9 replies to this topic
Posted 30 June 2008 - 05:30 AM
I just want to know what do different bibs do?
For example: A square bib will dive deeper than a round bib but a square bib will decrease the lure's wobble.
Posted 30 June 2008 - 06:03 AM
check out past threads. theres a wealth of info on this board. probably the most inventive folks on the planet.
Posted 30 June 2008 - 06:20 AM
WyldOne. First off welcome to TU. Next, congratulations on your question, a very good one. However, I feel you may be just as confused after getting all your answers, as it is a subject that many builders have differing opinions. So here I am just going to give you my humble opinions.
You first need to understand how the lip (bib) works to give the lure its movement or action. Rather than irritate everyone with technical explanations, here is a link to Wikipedia that explains vortex shedding very clearly.
The link shows vortex shedding behind a cylinder. The same happens behind a flat plate, only more forces are generated. Vortex shedding only happens on two sides of the lip. These are the vertical edges, as vortices are affected by gravity and prefer to turn in the vertical. So the bottom (horizontal) edge of the lip, be it flat, fan shaped, or coffin shaped, has little effect on the action. A round bottomed lip will show slightly more action, purely because the vortex has more edge to work with.
As for dive depth, it is accepted that steep angled lips result in a shallow swim and shallow lips are used if you want a deep diver. I personally do not believe that the shape of the lip has that much affect on dive depth, but I am sure lots of members will jump in here with contrary views.
Diving is all about the balance between the lip in front of the line tie and the body behind the line tie. Forces on the lip rotate the lure forward or nose down, forces on the body rotate the lure to the rear or nose up. When the lure moves through the water, these two forces reach a balance and this determines at what angle the lure swims. Too much lip and the lure swims too steep, too little and the lure will swim very flat.
If the angle is too steep, the lip will be close to vertical. The forces on the lip will be almost horizontal and will not provide any down force. The lure will have a really heavy, thumping action, but may only dive a few feet, indeed if it doesn’t roll over.
If the lure angle is too shallow, the lip will be at a shallow angle and the forces will be downwards. But again, even though the lip forces are pointing downwards, the lure will not dive, because at a shallow angle, the lip is not catching much water and therefore the down forces are greatly reduced. So there is an optimum setting, which, it pains me to say, can only be found by trial and error.
To get maximum dive depth, you will have to play around with either the eye position and/or the lip length, to find that optimum balance that will give you the dive you are looking for. I reiterate, these are only my views. Search through some of Skeeters early posts, he explains his views on the purpose of the different lip shapes and is a very good read.
Here's a couple more useful TU threads on the subject:
Edited by Vodkaman, 30 June 2008 - 07:17 AM.
Posted 30 June 2008 - 10:29 PM
Read Vodkaman's links and then take a look at some successful commercial crankbaits to give yourself more insight into lip design. Shadraps have long narrow lips that give them a tight wiggle and some body roll. A DT-16 has a wide lip relative to its body and has a wide wiggle and not much body roll. Many commercial crankbaits undergo lots of testing and tweaking before they go into production, so looking at their design can give you a headstart. Look at the length of the lip versus the body of the crankbait, the lip width vs the body width, the angle of the lip indexed from a line from the nose of the bait to the middle of the tail hanger. On baits where the line tie is out on the lip, the distance from the nose to the line tie and from the line tie to the end of the lip are important. Line ties closer to the nose of the bait tend to give a tighter wiggle. Too close and the bait loses stability. To far out and the bait loses action. An "average" lip typically has the line tie at about 40-45% of the distance from the nose to the end of the lip. Crankbaits are complicated little hydrodynamic systems. Change anything on the lip or the body and it affects everything else. So lips can't be considered in isolation - you have to consider everything together. The fore-aft balance point of the crankbait and the overall weight are also critical factors. Evaluating successful crankbaits is a shortcut but it still takes work and experimentation to get where you want to go.
Posted 01 July 2008 - 12:10 AM
Good points Bob.
Please do not be put off by the apparent complications above. I can't help the way I explain things.
At the end of the day, just build something and swim it. If it does not work how you wanted it to, post pictures and give as much information as possible about what you have built, then TU will do its job and help you correct the problem. Despite all the technical knowledge, you really have to build a few, to gain understanding. Then the more technical posts may start to make sense (or not).
Posted 01 July 2008 - 03:48 AM
If you do a search, (and have heaps of time) there is a link somewhere in here to an article by 'someone' about all the idiosyncrasies of various lips. Sorry I cannot supply you with the link, I usually keep them filed, but can't find it. Try searching 'Lip shape' and see what comes up, it was at least 6 months back. Also sorry I cannot remember his name, getting old. My apologies. pete
Posted 01 July 2008 - 11:59 AM
Good lord guys...you are going to scare him with all this Vortex shredding terminology!
Posted 01 July 2008 - 06:26 PM
C'mon, I did appologise and give him some links! I'm going to work to sulk now.
Posted 01 July 2008 - 06:40 PM
Vortex shedding!!! I'm surprised the moderators let that slip through!
Posted 01 July 2008 - 06:44 PM
I have a bunch different shape lips i use for testing, I just keep switching them till i find the right match. Of course it helps having a large built in swimming pool in the backyard for testing and tuning. But then theres always one of my idiot friends that stops by while I'm tuning a lure and shouts out "catching any thing" and I'm like " no, but stand still while I try A hook set test you moron!".