Final Checks Before The First Flight - GRAUPNER 400 Bedienungsanleitung

For the swashplate servos (collective pitch function) it is important to check that servo travels
are symmetrical, i.e. with the same values for both directions. The collective pitch function of
the swashplate servos should produce a range of blade pitch angles covering -5° to +13°,
also with symmetrical travels; you may find it necessary to remove the servo output arm,
move it round by one spline and fit the retaining screw again.
The mechanics should now be set up virtually perfectly. When the collective stick is at centre
(hover point), collective pitch should be about 5.5°, and the speed controller should be at the
"half-throttle" position.
Note:
The collective pitch and power curves can be adjusted later to meet your exact personal
requirements. However, if you have already set differential travels in the basic set-up
procedure, as shown in diagram "B" above, any fine adjustments required subsequently will
be more difficult!
6. Collective pitch and power curves
These adjustments are of fundamental importance to the flight performance of any model
helicopter. The aim of the procedure is to maintain a constant rotor speed when the model is
climbing and descending, i.e. regardless of load. This then represents a stable basis for
further fine-tuning, e.g. of the torque compensation system etc. (see also "Collective pitch
and throttle curves").
7. Static torque compensation
The tail rotor servo is coupled to the collective pitch function via a mixer in the transmitter in
order to compensate for torque changes when you operate the collective pitch control. On
most transmitters the mixer input can be set separately for climb and descent.
Recommended values for the basic settings are: climb: 35%, descent: 15%.
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.
The gyro system used in the Micro Star 400 features a gain adjustor; initially this should be
set to 50% gain.
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 would be amplified by the gyro! In this case the
solution is to mount the gyro inverted.
One factor which is common to all gyro systems 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.

3. Final checks before the first flight

WWhen you have completed the model, run through the final checks listed below before 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 flight batteries are fully charged.
Don't attempt to fly the helicopter until you have successfully checked everything as described
above.
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Micro Star 400