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SexyLoops Hot Torpedo - Instructor Rod

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Bernd Ziesche
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SexyLoops Hot Torpedo - Instructor Rod

#41

Post by Bernd Ziesche »

VGB wrote: How does this affect the cast and the "feel" of the rod?
Hi Vince,
am not sure the rod has any feel. :p :cool:
But to me adding more weight (while keeping the same (short) head length) results in too much rod bend. I will loose to much of proper tip path. This happens especially post RSP1. The cf will be too huge to be controlled for me. Usually I would reduce force application though...
Casting the rod with that much bend feels like casting a too bendy rod simply. Loop shaping gets difficult.
Greets
Bernd
http://www.first-cast.de
The first cast is always the best cast.
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VGB
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SexyLoops Hot Torpedo - Instructor Rod

#42

Post by VGB »

Thanks Bernd. I was discussing this with Lasse a while ago and described it as "not having enough arm". I hope your description makes more sense to him ;)

regards

Vince
Casting instruction - making simple things complicated since 1765

https://www.sexyloops.com/index.php/ps/ ... f-coaching
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gordonjudd
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SexyLoops Hot Torpedo - Instructor Rod

#43

Post by gordonjudd »

Power is used in so many directions. I find that weird often.
Bernd,
I also think the use of "power" is abused in many supposedly technical descriptions of rods and/or casting dynamics. Generally it seems like it is being used in a context that is similar to the "power of the President" rather than being the time derivative of the energy transfer or a force*velocity curve that can be characterized in watts.

As noted in Wikipedia:
Energy transfer can be used to do work, so power is also the rate at which this work is performed. The same amount of work is done when carrying a load up a flight of stairs whether the person carrying it walks or runs, but more power is expended during the running because the work is done in a shorter amount of time.
Thanks for your picture of the relative deflection of the Sage and HT rods. That shows the spring constant of the Sage is a bit larger than the value for the HT. I would like to see a similar comparison taken with a 45 degree butt angle. That will a better comparison of the tip flex (or action) of those rods than the comparative bendform you get for a horizontal orientation.

Gordy
Ré_

SexyLoops Hot Torpedo - Instructor Rod

#44

Post by Ré_ »

A little update on the ERN of my Hot Torpedo: for some weird reason I calculated with 2.35 grams as the weight of 1 cent instead of 2.5. So the correct ERN would be 7.5.
I just set up today the ultimate ERN-measuring-machine (ok, it is not a machine), so I will be able to measure without the effect of the cork grip or anything else.
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gordonjudd
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SexyLoops Hot Torpedo - Instructor Rod

#45

Post by gordonjudd »

Well I think we have a different view on this rod Gordy, the linear part of the stiffness is about 1N/m (some 10 grams for 9.9 cm deflection).
Merlin,
As we have found this rod may be better suited to doing a 5th order fit rather than the third order fit that we have used in the past. However, with a 5th order term I don't know if the Duffing-type non-linear spring analysis can still be used, and the k3/k1 characterization of the spring non-linearity no longer applies.

I have looked at doing a "hybrid" cubic fit to that data that gives results more in line with your values. This essentially calculates the best linear fit for deflections that are less than 12% of the clamped length, and then finds a cubic term to go along with that forced linear term that minimizes the square of the fitting errors. Matlab has a fmins function that makes such a fit easy to do. That gives a larger least squares error than a true cubic fit, but provides a much better fit to the force vs deflection points for small deflections. Essentially it reduces the fitting error for small deflection values at the expense of larger errors for the bigger deflections.

That approach tends to increase the linear term and reduces the cubic term coefficient, so it gave a k3/k1 ratio of around .96 for Bernd's data as noted below. That is a value we have seen before for other tip flex rods.
Image

Gordy
Alejandro
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SexyLoops Hot Torpedo - Instructor Rod

#46

Post by Alejandro »

Hi Bernd,

The difference in weight, for the tip, between using Recoil guides and mono guides HH (Seymo) single leg DLC or TiCh guides, top included, is very close to 1 gram.
Surely for the MOI is better to use Recoil, or HH (Seymo) thin wire snake guides, but for hard work the heavy wire has some advantages.

According to the CCS the Hot Torpedo 906 ERN would be around 7.5. The second Akos and Bernd measures are more accurate than the first.
Personally I think the CCS not help much to characterize a fly rod.
A fly rod should do many different jobs, and as Merlin says this often involves a nonlinear bending. I suspect if this nonlinearity follows the same pattern in models from different manufacturers is because it is easier to copy something that we know works, instead of wasting time looking for better alternatives :-)
Certainly could be described quite accurately a fly rod with numbers, or graphs, analyzing a wide range of bending, with different angles of force. But the result would be much more difficult to interpret for fishermen (and I suspect for everyone) than the classic Actión Medium-Fast for line # X

Alejandro
Ré_

SexyLoops Hot Torpedo - Instructor Rod

#47

Post by Ré_ »

Alejandro wrote: Certainly could be described quite accurately a fly rod with numbers, or graphs, analyzing a wide range of bending, with different angles of force. But the result would be much more difficult to interpret for fishermen (and I suspect for everyone) than the classic Actión Medium-Fast for line # X

Alejandro
So true. :closedeyes:

I measured the tip sections of a couple of HTs last night:

Blank: 2.7
Pro: 3.5
3.45
3.6
3.55
3.5
3.6
Comp: 3.9
3.9
4
Inst: 4.3
4.4
Michal Duzynski
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SexyLoops Hot Torpedo - Instructor Rod

#48

Post by Michal Duzynski »

Hi Akos
did somebody measured the HT Competition, or is it the same as HT Pro ERN 7.9 AA 72?
cheers
mike
Ré_

SexyLoops Hot Torpedo - Instructor Rod

#49

Post by Ré_ »

It must be the same. although we couldn't get the same result twice on any measurements (on the same rod). I would say ERN is somewhere between 7.4 and 8, depending on who measures it.
Until someone won't make the exact specifications on how to fix the rod for example it will be hard to have a precise data. If I fix the rod right before the handle I have higher numbers than if I fix it a little bit more behind.
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Paul Arden
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SexyLoops Hot Torpedo - Instructor Rod

#50

Post by Paul Arden »

So ERN should be X+/-0.3 ?

This is something I've been asking about for years!

Thanks Akos. :cool:

Cheers, Paul
It's an exploration; bring a flyrod.

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