Order No.
35 MHz: F 8042
40 MHz: F 8043
41 MHz: F 8044
FX-30
Setting up the swashplate mixer
If you have selected a model with an electronic three-point
swashplate linkage (120° ECCPM), click on Swashplate in the
Base menu.
Look at Swashplate AFR in the Swashplate menu, and you will
see that all values for roll-axis, pitch-axis and collective pitch
are set to +50%. These are the default values, which are suita-
ble for most model helicopters. When you have installed the
s
ervos in the helicopter and fitted the control linkages, the set-
tings will need to be fine-tuned to match each other and the
model.
A good tip at this stage is to use the Servo Monitor in the Base
menu. In the top part of the menu display you will find the
Servo Test function. Set this to Neutral Test, and all servos will
move to the neutral position and stay there. This procedure is
ideal for setting up an ECCPM helicopter.
An alternative is to centre the collective pitch stick with the
h
elp of the collective pitch display in the transmitter’s Start
screen. This screen is an excellent means of centring colle-
ctive pitch accurately, as the value is displayed in tenths of a
percentage point.
Fix the output discs on the servos as stated in the building
instructions provided by the model helicopter manufacturer,
with the aim of setting the linkage point exactly at right-angles
to the pushrod. Adjust the pushrods in such a way that the lin-
kage arms are at right-angles (i.e. neutral position) to the heli-
copter’s chassis.
Adjust the pushrods from the linkage arms to the swashplate
so that the swashplate is at precisely the correct height, and
exactly at right-angles to the main rotor shaft (rotor mast). Now
check whether the swashplate moves in the correct directions
when you apply collective pitch and cyclic commands.
If the collective pitch system works in the wrong direction,
change the value for Swashplate AFR to -50%: this reverses
the direction of movement of the swashplate. The next step is
to check the roll and pitch-axis systems and reverse them if
necessary by changing the prefix to - (minus). If one or more
servos now run in the opposite direction when you operate the
collective pitch stick, you need to move to the Servo Reverse
menu and change the direction of rotation of the servo or ser-
vos concerned. Repeat the check of the swashplate AFR dire-
ctions. Please move the collective pitch cautiously to the end-
points, to avoid the servos striking their end-stops if the tra-
vels are not correct. If the servo travels are too great, select the
Swashplate AFR menu, and reduce the set value for AFR until
the swashplate’s maximum travels are just short of the limits
dictated by the mechanical system. With the rotor blades fitted
and a pitch gauge to hand, you can now read off the neces-
sary main blade pitch angles, and set them accordingly in the
Swashplate AFR menu.
Swashplate Detail settings
Caution:
For this adjustment procedure it is very important that the ball-
end bolts on the inner ring of the swashplate line up exactly
with the ball-end bolts on the outer ring of the swashplate.
If this is not the case, the rotor head will move in the ‘pitch-
axis’ direction when you apply a roll-axis command, and vice
versa. In the same way, check carefully that a roll-axis or pitch-
axis command has no effect on the other function.
At this point you should fine-tune the servo travels in order to
maintain the swashplate orientation at right-angles throughout
the collective pitch range; accurate work here will eliminate
any interaction with the cyclic commands.
In the Base menu select the Swashplate menu, then the sub-
menu Swashplate Detail.
In the Mix Rate window you will see the first two mixers ‘Colle-
ctive pitch to roll-axis’, and ‘Collective pitch to pitch-axis’. The
purpose of these two mixers is to align the swashplate accura-
t
ely at both ends of the collective pitch travel.
When you move the collective pitch stick, you will see that the
input fields are marked accordingly. To alter a value, move the
cursor to an input field and use the 3-D hot-key to set that
point. Move the collective pitch stick to maximum collective,
and look at the swashplate from the nose of the model: adjust
the collective pitch to roll mixer until the swashplate is exactly
horizontal. Move the collective pitch stick to minimum colle-
ctive, and repeat the above adjustment.
T
ip: set your blade pitch gauge to 0 degrees, and attach it to
one flybar paddle. Taking the top edge of the rotor head as the
reference plane, you will be able to perceive even the slightest
movement in the swashplate.
Now turn the rotor head through 90 degrees, so that you see
the flybar paddle with the blade pitch gauge attached from the
side of the model. Now adjust the collective pitch to pitch-axis
mixer until the swashplate is exactly horizontal at minimum
and maximum collective pitch.
The next three mixers are used to eliminate interactions in the
swashplate when the collective pitch stick is located at 50%,
i.e. at centre. Set up the roll to collective pitch mixer in such a
way that at full roll to right and left the swashplate remains
orientated correctly in the direction of the pitch-axis; this is
most clearly visible if you observe the model from one side.
The next adjustment concerns the ‘pitch-axis to roll-axis’
mixer and the ‘pitch-axis to collective pitch’ mixer; now the
swashplate must remain aligned correctly in the direction of
the roll-axis at full forward-pitch and back-pitch; this is most
clearly visible if you observe the model from the nose.
The next step is to adjust the linkage compensation. This set-
ting compensates for unwanted interactive swashplate devia-
tions at extreme collective pitch settings.
There are four adjustment facilities for high collective pitch
values, and a further four adjustment facilities for low colle-
ctive pitch values. With the collective pitch stick at maximum,
observe the swashplate from one side, and adjust the value for
the roll mixer so that no pitch-axis deviation takes place when
full right-roll and left-roll commands are applied.
Now turn the rotor through 90 degrees, and adjust the pitch-
axis mixer analogously. Finally you should repeat the whole
procedure at minimum collective pitch.
Speed compensation
This setting is only required for 120° ECCPM rotor heads, and
its purpose is to compensate for the mechanical advantage of
the roll-axis and collective pitch servos, which are faster wor-
king together than the single pitch-axis servo when the pilot
applies a pitch-axis command. This problem only manifests
itself if you move the pitch-axis stick forward and back at high
speed. Adjust the speed compensation in such a way that the
ball-link in the centre of the swashplate does not jump up or
down when you apply rapid pitch-axis movements. This set-
ting will be in the range 15 to 20.
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