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9. Setting up
9.1 Swashplate linkage
The first procedure is to adjust the four-servo swashplate linkage:
•
First set the servos to centre by switching on the radio system with the collective pitch stick
at centre. Fit the output arms correctly on the servos, and fine-tune the settings using your
transmitter’s servo centre adjustment facility if required.
•
At the centre position of the servos the output arms on the roll / collective pitch servos
should be exactly vertical, while the bellcrank arms connected to the pushrods running to
the swashplate must be exactly horizontal. This has to be set by adjusting the four vertical
pushrods. First disconnect one pushrod from the swashplate, then set the swashplate hori-
zontal by adjusting the remaining three pushrods. Now adjust the length of the fourth
(disconnected) pushrod so that it can be re-connected to the swashplate without exerting
any force at all on the servo.
•
The direction of servo rotation, and therefore the working “sense” of the components in the
swashplate mixer (pitch-axis, roll, collective pitch) must now be set correctly; for this set-up
process it is again useful temporarily to disconnect one of the pushrods running to the
swashplate:
When you increase collective pitch, all the pushrods should move upward, thereby moving
the swashplate in the axial direction. If one of the servos rotates in the wrong direction,
correct it using the
servo reverse
facility on your transmitter.
When you apply forward cyclic, i.e. a pitch-axis command in the forward direction, the
swashplate should tilt forward; if it tilts to the rear, you need to reverse the
pitch-axis
function in the swashplate mixer
.
When you apply a right-roll command, the swashplate should tilt to the right. If it inclines to
the left, you must reverse the
roll function in the swashplate mixer
.
9.2 Setting up the cyclic control system
The basic settings of the roll and pitch-axis control systems should already be correct if you
have fitted the pushrods exactly as described in these instructions. The pushrod linkage points
on the servo output arms are pre-defined, so any servo travel adjustment required must be car-
ried out via the transmitter’s electronic adjustment facilities. Please note that servo travel must
not be set at too high a value; the swashplate must not foul the main rotor head when the roll
and pitch-axis stick is at its end-points, as this would mean that smooth collective pitch control
would no longer be possible, since the swashplate could not move any further along the shaft.
9.3 Main rotor collective pitch settings
The collective pitch values are measured using a rotor blade pitch gauge (not included in the
kit). The following table shows good starting points; the optimum values may vary according to
the rotor blades you are using and the model itself.
Minimum
Hovering point
Maximum
Hover
+1°
9...10°
18°
Cruise
+1°
8...9°
18°
Auto-rotation
+1°
10°
18°
The collective pitch settings are adjusted at the transmitter. This is the procedure:
1. Measure the setting for hovering collective pitch and set it correctly.
2. Measure collective pitch maximum and minimum, and adjust the values using the collective
pitch adjustment facility on your transmitter.
