Drag Fade

Started by Rivverrat, November 20, 2016, 07:34:54 PM

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Alto Mare

Quote from: Tightlines666 on November 23, 2016, 11:35:13 PM
Quote from: Alto Mare on November 23, 2016, 10:09:03 PM
Let's not start swapping parts until we see a problem. I haven't run into any melted Delrin to date, some of my tests have been hard on the reel.

A while back Lee sent me some perforated keyed washer per my request, I decided to give them a shot...why not

Numbers were lower but only by 8 degree. Still, going in the right direction.
Keep in mind, my test here is short, maybe these numbers will make a difference when the fish goes for a run.

Sal


I am not saying we have seen problems with Delron melting, but there are numerous documented cases of the drags binding or getting frozen after heating up.  I myself have had a star become immovable on a 9/0 when the reel was getting spooled by a large Blue.  In this case the inability to back the drag off led to a line part.  There are also cases of stars cracking when the gear sleeve heats up and expands faster/more then the star.  I have seen this with aluminum stars and SS sleeves from local Ulua fishermen.  Drag fade is one issue, increased drag surginess is another, and the binding of drag components due is yet another possible problem related directly to heat.  In most cases both, these issues can usually be managed by the angler.

Don't get me wrong, I like and trust star drags, and the upgrades we have available have increased their performance significantly. 

Just exploring how to deal with the negative effects of heat on the reel, and asking if someday it might he possible to build an even better mouse trap.
John, on your last comment, of course, that's what we do here.
Our Jigmasters and 4/0's, are unmatched...we're not done yet.
Forget about all the reasons why something may not work. You only need to find one good reason why it will.

Shark Hunter

Quote from: Lowprofile on November 24, 2016, 04:59:31 AM
I haven't read through the whole thread but I can tell you from catching multiple Marlin on senator 12/0's with greased carbon fibers drags that after the initial run, taking 300-400yrds of line with around 35lbs of drag, the entire reel heats up, grease from The drags, the gears and anywhere else you might put it comes pouring out from under the handle and there is virtually no useable drag at that point. I always pour cold, fresh water over the reel to cool it down and get it to a point a customer can start reeling but it takes awhile for the drags to cool and when they do the reel is now putting out over 50lbs of drag and it takes adjustment. This is where the old saying of "my reel seized up" came from. Burned up drags that's finally cooled and the drag, due to the lack of line in the spool, was 3-4 times what it started out as and the reels or like couldn't handle it.

The drag inserts that have come from this site are great, especially for the 4/0 size reel because we can beef them up, throw on 80lb line and lock it down to 30lbs of drag and stop a fish from getting into the reef. The grease helps it cool after short hard runs and everything works like it's supposed to.

For lighter lines or fish that will take 3-400 yards of line we need to look at wider surface areas for drags, not just overall and air cool systems.
Chris,
I built you the 12/0 with the insert for this same reason. I think the outcome would be different
Life is Good!

Dr. Jekyll - AKA MeL B

#77
Quote from: Tightlines666 on November 23, 2016, 06:07:05 PM
The other option for dealing with excessive heat is to use ceramics.

Quantum claims that their drag system is "Magnum Carbon Fiber and Ceramic"  but as Alan Hawk discovered in his review of CABO 120 it's not true;

http://www.alanhawk.com/reviews/cbo14.html

Personally I have to dig/look deeper into this because I have the 60 and 80 PTSEs. Also in fairness to Quantum I had the KVD baitcaster, gave it to my ex-father in law, it has the ceramic washers.

seacane

I have no scientific basis for my theory, the following is strictly a personal observation!
Drag fade is the initial reaction when the drag begins to heat up. However, after a of period of continued heating, the drag washers act as a centrifuge with the lubricant being spun out the sides of the washers. When this action occurs the drag experiences what John termed as "surginess".
I think there is a third level which is reached on large/fast fish and that is when very little lubricant is left on the carbon fiber. Then the washers become glazed and ineffective.
This happens to all reels but the difference is in how much time before each level is reached.  Since surface area dissipates heat, a Penn 80 would take considerably longer to go through these stages than a Senator 4/0.

