Handle torque measurement and physics

[bill19803]

Joe  if  you  want  to   find  the  torque on  a real  world reel to   crank a  given load,  on a penn  remove  the   handle nut locking   screw   and  use a  torque  wrench  in  the handle  nut itself.  that  will   give   you  the   lbs ft  required.  Divide   this  by the   distance    from  the  pivot point of handle   to  knob   shaft (in  feet)  and   you have  the   force required  to   crank in  lbs

Input   always is more then  output   because of  friction

Remember  that  pulling in line   is  doing   WORK (line pull   times  distance moved) if ya  change one  distance   you have   to  either increase the  other  distance  force moves   or the amount of   force  applied   if  you want  to   do more   work  (bigger  fish)  you   have  to put in more   work  (force X  distance  the  force   moves)
hope i  didnt confuse the issue

[Decker]

Joe  if  you  want  to   find  the  torque on  a real  world reel to   crank a  given load,  on a penn  remove  the   handle nut locking   screw   and  use a  torque  wrench  in  the handle  nut itself.  that  will   give   you  the   lbs ft  required.  Divide   this  by the   distance    from  the  pivot point of handle   to  knob   shaft (in  feet)  and   you have  the   force required  to   crank in  lbs

Input   always is more then  output   because of  friction

Remember  that  pulling in line   is  doing   WORK (line pull   times  distance moved) if ya  change one  distance   you have   to  either increase the  other  distance  force moves   or the amount of   force  applied   if  you want  to   do more   work  (bigger  fish)  you   have  to put in more   work  (force X  distance  the  force   moves)
hope i  didnt confuse the issue

Bill, this is a great explanation.  Old tuna fishermen are full of surprises   Thanks, my friend!

[Rothmar2]

The Tank used to sport a Sumo Tackle adjustable crank....I made a few comments about it while I had the Tank a couple of seasons ago

http://alantani.com/index.php?topic=15832.45

I actually like the function of it, but the ring nut was constantly working loose and causing to much slop. A shame, as I really thought the concept had great practical application.

[jurelometer]

As Robert noted, discussed many times.   My contribution here with a formula:

http://alantani.com/index.php?topic=14241.msg145318#msg145318

You need to input the gear ratio, spool fill diameter, and amount of forcce you want to come out of the reel (in place of drag). Just multiply the result by the shaft to arm length in inches.

The handle with two knobs at different lengths thing has been tried before.  The biggest problem is getting useful size/shape knobs  without  one getting in the way when using the other. 

I was working on a couple improved adjustable arm designs when my shop closed down.  If  anyone is interested in moving forward on this, feel free to PM me.

-J

[Tightlines667]

As Robert noted, discussed many times.   My contribution here with a formula:

http://alantani.com/index.php?topic=14241.msg145318#msg145318

You need to input the gear ratio, spool fill diameter, and amount of forcce you want to come out of the reel (in place of drag). Just multiply the result by the shaft to arm length in inches.

The handle with two knobs at different lengths thing has been tried before.  The biggest problem is getting useful size/shape knobs  without  one getting in the way when using the other. 

I was working on a couple improved adjustable arm designs when my shop closed down.  If  anyone is interested in moving forward on this, feel free to PM me.

-J

I have a roughed out formula somewhere as well that provides a ratio which allows comparisons of different reels, gears, handle arms as far as the power achieved is concerned.  I factored in gear and drive shaft/spool shaft diameters as well as spool diameter and arm length.  However, my ratios did not provide a true measure in units of force applied/achieved.  Basically, smaller gears give, larger spools, and longer handles provide more power, then the opposite.

2 scales could be used to easily test a given reel to obtain actual numbers.  Calculating the force on the dog(s) or gears themselves is another matter which is easier with math then testing directly IMHO.

John

[jurelometer]

As Robert noted, discussed many times.   My contribution here with a formula:

http://alantani.com/index.php?topic=14241.msg145318#msg145318

You need to input the gear ratio, spool fill diameter, and amount of forcce you want to come out of the reel (in place of drag). Just multiply the result by the shaft to arm length in inches.

The handle with two knobs at different lengths thing has been tried before.  The biggest problem is getting useful size/shape knobs  without  one getting in the way when using the other. 

I was working on a couple improved adjustable arm designs when my shop closed down.  If  anyone is interested in moving forward on this, feel free to PM me.

-J

I have a roughed out formula somewhere as well that provides a ratio which allows comparisons of different reels, gears, handle arms as far as the power achieved is concerned.  I factored in gear and drive shaft/spool shaft diameters as well as spool diameter and arm length.  However, my ratios did not provide a true measure in units of force applied/achieved.  Basically, smaller gears give, larger spools, and longer handles provide more power, then the opposite.

2 scales could be used to easily test a given reel to obtain actual numbers.  Calculating the force on the dog(s) or gears themselves is another matter which is easier with math then testing directly IMHO.

John

Hmmm...

In one of the threads,  Robert actually hobbed some fresh gears to test the formulas (amazing!) and came out with numbers that were pretty close.    Another member attached a spring scale to a Penn 349 handle and measured numbers that were pretty close to the formulas as well.     There is going to be some added  friction in the system, so the measured numbers won't exactly match,  but if the friction is significant, the reel isn't going to be very useful.  The test with two scales is a good idea, but a bit tricky to get exactly right.  the force on the handle is rotational, but the scale is measuring linear force, so as the handle turns the force is no longer tangent to the radius. Some of the force is directed against the side of the shaft and not the gear/spool system,  so the readings will go too high.  This is why I believe the formulas to be more accurate than ad-hoc measurement techniques.  A torque measurement tool attached directly to the handle shaft would be an accurate way to measure, but you would need some sort of adapter, and typical torque wrenches might not be accurate enough at the relatively lower levels or force being applied.

Shaft diameters don't matter  (maybe I misunderstood your statement?).    The diameter of the filled spool (measure diameter at the current line fill level), the gear ratio (more exact by counting teeth rather than printed specs), and the handle arm length (from gear shaft center to knob center)  are the variables that affect the result.   

Thinking through the spool diameter part of it: Given a constant amount of force (e.g.  lifting an eight lb weight) less filled spool diameter means less line retrieved per revolution, therefore you are doing less work per revolution (same amount of work per foot of line, but  more revolutions per foot).  Therefore,  a smaller spool requires less effort to turn.   This is because a larger spool fill diameter creates a longer lever arm, and the handle is on the disadvantaged end of the leverage equation.  Same reason that a longer handle arm helps (leverage is now in your favor).

For a given load, larger spool fill diameters, shorter handle arms and higher gear ratios all increase the amount of force required to turn the handle arm.   

-J