Physics messages

From Len Zickler :

Thank you Gordy!!

Len Zickler, AICP, FASLA, LEED AP | Principal

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John Johnson weighs in :

Gordy,

Thanks for sending the articles on the physics of fly casting. The first one involved concepts that I was familiar with but the end of the article was very useful for me.

For some time I have been interested in simulating rod loading by using the equations in the article and empirical bend equations. I have been working with a friend of mine who is a college calculus instructor to generate these equations that relate fly rod and line angular motion to linear motions.

Once I pass the masters I plan to make several measurements of deflection vs forces and angles for various rods. I should be able to simulate the effect of different loading rates with rods of various stiffness and line lengths. It seems that many people talk about doing this but no one has done it yet for some reason. I have the time, engineering background, and motivation to do it. I am looking forward to writing some interesting magazine articles on this.

I have another question. In all of your discussions of casting mechanics and the spring effect I never saw a reference to Borger's article “The Rod and the Cast”. It deals with the issue of the spring effect very well.

Also I have never seen a reference to Dr. William Hannemans’s paper on “The Common Cents System” of rating fly rods. It seems to be a good way of defining rod weights and flexes.

John

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[GH] John,

I have attached the article on "THE ROD AND THE CAST". It was authored by Grunde Lovoll and Jason Borger. In the second attachment, I've included Wm. Hanneman's paper.

Another article on that subject was written years ago by Al Kyte. It was never formally published. Don Simonson showed me a typed copy of it entitled, (as I recall), SWING Vs. SPRING. I contacted Al about it. It was written so long ago that for a few minutes he didn't recall having written it.

I try to be careful not to include extremely deep scientific messages, especially very long detailed ones or ones with lots of calculus equations. In the past after I had done that, I gained sufficient feedback to know that I had offended a few of our members and bored some others even as a few embraced them.

Gordy

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From Allan Dozier :

I agree with Gordy that Server and Craig are both right in a way depending on how we define things. I think Craig is referring to the statement we have all been told that the line will go where the tip is moving at the stop while Server is probably referring to the path of the tip all through the cast.

I do the same as Craig with beginners. The simplistic statement that the line goes where the tip is moving at the stop ignores what the tip was doing all during the cast and the momentum it has developed during it. For instance, if you make your backcast out to your right side and then make your forward cast straight the momentum of the line will cause the end of the line to kick out to your left. The momentum effect is used for all sorts of curved casts but that is not something we are concerned with for beginners.

Allan

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