canoecaper

Clearly, brass is a better conduit of heat than either SS or Alloy.
The AFTCO upgrade uses a huge chromed brass star of noble thickness.
The matching handle blank also has a big disk area at the sleeve end, again of chromed brass.
Further down this route, SS bridge and sleeve will certainly be stronger but brass for the bridge and sleeve together with a bronze main will dissipate heat better.
Come to think of it, a bronze spool is a better bet too.  LOL.
Serious questions.
Could a SS gear be thin enough in the disk to accommodate an extra drag stack cycle?
With, after upgrade, drag washers being in contact with both the lower and the inner faces of the gear disk, does SS or bronze create the greater friction.
Should the coarse texture pattern or the fine texture pattern make contact with the bronze?
Presumably, with a SS gear, providing it is matt and clean, it doesn't matter.
Is there a sensible way of leaching heat from the bridge into the one piece frame?  Any way of strapping the bridge screws to the frame?

jurelometer

Quote from: canoecaper on November 27, 2016, 02:54:56 AM
Clearly, brass is a better conduit of heat than either SS or Alloy.
The AFTCO upgrade uses a huge chromed brass star of noble thickness.
The matching handle blank also has a big disk area at the sleeve end, again of chromed brass.
Further down this route, SS bridge and sleeve will certainly be stronger but brass for the bridge and sleeve together with a bronze main will dissipate heat better.
Come to think of it, a bronze spool is a better bet too.  LOL.
Serious questions.
Could a SS gear be thin enough in the disk to accommodate an extra drag stack cycle?
With, after upgrade, drag washers being in contact with both the lower and the inner faces of the gear disk, does SS or bronze create the greater friction.
Should the coarse texture pattern or the fine texture pattern make contact with the bronze?
Presumably, with a SS gear, providing it is matt and clean, it doesn't matter.
Is there a sensible way of leaching heat from the bridge into the one piece frame?  Any way of strapping the bridge screws to the frame?

If by "alloy" you mean aluminum, from what I have read,  alumium is a better conductor of heat than brass.  There is some small variation based on the alloys involved, but aluminum will still come out way ahead.  I put some of the numbers in reply 41 on this thread.   Also, from what I have read, while greater surface are will generally help transfer the heat,  thickness is generally an inhibitor.

The science around friction and heat transfer  is often non-intuitive,  and I am not claiming any sort of deep expertise, but there are some basic principles that might help us move forward on the discussion (any  physics experts out there, feel free to correct or clarify):

1.  The amount of slowing  that the drag is applying (how much force to turn the spool  and the amount of line pulled off the spool) determines the amount of heat that is generated.  More accurately, energy in the form of motion is being converted into  energy in the form of heat.  The design and materials of the drag does not change the amount of energy involved.

2.  When the drag settings and distance  reach the levels found in open water fishing (let's say over 8 lbs of drag and 100 yards of line taken),  the amount of energy being transferred to heat becomes significant.  As in enough to heat a some internal reel  parts several hundred degrees Fahrenheit.  There are some examples in this thread.

3.  In order for the drag performance to remain unchanged, the static (startup) and dynamic (running) coefficient of friction on the drag surfaces has to remain unchanged.  The coefficient of friction is a measurement of the stickiness of a pair of mating surfaces.

4.  Heat transferring between solid materials (conduction) will follow the path of least resistance.  This is determined by temperature differences, the thermal conductivity of the materials, and the distances involved (e.g. the thickness of the material). The greater the temperature diffrence and the shorter the distance,  the less resistance.

5. Heat transferring to a fluid (gasses including air count as a fluid here), is controlled by relative temperature, and the motion of the molecules in the fluid past the object surface. The greater the amount of cooler molecules flowing by and  the larger the surface area, the greater the opportuity for these molecular collisions that result in the transfer of heat energy.  This is called convection,  and gets a bit complicated.  However, fluids are in most cases a very poor conductor of heat.  Trapped air will hold heat more effectively  than solid stainless steel (this is how a thermos or styrofoam insulation works).   In other words, while fluids are not effective  for conducting heat,  they are very effective when used the right way for convection.  If you think about the  example of a water cooled engine- you wil see a combination of conduction and convection in action, taking advantage of the properties mentioned above. 

