Dynamic Response

[Magnus]

Bernd

The term "stopless" was born, because some people realized that some casters were using a wider arc as that old arc being recommended in many old books (10/2).

That term was probably coined on SL. As far as I can remember it was a description of how the casting action felt/feels. Pushing through to a fully extended arm. If you look at your clip of Paul and Steve and compare a little of how they shift weight and use muscle to the ground there are style differences - Steve blocks like a throwing athelete - much less of that from Paul (who was hungover?)

Vince

At the moment, Merlin is taking an input (presumably derived form the Sage Analyser) and putting it into his model. Because I have not been here since 19 oatcake like the rest of you, I do not know if the co-ordinate issue has ever come up before.

Interesting! Bruce and Noel based the CA on their understanding of casting mechanics, so their gadget is the egg derived from a 'traditional' casting mechanics chicken. I've never heard Merlin mention a CA - I'd be interested to know if he has one. I assumed his reference to what Bruce likes was his use of 'constant acceleration' in the example calculations he made to demo harder and softer stops.
We had a very long argument about constant acceleration a few years back. We had a CA record of Paul distance casting which showed his angular acceleration was not constant, according to the CA he was throwing tailing loops and would improve if stroke was smoother and the rate of acceleration more constant.

[Bernd Ziesche]

Hi Magnus,
http://www.sexyloops.co.uk/cgi-bin/theb ... 13728;st=0
that's (I think) the last exchange we had about constant acceleration.

Today I like to work with the term: proper acceleration = smooth (controlled) increase in rod bend.
Are you going to argue with that?
Greets
Bernd

[Magnus]

Hi Bernd

Would you like me to argue with that?

We had a fair few threads where constant acceleration was argued about long before that one Bernd. Back when the CA was new, and when we were working on definitions. Including early thread(s) where Bruce defended his claim that smooth acceleration is constant acceleration. IMHO he was conflating a couple of ideas just as you do in your posts in that thread by the way.

You going to argue about that?

[Bernd Ziesche]

No, I don't Magnus
At that time (in that thread) I started on a wrong course (I think today).
Since the CA refers to the butt section, I find it hard to say (in general) what exactly will happen to the tip path when changing the type of acceleration for the butt section. There are too many factors like the angle between line outside the tip and the rod and so on. I do believe that a good caster is able to control the increase in rod bend. This is what I believe should happen smoothly always. Which exact type of acceleration for the butt section might match best for the smooth increase in rod bend, depends probably on key elements like size of arc, stroke length and others.

Besides that I still think that Bruce's method of teaching to be constant in one's acceleration works fine in many situations.
Constant acceleration should mean a smooth increase in rod bend. But it might not be the most effective way of creating the desired speed at the same time!
Greets
Bernd

p.s.: If we start to argue about it, I would want Frank to be back in here, too.

[Magnus]

Hi Bernd

Maybe Frank would rather not be back.

Thing about the CA and constant acceleration, Bruce claimed to have found constant acceleration was common to sample casts from expect casters. Then we opened one of the expert samples used by the CA and found the acceleration was not constant, that the rate of acceleration increased to max angular velocity in that sample file.

Anyway, IMHO visual cues, seeing the line and the loop, and adjusting your motions to change the next loop are crucial parts of learning to cast well. As a teaching regime, the CA has the advantage of advising on what change to make 'next time' in terms we can understand and apply.

[VGB]

Thank you both for the information

It appears to me that the input profiles that Merlin is using are derived from the various measured data. For a standard overhead cast that is the correct route to take. However, looking at the Paul/Steve video I do not see that the standard acceleration profile is just stretched over time to fit the larger arc and may account for the low velocity results. What I see is that rotation is delayed and then a large rotation occurs very quickly ending in a hard stop aligned to the -ve y axis. It would be interesting to compare the duration of the 2 types of stroke. This wider arc also means that your x and y axes become inverted during the cast, can the CA cope with that?

As I mentioned earlier , the additional arc that they both employ on the delivery stroke changes the relative load angle between the rod and the line such that if the acceleration causes a substantial tail like bend to occur then it does not really matter as the tip path does not vary greatly. Are there any videos that show the tip?

Maybe we could steal the golfers mantra "smooth acceleration for show and aggressive for dough"

[gordonjudd]

his wider arc also means that your x and y axes become inverted during the cast, can the CA cope with that?

Vince,
I don't know what your mean by inverting the x and y axes or how that would have anything to do with the angular velocity that the CA is measuring. You could put the MEMS sensor used in analyzer on a spinning drill and it would still produce the correct angular velocity value.

The CA is measuring the angular velocity for just one rotation axis however, so it does not produce the true 3-D related value for people who rotate their arm and wrist during the cast. For that you would need to use one of the six degrees of freedom sensors that are used for more complete sports motion analysis.

An example of the acceleration profile (assuming a single rotation axis) in one of Paul's distance casts is shown here. He produces some very high rotation values with the exponentially increasing late acceleration profile used in that cast as discussed in an old thread.

Gordy

[Walter]

Some history as I recall it:

- The 170 cast was commonly called the stopless cast because the cast blew through what was then thought to be the usual place to consciously stop the rod and relied on running out of arm to stop the rod instead. It was also called the bouncing bomb backcast for obvious reasons. It was also occasionally called the 170 cast and after some discussion on SL the concensus was that 170 cast seemed to be the best name for it. The name "stopless cast" lost favour because there is truly a stop, it just happens in a different place and in a different way than what traditional wisdom said it should be.

- there has been discussion in the past on SL that the 170 cast can't (or shouldn't) be used for heavier weight rods (8 and above?) because it is too hard on the muscles and joints. Given that 5 wt distance is a relatively new sport I would expect to see a lot of discussion around the best way to cast a 5 wt for distance and some evolution of the sport. It also looks to me like Rajeff has changed his style in the past couple of years with respect to his stop on the presentation cast. When you look at his cast in 2008 he is still doing an early stop followed immediately by a stab. In the 2012 video earlier in this thread he looks like he has eliminated the stab in favour of a wider arc on the presentation.

[Lasse Karlsson]

- there has been discussion in the past on SL that the 170 cast can't (or shouldn't) be used for heavier weight rods (8 and above?) because it is too hard on the muscles and joints.

I would love for someone knowledgable to confirm that. A more contrieved cast makes my joints go bump, actually my only real casting injury came from stopping a T38 outfit hard. Took me the better part of a year to heal, in the mean time, the only way I could throw any distance was using "170".. And it happened just as pike season took of, 8 weight rods, 10 weight shootingheads and big flies Cool thing was it forced me to rethink some things about casting

[vimeo]55401772[/vimeo]

Cheers
Lasse

[VGB]

Gordy

Thank you for your response

The CA is measuring the angular velocity for just one rotation axis however, so it does not produce the true 3-D related value for people who rotate their arm and wrist during the cast.

I was comparing it to an airborne Inertial navigation platform that even with 3-D still needs attitude stabilisation to give correctly orientated values during aerobatic manoeuvres. I am aware time has marched on with the available sensors but many still have rate limitations. My eldest son is doing some development work with a new generation that fits to the tips of your fingers, so that the Minority Report scenes with Tom Cruise waving his hands to manipulate data are becoming real. I cannot talk in detail about his project but it is very interesting.

I am pleased that your data backed up my intuition and I can see why Paul destroys so many rods, he is effectively high sticking the rod during a cast.

Vince