S-12
The LST trim feature has two options, LST and normal. In
normal, when making trim changes using the Aileron elevator
or rudder digital trims, the center as well as each end point is
affected by the trim value (i.e. right trim causes the center, the
right end point and the left end point to all shift to the right).
When LST is activated, only the center position is trimmed.
(i.e. the center is shifted to the right but the end points are not
affected). This is useful for control surfaces that have a hard
stop end point to prevent over-travel caused by trim or if it’s
desired to have trim changes not affect the total roll pitch or yaw
rate. LST trim is normally turned off for sailplanes.
The Trim System function adjusts the sensitivity of the spoiler,
aileron, elevator and rudder trims, plus the Flap trim and
Flaperon trim levers. The aileron, elevator and rudder trims are
adjustable from 0–10, with 10 being the coarsest adjustment
and 0 being trim off. The Flap and Flaperon trims are adjustable
from 0 to 30 in 3-step increments. Adjusting the digital
trim values has no effect on the total trim travel (unless 0 is
selected), however, it affects the resolution of each trim input.
When the value is set to 10, each click of trim adjusts the servo
output by 10µs and there are only 10 trim increments from
center to each end. When set to 5, the output is changed 5us
per trim step and there are 20 trim increments from center to
each end. When set to 1, each click of trim changes the servo
output by 1µs and there are 100 trim increments. When set to 0
the trim levers cease to function effectively, turning off the trim
function. The right and left trim levers are adjustable from 0 to
200 and can be turned on/ off. When adjusted to above 100%
the trimmer functions as a three-position switch. Reducing the
value increases the number of output positions.
When adjusting the digital trims (AILE, ELEV, RUDD), the total
trim travel does not change – only the number of increments
(beeps) changes, which makes for finer or coarser trim
movements. When adjusting the analog spoiler trim, however,
the total trim travel is actually reduced when set to less than
100%.
It is recommended to use a fairly coarse setting, such as the
factory default 4, when test flying a model for the first flights in
order to be able to trim it quickly, and then use a finer setting,
such as 3–1, for final precision trimming.
83: Trim System
LST Trim
Summary of Contents for JR DSM 12X
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