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Vodkaman

How do lips/bills work

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Mark - This is the theory behind it all. I don't know how significant the chamfer is, but the same goes for diving lures.

If you take a perfectly balanced and tuned diver and then add the chamfer, you will likely find that the lure is now out of wack. Because the vortices are stronger, the lip pulls down to a slightly deeper angle. If the tow eye was positioned for maximum depth then the lure will no longer hit that depth.

As for the lure getting down faster; yes, the slightly lower pressure behind the lip will pull down harder, making the lure dive faster.

Dave

Edited by Vodkaman
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Bass Shack - actually yes, but not for any of the reasons in my previous posts. In fact, I don't think this effect has been previously discussed.

I discovered the effect in my very early days of experiments but I cannot remember whether I posted it or not, I may have thought it too rudimentary to mention. Let's call it the 'lip/body funnel effect' as it describes what is going on.

As I only had a few hand tools, working on the draining board of my apartment in Sweden, I thought it unnecessary to cut a lip slot when you can just chamfer the nose at the required angle and simply glue the lip onto the face. Admittedly not a secure attachment, but perfect for prototyping. However, I discovered that the action of front mounted lip was significantly less than a slot mounted lip.

It did not take long to figure out that flow is trapped at the junction of the lip and the body, causing the flow to accelerate just like flow through a funnel. This increase in speed increases the action.

So, getting back to your point; I would say yes, a wider nose would increase the flow and generate a stronger vortex.

I believe there is a lure out there waiting to be invented by taking this effect to the next level. If you fancy some extrovert prototyping to explore the idea, be my guest. Just give me a mention when you crack it wide open :)

Dave

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5 hours ago, Vodkaman said:

Bass Shack - actually yes, but not for any of the reasons in my previous posts. In fact, I don't think this effect has been previously discussed.

I discovered the effect in my very early days of experiments but I cannot remember whether I posted it or not, I may have thought it too rudimentary to mention. Let's call it the 'lip/body funnel effect' as it describes what is going on.

As I only had a few hand tools, working on the draining board of my apartment in Sweden, I thought it unnecessary to cut a lip slot when you can just chamfer the nose at the required angle and simply glue the lip onto the face. Admittedly not a secure attachment, but perfect for prototyping. However, I discovered that the action of front mounted lip was significantly less than a slot mounted lip.

It did not take long to figure out that flow is trapped at the junction of the lip and the body, causing the flow to accelerate just like flow through a funnel. This increase in speed increases the action.

So, getting back to your point; I would say yes, a wider nose would increase the flow and generate a stronger vortex.

I believe there is a lure out there waiting to be invented by taking this effect to the next level. If you fancy some extrovert prototyping to explore the idea, be my guest. Just give me a mention when you crack it wide open :)

Dave

Dave,

The Yozuri rattle traps I used to fish had a "scooped" forehead, so I did the same thing when I made some shallow cranks, using a rat tail file to carve a channel up from the line tie to the back.

I did it because I thought it would make the bait more stable, and give it a tighter wiggle.

Is this right, or did I get it all wrong?

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Mark - a concave face, which is what you are talking about, is going to increase the vortex strength, a convex will reduce the action. As for '.....to the back', I am not sure what a concave cut into the back of the lure would have.

I think it may have an effect on roll. I have just checked a few of my under water videos, and I think that a hollow feature down the back might reduce roll. I am thinking that it would have a similar but lesser effect of having a dorsal fin down the center of the lure.

To kill the roll would only require a short dorsal fin, say 5mm (3/16"). But again, as with all my stuff, this is theoretical, but it does fit.

Often it is difficult to see what effect, if any, such features have. I am thinking back to my 'various lips' video, were I compared round, square, coffin and shaped lips. It was very difficult to see any difference between round and square, also coffin and shaped. Likewise, your concave back will be a subtle effect.

In order to confirm an effect, you have to exaggerate the feature; a wide shaped body with an exaggerated concave back, directly comparing with the exact shaped body with a rounded back. And then, you may need close video, preferably submerged, head on, to observe the difference if it is too subtle, but if the effect is too subtle when exaggerated then then there is hardly any point in taking it further. Who knows, there may be another new idea waiting to be discovered.

