UNIVERSAL Helicopter
- 8 -
5. Adjustments to the COLLECTIVE
PITCH control which apply to all
flight modes
In addition to the DIRECT THROTTLE switch the fol-
lowing options are available:
3. Trim method
You can switch between Centre Trim and Stan-
dard Trim. More on this under the title „This is
how it works ...“.
4. Trim travel and direction
Trim travel can be set to any value in the range
0% to 100%, giving you the option of anything
between super-fine trim and ultra-coarse trim.
You can also reverse the direction of effect of the
trim slider by pressing the button (prefix
changes from „+“ to „-“). If you change nothing,
trim travel stays at the default +30%.
5. AUTOTRIM
The default setting for Autotrim is OFF, and we
will leave it that way. More on this under the title
„This is how it works ...“.
6. COLLECTIVE PITCH MAX
Here you can define whether the collective pitch
stick has to be moved FORWARD or BACK to
obtain maximum climb. Unless you are already
used to flying with a different arrangement we
recommend that you leave this setting at the de-
fault FORWARD. To change it press then .
TIP: VITAL POINT!
If you change COLLECTIVE PITCH MAX to BACK,
you must also reverse the TRIM TRAVEL.
(change prefix from + to – by pressing R)
6. Setting up flight mode 1 (Hover)
Now you can define how you want the helicopter to
„behave“ when hovering. We will do this in four steps:
1. Adjust the swashplate servos
2. Adjust the tail rotor servo
3. Adjust the throttle servo
4. Adjust the curves (COLLECTIVE PITCH,
TAIL ROTOR, THROTTLE)
TIP:
In steps 1 to 3 you will be
reversing and/or switching off mixer inputs.
These settings are not flight mode dependent.
In Step 4 you will make adjustments which can be
vary from flight mode to flight mode.
6.1 Adjusting the swashplate servos
In our example we have opted for a helicopter with
three swashplate servos arranged at 90°. At the servo
assignment stage we have also laid down that the
swashplate is controlled by servos 2, 3 and 4. Now all
we need to know is the location of each servo relative
to the swashplate. The drawing below shows the ar-
rangement we have assumed for our example.
Servo positions at the swashplate
If the swashplate is to work correctly the servos must
carry out the following movements:
1. Collective pitch stick in the
„maximum“ direction:
All three servos up
2. Roll-axis stick to the left:
Servo 2 down
Servo 3 no movement
Servo 4 up
3. Pitch-axis stick forward:
Servo 2 and 4 no movement
Servo 3 up
If you now try to operate the three swashplate servos
in the model you are in for a surprise, as the swash-
plate will be „all over the place“. The reason for this is
that we are controlling all three servos with the same
mixer type: HEADMIX. The pre-set default values for
the three mixers are the same, but that is not what is
required: we want the servos to respond differently
depending on their task. We have to carry out further
adjustments to make this happen.
The next step is to correct the servo movements stick
by stick and servo by servo.
Starting with COLLECTIVE PITCH
Preparation: set the roll and pitch-axis sticks and the
associated trim sliders to neutral (centre). This avoids
confusing side-effects.
If you now move the COLLECTIVE PITCH stick for-
ward the swashplate should move up the mast without
tilting.
Let us assume that servos 2 and 3 now run correctly,
but servo 4 moves the swashplate down instead of up.
Direction
of flight
To Next Page
Loading...
