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In article <93025.101906U40348@uicvm.uic.edu> U40348@uicvm.uic.edu (Jay Lorenzana) writes:
>
>Hello,
>
>I have some questions about RC car motors.  In particular the
>Kyosho 24 degree stock motor.
>
>What are the pros and cons of changing the timing on such motors?
>
>Will the motors life degrade?
>
>How much faster can it go?
>
>Does it increase torque or increase RPM (or both)?
>
>How much work is involved in changing the timing?
>
>An aside:  Does motors have the same charactoristics in forward and
>reverse?  How much percent decrease is there in reverse compared to
>forward (if any)?


I don't really know the answers to most of the questions, except that
if the endbell is crimped onto the motor can, then changing the timing
(except through timed brushes) may be a challenge.

What is clear, however, is that a motor with 24 degrees of timing has
negative 24 degrees of timing (at least approximately) in reverse.  Some
people also dislike reverse because they feel it unseats their brushes
and thus impairs the next burst of forward.  If you had a motor with zero
degrees of timing, then it should behave well in either direction.
For what it's worth, if you increase the timing from zero to 180 degrees,
you get a "reverse wind" motor.

By the way, I once used a Kyosho Mega motor (22x1) and a Slot Machine motor
for parking lot racing.  Realizing that I would never use the motors in
their present form, I took them apart.  I still have their armatures that
I could put into another motor can if I ever need to do a 12 minute race.
I noticed that the Slot Machine bushings were bronze-looking and decent feeling,
while the Kyosho bushings had a steel color, but were about as soft as bronze,
yet not as smooth.  The Kyosho motor was much easier to tear apart.  The
commutator wear was unlike the wear I am accustomed to in that there were a
few dents, scratches or pits in the copper, FWIW.  I found the Mega motor
to lag behind the Slot Machine, and so I do not know if their 27x1 24 degree
motor would be all that good to worry about tweaking.

Good day,
Bob Woodhouse

I'll answer what I can:

Jay Lorenzana <U40348@uicvm.uic.edu> writes:

> Kyosho 24 degree stock motor.
> 
> What are the pros and cons of changing the timing on such motors?
Pros: You'll get higher RPMs
Cons: It'll run hotter, you'll lose power

> 
> Will the motors life degrade?
Almost definitely... depending on the maintenance you perform on the
motor after each run.

> 
> How much faster can it go?
This is a variable placed on the motor itself. I have not owned the 24
degree but have got several other Kyosho motors. If I adjust their timing
and I usually get around 4-7 thousand more RPM... but it wears 'em out.

> Does it increase torque or increase RPM (or both)?
> 
Less torque and higher RPM.  From my understanding on this it is a tradeoff
that the manufacturer takes into consideration when they set the timing 
on a motor. The optimal setting is most often exactly where it is when you
get it. However, if your into high speed races where you've got nice smooth
turns with little loss of speed... go for the high RPMs. If you've got a lot
of slowing and turning to do, you need more torque. 

> How much work is involved in changing the timing?
On my motors, to adjust the timing is to loosen two screws and turn the
bell housing. Simple. But don't overturn it.

> 
> An aside:  Does motors have the same charactoristics in forward and
> reverse?  How much percent decrease is there in reverse compared to
> forward (if any)?

Depends on the motor. I would say that there is no difference (although I've
never reversed a motor myself) theoretically... but there probably is a 
difference simply from the point that the motor was designed and made to
run forward vs reverse. If it didn't matter, would they make motors 
specifically to run in reverse?

bill


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