Jump to content

Leaderboard

Popular Content

Showing content with the highest reputation on 03/09/2019 in all areas

  1. This article offers up a hypothesis (unproven theory) of a triple point in fishing lure design that will result in the most erratic action usually associated with ‘hunting’, a zigzag motion, often observed in lures when retrieved at just the right speed. It is a complex and technical article, and as with a lot of my stuff; a difficult read. If you don’t understand any of it then ask questions, but don’t knock it, I am doing my best. Triple point is most commonly known in the field of metallurgy; a particular combination of variables such as temperature, pressure etc. that enables a metal to pass from a solid to a gas directly, totally skipping the liquid phase. The three forms; solid, liquid and gas all occur at the same point, hence triple point. I believe that there is a similar point in lure design. The variables that control this ‘triple point’ are the same variables that we adjust when designing any crank-bait lure; lip length, lip width, tow eye position, body shape, ballast location in ‘X’ direction (length), ballast location in ‘Z’ direction (depth). Buoyancy of body material and hardware location also play their respective parts as always. Also playing its part in the search for the ‘triple point’ is ‘resonant frequency’. Regular hunting – I published the theory of hunting 9th April 2017 ‘Hunting Cranks - Theory, Design and Build’. Here I outlined what is happening when a lure hunts and how to achieve this condition. You could refer to the point at which hunting occurs as a transition point between pitch (porpoising) and yaw (waggle). But this is not entirely true. It is simply the point when the swimming lip angle reaches/passes 90 degrees to the water flow, at which point the lure stops waggling and starts to porpoise. The transition is where waggle and porpoising are mixed together. This condition is easily achieved simply by making the lip too long and trimming back until the lure just starts to waggle. The transition is not a precise point. The position through this ‘transition’ that you trim the lip to, will determine the qualities of the hunt; slow wide hunt through to rapid shallow hunt. Back in 2007 when I first started working on the hunting project, I did stumble upon the triple point totally by accident. I can only describe the action as wild. Unfortunately the lure was butchered by me to make another adjustment, but I was unable to reproduce the action. At that time, I had not discovered what was actually causing the hunt, let alone the triple point. I had theories that turned out to be partially correct, namely the transition between pitch and yaw. After seeing the ‘wild’ action, I also speculated on the triple point, but was unable to figure it out for a build. Ironically, I had stumbled upon a lure with a slow ‘S’ motion rather than a waggle when experimenting with some weird designs. I didn’t figure out was going on, what was causing this lazy ‘S’ motion until yesterday. Actually not a transition like I suspected, but caused by resonant frequency. Resonant Frequency (RF) – this is what causes panels to vibrate on your vehicle when it travels at a certain speed, causing that irritating ‘buzz’ that you can never quite locate. RF is also what keeps architects awake at night. RF can cause buildings and bridges to collapse. One of the most famous incidents involving RF was the Tacoma bridge disaster. The frequency of the lure, the speed at which it waggles, is determined by the speed at which the alternating vortices form behind the lip, controlled by the width of the lip. A narrow lip produces faster alternating vortices, a wider lip produces slower vortices. The ability of the lure to roll is controlled by the ballast ‘Z’ location (height). To understand roll, think of a pendulum, a swinging weight on the end of a piece of string. The longer the piece of string, the slower the pendulum swings. The string can be shortened so that the roll period (back and forth time) is extremely fast. The ideal length of the piece of string is that which gives a pendulum period equal to that of the lip vortices. This ideal pendulum speed is called the resonant frequency of the lure, and will give the best waggle/roll combination. At resonant frequency the roll and the waggle enhance each other, and this causes the lure to ‘blow out’, so not ideal after all. As the length of the hypothetical string increases from the ideal length, the ability of the lure to roll is in conflict with the vortex speed, thus the lure roll is inhibited. There comes a point where the vortex period is 3X the roll period. At this point, the roll and the vortices are in line with each other again, and resonant frequency is once again achieved. But this time the roll period is 1/3rd the period of the RF ‘blow-out’ frequency. It is at this point that I believe the wild action occurs, when the period of the zigzag aligns exactly with the 1/3rd RF of the roll. My next step is to prototype for this ‘S’ motion. I must then combine this with the regular hunt geometry. This combination should give me the ‘wild’ action that I witnessed all those years ago. This combination of geometry I would refer to as the ‘Triple point Hunt’, a combination of the tuned pitch/yaw transition with the 1/3rd RF of the roll. And so, although Mark Poulson was correct when he said that he suspected ballast height may well be the trigger to cause an erratic hunt, the solution is actually to lower the ballast to find the 1/3rd RF, or even lower to find the 1/5th RF. However, this is not enough. The position in the pitch/roll transition must also be tuned to the 1/3rd RF. Once this balance has been achieved, the width of the zigzag will be enhanced by the 1/3rd RF roll, the roll will be enhanced by the vortex waggle, and the lure will really start to dance. My intention is to build a prototype with an adjustable ballast, to tune in to the 1/3rd RF roll, and find the best ‘S’ motion. I will then adjust the lip length to match the hunting zigzag period with the 1/3rd RF roll. This should result in the ‘wild’ action of the Triple Point Hunter. Once the wild hunt is found, a body can be designed to contain the ballast. This is probably going to result in a lot more prototype attempts and a rather weird looking body. Actually, when all the relevant periods are perfectly aligned, a wide, regular hunt should result, but if the periods are close and not perfectly aligned, then a wild, irregular motion should result. As with such a build, such precise alignment would be difficult, and so the wild action will be the most likely outcome. From what I remember of the ‘S’ swimming prototype, there was no visible waggle, just the pure ‘S’ motion. In theory, if the periods are perfectly tuned, there should be a visible waggle 3X faster than the ‘S’ motion. More possibilities will be available by tuning to different harmonics; The lip waggle is the first RF harmonic, the pitch/yaw could be tuned to the third RF harmonic, and the ‘S’ motion tuned to the 5th RF harmonic. This would produce a really weird swimming action, but first thing’s first, let’s not get too far ahead of ourselves. Thinking about it, what I saw all those years ago, may well have been this 1/3/5 harmonic triple point hunt. Dave
    1 point
  2. VodkaMan, this is my first post but i have been scouring the hardbait forums for quitesome time now and I greatly appreciate all the effort you put into the information you share with us all here! I have like so many others here grown very addicted to building and painting crankbait's and jerkbait's! Thanks to you and this forum I have been able to build some pretty successful lures and when I am experimenting with new ideas and can't quite figure something out I can reference these forums and usually always find the answer. Thanks again, Jesse
    1 point
  3. shooting candys is all about the base.
    1 point
×
×
  • Create New...
Top