drag pressure versus temperature for greased carbon fiber drags

Started by alantani, November 14, 2015, 01:32:09 AM

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Tiddlerbasher

Alan - One further 'variable' that occurs to me is as follows:

On a star drag reel we have a shaft with gear and drag stack at one end and the star on the other.
In between the drag stack and star are usually bellevilles or similar. The washers are compressed to apply a gradual force to the drag stack.
When this whole assembly is heated the shaft lengthens (linear expansion). It may only be a fraction of a millimetre but it may be enough to reduce the applied torque on the washers.
Others parts will expand as well but the length of the shaft is the most important dimension.

A 50mm steel shaft heated by 50°C will expand to approx. 50.03mm (if my math is correct ;)) Whether that is enough to affect the drag is open to question :-\ It was certainly hot enough judging by your reaction ;D

Dr. Jekyll - AKA MeL B

how about a non-stationary test, attached the drag scale to a post or such and attached the reel to a bicycle or automobile and drive to a certain speed while somebody is filming the scale. this will simulate a fish taking line off the reel, just a suggestion...

alantani

peeling line off at a pretty fast rate would not be a problem.  off the top, i would guess that we would have to "spool" this reel a couple of times to get the temp as high as we did by just running this reel at a constant rate. to know for sure, i would have to measure the temp.  matt is going to help me out with this. 
send me an email at alantani@yahoo.com for questions!

Ling

Quote from: Tiddlerbasher on November 16, 2015, 01:54:10 PM
Alan - One further 'variable' that occurs to me is as follows:

On a star drag reel we have a shaft with gear and drag stack at one end and the star on the other.
In between the drag stack and star are usually bellevilles or similar. The washers are compressed to apply a gradual force to the drag stack.
When this whole assembly is heated the shaft lengthens (linear expansion). It may only be a fraction of a millimetre but it may be enough to reduce the applied torque on the washers.
Others parts will expand as well but the length of the shaft is the most important dimension.

A 50mm steel shaft heated by 50°C will expand to approx. 50.03mm (if my math is correct ;)) Whether that is enough to affect the drag is open to question :-\ It was certainly hot enough judging by your reaction ;D

My guess is that the change in spool diameter would be a much greater % than the change in drag due to temperature....therefore friction.  I suppose understanding how temperature increases in relation to line lost is a large factor needing to be answered.  Cool stuff to investigate.  Love the questions that pop up here!

jurelometer

Quote from: Tiddlerbasher on November 16, 2015, 01:54:10 PM
Alan - One further 'variable' that occurs to me is as follows:

On a star drag reel we have a shaft with gear and drag stack at one end and the star on the other.
In between the drag stack and star are usually bellevilles or similar. The washers are compressed to apply a gradual force to the drag stack.
When this whole assembly is heated the shaft lengthens (linear expansion). It may only be a fraction of a millimetre but it may be enough to reduce the applied torque on the washers.
Others parts will expand as well but the length of the shaft is the most important dimension.

A 50mm steel shaft heated by 50°C will expand to approx. 50.03mm (if my math is correct ;)) Whether that is enough to affect the drag is open to question :-\ It was certainly hot enough judging by your reaction ;D

.03 mm = ~. 0012 in - at 32 TPI for a fine threaded sleeve we are talking about .0315 in per full revolution.
.0315/.0012 = 1/26 of a revolution or about 14 degrees.   Not enough to cut the drag in half.   Plus all the heated elements (drag washers...) will expand-  not sure how much if any springiness a belville or wave washer will lose- but this could contribute.

But you brought up an interesting point.  One or both of the following had to have changed: the coefficient of friction or the force on the stack.    Changes in the force on the top of the stack can be measured by hacking a star adapter to a torque wrench. 

Changes to the coefficient of friction might be  cauesd by viscosity changes in the grease.

I am looking forward to the dry drag test!

jurelometer

Quote from: jurelometer on November 17, 2015, 11:59:06 PM
Quote from: Tiddlerbasher on November 16, 2015, 01:54:10 PM
Alan - One further 'variable' that occurs to me is as follows:

On a star drag reel we have a shaft with gear and drag stack at one end and the star on the other.
In between the drag stack and star are usually bellevilles or similar. The washers are compressed to apply a gradual force to the drag stack.
When this whole assembly is heated the shaft lengthens (linear expansion). It may only be a fraction of a millimetre but it may be enough to reduce the applied torque on the washers.
Others parts will expand as well but the length of the shaft is the most important dimension.

