Elaborate on mathematical modeling of lures IMO…..
, Dec 20 2007 01:38 PM
26 replies to this topic
Posted 24 December 2007 - 03:13 AM
I'm not sure what this topic will bring about, but i think most will find it interesting to some degree.
ok,ok.... i originaly posed this question to the forum. it brought alot of mixed feelings. tons of debate. i think allot of old school builders were somewhat against this concept. with a simple model it might be possible to design all the theoretical ideal balances of bill shape to body. my interest was not to perfectly model all the aspects of fluid dynamics, or taking acount of surface drag differences(between different paints or textures). instead i think that if as many of these varriables are removed and distilled into a simple function then we could explore/understand that say for every body length and body height we have set ideal lips that will produce the absolute theoretical maximum/and or ideal wobble. many people previously believed that there are too many varriables that affect lure motion. while many things may affect it, i still believe that a distilied grand unification(simplification) theory is possible in the universe of lure building. this holy grail of formulas would greatly help and accelerate many peoples understanding of lure design.
finaly. i would mention that i have recently come apon the realization that each lure probably has an optimal speed that it will occelate maximaly at. that said, i think that i can roughly mentaly see, that as the lure gets bigger and bigger the running speed must get progressively faster to produce the affect of wobbling.
now at least if nothing else a simple formula could be written that could be used to estimate lure size based on the speed that the target species typicaly chases it prey.
but again, my original interest was to graphicaly show all the optimal lip shape and size in relation to the length of the lures. we are just on the verge of this simple function being openly understod.
Posted 24 December 2007 - 05:06 AM
Goldenshiner. That was one of the great threads, at least in my lowly opinion, but I would say that, I am left brained!
I am in total agreement with you on all your points above. If people are not interested in the technical discussion, they should step aside and let those that are get on with it, everyone has a choice. I firmly believe that if you have nothing positive to say then say nothing.
Yes, there are a lot of variables to take into consideration. But, as we are not trying to nail the solution to the milligram, I believe many of them can be side stepped and we should concentrte on the biggies, namely: lip geometry, eye location, ballast location and body shape.
It is a daunting task to deal with even just these four at once, but it is possible to nail three and vary the fourth, in fact this is the standard procedure for prototype testing. You only change one thing at a time, otherwise you don't know which adjustment worked and you have to go back twice more to find out. Patience is the name of the game.
When I joined TU
, it was my intention to create a spreadsheet to do exactly as you stated. Enter your lures parameters and it will tell you the result. I tried for a while and will probably return to it some time in the future, but I am more of the opinion that it is sufficient to just understand how everything works, to design a new lure from scratch.
Yes, the calculations are complex and require a fast computer, days to run a simulation. But I believe that an approximation is possible, like we said, we are only looking for a rough guide.
But, before I could calculate anything, I had to find out exactly how everything works. This too has been a real trial. I feel that I am close to understanding the major principals, but not absolutely confident. Unfortunately, the learning curve has now kicked in. All the testing that I have done has given me an instinct for a lure, I can usually tell how it is going to behave in the water.
But the whole point of this exercise was to help the newcommer to the addiction and try to minimise the learning curve. This is the part that dissjointed a few noses, "why should anyone get my hard earned knowledge on a plate"? Well, if anyone has that selfish opinion, then tough, because that is my intention, to put it on a plate, for new members and hopefully enough to enhance the knowledge of a few of the more experienced builders. As I work out little parts of the puzzle, I will continue to post them for debate. This process is a good way to test the theories, as all the theories should work together for every case, for all baits, hard, soft, lipped, lipless etc.
Well enough soapbox. As for your reference to the size and speed. Very simple calculations are available for this one. Do a web search on Strouhal number. Top of the page will be wikapedia. This pretty much covers it in a nutshell. While you are there, look up vortex shedding and Karman vortex street. This covers all the lip theory. Having read these subjects, designing new lures is just a matter of interpretation and application of these principles.
Anyone else have any ideas or theories? Publish or be damned I say, bring it on!
Posted 24 December 2007 - 10:19 AM
My theory is that I can understand what you guys say when I read it, but it vaporizes from my mind the minute I turn the computer off! Probably due to some vortex in the back of my head.
But it's fun reading what you write.
Posted 24 December 2007 - 12:37 PM
In my messed up right brained head, I really do find that I consider lure making to be more "art" than "science" and tend to use a "gut" feeling when I set out to catch a particular species of fish or consider if a given lure will catch them. When I was growing up my attempts at lure crafting centered around tying flies and streamers, trying to match nature and the “natural flow” of the hatch in the water.