Note that drag grease is also mostly a fluid.

6.  When heated, most materials will expand.  There have been some reports of drags binding due to heat.   If my math is right, the amount of linear thermal expansion of metal parts at the size found in fishing reels does not seem to be significant enough to bind the drag.  My guess is that something else is going on here.

-----
There are two approaches that can be used to maintain a consistent coefficient of friction on the drag surfaces.  One is to use materials and designs that are less affected by the heat, the other is to evacuate the heat being generated via a combination of conduction and convection. 

Complicating factors include the vulnerability to heat of surrounding materials (e.g., bearing grease, plastic parts),  the harsh saltwater environment that these reels are used in (e.g.,trade off between improving convection and protecting the mechanical components from salt water), and the necessary dimensions and materials for the parts to perform their purposes.

From what I have read,  heat transfer behavior is difficult to predict beyond the most rudimentary situations,  so understanding the science is a starting point, but trial and error testing is essential.

Hopefully not too long winded, but at least I feel better now :)

-J

rippin_lips

Most of what you're saying is on the right path J.  The drag force does not create heat, it is the motion. You can crank your star down and create 40 lbs of drag just sitting there not moving will create no heat, but a light drag moving fast will get hot. The drag force and the force applied by the fish will determine how fast it moves. Conductive heat transfer depends on surface area and thickness, but the thickness can be adjusted based on the temperature difference.  The formula has the term dT/s which is the temperature difference divided by the thickness which is then multiplied by the area.  Increasing thickness decreases heat transfer, but increasing temperature gradient increases heat transfer. Increasing area will always increase heat transfer. The convective heat transfer is also dependant on area, but not thickness.  The motion of the fluid used in convection will determine the convective heat transfer coefficient, so yes it will change the heat transfer but the area and temperature gradient will usually have a larger effect.  When it comes to heat transfer area and temperature gradient are big factors, which is evident if you look at the formulas. It can be a very complicated issue with so many variables inside a fishing reel.

Lowprofile

200 yards of line stripped from a 12/0 @ 10lbs of drag going 20mph will not generate the same amount of heat as 200 yrds stripped at 30lbs going 20mph.

If you don't believe me, hook one up to a car and try it.

Alto Mare

#83
Quote from: Lowprofile on November 29, 2016, 11:51:01 AM
200 yards of line stripped from a 12/0 @ 10lbs of drag going 20mph will not generate the same amount of heat as 200 yrds stripped at 30lbs going 20mph.

If you don't believe me, hook one up to a car and try it.
I believe you!

Sal
Forget about all the reasons why something may not work. You only need to find one good reason why it will.

rippin_lips

#84
Quote from: Lowprofile on November 29, 2016, 11:51:01 AM
200 yards of line stripped from a 12/0 @ 10lbs of drag going 20mph will not generate the same amount of heat as 200 yrds stripped at 30lbs going 20mph.

If you don't believe me, hook one up to a car and try it.

I believe you.  That wasn't my point though.  They both create heat, due to the motion not necessarily due to the drag force.  The increased drag force is a result of the surfaces being forced closer together with a greater frictional force to overcome and more energy is created when this is overcome.  My only point was that the drag force itself is not the creator of the heat, it is the motion of the surfaces past each other at a molecular level.  Pulling at 20 mph against 30 lbs of drag is a lot more energy.

jurelometer

But what we are saying is that for THE SAME drag and distance, the same amount of heat will be generated.  The type of reel or drag system, and how fast the line is going out does not change the amount of work being done (pull 30lbs 100 yards).

In lowprofile's example,  a different amount of heat  is being generated because the drag setting has been changed. 

At the same time that the heat is being generated, some of it is  being transferred out of the drag into the surrounding air.  This is why the reel will be hotter for the same amount of line at 30 miles an hour instead of 10.   The reel had 1/3 the time to cool at 30 mph.

Also,  different reels can have different final drag temps for the same real world test because:

1. the change of actual drag applied during the test (drag coefficient of friction changing, spool diameter changing, etc) are different.  BTW, a good bumper test would include a drag scale at the reel end, so the variance in actual drag applied could be factored in.

