The problematic is not far from the casting modeling although it does not exactly fit to the problem, but nevertheless what we are interested in demonstrating the usefulness of a spring. Some of us modeled Aitor’s experiment so we have the means to guide him for the experiment.


As a representative of the foolish engineers club I confirm that the usefulness of a spring is that the basic mechanism is to move some force along a large distance and not to store elastic energy in the rod which is supposed to be feed back into the line.
Many times the question comes up to know whether using a spring is minimizing the amount of energy a caster has to use, but we have to recognize that we engineers are failing to convince readers this is real. In fact we are relying to our (good) models but suspicion is the rule. The lock up comes from the fact that readers are not accustomed to physics laws and this makes the dialogue very difficult. At the end of the day there is no miracle: the caster has to provide the energy that will be nicely provided to the line by a smartly designed fly rod.
We are not discouraged (in both camps) so we encourage Aitor to test his concept until we can get a visible evidence of what the engineers’ club is arguing about; and what the “I believe what I see” club is convinced about.
I may be provocative in suggesting to Paul that any contesting argument which appears to be wrong should entitle its creator to give some money for a good cause supported by the SL forum. Not sure this is a good idea; it may dry up the discussions…
Aitor, we rely on your willingness to succeed in making your experiment real. We are ready to help you for the design and wish you all the best.
Now I have some doubt coming to my mind: even if Aitor can demonstrate the usefulness of a spring in casting, how many people will believe this is true? I may well have a too much tortuous mind...
Merlin