As a kid, I used to lie on the dock with my little brother, staring into the water below. We’d play with fish, a few feet of fishing line, a hook, and some bait. We would do this for hours… Seeing how a yellow perch would suspend under the dock in the shadows, watching the minnows just inches away. The predator and the prey would maneuver just enough to maintain position, trying not be seen the one another. As this game of life builds, there is a quick, sudden flash of movement and a fraction of a second later, only the perch remains. We would also experiment with different baits, things like corn, hot dogs, worms, bugs, anything we could our sticky little fingers on would likely end up on that hook. We would watch and repeat this process over and over to study the effects in detail.
In my heart, the idea of developing a model formula for specific lure types makes perfect sense. I can see how a formula to compute depth, wiggle, distance, etc., can establish “fixed” variables to a standard equation. However, when I apply my goofy, right brain tendencies, that I’ll refer to as the “spike-a-pike” factor (or “SAP” factor for short), the fixed variables quickly fall out of equation.
Will I twitch the “perfect lure” 2 inches or 2 feet? Do I leave it settle in the water until it’s perfectly still or do begin to retrieve with a sharp pull on my pole, getting the lure to a depth of 2 feet; suspend the lure completely still for a second, rip it a few feet, stop, suspend, rip, repeat… This “SAP” factor is my feeble attempt of applying the elements I watched dock side 40 plus years ago into each lure I touch.
As a mechanic, I could bolt a jet engine onto a test stand. If it was a “new” engine, fresh from build up, the first step was to assess the current condition of that engine. Was anything loose or missing? It had to meet a set specification before we would ever attempt to spin the compressor. As we applied air to the turbine wheel, we would perform a detailed set of leak checks for JP-4, oil, and hydraulic fluid. Did the nozzle travel of the afterburner comply with the established measurements for “0” percent and “100” percent nozzle dimensions? Every aspect of a test cell run was to make absolutely positive that each engine was a perfect copy of the engineering spec and we’d bet the pilots lives that on that fact.
I just can’t apply an absolute engineering specification to a fishing lure when there are so many factors that aren’t absolute. We can make them all exact duplicates to zero deviation tolerance in size and weight, but, there is no absolute manner to ensure it will always be employed by other goofy right brained fools like me. The SAP factor happens.
Just more fodder to factor on that der slide rule ya’ all.
Merry Christams and thanks for making me think... Cheers
Posted 24 December 2007 - 01:53 PM
Bruce, a good response, I can live with that opinion, even agree. What I have a problem with is being told, "can't, it's too hard". Any solution is going to be an approximation or even statistically based. maybe using real feedback from testing prototypes and interpolating between cases. It will be a while before I consider tackling that one again, but I will, one day.
I too studied the fishies from a dock. My problem was I very rarely caught anything. One day I asked a guy fishing next to me, with a net full, what was I doing wrong. He took a time out and came over to my swim, took one look at my gear and told me the line was too thick, the fish can see it. There was a pier there. So I dropped a handful of maggots in. They never reached the bottom. I then lowered my loaded hook with another handful. Same happened again, except my hook maggot was not touched. Life changing experience. From that day on I slayed them, using 2lb line max. Some days, when the fish were difficult, I would go down to 3/4lb line with No24 spade hook.
So, when I joined TU
and found that you used 10lb line I was horrified! But, fishing lures is a very different game to bait fishing. I now enjoy both. Glad I got to exercise your mind.
Happy holidays to you all.
Posted 24 December 2007 - 08:03 PM
Well this kinda turned out to have some helpfull info!
I did make a lure the other day. My first so at her.
Not bad but a long way to go!!!!!!
I poster on here soon enough for you all to laugh at!
Posted 25 December 2007 - 12:04 AM
Applied physics tonight.
Christmas eve, neighbor is locked out of her house, key in lock turns but doesn't open the lock. After I tried to jiggle the key and the lock, checked for a window I could jimmy, removed the mail slot and snaked my arm up to the inside thumb turn and turned it, all to no avail, I applied physics.
I use my 20oz hammer and superbar, and pried the door open. Diagnosis, old pot metal lock keeper died of metal fatigue.
The equation for this is as follows:
When in doubt, get a bigger hammer.
Merry Christmas to all, and to all, a good night.