull the fly leg along. The fly leg is the Mass that has the movement= Kinetic energy.”

 

If the top leg is not “pulled along” to some extent, then it would behave as a simple detached object (such as a bullet fired from a gun) – and would immediately begin to fall when the initial driving force was removed.  The fact that the loop does not appear to fall directly with gravity indicates that the unrolling loop face (or something else) counteracts the direct effect of gravity.  Try the trick where you drop a coiled up length of flyline at the same instant that your loop forms and see which hits the ground first…

 

Regards -- TAM

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Troy...

Good point.  The time difference can be quantified.   Now, simple as it may seem,  THAT IS A MEASUREMENT.

Having said that, however, we must be aware of the numerous theories as to why the traveling loop does not fall sooner than it does and even tends, in some cases, to climb.

The, "climbing loop" subject would be another good topic for discussion !

Gordy