Drag Washer Friction Estimates

[Norcal Pescador]

WOW Now I'm completely in the dark. So is it better to have more surface? Say more cf washers or is there a tipping point where it becomes pointless.

Bob, all I can say is I get a lot more drag from reels with bigger washers and more of them....

[BMITCH]

Rob, enough said. Bigger is better. Now let's talk about the hex washers and their dual(both sides) being used. This would be more drag surface= bigger, right?

[Norcal Pescador]

Rob, enough said. Bigger is better. Now let's talk about the hex washers and their dual(both sides) being used. This would be more drag surface= bigger, right?

In my opinion...  but Jedi Sal knows more about "The Force" than I.


I think it's time to lock this thread. If someone else can devise a formula or program to calculate drag then that would be a benefit. It's just beyond me...

[Mandelstam]

http://answers.yahoo.com/question/index?qid=20070603182434AAxTKI2 - How does the surface area influence the sliding force of friction? Lets say I slide something on a smooth?

...This equation applies to both static and kinetic sliding friction. Static friction is the friction before an object starts to slide. Kinetic friction is the friction when the object is actually moving or sliding.

Static friction and kinetic friction have different coefficient of friction values.

An interesting result of this equation is that in the case of sliding friction of hard surfaces, the friction is independent of the area of the surfaces. In other words, it is just as difficult to move a 1 square-cm object as a 1 square-meter object, if they both are pressed to the surface with the same amount of force.

This is not intuitive. You would think that there is more friction when the surfaces are larger, but the friction equation states otherwise. You can verify this fact with experiments.

In situations where the surfaces deform or there is molecular adhesion, the friction is not independent of the areas in contact. In these cases surface area usually comes into play. This is also true for rolling and fluid friction.

When solid surfaces are soft and deform or when one material is a fluid, the shape of the solid object may be a factor.

Although the standard friction equation still holds, the coefficient of friction may have area, shape and other factors included in it."


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I think this is beyond me to fully apply to our greased drag washers, but interesting read none the less...

/Karl

[Robert Janssen]

We discussed this a bit last year.

http://alantani.com/index.php?topic=4593

[Robert Janssen]

Norcal Pescador, your thoughts and calculations are not without merit, even if the formulas themselves are a bit out of whack. As someone else mentioned, if seen only for their comparative values, it still makes some sense. So if you stop quantifying things in terms of millimeters and pounds, and instead describe them as say, The NP Factor, their relationship still carries a comparative value. Sort of.

HOWEVER,

and much to the disappointment of many i'm sure, there is a much easier method of thought. In the example of a given reel with say four drag washers known to make sixteen pounds of drag, each washer is worth four pounds, because 16 / 4 = 4.

Adding another washer would make twenty pounds.

That's all.

Sorry.

.

[Norcal Pescador]

..... In the example of a given reel with say four drag washers known to make sixteen pounds of drag, each washer is worth four pounds, because 16 / 4 = 4.

Adding another washer would make twenty pounds.

That's all.

Sorry.

That is where all of this started. I have reels that give a certain amount of drag. Reels that have similar-sized drag washers give similar results. Using the example you gave of 16 / 4 = 4, I grouped washers with similar surface area to give similar values and then tried to create a formula to fit my "findings".

As the carnival hawker would say, "Close, but no cigar."

[Ron Jones]

and much to the disappointment of many i'm sure, there is a much easier method of thought. In the example of a given reel with say four drag washers known to make sixteen pounds of drag, each washer is worth four pounds, because 16 / 4 = 4.

Adding another washer would make twenty pounds.

That's all.

Sorry.

First, drag disks are normally installed in odd numbers 3-5-7. What you are saying is absolutly true. But it does not mean that 5 big washers produce more drag than 5 small washers. That depends on how much force you can put on the washers and how much surface area that force is applied over.

I guess we also need to talk about what we are calling drag. I (and I think everyone here) considers drag the force required to pull line off the spool when the star is set at a specific position. If that is the definition we are going with then the diameter of the spool and the gear ratio has to be taken into consideration. Not as much as the disks maybe but definatly thought about. For instance, if we took a 500 and connected a spring scale to the line and adjusted the drag to where no more line could be pulled out when the scale reads 12 pounds and then took the same drag/gear trane and put it in a 112h at the same setting the spool would pay out line because of the increased mechanical advantage of the larger spool. So the disks are seeing the same force from the star but the effective drag is different. Swapping in a set of 5:1 gears would change things also.

Ron

[Robert Janssen]

Yes, we chatted about that and some other stuff earlier this year.

http://alantani.com/index.php?topic=6203.msg52156;topicseen#msg52156

.

[Norcal Pescador]

First, drag disks are normally installed in odd numbers 3-5-7. .......

Unless you're talking keyed washers like the 113HN (4) or hex washers.

[Makule]

I'm puzzled.  What, exactly, are you trying to figure out? 

For example, if you have four washers and get 10 pounds of drag, adding one more will give you 12.5 pounds, everything else being equal.  You find out how much drag comes out with the 4 washers by actual measuring, in order to avoid the "confounding variables" that you have mentioned (e.g., reel mechanics, amount of force used to tighten, etc). 

It is possible to know the coefficient of friction of materials (there are charts for that), but knowing those numbers probably won't help you to find out what actually the result will be when pulling on a line from the spool (because of the variables you mentioned).  Yes, you could probably theoretically calculate some number, but it would be much faster, easier, and more accurate to just measure with a scale.

I launched on this project to make it easier to find out how much adding another washer or two to a drag stack will increase the expected drag. Remember this is an estimate. The reel mechanics, amount of force used to tighten the drag star, amount of grease applied to each washer, and other, unknown variables may affect outcomes.

[Ron Jones]

The data would be beneficial for shopping and modifying reels. For instance, would it make sence to 5+1 a small reel to make a dynamite little powerhouse? If the surface area of the drags mattered then this chart would help give you some idea as to what to expect between say a 180 and a 146. However, A 180 and a 146 are about the same except for the gears and so the drag pressure would be pretty much identical. If surface area mattered then the 146 would have the advantage.

Ron

[Makule]

The data would be beneficial for shopping and modifying reels. For instance, would it make sence to 5+1 a small reel to make a dynamite little powerhouse? If the surface area of the drags mattered then this chart would help give you some idea as to what to expect between say a 180 and a 146. However, A 180 and a 146 are about the same except for the gears and so the drag pressure would be pretty much identical. If surface area mattered then the 146 would have the advantage.
Ron

This is what confuses me:  The size and number of drag disks, alone, do not determine final drag (i.e., line coming out of the reel).  As has been mentioned before, gear ratio plays an important part.  Thus, to say that the 180 and 146 are about the same except for gears, isn't very revealing since the change in gear ratio throws the whole thing out of whack.  Surface area does, in fact, have a great bearing on the outcome.  It's the other variables that is making all of this confusing.  Such things as gear ratio, diameter of spool, psi that can be applied to the disks, etc. all are different with different reels, and all of these factors affect the final drag (significantly).  This is why, unless one is talking about the differences between a Senator 114H using CF or not, or a 114H using 4 or 6 disks in a stack, it's not possible to determine what the effects will be (unless one is willing to do a lot of math, and then the comparison is only theoretical).  Trying to predict a 3 disk 114H based on a 6 disk 113H, based on diameter of drag disks alone, is not possible except, as I've said before, unless doing the engineering math.

[Ron Jones]

Surface area does, in fact, have a great bearing on the outcome

Makule, I'll let you argue with Mr. Comumb about that.



Ron