Whether roll is a good or a bad thing, I do not know. What I do know; is that fish do not roll when they swim. Personally; I do not like roll, but I know other very experienced builders do.

So, after pouring my thoughts out, getting back to your point; I think more action due to the concave front end, and a more stable swim (less roll) due to the concave back. Boy I wish I had my workshop and a test tank, I would be out there right now. carving up a bunch of test lures, to test this idea and the lip/body funnel effect.

I hope someone takes on these ideas and comes back with a report. BUT, they re only ideas, they not pan out.

Of course, rattle traps swim back first, and so the whole of the back length is effectively the lip.

Dave

Edited by Vodkaman
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On 1/27/2019 at 6:21 AM, Vodkaman said:

Mark - a concave face, which is what you are talking about, is going to increase the vortex strength, a convex will reduce the action. As for '.....to the back', I am not sure what a concave cut into the back of the lure would have.

I think it may have an effect on roll. I have just checked a few of my under water videos, and I think that a hollow feature down the back might reduce roll. I am thinking that it would have a similar but lesser effect of having a dorsal fin down the center of the lure.

To kill the roll would only require a short dorsal fin, say 5mm (3/16"). But again, as with all my stuff, this is theoretical, but it does fit.

Often it is difficult to see what effect, if any, such features have. I am thinking back to my 'various lips' video, were I compared round, square, coffin and shaped lips. It was very difficult to see any difference between round and square, also coffin and shaped. Likewise, your concave back will be a subtle effect.

In order to confirm an effect, you have to exaggerate the feature; a wide shaped body with an exaggerated concave back, directly comparing with the exact shaped body with a rounded back. And then, you may need close video, preferably submerged, head on, to observe the difference if it is too subtle, but if the effect is too subtle when exaggerated then then there is hardly any point in taking it further. Who knows, there may be another new idea waiting to be discovered.

Whether roll is a good or a bad thing, I do not know. What I do know; is that fish do not roll when they swim. Personally; I do not like roll, but I know other very experienced builders do.

So, after pouring my thoughts out, getting back to your point; I think more action due to the concave front end, and a more stable swim (less roll) due to the concave back. Boy I wish I had my workshop and a test tank, I would be out there right now. carving up a bunch of test lures, to test this idea and the lip/body funnel effect.

I hope someone takes on these ideas and comes back with a report. BUT, they re only ideas, they not pan out.

Of course, rattle traps swim back first, and so the whole of the back length is effectively the lip.

Dave

 

Great post Dave, as always they suck me in, especially anything related to your favorite, "Street Vortices".

If anyone wants to play with this (I do often), after dinner get your black fry pan (the bigger the better), 2/3 fill it with a mixture of water and some detergent and heat it to just below boiling and the detergent will make a thin white foam on top of the water.

Now get your square edged (or round, or coffin shaped) lips and slowly drag them slowly across the pan and see, wonder of wonders ''Street Vertices'' or whatever you want to create, an egg flip works good.

Mark-  I have been playing with concave/convex lips for years and rarely use a flat lip, also have been using rear bibs (horizontal). In the past year or so I have graduated to a concave top on a lot of my lures, I have  had some success and some failures but I am thinking this is probably a weight issue.

It's all worth pursuing, I will try and scrounge up some lure pictures and post them in the next few days.

 Thanks again Dave.

Pete

 

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Good comments Pete. I was thinking of you when I wrote about the concave lips thing. If anyone wants to experiment with curved lips, Pete wrote a super article on the manufacture of a tool for bending polycarbonate sheet.

One of my tricks for visualizing vortices; a mirror placed on the bottom of the water container.

