Analyzing tails

[Aitor]

I have shared a long week-end with a fellow instructor giving a course and talking about how fly casting works. Proper application of force has been an issue that we have debated at length. We have been talking about this example.
What's in your opinion the reason for the tailing loop shown on this video?

[Bernd]

Hello Aitor!

Who was that fellow Instructor?

Let us know what you thing about the arc, rebound and
when exactly the concave tip path shows up on that cast!

Greets
Bernd

[Aitor]

Who was that fellow Instructor?

Humm, he is a great caster, teacher and friend. There aren't many of those.

[mazda323]

Hi!!

Yes, Aitor, there is at least one more: you.

Thanks you and Bernd.
Haritz.

[WetWading]

Caster begins with a lot of acceleration, but doesn't maintain it throughout the stroke, causing the rod tip to move above SLP and the line to tail.


C

[Aitor]

Well, the graph generated by the CA indicates that the caster has increased his acceleration right up to the beginning of the stop.

[James9118]

What would the differential look like though (da/dt)?

[Aitor]

http://www.physicsclassroom.com/Class/1DKin/U1L4a.cfm

http://www.physicsclassroom.com/Class/1DKin/U1L4b.cfm

[Bernd]

Hello Ww,
what would be your advice for a student if he would show this cast?
Accelerating more smoothly?

I agree with Aitor. The acceleration is well until the process of the stop starts. At least that's what the graph AND the video shows to us.

What about the adjustment of arc and amount of bend in the rod (based on the style shown in the video = not talking about changing the style to solve the problem)?

Greets
Bernd

[WetWading]

Hi Aitor,

I took another look at it with the aid of the graph, and I was mistaken. The rise in tip path occurs after the stop, which can only be the result of an insufficient forward cast arc.

End of power application, SLP is maintained:


After stop, tip rises above SLP:


Chase

[James9118]

Well, the graph generated by the CA indicates that the caster has increased his acceleration right up to the beginning of the stop.

Aitor - sorry I thought these plotted a vs. t, i.e. a direct output from the accelerometers.

If it's v vs. t then obviously the differential is a then isn't the tail caused by the inflexion - i.e. the non linear accel?

[Bernd]

Hi Chase,
we agree on that. Arc is to small for the amount of bend.
What about the 180° principle?
Focuse on how high the line is in the bc when already accelerating the forward cast horizontal.
When you are accelerating a line horizontally forward which is straightened above the horizontal in the backcast it can easily cross the tip path already in the process of the stop.

My advice would be:
1. Open the arc a little and
2. Wait a very little longer on the bc (carefully saying this here ...without having seen the whole line here).

What do you think?

James,
rod tip is accelerated straight, isn't it?

Greets
Bernd

[Aitor]

Hi Chase,
Spot on! In fact I had prepared a couple of pics like those of yours to prove that same point.

James,
The problem isn't in power application but in an insufficient arc for the load. I think that the video combined with the graph is explicit enough.

[Lasse Karlsson]

Hi Aitor

What if the amount of arc is perfect for the length of line and distance targeted, wouldn't it then be a problem in the power application?

Cheers
Lasse

[James9118]

Would your advise to correct this be to drift back more or to make the stop on the f/c later? I'm guessing the former otherwise the cast will be orientated down?