A 50mm steel shaft heated by 50°C will expand to approx. 50.03mm (if my math is correct ;)) Whether that is enough to affect the drag is open to question :-\ It was certainly hot enough judging by your reaction ;D

.03 mm = ~. 0012 in - at 32 TPI for a fine threaded sleeve we are talking about .0315 in per full revolution.
.0315/.0012 = 1/26 of a revolution or about 14 degrees.   Not enough to cut the drag in half.   Plus all the heated elements (drag washers...) will expand-  not sure how much if any springiness a belville or wave washer will lose- but this could contribute.

But you brought up an interesting point.  One or both of the following had to have changed: the coefficient of friction or the force on the stack.    Changes in the force on the top of the stack can be measured by hacking a star adapter to a torque wrench. 

Changes to the coefficient of friction might be  cauesd by viscosity changes in the grease.

I am looking forward to the dry drag test!

Aaargh.  Just realized  that a change in the coefficient of friction will change the torque to force ratio.   So measuring the torque probably won't help to differentiate between  a change in force to a change to COF. 

Back to your regularly scheduled programming. 

-J

Tightlines667

#36
That was an interesting thought, and well worth considering, though it seems other factors are at play here as well.

This seems to be a popular topic of discussion here at AT, and elsewhere on the net.  I seem to remember a post (somewhere deep in the AT archieves) related directly to the effects of heat on COF in greased verses dry CF.  I did a quick search and ran accross these other somewhat related threads, and thought I would share*....

*not a comprehensive list, and in no particular order

Be forewarned though...

You might need more then one cup of coffee to work your way through the body of work that has been amassed on this site.

DRAGENSTEIN
http://alantani.com/index.php?topic=15510.0

Coating metal drag washers.
http://alantani.com/index.php?topic=12514.0

A word on Friction & Heat
http://alantani.com/index.php?topic=9168.0

Calculating main gear shaft torque from drag settings
http://alantani.com/index.php?topic=14241.0

Drag Washer Friction Estimates
http://alantani.com/index.php?topic=7412.0

Experimenting with the 113H drags
http://alantani.com/index.php?topic=6517.0

helpin do the math on square area calculations!
http://alantani.com/index.php?topic=10024.0

Re: Why carbontex under main gear?
http://alantani.com/index.php?topic=7711.15

Teflon, Delrin or UHMW
http://alantani.com/index.php?topic=12464.0

penn drag washer surface area
http://alantani.com/index.php?topic=6203.0

Myth Busters sets a fishing reel on fire?
http://alantani.com/index.php?topic=2283.0

Yet another drag question but one that I can't find an answer for.  High Speed Runout
http://alantani.com/index.php?topic=576.0

avet's response to the grease issue
http://alantani.com/index.php?topic=168.0

Re: Proper way to test drag *
http://alantani.com/index.php?topic=5527.msg45454#msg45454

How hot do drags really get? *
http://alantani.com/index.php?topic=8670.0

*Note: The photo of Robert Janssen's wonderfull 'Drag Machine Test Rig'

o yea... and there are something like 200+ threads that mention 'Drag Grease' in them.

http://alantani.com/index.php?action=search2

I like Alan's simple, no nonsense approach... simply test, and note the results.  Examining exactly what is going on, why, and looking into the engineering, physics, and math behind these is another slightly more complicated matter altogether.

:-\
Hope springs eternal
for the consumate fishermen.

ALASKAFISHMAN

Wow another great thread.  I have been visiting this site for a while and just became a member.  I am amazed at all the information, tests, results.  One thing for sure you guys are getting everything you can get out of your reels.  It has also opened my eyes to how ineffective my reel maintenance has been.  I have gone thru a few of my reels applying what I have learned here and What a difference it has made in the performance of the gear I have been able to service.  All of my reels thank you. 

Brent
Fish and hunt, Fish and hunt, eat, sleep fish and hunt, fish and hunt

alantani

brent, probably the main thing is that there is no advertising money to hold sway over anyone.  i think that is the reason that things here are reported so honestly.  throw money into the mix and things get cloudy really quickly.  it also means that none of us are going to get rich.   ;D
send me an email at alantani@yahoo.com for questions!

MolBasser

Quote from: Tightlines666 on November 18, 2015, 06:52:46 AM
That was an interesting thought, and well worth considering, though it seems other factors are at play here as well.

This seems to be a popular topic of discussion here at AT, and elsewhere on the net.  I seem to remember a post (somewhere deep in the AT archieves) related directly to the effects of heat on COF in greased verses dry CF.  I did a quick search and ran accross these other somewhat related threads, and thought I would share*....

