Welcome Dr William McGlinn

[gordonjudd]

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

Paul,
Think of this as a series of point masses that are linked together and attached to the tip of the rod, much like a train on a curved track pulling a bunch of cars (masses) that are coupled together with flexible connections.

If the train increases its speed along the track (even though it may start to go around a curved section of track) the speed of the caboose will also increase even though it may be on a section of track that is headed in a different direction than the engine.

The only way for that to not be the case is if you loose the linked connection between the engine and the caboose. Thus if you get slack in the line, then all bets are off as to how the fly will respond to a movement in the the rod tip.

Gordy

[Paul Arden]

It's OK I don't need to think about that and it was my original point Gordy, however you've said it much better than I could!

Cheers, Paul

[VGB]

Paul, you may remember Dirk provided a practical demonstration of this:

https://vimeo.com/119066423

Regards

Vince

[Lasse Karlsson]

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

Paul,
Think of this as a series of point masses that are linked together and attached to the tip of the rod, much like a train on a curved track pulling a bunch of cars (masses) that are coupled together with flexible connections.

If the train increases its speed along the track (even though it may start to go around a curved section of track) the speed of the caboose will also increase even though it may be on a section of track that is headed in a different direction than the engine.

The only way for that to not be the case is if you loose the linked connection between the engine and the caboose. Thus if you get slack in the line, then all bets are off as to how the fly will respond to a movement in the the rod tip.

Gordy

The tracks make the train analogy valid only for a fixed pulley, the loop is not.

Cheers
Lasse

[Paul Arden]

In practical terms it must be, otherwise the line wouldn't curve but would be straight, Lasse.

[Walter]

Great. Please tell Lasse

You really do see what you want to see and hear what you want to hear. As Lasse has pointed out the train is a bad analogy.

Since you like talking about little balls lets go back to the bead chains and the huge number of videos that have been posted where someone lays out a loop of bead chain on a table and then pulls on the "rod leg". There are three possible outcomes:

1. The fly leg moves in the same direction as the rod leg. If you can ever remember seeing this happen in any of the videos than I recommend that you stop drinking now and return to this post after a good night of sleep.

2. The fly leg basically does not move. The fly leg is pulled into the loop and into the rod leg but the fly end of the chain remains stationary until just before turn over or near turn over. The loop moves in the same direction you are pulling on the rod leg. If you can remember seeing this happen in some videos then your memory is at least partly in tact and you can read on to the next scenario.

3. The fly leg moves in the direction opposite the rod leg. Usually there is a bit of a pause during which the fly leg does not move but then it begins to accelerate into the loop. The loop basically remains stationary. Again, if you remember seeing this in any of the "form a loop in bead chain and pull on one end videos" then your memory seems to be working. Good for you.

Let's concentrate (if you can) on what makes the difference between 2 and 3. What do you think it is? Why don't we see only 2 or 3 in 100% of the cases? Think about tension, the kind that results from a force applied to one end of a long chain of tiny little balls. What causes that tension?

I'm sure you will ignore this but I thought I would try one more time.

Cheers

[Paul Arden]

If you pull ten feet of line out of the fly leg what happens to the end of the fly leg, Walter? Assuming it doesn't stretch it must move 10ft forward!

[Lasse Karlsson]

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?

I don't really care for hypothetical examples that aren't humanly possible to do in a real world cast, so let's keep it within reason

Cheers
Lasse

[Paul Arden]

We don't have those numbers. However we do know that the tip speed increases to RSP and is not slowing down.

Cheers, Paul

[Walter]

If you pull ten feet of line out of the fly leg what happens to the end of the fly leg, Walter? Assuming it doesn't stretch it must move 10ft forward!

Paul,

Either 2 or 3 or 3 happens. Stretch is not an issue. Net forces and inertia are the issues and they will determine which one it is.

What do you say? Only 3? Get you balls off the train track.