2.  The heat shedding properties  of the reels are  different.

The reason to make this distinction is to help us evaluate and modify drag systems in reels. For any specified load/distance, the same amount of heat is going to show up.  The question is how does a given reel deal with the heat to maintain consistent performance and reliability.

rippin_lips

Coefficient of friction, contact pressure, and relative velocity of the two surfaces are what determine heat generation per unit area.  Contact pressure is not the same as the drag force.  In lowprofile's example, a greater contact pressure is needed to achieve a higher drag force from the same washers thus increasing heat generation and temperature.  If you want to reduce heat generation you can:
- reduce friction coefficients, that will reduce drag force or cause you to increase contact pressure
- reduce contact pressure, which will reduce drag force unless you make other changes such as increasing drag washer area
- The last option is to reduce the relative velocity of the two surfaces. 

This doesn't answer how to increase heat transfer to remove excess heat, but it is a start in understanding the problem.  The problem with a senator in this instance, is the surface area of the drag washers.  The smaller area of the drag washers is an issue for heat transfer and heat generation.  The smaller drag washers require more contact pressure to achieve the same drag force, which increases heat generation.  At the same time the reduced area of the smaller drag washers reduces heat transfer, add on top of this the need to use a thick stack of washers which increases thickness and decreases heat transfer. 

I'm curious, can anyone give a first hand account on the heat buildup from the drag of a reel such as an international that uses much larger diameter drag washers and a thinner stack?  My initial guess, would be that the increase in diameter and surface area would need less contact pressure to achieve the same drag load using less washers.  This would generate less heat.  The larger surface area would increase heat transfer cooling the drag faster.  On top of that the aluminum used to build the frame and body of the reel would act as a heat sink drawing heat away from the drag.  This is just my guess, but I would love to hear if this is what has been observed fishing for large game fish.

jurelometer

Hi Rippin,

BTW- thanks for the reply to my earlier post-  I am still struggling a bit with convection.

Quote from: rippin_lips on November 29, 2016, 06:58:28 PM
Coefficient of friction, contact pressure, and relative velocity of the two surfaces are what determine heat generation per unit area.  Contact pressure is not the same as the drag force.  In lowprofile's example, a greater contact pressure is needed to achieve a higher drag force from the same washers thus increasing heat generation and temperature.  If you want to reduce heat generation you can:
- reduce friction coefficients, that will reduce drag force or cause you to increase contact pressure
- reduce contact pressure, which will reduce drag force unless you make other changes such as increasing drag washer area
- The last option is to reduce the relative velocity of the two surfaces. 

This doesn't answer how to increase heat transfer to remove excess heat, but it is a start in understanding the problem.  The problem with a senator in this instance, is the surface area of the drag washers.  The smaller area of the drag washers is an issue for heat transfer and heat generation.  The smaller drag washers require more contact pressure to achieve the same drag force, which increases heat generation.  At the same time the reduced area of the smaller drag washers reduces heat transfer, add on top of this the need to use a thick stack of washers which increases thickness and decreases heat transfer. 

The "problem" (I would say current challenge) with the star drags is that the drag system is encapsulated within the main gear.   In order to handle high loads, stainless steel upgrades for the Penns were developed by folks here for the gear, gear sleeve, bridge plate, etc.  These increase the strength, but probably decrease the ability to shed heat quickly by some unknown amount.  One of the upgrades does includes increasing the drag surface area by adding more thinner drag washers.   But since the extras surfaces are encapsulated in the same space,  the heat is trapped just the same as before. My guess is that most of the heat transfer is via the spacer sleeve and star (the stars get hot, but the handles not as much).  It is possible that some is traveling down to the bridge plate which is cooled by the rotating spool.

All of this customization allows the upgraded reel to run smoothly at a much higher drag setting than a stock reel. The question now is how well can ir handle a long run at this new capability.

Also I think we need to be accurate regarding heat "generation".    The same amount of heat is being generated in your description, but the temperature is higher at the drag surface because the surface area is smaller.  Do you agree?

