Welcome Dr William McGlinn

[gordonjudd]

A flycast?

Lasse,
So if the trailing leg has no slack are you saying the speed of the fly end of the line along its path will be different than the tip speed along its path up to a point just before RSP1?

If the length of the line from the tip to the fly does not change (i.e. no stretching or slack) how could that be possible?
Gordy

[VGB]

Lasse,
So if the trailing leg has no slack are you saying the speed of the fly end of the line along its path will be different than the tip speed along its path up to a point just before RSP1?

If the length of the line from the tip to the fly does not change (i.e. no stretching or slack) how could that be possible?
Gordy

Gordy

Can you draw what this line layout looks like?

Vince

[VGB]

Paul, tell me how this works, you're moving the line in direction x at a velocity of 100 mph (tip plus haul) haul ends and the tip goes in direction y at 80 mph and slowing down. How does that increase the lines velocity?

Ah, I think I see the issue now, Lasse was talking about fly leg velocity and the tip slowing down, Gordy is talking about fly speed and the tip being at its highest speed. It would help if the scenario didn't keep moving.

[Walter]

And nobody is thinking about x and y components of velocity.

[Paul Arden]

Did the fly end move? How far did you have to move the rod end before the fly end started to move?

No but somehow it doesn't look like a fly cast. So what keeps the rail tracks in place? Skin drag?

Cheers, Paul

[Walter]

Did the fly end move? How far did you have to move the rod end before the fly end started to move?

No but somehow it doesn't look like a fly cast. So what keeps the rail tracks in place? Skin drag?

Cheers, Paul

Normally I would say Newton, but this is Sexyloops where two of his laws have already been disproven, and the most obvious solutions are debated ad nauseum (with a big emphasis on the nausea part). So I'm going to say it has something to do with dark matter.

Ps. Does it look a bit like that brief period between fly line all straight and loop formation?

[gordonjudd]

No but somehow it doesn't look like a fly cast. So what keeps the rail tracks in place?

Paul,
As Walter said there are no physical constraints like train tracks that would force the path of the fly to exactly follow the exact same path of the rod tip. I think that is a pretty obvious fact that you can see from high speed videos. Gravity seems to have its own say about these things.

I can now see that for the literally minded the train example was a poor analogy. I was just trying to point out that as long as there was a fixed length between the engine and the caboose then the caboose would have the same speed along its path at any point in time compared to the speed of the engine even though the caboose may be on a straight piece of track while the engine is going around a curve. I.e. thinking about comparative speeds not comparative velocities.

In regards to paths, a section of line will tend to follow the path of the line in front of it, so you will find the fly end of the line follows a path that is similar to the tip path. You can see that fact in high speed videos as well. Note I said similar not exactly the same.

The way I calculate the tip speed along its path is to measure the arc length of that path as function of time and then take a derivative of that length vs time function to get ds/dt speed curve along that path.

I have yet to see a video that tracks the tip path and the path of the fly in the same frame, but if one existed I am saying that you could calculate the ds/dt speed curve for the tip along its path and the ds/dt speed curve for the fly along its path and you would find that the two ds/dt speed profiles would nominally be the same.

That is assuming the length of line connecting the two remains constant and that line shape does have any slack or crazy shapes. But I think that for good casts the shape of the line between the rod tip and the fly while the rod tip is accelerating along its path (another derivative unfortunately) may not be straight, but is not full of twists and turns either.

So back to your original question,

what I'm asking is if the rod tip is still accelerating will this result in acceleration at the fly end?

The absolute value of the acceleration in the x and y directions will be different, but the acceleration of the rod tip along its path and the acceleration of the fly along its path (the derivative of similar ds/dt curves) will nominally be the same. So the answer to your question is yes.

Gordy

[Walter]

No.

A^2 + B^2 = A^2 iff (if and only if) B = O.

[VGB]

The engine is pulling and the caboose doesn't move at the same time

https://vimeo.com/163408827

[gordonjudd]

The engine is pulling and the caboose doesn't move at the same time

Vince,
Do you think there might be a difference between your static example (i.e. fly end is not moving), and what I am talking about where the fly is trailing behind the rod tip as the rod tip is being accelerated along its path? I do.

Lets try to compare apples to apples, and find an example where the trailing fly's velocity does not increase at the same time the rod tip speed is increasing as it goes to RSP1.

Thanks for looking,

A^2 + B^2 = A^2 iff (if and only if) B = O.

Walter,
I am not sure of the point your are trying to make but how would you compute the speed of an object that was moving along some curved path?

I would do it by setting it equal to sqrt(x_vel.^2 + y_vel.^2), and I think if you did the comparative calculations you would find the ds/dt calculation would give you the same value as taking the square root of the sum of the squares. Pythagoras was on to something don't you think?

Gordy