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8. Gyro adjustment
Gyro systems damp out unwanted rotational movements around the vertical (yaw) axis of the
model helicopter. They do this by detecting the unwanted motion and injecting a
compensatory signal into the tail rotor control system, and in order to achieve this effect the
gyro electronics are connected between the tail rotor servo and the receiver. Many gyro
systems also allow you to set two different values for gyro gain, and switch between them
from the transmitter via a supplementary channel. The extra channel is controlled via a
proportional slider or rotary knob, or a switch, depending on the gyro system.
If your gyro features an adjustor box with two rotary pots for two fixed settings, and you can
switch between them from the transmitter, it is best to set one adjustor approximately to
centre (50%), and the other to 25%. If the gyro system provides proportional control between
the two set values, then the one pot should be set to „0", the other to about 80%.
If you have a gyro system whose effect cannot be adjusted from the transmitter, i.e. there is
only a single adjustor on the gyro electronics itself, the pot should be set to 50% gain as a
starting point.
Check that the direction of the gyro's compensatory action is correct, i.e. that it responds to a
movement of the tail boom with a tail rotor response in the opposite direction. If this is not the
case, any yaw movement of the model will be amplified by the gyro! Most gyro systems are
fitted with a change-over switch which reverses their direction, and this must then be moved
to the appropriate position. However, some systems have no such switch, and in this case
the solution is to mount the gyro inverted.
One factor which all gyro systems have in common is that flight testing is necessary in order
to establish the optimum settings, as so many different factors influence the settings.
The aim of the gyro adjustment process is to achieve as high a level of gyro stabilisation as
possible, without the gyro causing the tail boom to oscillate.
13. Final checks before the first flight
When you have completed the model, run through the final checks listed below before carrying
out the first flight:
•
Study the manual again and ensure that all the stages of assembly have been completed
correctly.
Check that all the screws in the ball-links and brackets are tightened fully after you have
•
adjusted gear meshing clearance.
Can all the servos move freely, without mechanical obstruction at any point? Do they all
•
rotate in the correct direction relative to the stick movements? Are the servo output arm
retaining screws in place and tight?
•
Check the direction of effect of the gyro system.
•
Ensure that the transmitter and receiver batteries are fully charged. We recommend using a
voltage monitor module to check the state of charge of the receiver battery on the flying
field.
Don't attempt to fly the helicopter until you have successfully checked everything as described
above.
14. Maintenance
Helicopters, whether large or small, place considerable demands on maintenance. Whenever
you notice vibration in your model, take immediate steps to reduce or eliminate it. Rotating parts,
important screwed joints, control linkages and linkage junctions should be checked before every
flight. If repairs become necessary be sure to use original replacement parts exclusively. Never
attempt to repair damaged rotor blades; replace them with new ones.
39
Skalar
elektro
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