S-12
The L.S.T. trim feature has two options, L.S.T. and normal. In
normal, when making trim changes using the Aileron elevator
or rudder digital trims, the center as well as the endpoints is
affected by the trim values (i.e. right trim causes the center,
the right endpoint and the left endpoint to all shift to the right).
When L.S.T. is activated, only the center position is trimmed
(i.e. the center is shifted to the right but the endpoints are not
affected). This is useful for helicopters that have a hard stop
endpoint 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.
L.S.T. trim is normally turned on for helicopters.
The Trim System function adjusts the sensitivity of the spoiler,
aileron, elevator and rudder trims, plus the Flap Trim and
Flaperon Trimmers. 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 10µs and there are only 10
trim increments from center to each end. When set to 5, the
output is changed 5µs 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 Flap and Flaperon
Trimmers 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.
The trimmers can also be set to function as a Momentary switch
by selecting ON under Moment for either or both trimmers.
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.
83: Trim System
L.S.T. Trim