Aircraft
(ACRO)
Section
– 35 –
24. Before we set the servo neutrals, we need
to be sure that all the trims are centered. Press
both
Edit
keys to get to the main menu, where
voltage and time are displayed. Press the Up
arrow until the word TRIM appears. By
moving each of the four trim levers around,
you can see their positions, and move them
back to zero for the next step.
25. Once you have centered all the trims,
unscrew the screws holding the servo arms
onto the elevator, aileron, and rudder (we’ll
set the throttle travel later). You will want to
place the servo arms on the output shback so
they are near neutral — that is, about 90° to
the servo case sides or, if the servo is mounted
sideways, 90° to the pushrod (sideways
mounting is not recommended). This way you
won't run out of subtrim authority. Remove
all the arms that are in the way or interfere
with your pushrods.
90°
Servo
1
3
4
Pushrod
Adjust the clevises on each servo pushrod to
get the position of each control to be as close
as you can to neutral (lined up with the
adjacent portion of wing or tail).
Setting Subtrims. Now we’ll adjust all the
subtrims to electronically set the desired
neutral locations. To do so, go back to the
programming menu by pressing both
Edit
keys,
then press the
Up
or
Down
arrow key
repeatedly until STRM appears.
STRM 5
CH
421 3 567
26. Set the right aileron subtrim first. If the
little arrow is not pointing at channel 1, press
the one of the
Cursor
Left
or
Right
buttons
until it is (see figure). Then, adjust the subtrim
amount by adding or subtracting with the
Data
+Increase
or
–Decrease
keys. When you reach
a place where the right aileron matches up
with the fixed portion of the wing, you are
done. If you can’t get both to match up, then
set the subtrim back to zero and mechanically
adjust the clevis to get as close as you can,
then readjust the subtrim if necessary.
27. Note 1: you should NOT use subtrims
instead of mechanically adjusting the pushrods
to be close. This is because you can reduce
the travel of the radio, especially if you have
to set the subtrim near 100%. As we stated
before, get the pushrods close mechanically
first, then use the subtrim adjustment to get it
just right.
28. Note 2: if you mess up the number you’ve
entered or find the percentage the wrong
direction, you can get back to zero quickly by
pressing the
Active/Inhibit
(
Clear
) button.
29. Repeat the subtrim adjustment with the
elevator servo (CH2). First set the pushrod
length mechanically to get as close to neutral
as possible, then set the subtrim to get the
elevator lined up to be parallel with the
stabilizer portion. For full-flying surfaces, use
an incidence meter or another method to get
the incidence angle recommended by the kit
manufacturer or model designer.
STRM -8
CH
421 3 567
30. For the throttle, we recommend not setting
a subtrim at this time. You will use the trim
tab on the transmitter for setting your idle
RPM. To shut off the motor you will use the
Engine Cut function. In this way, you don’t
lose your carefully-set idle position.
31. Most people set up their engines to idle
with the throttle trim near center, so that there
is room for changes due to humidity and other
factors.
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