27
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 co1° to +18°
with symmetrical travels.
The mechanics should now be set up virtually perfectly. When the collective stick is at centre
(hover point), collective pitch should be about 9.5°.
Note:
The collective pitch curve can be adjusted later to meet your exact personal require-
ments. However, if you have already set differential travels in the basic set-up procedure any
fine adjustments required subsequently will be much more difficult to get right!
6. 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. Recommen-
ded values for the basic settings are: climb: 35%, descent: 15%.
7. 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 com-
pensatory 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. Some gyro systems
also allow you to set two different values for gyro effect (gain), and switch between them
from the transmitter via a supplementary channel. Some gyros even offer proportional con-
trol of the gain setting. The extra channel is controlled via a proportional slider or rotary knob,
or a switch, depending on the gyro system.
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! 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 influences affect the settings.
The aim of the gyro adjustment process is to achieve as high a level of gyro stabilisation as
possible, without the system causing the tail boom to oscillate.
Notes regarding the use of the Graupner/JR „PIEZO 550“ piezo gyro system in
conjunction with a computer radio control system (e.g. mc-12 ... mc-24)
1.
Set the servo travel for the tail rotor channel to +/-100% at the transmitter.
2.
If you have a gyro mixer („Gyro-Control") which suppresses gyro gain when you operate the
tail rotor control, it is essential to disable it permanently.
3.
Disconnect the tail rotor pushrod at the tail rotor servo.
4.
4. Operate the tail rotor control at the transmitter; at about 2/3 of full travel in either direction
the servo should stop, even when the stick is moved further (travel limiting).
5.
Connect the tail rotor pushrod to the servo in such a way that the tail rotor’s mechanical end-
points in both directions are the same as the travel set by the travel limiter (servo should be
just short of stalling on its mechanical end-stop at this point).
It is essential to make these adjustments mechanically, i.e. by altering the linkage
points and pushrod length. Don’t try to do it electronically using the transmitter’s
adjustment facilities!
6.
Now correct the tail rotor setting for hovering, i.e. when the collective pitch stick is at centre,
using the servo travel centre adjustment facility at the transmitter.
7.
Gyro gain can now be adjusted between „0“ and maximum effect via the auxiliary channel
only, using a proportional control on the transmitter. If required, maximum gain can be
reduced by adjusting the travel of the auxiliary channel or by adjusting the transmitter
control. This gives you a useful range of fine adjustment for tailoring gyro response to your
requirements.
8.
If you find that the tail rotor control system is too responsive for your tastes, adjust it using
the exponential control facility; on no account reduce servo travel, as it must be left at +/-
100%!
Содержание JetCat 6810
Страница 31: ...31 Bedienungsanleitung ...
Страница 101: ...31 Operating Instructions Graupner Jetcat Modell Helicopter Turbine PHT 3 ...
Страница 107: ...37 Wiring diagram fuel pump and starter glowplug Connections overwiew of the turbine s operating components ...
Страница 171: ...31 Instructions d utilisation ...
Страница 177: ...37 Schéma de connexion Pompe à carburant et Starter Bougie Connexions des éléments de commande Généralité ...