Quote
I'm curious, can anyone give a first hand account on the heat buildup from the drag of a reel such as an international that uses much larger diameter drag washers and a thinner stack?  My initial guess, would be that the increase in diameter and surface area would need less contact pressure to achieve the same drag load using less washers.  This would generate less heat.  The larger surface area would increase heat transfer cooling the drag faster.  On top of that the aluminum used to build the frame and body of the reel would act as a heat sink drawing heat away from the drag.  This is just my guess, but I would love to hear if this is what has been observed fishing for large game fish.

Same point as before- toal heat energy  is the same, surface temp is decreased due to increase in area, right?

Somebody posted a photo of a melted nylon bushing inside of a drag chamber on a big lever drag reel.   I think tightlines has posted some experience with heat damage on big lever drags.  If he is reading perhaps he will share.

Most lever drag reels attach the CF washer against the spool and  press a stainless drag plate against it.  I believe that the CF washer has much less thermal conductivity, so the heat will first go to the drag plate.  On most reels there is an additional cover to encapsulate the whole assembly.  I suspect these actually inhibit convection, but the help protect the drag from contamination and acts a a heat shield for the rest of the mechanical parts. at least for awhile.   Heat getting into a spinning spool is not a bad thing, but not sure how fast it would get there.   According to fishing line manufacturers and contrary to popular opinion,  heat below the melting point does not affect nylon line strength.  So the spool may be part of the mechanism to shed the heat, but not sure how efficient these reels are at getting the heat to the spool since the CF washer will be acting as an insulator. 

When I did the math (risky  ;D)  I got ~ 48000 joules of energy for a  400 yard run at 30 lb drag average.   This equated to increasing the temp of a 100x10 mm stainless drag plate with a 20 mm hole in the center about 583 degrees F.  If all the heat went to a spool, this would heat a  450 gr (about 1 lb) spool only 50 degrees F.  When Avet did some 75 yard- 35 lb drag bumper drag tests, they actually heat tinted the the stainless drag plate- which is consistent with the temps described above.  Straw color on stainless is around 600 degrees F.  (see the thread at http://alantani.com/index.php?topic=168.0)  This would also indicate that the heat does not get to the spool quickly- at least for Avet design.

Note that it takes less than a minute to run off 400 yards at 15 MPH,  so I think that in real life those screaming runs that nearly empty the reel are usually not moving as fast as we think.  These reels do okay because they are not being pushed as hard in real life use as they are in parking lot tests.

Cork drag fly reels catch reasonably big tuna and billfish - usually running under 10 lbs of drag.  I recently caught a 40 kilo GT that took a couple hundred yards at around 8 lbs of drag on a cork fly reel- no heat detected whatsoever.    Cork has a relatively high COF, and a very low max temp rating.  The good cork reels do just fine- a  very large cork disc is attached to a drag plate which presses directly against the aluminum spool (the spool is the other drag surface).  Since cork is such a poor thermal conductor,  the heat travels through the spool which is large, highly ported and spinning fast.   The good reels stay surprisingly cool.   The not-so-good ones will toast the cork.  So lots of convection involved here.

FWIW,  I have been playing with drag design and materials a bit lately and my personal conclusion is that convection has to be a big part of a high quality solution. 

rippin_lips

Quote from: jurelometer on November 29, 2016, 09:43:44 PM

Also I think we need to be accurate regarding heat "generation".    The same amount of heat is being generated in your description, but the temperature is higher at the drag surface because the surface area is smaller.  Do you agree?

Quote
I'm curious, can anyone give a first hand account on the heat buildup from the drag of a reel such as an international that uses much larger diameter drag washers and a thinner stack?  My initial guess, would be that the increase in diameter and surface area would need less contact pressure to achieve the same drag load using less washers.  This would generate less heat.  The larger surface area would increase heat transfer cooling the drag faster.  On top of that the aluminum used to build the frame and body of the reel would act as a heat sink drawing heat away from the drag.  This is just my guess, but I would love to hear if this is what has been observed fishing for large game fish.

Same point as before- toal heat energy  is the same, surface temp is decreased due to increase in area, right?

Somebody posted a photo of a melted nylon bushing inside of a drag chamber on a big lever drag reel.   I think tightlines has posted some experience with heat damage on big lever drags.  If he is reading perhaps he will share.