Dave

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Very interesting read! I missed when this was originally posted.   I have a large musky crankbait that I designed for shallow use but when I tried it out, the action was minimal.  Note to self, when prototyping a lure, make the lip oversize so it can be paired down to optimal size.  The lip was too small in my case (and thick) to produce the action I was hoping.  But after reading this I think I can cut a chamfer in the backside of the lip to see if this will increase the action.  And if that is not enough, I could even sand away the face of the lip producing a concave shape.  I will experiment with it and see if I can get it useable! As always Dave, excellent research and information on a very complex topic.

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Back when I was playing around with moving ballast I made three "identical" crankbaits, using an already successful design.  All of those had a concave forehead, leading to the back (I misspoke when I said concave back) .  They had a tight Xing (wiggle) and ran down to 6'+-.  Without the concave the same bait would only run down 4'+-.  The moveable ballast was at the kill spot.  The higher the ballast, the more erratic the bait would act on the retrieve (hunting).

 

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I saw a lure entered for the competition, with the concave under the chin down to the belly. I thought this was an interesting idea that I would like to try. The body was a weird shape in order for the concave to catch the water.

I have an idea for a very small crank, lipless but with a rear concave. could be as short at 3/4" body. A smooth rounded nose with the vortices forming into the rear concave hollow. This would give a very fast waggle, more a vibration. With the single hook treble coming out the back, this would make a rattle sound. This is in my head, inspired by the conversations above, nothing down on paper yet. I need to model it up on CAD to see what it looks like, basically a swimming lip with a nose attached. I will post when modeled.

Dave

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OK, I dug up some old and a few new attempts with convex and concave lips.

As we know there can be a lot of variables in action and depth with just one lip shape- I wonder why it's not used a lot more

''Text'' is on each photo, just in case I can't post this many pictures here  -----hope this is legal, otherwise I will post them in my attachments, or somewhere??

Pete

**** SORRY, pic's 4 and 5 should read ''Concave Lip"

Shovelhead 13.JPG

Convex front view.JPG

shovelhead 2.JPG

Shrimp2.JPG

Shrimp1.JPG

Convex w snagless hook 1.JPG

Convex Par Trout 1.JPG

Edited by hazmail
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On 2/24/2019 at 11:57 PM, hazmail said:

 

OK, I dug up some old and a few new attempts with convex and concave lips.

As we know there can be a lot of variables in action and depth with just one lip shape- I wonder why it's not used a lot more

''Text'' is on each photo, just in case I can't post this many pictures here  -----hope this is legal, otherwise I will post them in my attachments, or somewhere??

Pete

**** SORRY, pic's 4 and 5 should read ''Concave Lip"

Shovelhead 13.JPG

Convex front view.JPG

shovelhead 2.JPG

Shrimp2.JPG

Shrimp1.JPG

Convex w snagless hook 1.JPG

Convex Par Trout 1.JPG

Beautiful lures!  You really do have this stuff mastered.

Would those work up here in the US, or would they swim upside down?  

 

 

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On 4/24/2019 at 3:36 AM, mark poulson said:

Beautiful lures!  You really do have this stuff mastered.

Would those work up here in the US, or would they swim upside down?  

 

 

Thanks Mark :lol: I hope so!! :oooh:

Sorry, I got a bit carried away above, (there is a lot of years there)- I was trying to demonstrate how with one curved lip, and the same or a similar blank you can have so many options in depth and action--a lot of people don't seem to get it though.:yay:

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So this would be the big reason that a wake bait has a near vertical lip.  One experiment I did a few years ago was to take a standard square bill lure and heat the lip.  Once heated I would bend it to a vertical and it would gain tremendous tail action.  When I did that I never understood why but now I do.  Boy this has me thinking

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Thank you for sharing the great idea, Dave.

I'd like to add a small one to yours.

First, thin circuit board lips are more flexible than the thick lexan lips.

So, when we retrieve a crankbait, the thin circuit board lip is twisted to one side (right or left) by the pressure of the water.

Then the twist of the lip turns back to the original state, and ths moves the crankbait waggle faster.

This process will occur continuously every times the crankbait swim to one side (right or left). 

 Sorry for my long absence and poor English. 

IMG_5253.JPG

IMG_5252.JPG

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