Analyzing tails

[Aitor]

That straight line goes from RSP to RSP, just like yours. Have you found your lost wave in the line? :whistling:

[Magnus]

is this a dip?

[Aitor]

It is a slight dip that doesn't go below the line you have drawn (SLP I suppose; or just a straight line through two point to prove that a third is lower than that straight line?).

Is that rise over your line (SLP?) after the stop conducive to a tailing loop?

[Magnus]

Aitor

We agree that in a normal tight loop cast the tip path is domed to form a shallow curve?
So if we draw a straight line between RSP and RSP the tip should be above that line from RSP to RSP travelling in a smooth curving path?

When I draw a line from RSP to RSP as far as I can see the tip rises then falls to that line then rises again to the peak late in the stop that you are pointing out then finally curves down to RSP.

In my opinion there is a dip at the point I indicated in the last post. Without question the tip also rises exactly as you have pointed out.

In my opinion both those factors go to make the tail in this cast. I frankly don't know if those two can occur separately. Before speculating on that I would like to see examples.

[Aitor]

Magnus,

Now we are reaching an agreement! :oh:

Out to cast some (hopefully) not so taily loops.

[Bernd]

Hello guys
Seems as if both of you had a long night of analyzing this cast again and again .

Magnus, yes there is a dip. And as I can see it, it starts to happen while rod is unloading (rebound) = after max force is added into the butt section (rotation + translation) by Bruce (of course time change butt/tip makes this statement a little risky maybe).

Magnus, can you mark the problem in non proper power application directly on the graph?

My resumee is a too small arc for the amount of bend still.

Aitor, are you sure Magnus and you are using the simple word stop in the same way here?
You should define it, maybe (max angular velocity of the butt section?)?

Greets
Bernd

[Aitor]

Bernd,

Take into account that on any cast the rod tip keeps accelerating after the caster begins the deceleration of the rod butt. But you already know that.
In this case it is at that point (tip acceleration after the beginning of the stop due to elastic energy stored in the rod) where the tip dips. But IMO that dip isn't big enough to produce such an obvious tailing loop. That dip should result, IMO, in just a hint of a tail.

[Magnus]

Hi Bernd

This is what I get from these images.

The tip rises until about the first t in Start. It climbs quite steeply to that point, just as one might expect since the graph indicates acceleration then is low.
Then the dipping begins. And this is before the rod butt has reached vertical as far as I can see. The bottom of the dip comes after Maximum Angular Velocity. That is what I would expect since that is when minimum chord length happens, ie after MAV when the rod butt is at a slight angle beyond vertical However in a 'normal' cast of this type at minimum chord length the tip would be at the highest point on the curving tip path.
As the stop, ie negative acceleration, continues the tip rises from the dip to peak shortly before RSP

[Bernd]

Hello Magnus,
do you know what is really intersting on the tip path you added to this picture?
It doesn't go horizontal!
And as I wrote before:
When casting horizontal the arc should be symmetric to the 180° Line between the fc & the bc.

You wrote: "Then the dipping begins." I agree. But it always depends what is happening later in the tip path. If the arc would be a little more opened, the beginning (of dipping) wouldn't be there anymore

What I see is a high bc and a pretty much horizontal fc.
And the (sl) tip path doens't really match this way.

Greets
B

[Magnus]

Hi Bernd

The tip path during casting strokes don't need to be horizontal as far as I know.
When the CS starts the line is angled up, as in a high backcast - I agree. The trajectory of the tip, the drawn straight line from RSP to RSP, angles down a few degrees - just as it would on a Pickupandlaydown. The direction of the line into the forward cast looks to me to be pretty much horizontal - hard to be certain from the clip.

The dip is caused by the acceleration. The acceleration is how the rod is moved - to change the arc during that part of the stroke you need to change the acceleration.

[Bernd]

Hello Magnus,

I still think it happens mostly during the decceleration part (butt) of the stroke.

But anyway what would be your "advice" (help) for a student showing this cast?

How should he change his acceleration to get it more proper?

Greets
Bernd

[Magnus]

Hi Bernd

Looking at the graph and the clip gives us some technical insight, but IMHO telling a student to change the form of acceleration they are using will probably confuse them.

From our perspective, I could accept that graph as a description of a stroke or a caster suffering from Creep. Slow initial acceleration, sudden late acceleration.

What advice would I give is another matter.
I would probably ask them to watch me (or you or Aitor) casting the same length of line and tell me what difference they could see. I would expect them to say the rod was not moving as fast and possibly the the arc I used was narrower. Then I would encourage them to take than on board, trying to get them using a smoother stroke, trying to get them aware of loop control and variable casting arc.

I would NOT suggest they used a wider arc.

[Bernd]

Looking at the graph and the clip gives us some technical insight, but IMHO telling a student to change the form of acceleration they are using will probably confuse them.

From our perspective, I could accept that graph as a description of a stroke or a caster suffering from Creep. Slow initial acceleration, sudden late acceleration.

Hey Magnus
here we are on the same line .
Greets
Bernd

[victor]

I would NOT suggest they used a wider arc.

Even if that was the simplest and easiest and least confusing solution?

I agree the cause of the tail is the tip rising to RSP, and stopping a fraction later might have prevented the tail in that particular tail. I still think the casting angle would have been perfectly ok if power had been applied properly in the first place.

I still think that Bruce deliberately shock loaded the rod beween the 4th and 5th rod from the left as shown in post 113.

Mike

[Aitor]

I would NOT suggest they used a wider arc.

Even if that was the simplest and easiest and least confusing solution?

It is better to say to the student that he must reduce his smoothness ratio. He will do it immediately.