Cork drag fly reels catch reasonably big tuna and billfish - usually running under 10 lbs of drag.  I recently caught a 40 kilo GT that took a couple hundred yards at around 8 lbs of drag on a cork fly reel- no heat detected whatsoever.    Cork has a relatively high COF, and a very low max temp rating.  The good cork reels do just fine- a  very large cork disc is attached to a drag plate which presses directly against the aluminum spool (the spool is the other drag surface).  Since cork is such a poor thermal conductor,  the heat travels through the spool which is large, highly ported and spinning fast.   The good reels stay surprisingly cool.   The not-so-good ones will toast the cork.  So lots of convection involved here.

FWIW,  I have been playing with drag design and materials a bit lately and my personal conclusion is that convection has to be a big part of a high quality solution. 

In regards to heat generation, it is not the drag force and length of line that will give you the heat generation.  Heat generation is dependent on the friction coefficient, the contact pressure (not drag force), and the relative velocity of the two surfaces.  Change any of those and you will change the heat generation due to friction.  That's heat generation per unit area.  Alto mare showed some perforated drag washers, I would speculate that if you could reduce the amount of surface area making contact while still maintaining drag force you would reduce some heat generation.  Heat is generated where the surfaces make contact.  The key to that would be balancing contact pressure with surface area and dimensions of the drag washers to achieve the desired effect. 

For simplicity sake if we just assume large amounts of heat generation will occur, then the next step is to transfer the heat.  You are correct that convection can play a large role in the solution, but you need to get the heat to a surface that will lend itself to convection.  Look at heat sinks on electronics, usually a large aluminum section with many thin fins.  The reduced thickness of the fins aids in conduction to the surface while the increased surface area aids in convection.  The cork fly reel example shows a good way to increase heat transfer.  Using the spool as a drag surface generates the heat in a place where it can be readily removed.  Using a good aluminum with large surface area and access to moving air will increase the heat transfer, the aluminum will conduct the heat to the surface where convection with the air can occur and the convective heat transfer is increased by the motion.  Similar to something I speculated about large lever drag reels, the aluminum of the spool/frame/plates can be used as a heat sink to transfer heat away from the drag.  That's not to say it wont still generate heat, but it could work to move the heat.  I would make a guess that on senators, aluminum side pates and frames would aid in heat transfer away from the drag/gear area some.   The heat needs to move by conduction, to a surface where the convection can occur.  We still haven't even touched on radiation, but for this conversation I think we can leave that out.  Let's not also forget, that a fishing reel being used in a climate with high temperatures will experience a drastic reduction in heat transfer due to the reduction in temperature difference compared to a reel used in a cooler climate.

I'm no expert so feel free to correct me I won't be offended, I'm just basing this on what I have learned as a mechanical engineer and my interpretation of the situation.

jurelometer

Quote from: rippin_lips on November 30, 2016, 03:14:37 PM
Quote from: jurelometer on November 29, 2016, 09:43:44 PM

Also I think we need to be accurate regarding heat "generation".    The same amount of heat is being generated in your description, but the temperature is higher at the drag surface because the surface area is smaller.  Do you agree?

Quote
I'm curious, can anyone give a first hand account on the heat buildup from the drag of a reel such as an international that uses much larger diameter drag washers and a thinner stack?  My initial guess, would be that the increase in diameter and surface area would need less contact pressure to achieve the same drag load using less washers.  This would generate less heat.  The larger surface area would increase heat transfer cooling the drag faster.  On top of that the aluminum used to build the frame and body of the reel would act as a heat sink drawing heat away from the drag.  This is just my guess, but I would love to hear if this is what has been observed fishing for large game fish.

Same point as before- total heat energy  is the same, surface temp is decreased due to increase in area, right?

Somebody posted a photo of a melted nylon bushing inside of a drag chamber on a big lever drag reel.   I think tightlines has posted some experience with heat damage on big lever drags.  If he is reading perhaps he will share.


