H-12
The Trim System function adjusts the sensitivity of the 12X
trims, hovering throttle and hovering pitch trim levers and the
high pitch lever. The digital trims are adjustable from 0–10
with 10 being the coarsest adjustment and 0 being trim off.
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 10us 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 1us 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.
83: Trim System
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 throttle trim, and the
high pitch 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.
LST Trim
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 the end points is
affected by the trim values ( 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 helicopters 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 on for helicopters.