*not a comprehensive list, and in no particular order

Be forewarned though...

You might need more then one cup of coffee to work your way through the body of work that has been amassed on this site.

DRAGENSTEIN
http://alantani.com/index.php?topic=15510.0

Coating metal drag washers.
http://alantani.com/index.php?topic=12514.0

A word on Friction & Heat
http://alantani.com/index.php?topic=9168.0

Calculating main gear shaft torque from drag settings
http://alantani.com/index.php?topic=14241.0

Drag Washer Friction Estimates
http://alantani.com/index.php?topic=7412.0

Experimenting with the 113H drags
http://alantani.com/index.php?topic=6517.0

helpin do the math on square area calculations!
http://alantani.com/index.php?topic=10024.0

Re: Why carbontex under main gear?
http://alantani.com/index.php?topic=7711.15

Teflon, Delrin or UHMW
http://alantani.com/index.php?topic=12464.0

penn drag washer surface area
http://alantani.com/index.php?topic=6203.0

Myth Busters sets a fishing reel on fire?
http://alantani.com/index.php?topic=2283.0

Yet another drag question but one that I can't find an answer for.  High Speed Runout
http://alantani.com/index.php?topic=576.0

avet's response to the grease issue
http://alantani.com/index.php?topic=168.0

Re: Proper way to test drag *
http://alantani.com/index.php?topic=5527.msg45454#msg45454

How hot do drags really get? *
http://alantani.com/index.php?topic=8670.0

*Note: The photo of Robert Janssen's wonderfull 'Drag Machine Test Rig'

o yea... and there are something like 200+ threads that mention 'Drag Grease' in them.

http://alantani.com/index.php?action=search2

I like Alan's simple, no nonsense approach... simply test, and note the results.  Examining exactly what is going on, why, and looking into the engineering, physics, and math behind these is another slightly more complicated matter altogether.

:-\

Yeah, this forum is such a damn rabbit hole.......  I love it.  Did any experiments with dry drags get done or is it in another thread.... 

Hoo boy do I have a lot of reading to do....

MolBasser

Glos

I wonder, does spinning reel rotor depending on material it is made of, participates in heat dissipation from prolonged drag activation ?
Metal being better at it than composite.
I know it has no real contact with spool, but I also think that somewhere along the line I have seen images of aluminium rotor being better at heat dispersion than plastic...
.........or have I ??
Luck is when good preparation meets opportunity.

Squidder Bidder

Quote from: Glos on February 16, 2023, 10:28:18 AMI wonder, does spinning reel rotor depending on material it is made of, participates in heat dissipation from prolonged drag activation ?
Metal being better at it than composite.
I know it has no real contact with spool, but I also think that somewhere along the line I have seen images of aluminium rotor being better at heat dispersion than plastic...
.........or have I ??

I think it does, at least according to Shimano, which advertises a heat dissipating material in the rotors of its high end spinning reels (i.e., Stella) which is supposed to maintain even drag pressures. 

jurelometer

Quote from: Squidder Bidder on November 20, 2023, 03:10:48 PM
Quote from: Glos on February 16, 2023, 10:28:18 AMI wonder, does spinning reel rotor depending on material it is made of, participates in heat dissipation from prolonged drag activation ?
Metal being better at it than composite.
I know it has no real contact with spool, but I also think that somewhere along the line I have seen images of aluminium rotor being better at heat dispersion than plastic...
.........or have I ??

I think it does, at least according to Shimano, which advertises a heat dissipating material in the rotors of its high end spinning reels (i.e., Stella) which is supposed to maintain even drag pressures. 

Don't see how the rotor material helps.  And didn't see this in the Shimano marketing babblespeak after a quick check.

The heat would have to travel from the drag through the shaft, bearings, pinion, etc, before reaching the rotor. All materials and shapes that are not good heat conductors.   The spool is a much shorter path, and  would probably have to have gotten hot enough to melt all the line before the rotor would even warm up a degree or two.

You could design a rotor that works a as a cooling fan to blow air through some spool ports to cool the drag, but you usually are not turning the handle when the drag is heating up.  Somebody must of though of this fan idea, as it is a nice feature to market, whether or not it works.

Shimano does advertise using a heat sink under the spool on the high end spinners, which might actually help a little with heat.  While it probably won't dissipate much heat very quickly itself, it could draw some of the heat off the drag stack (which is what a heat sink technically does). I wouldn't be surprised if the greatest benefit is in justifying a higher price point.  :D

-J