Cork drag fly reels catch reasonably big tuna and billfish - usually running under 10 lbs of drag.  I recently caught a 40 kilo GT that took a couple hundred yards at around 8 lbs of drag on a cork fly reel- no heat detected whatsoever.    Cork has a relatively high COF, and a very low max temp rating.  The good cork reels do just fine- a  very large cork disc is attached to a drag plate which presses directly against the aluminum spool (the spool is the other drag surface).  Since cork is such a poor thermal conductor,  the heat travels through the spool which is large, highly ported and spinning fast.   The good reels stay surprisingly cool.   The not-so-good ones will toast the cork.  So lots of convection involved here.

FWIW,  I have been playing with drag design and materials a bit lately and my personal conclusion is that convection has to be a big part of a high quality solution. 

In regards to heat generation, it is not the drag force and length of line that will give you the heat generation.  Heat generation is dependent on the friction coefficient, the contact pressure (not drag force), and the relative velocity of the two surfaces.  Change any of those and you will change the heat generation due to friction.  That's heat generation per unit area.  Alto mare showed some perforated drag washers, I would speculate that if you could reduce the amount of surface area making contact while still maintaining drag force you would reduce some heat generation.  Heat is generated where the surfaces make contact.  The key to that would be balancing contact pressure with surface area and dimensions of the drag washers to achieve the desired effect. 

For simplicity sake if we just assume large amounts of heat generation will occur, then the next step is to transfer the heat.  You are correct that convection can play a large role in the solution, but you need to get the heat to a surface that will lend itself to convection.  Look at heat sinks on electronics, usually a large aluminum section with many thin fins.  The reduced thickness of the fins aids in conduction to the surface while the increased surface area aids in convection.  The cork fly reel example shows a good way to increase heat transfer.  Using the spool as a drag surface generates the heat in a place where it can be readily removed.  Using a good aluminum with large surface area and access to moving air will increase the heat transfer, the aluminum will conduct the heat to the surface where convection with the air can occur and the convective heat transfer is increased by the motion.  Similar to something I speculated about large lever drag reels, the aluminum of the spool/frame/plates can be used as a heat sink to transfer heat away from the drag.  That's not to say it wont still generate heat, but it could work to move the heat.  I would make a guess that on senators, aluminum side pates and frames would aid in heat transfer away from the drag/gear area some.   The heat needs to move by conduction, to a surface where the convection can occur.  We still haven't even touched on radiation, but for this conversation I think we can leave that out.  Let's not also forget, that a fishing reel being used in a climate with high temperatures will experience a drastic reduction in heat transfer due to the reduction in temperature difference compared to a reel used in a cooler climate.

I'm no expert so feel free to correct me I won't be offended, I'm just basing this on what I have learned as a mechanical engineer and my interpretation of the situation.

If I get something wrong here, I would appreciate  being corrected as well.

I think this is our disconnect.  We are making two different points:

What you are describing is the capability of the drag system to transfer kinetic energy (motion)  to thermal energy (heat) For a given drag system at a given setting it will generate specific amount of conversion per revolution.   Designing/setting  a system for a lower level of conversion means less heat, but also less effort to stop the fish (effectively running at a lower drag)

My point is that that 10 lbs of drag (linear force) for 100 yards  is a specific amount of work  (4067 joules).  4067 joules of thermal energy will always be showing up, no matter what  materials, surface area, coefficient of friction, force, etc. are used to get us this this level of linear force resistance (drag). There is no magic to have less heat energy show up for the same workload. 

So how much does 4067 joules of energy heat up the reel parts?  I weighed some parts lying around:

stainless 98-320 AT gear sleeve (26 gram) -> temp increase of 583 degrees F (this would only happen if all the heat was directed to the gear sleeve,which won't happen).

stainless jigmaster bridge, main gear, washers, gear sleeve, spacer and stainless star (110 gram)   -> temp increase of 133 degrees (assumes the heat is distributed evenly- which it won't be).

These temp increases would not be that high in the real world as the reels do some amount of conduction and convection already.   But the designs are not optimized for it.

I am still curious about the binding up of star drag reels.  As noted before, I don't think thermal expansion of such loose fitting metal parts would explain it.  The expansion is so minimal.  Maybe stamp cut washers from sheet stock warping?  Lots of surface tension in rolled sheet stock. Dunno....

Probably should start a separate general forum thread on drags and heat at some point.