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Vodkaman

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Vodkaman last won the day on September 18

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  1. Can you try it now and let me know if it works. YouTube have made changes and messed up the permissions. Dave
  2. Here is the Big Ed video. If you require anything else, quote the page number and the post number on that page. I'll do my best to help. Dave
  3. Yes. Vortices always want to be vertical, there is a reason for this but I cannot remember. tornadoes are formed by a horizontal vortex switching to vertical. So, if you provide a square(ish) boot then the vortices will form on the sides. Be prepared to experiment and prototype more variations. Shoot video and study the swim in slow motion. If the tail flips/twists as in the Shafteez video then you may have to reverse the tail. The rounder body may give you problems, but good luck with it. Always best to change one feature at a time or you will not learn what works and what doesn't. Dave
  4. Correct, the reason being; Injecting polycarbonate or any other material as used in the technique for smaller baits does not work for larger baits. The material thickness required to get the buoyancy right, will result in sink holes and an extended material cooling time. So, for large baits, dense foams are the way to go. Dave
  5. Very good thinking Mark. I cannot reply with any conviction. My first instinct is that the extension would allow the tail to rotate further until the resistance from the body trying to rotate stopped the tail and the vortex reversed. So, the result would be the tail traveled further but the body would still rotate the same amount. But, all of this discussion is highly hypothetical, unproven conjecture, just me applying what I have learned about vortices. But, if ever I was to design a paddle tail, this post would be high on my considerations list. Dave
  6. I have given this problem some thought. I get my best ideas in sleep and this problem just gave me a rude awakening. Theory - If you tow a round plate behind a swivel then it will rotate in one direction infinitely. The reason being is that the single vortex is continually propagating as it advances around the disk, the vortex never finishes and thus vortex shedding never occurs to cause the vortex to reverse. The Shafteez video above is very enlightening. First notice that the tail is rotating back and forth over the back of the lure rather than underneath the lure as designed. From the start of the swim, the lure tail is rotated through 180° before the alternating action even starts. This means that the bait is already loaded heavily from one side only with a 180° twist, and this loading causes the lure to swim on its side. Even though the tail shape is close to circular, the vortex is terminated when the tail section reaches the limit of twist. A new vortex forms on the opposite side and the tail twists in the opposite direction. I cannot explain everything because the action changes with speed. At very slow speeds, the tail swims under the bait as designed. At medium speeds, the tail swims in a figure-8 shape. At higher speeds the tail twists 180° and swims above the lure. To stop the rotation, you have to abandon the circle lip and adopt a shape that naturally causes the vortex to shed and initiate a vortex reversal. This shape involves an inverted ‘V’ shape with straight edges, a bit like the front lip of a hard bait lure. If you want to troll a circle tail at the higher speed then reverse the tail design; point the tail up rather than the normal down, this will cure the lure swimming on its side. Y’all know that explaining is not my thing and I have given you some heavy explanations to think about, explanations that basically say that you have been designing paddle-tails wrong all your lives. I suggest that you study the Shadteez and any other paddle-tail swim videos very closely and make up your own minds. Some of you are not going to like this post, particularly as I don't do soft plastics. That is too bad. Dave
  7. Photos and a video would be very useful, as your description offers us little to go on. You may be concerned about offering photos, but this is a perfect case were photos are justified. BUT, we really need a video of what is going on in the water. Dave
  8. This sounds like a paint dipped tooth brush solution. Draw your thumbnail across the loaded bristles and make a mess. BUT, I have not painted since school, and very badly then. Dave
  9. Good luck, hope your stress levels are not too high Dave
  10. As for Strouhal number, you have to figure out the value of 'S' to apply to the equation. The value I came up with was S=0.12 but this was before video and so not accurate. Video is your friend as the cycles are too fast to count and operate a timer at the same time. 'S' is a function of lip width, distance and time. Once you have a value for 'S', you can apply this to different widths to calculate the new frequency, or the retrieval speed to achieve a specific frequency. If you do a TU search for Strouhal, I am sure I have posted about this before. Dave
  11. OK, I was starting to think that you were some scientist come here for amusement. An easy mistake to make is to think of vortices as separate from the rest of the water. The water and all the disturbances like turbulence, vortices, displacement, laminar flow and static, all interact with each other, think of it as a complete system. A predator say one meter away is sensing all the disturbance coming from the lure; the result of the body movement, the disturbance caused by the vortices. Among all that chaotic noise is the pulse of something alive. Place a mirror in a bath tub of water, and drag your finger or any object over, you will clearly see all the micro pressure changes. Run a knife blade and see the vortices, they are clearly visible but not as clear as the theoretical diagrams would have you believe. Dave
  12. I used sound/ears as an analogy. The lateral line senses minute changes in water pressure. The lure's movement disturbs the water causing minute changes in pressure. The fish senses these pressure changes and I would guess creates a perception of what is causing the disturbance. You have obviously read up on the subject, so I am mystified by your confusion. I could try and explain more but I would only be repeating myself. To control the frequency of the lure movement, look into the Strouhal equation. I use this to select my lip width to achieve my required frequency. Dave
  13. As I understand the subject, the lateral line is the fish's ears, a row of sensitive pressure sensors along each side of the fish's body. Just like with our hearing were not only can we hear sounds, but with an ear on each side of our head, we can tell roughly where the sound is coming from. When a fish moves through the water, it is pushing and pulling at the water making pressure changes, just like when you shout, you set up pressure changes or waves in the air. those changes in pressure travel away from the source, gradually getting weaker until they dissolve away to nothing. it is the same in water except it is movement rather than sound. The vortex disturbance that our lure sends out create an image of something moving rhythmically through the water. An inanimate object would not send out such a sound wave, thus creating an image of something alive and possibly edible. Of course, the image may be the equivalent of a Keystone Cops video, but real enough to warrant further investigation. I hope this helps. Dave
  14. An error was found in the ‘lip’ section of the spreadsheet ‘TU wood lure calc’ I have sent emails to members who have received this spreadsheet in the last 6 months. If you have not received an email then message me with your email address and I will send you the updated file. Object of spreadsheet – To simplify the build of carved lures. To achieve the float/sink required without extensive trial and error. Apologies for any inconvenience. Dave
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