Swing vs Spring Velocity - Page 2

Mog · 07-10-12, 08:17 PM

If you built a robot arm to simulate a casting stroke at the exact same speed every time the flexible rod will still outcast the broom handle.

nielson · 07-11-12, 11:01 AM

Mog,
Is this something you have actually seen done, have read about someone else doing or is this just a theory?

If there is such a gadget, I'd like to see the experiment details. If not, but one is constructed, I'd similarly like to see the details. Seems to me that this would be an extremely complicated experiment to set up and run in a manner that would accurately replicate what goes on in a cast.

A mathematical model would probably be a better means of determining the answer; however, I suspect I'd have a difficult time understanding and evaluating the models accuracy given my vastly deteriorated mathematical knowledge. Perhaps 40+ years ago when I had a passable understanding of differential equations I might be able to understand it but at this point I'm lucky if I can make change or, for that matter, get my shoes on the right foot each morning.

Your pal, Jim

Riverpirate · 07-11-12, 11:44 AM

But faster rods are stiffer with less flex? hmm.

Fish Gazer · 07-11-12, 02:58 PM

I am looking at all this and thinking wow, way beyond anything I want to know. But the cool thing about casting is you can have a PHD and make it as complicated as you want or be satisfied with lets say a high school diploma.

One thing I do know is as soon as I pick up a rod I can tell if I like it. I can also tell the relative power, and weight, and the "smoothness,stiffness" of a rod.

Its cool that you guys enjoy enjoy picking this stuff apart.

Kent · 07-11-12, 10:50 PM

RP, faster rods don't necessarily have less flex, but just have it in different places. Fast rods generally have a tip with a lot of flex. `Seems counter-intuitive at first but it has to bend somewhere.

Mog · 07-12-12, 12:06 AM

I have heard of casting machines but never seen one. Trade secrets perhaps. I think you can see the same effect with an experiment of your own. Hold a length of line between your fingertips and try to throw or cast it as far as you can keeping your elbow and wrist rigid. Now do it again putting flex into your joints that you release (straighten) at the last moment of flipping the line forward. I believe you will see that the line will travel further with flex in the system.

It does seem counter-intuitive that the unflexing of the rod puts more speed into the line. This happens because the energy you put into the blank during the cast is generated by the acceleration from dead stop to maximum speed over umpteen inches of motion. That energy is transferred into the blank and stored as potential energy for as long as the rod is accelerating. If the rod is accelerating continuously until the stop at the end of the stroke the energy that was put into the blank over the length of that stroke will be released all at once. How fast the energy is released is determined by the rod's resistance to the flex put into it during the cast.

I don't recall if the concept is covered in this interview with Gary Loomis but I think it is a good source for learning more about how rods are designed. http://www.steelheadstalkers.com/tit...ary-loomis.htm

nielson · 07-13-12, 08:57 PM

I'm about ready to tape a single foot guide on the end of a butt section of a
9' 6-wt rod and see how it casts as compared to just the tip section. Also:
a. Same line
b. 30 or 40' of line out from the tiptop.

According to conventional wisdom the tip section should noticeably cast better (whatever that means) than the butt section. According to the nielson crackpot theory, the converse should be true.

Will wait until I sober up to give it a try. Then again .......

Your pal, Jim

Mog · 07-13-12, 09:34 PM

Quote:

Originally Posted by nielson

Will wait until I sober up to give it a try. Then again .......

I love it. But I think you should do it before you sober up. You might not do it otherwise and I want to hear the results.

nielson · 07-15-12, 08:33 PM

Started testing Saturday AM. Butt and tip section of 2-piece TFO signature 6wt, 40 ft of 6 wt WF line.

Results inconclusive as mid -test I was accosted by roving band of Jehovahs Witnesses on front lawn who plied me with Watchtowers before I could send them on their way. Immediately following, wife started banging on upstairs window to get my attention to come in and get ready to take her to antique show.

That said, did manage casts from both sections. Results:

1. No noticeable difference in length of casts or effort to do so.
2. Tip section made for tighter loops.
3. Butt section casts very open and unnatural due to rod stiffness.

This afternoon I tried again with siimilar results. Did push both to limits of my casting ability and again equal distance: 50' of line making for about 60-65' cast given leader and rod length. Same open vs tight loops.

Based on anectdotal results, I'm ready to conclude:
1. it's a wash on distance.
2. A flexing rod allows for a more conventional casting style and provides for tighter loops.

Probably more insights to be reached based on the tests but that's the best I can do for now.

