SOMEONE EXPLAIN THIS TO ME...

[gordonjudd]

The top point come from accelerating the line as straight as possible,

Lasse,
Can you explain the reasoning behind that statement?

Where does that "straight line as possible" happen? Just about all of the tip paths I have seen (for typical fishing casts anyway) such as the one Grunde recorded in his high speed video measurements have a slightly convex shape as shown in the white tip marker path below:


Does that point show up when the loop is first formed, or does it take some loop morph before the point is actually formed in the videos you have measured?

If you have an example (other than the one I showed for Alejandro's broomstick rod) where the point was evident at MCF I would like to see it. Most of the initial loop shapes I have seen have an elliptical shape as shown below:


Gordy

[aldear]

Give me a few minutes to take some pics...I have some more details to add to the drama....I fall partially into the Lasse camp by the way.

[Paul Arden]

I would be careful about that Andy; he's usually wrong

[aldear]

Ok....phone not cooperating at the moment so I cant upload pics, so here's a short youtube video showing the magical wedge rod...lol It is the upper section of a junked out solid core fiberglass spinning rod made about 40-50 years ago. It also has a metal butt over tip (not the normal tip over butt) about halfway up the length. I'd like opinions on what these two "anomolie"s contribute (if any) to the rod throwing wedge shaped loops so consistently.

https://www.youtube.com/watch?v=IBSRXGfbQ8A

[Lasse Karlsson]

Hi Gordy

I see a pretty straight acceleration of the line in the grunde pic, and a quite big deceleration part going away from that straight part, but I know we look different on how this works...
I dont care to see it at MCF, and I showed it ages ago, that the point in the backcast of an extreme 170 appears where the velocity of the line was greatest, ie. where tip and haul together gives the highest acceleration of the line.

Cheers
Lasse

[gordonjudd]

I fall partially into the Lasse camp by the way.

Andy,
Does that mean your old spinning rod has a soft (i.e. flexible) tip? With a stiff metal ferrule, and a solid cross-section I would have thought it would be stiffer than a hollow thin, fly rod tip.

Were you just casting the 3.5 long rod tip section in your tests? That is going to have a much different tip path going from MRF to MCF than a full length fly rod.

How pointed of a loop can you see just by hauling that length of yarn around your thumb? That can produce some very narrow dolphin nose loops in a length of fly line where the thumb path has very little change in the y direction while stopping as shown below:

Gordy

[gordonjudd]

I don't care to see it at MCF, and I showed it ages ago, that the point in the backcast of an extreme 170 appears where the velocity of the line was greatest,

Lasse,
Do you mean you saw the point just before RSP1 when the line speed is at its maximum? That would really be unusual, which probably means my idea of what a pointed loop looks like must be different than yours.

Usually the line is still trailing the tip at when the tip speed is at its max as shown in Mathias's cast showing the rod and line shapes when his tip speed using a TCR rod was at its maximum. Therefore I do not see anything that even resembles a loop at max tip speed let along a pointed loop.


Even with a 170 style back cast I would think the line would still be trailing the tip just before RSP1 in this extreme example of Mathias's bouncing bomb back cast.


Gordy

[Lasse Karlsson]

Nope, I dont mean that, and that is not what I wrote

Where do you expect to see the point appears in Matthias supersonic backcast, and what would you trace that back to?

Cheers
Lasse

[Paul Arden]

How about comparing bends with a weight on the tip, Andy. I'm actually happy to agree with Lasse's reasoning, but don't let him know

Cheers, Paul

[gordonjudd]

Where do you expect to see the point appears in Matthias supersonic backcast,

Lasse,
I expect it will appear after loop morph affects the shape of the propagating loop. I think the fact that you sometimes end up with a tight pointed loop on the supersonic backcast is because of loop morph, not because the there was a straight tip path while the line was being accelerated.

Here is a case that had a straighter tip path earlier in the cast as compared to that one of Mathia, but , then morphed into a more rounded loop shape.


I don't understand loop morph at all, so I don't know why you might see a pointed loop on some casts and a rounded loop on others when they morph from the big elliptically shaped loop at MCF to something that is much tighter later on in the cast, but I don't think it has much to do with accelerating on a straight line path.

Gordy