HOW FAR CAN IT GO?
QI bought an RTR nitro buggy for bashing and after a couple of months, the steering servo burned out, so I replaced it with a new
one with tougher internals. I am trying to get it set up and I am confused
about where to set the endpoint adjustment for the servo. Should I set
the endpoint where the servo starts to make a buzzing sound or is there a
better way to set it?
A;e endpoint adjustment, sometimes called EPA, sets the limit for how far the servo can travel in each direction. For a nitro buggy, you
will usually want as much steering travel as you can get without over-
traveling the servo. Most buggies have a linkage setup that allows a cer-
tain amount of travel before the steering arm impacts the upright or hub
carrier and prevents further steering angle. ;e EPA should be set up so
that the linkage will steer the tires a few degrees short of this mechani-
cal stop. If the servo has too much travel, it will keep trying to steer past
the linkage stop and the servo motor will stall which creates the buzzing
that you are hearing. When the servo stalls, it puts a lot of wear and tear
on the servo and it will deplete the power in your receiver pack. Nitro
buggies are notoriously hard on
servos, even when they
are set up correctly. To
prolong the life of
your servo, set
the EPA limit just
shy of maximum
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WHY DOES IT LOCK UP? Q I just finished building my new electric 4WD short course kit and I am having a problem with my drivetrain. My kit has three gear di;erentials in it. ;e front and rear
di;erentials both seem to work
right because when I turn one tire
by hand the opposite tire turns
the other way. However, when I give the truck full throttle, the entire
drivetrain locks up and the motor stalls. Did I make a mistake when I
assembled the di;s?
A;e first thing to do when having drivetrain issues is to inspect and try to spin all of the components. If the front and rear di;s
feel smooth and the tires turn in opposite directions when you turn
one wheel, most likely the problem is somewhere else. Sometimes
during new builds, screws or other spare parts will fall into the chassis
and they can get lodged between the center gear and the chassis.
Inspect the areas around the center gear for stray parts and turn the
truck upside down and shake out any culprits. If that does not help,
then you need to look more closely at the center di;. Make sure that
the pinion gear is meshed correctly and not binding. Inspect both
of the center axles to make sure they are not being impeded by any
misplaced components or that a drive pin has not come loose and
is slamming into the chassis. If this inspection does not yield the
problem, there is a chance that the problem could be in the motor.
Sometimes stray washers or other small parts can get lodged in the
motor, especially if it has cooling vents. Remove the motor from the
truck, but leave it electrically connected. ;en try to pull throttle with
the motor detached from the truck and see if it moves. If the motor is
jammed, you will have to rebuild it or replace it.