Your pal, Jim

07-10-12, 08:17 PM	#11
Mog Hall of Fame Member Join Date: Nov 2008 Location: Hoschton, GA Posts: 1,570	If you built a robot arm to simulate a casting stroke at the exact same speed every time the flexible rod will still outcast the broom handle. __________________ These brook trout will strike any fly you present, provided you don't get close enough to present it. -- Dick Blalock

07-11-12, 11:44 AM	#13
Riverpirate Native Join Date: Dec 2008 Location: Milner Ga Posts: 959	But faster rods are stiffer with less flex? hmm. __________________ I only envy those who catch more fish than me.-Issac Walton

07-11-12, 10:50 PM	#15
Kent Hall of Fame Member Join Date: Sep 1998 Location: LaGrange, GA Posts: 1,490	RP, faster rods don't necessarily have less flex, but just have it in different places. Fast rods generally have a tip with a lot of flex. `Seems counter-intuitive at first but it has to bend somewhere. __________________ Kent Fly Fish GA

07-12-12, 12:06 AM	#16
Mog Hall of Fame Member Join Date: Nov 2008 Location: Hoschton, GA Posts: 1,570	I have heard of casting machines but never seen one. Trade secrets perhaps. I think you can see the same effect with an experiment of your own. Hold a length of line between your fingertips and try to throw or cast it as far as you can keeping your elbow and wrist rigid. Now do it again putting flex into your joints that you release (straighten) at the last moment of flipping the line forward. I believe you will see that the line will travel further with flex in the system. It does seem counter-intuitive that the unflexing of the rod puts more speed into the line. This happens because the energy you put into the blank during the cast is generated by the acceleration from dead stop to maximum speed over umpteen inches of motion. That energy is transferred into the blank and stored as potential energy for as long as the rod is accelerating. If the rod is accelerating continuously until the stop at the end of the stroke the energy that was put into the blank over the length of that stroke will be released all at once. How fast the energy is released is determined by the rod's resistance to the flex put into it during the cast. I don't recall if the concept is covered in this interview with Gary Loomis but I think it is a good source for learning more about how rods are designed. http://www.steelheadstalkers.com/tit...ary-loomis.htm __________________ These brook trout will strike any fly you present, provided you don't get close enough to present it. -- Dick Blalock

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07-11-12, 11:01 AM	#12
nielson Native Join Date: Jan 2009 Location: Athens Posts: 848	Mog, Is this something you have actually seen done, have read about someone else doing or is this just a theory? If there is such a gadget, I'd like to see the experiment details. If not, but one is constructed, I'd similarly like to see the details. Seems to me that this would be an extremely complicated experiment to set up and run in a manner that would accurately replicate what goes on in a cast. A mathematical model would probably be a better means of determining the answer; however, I suspect I'd have a difficult time understanding and evaluating the models accuracy given my vastly deteriorated mathematical knowledge. Perhaps 40+ years ago when I had a passable understanding of differential equations I might be able to understand it but at this point I'm lucky if I can make change or, for that matter, get my shoes on the right foot each morning. Your pal, Jim

07-11-12, 02:58 PM	#14
Fish Gazer Native Join Date: Feb 2004 Location: Woodstock Posts: 1,472	I am looking at all this and thinking wow, way beyond anything I want to know. But the cool thing about casting is you can have a PHD and make it as complicated as you want or be satisfied with lets say a high school diploma. One thing I do know is as soon as I pick up a rod I can tell if I like it. I can also tell the relative power, and weight, and the "smoothness,stiffness" of a rod. Its cool that you guys enjoy enjoy picking this stuff apart.

07-13-12, 08:57 PM	#17
nielson Native Join Date: Jan 2009 Location: Athens Posts: 848	I'm about ready to tape a single foot guide on the end of a butt section of a 9' 6-wt rod and see how it casts as compared to just the tip section. Also: a. Same line b. 30 or 40' of line out from the tiptop. According to conventional wisdom the tip section should noticeably cast better (whatever that means) than the butt section. According to the nielson crackpot theory, the converse should be true. Will wait until I sober up to give it a try. Then again ....... Your pal, Jim

07-15-12, 08:33 PM	#19
nielson Native Join Date: Jan 2009 Location: Athens Posts: 848	Started testing Saturday AM. Butt and tip section of 2-piece TFO signature 6wt, 40 ft of 6 wt WF line. Results inconclusive as mid -test I was accosted by roving band of Jehovahs Witnesses on front lawn who plied me with Watchtowers before I could send them on their way. Immediately following, wife started banging on upstairs window to get my attention to come in and get ready to take her to antique show. That said, did manage casts from both sections. Results: 1. No noticeable difference in length of casts or effort to do so. 2. Tip section made for tighter loops. 3. Butt section casts very open and unnatural due to rod stiffness. This afternoon I tried again with siimilar results. Did push both to limits of my casting ability and again equal distance: 50' of line making for about 60-65' cast given leader and rod length. Same open vs tight loops. Based on anectdotal results, I'm ready to conclude: 1. it's a wash on distance. 2. A flexing rod allows for a more conventional casting style and provides for tighter loops. Probably more insights to be reached based on the tests but that's the best I can do for now. Your pal, Jim