GRAUPNER mx-16 ifs, Programming Manual

Page: 85 / 132

85 Program description: helicopter mixers – model helicopter
This causes the rotor to accelerate quickly, resulting in
premature wear of the clutch and gear train. The main
rotor blades are generally free to swivel, and they may
be unable to keep pace with such swift acceleration, in
which case they might respond by swinging far out of
their normal position, perhaps resulting in a boom strike.
Once the motor is running, you should
s l o w l y in-
crease system rotational speed using the throttle limiter .
This completes the set-up procedure for throttle and
collective pitch.
Important fi nal notes
Before you start the motor, check carefully that the throt-
tle limiter is completely closed, so that the throttle can
be controlled by the Ch 1 trim lever alone. If the throttle
is too far open when you switch the transmitter on, you
will see and hear a warning. If you ignore this and start
the motor with the throttle too far advanced, there is a
danger that the motor will immediately run up to speed
after starting, and the centrifugal clutch will at once
engage. For this reason you should:
always grasp the rotor head fi rmly
when starting the motor.
However, if you accidentally start the motor with the
throttle open, the rule is this:
Don’t panic!
Hang on to the rotor head regardless!
Don’t let go!
Immediately close the throttle, even though there may
be a risk of damaging the helicopter’s drive train, be-
cause:
it is vital that YOU ensure
that the helicopter cannot possibly
move off by itself in an uncontrolled manner.
The cost of repairing a clutch or even the motor itself is
negligible compared to the damage which a model heli-
copter can cause if its spinning rotor blades are allowed
to wreak havoc.
Make sure that nobody else is standing in
the primary hazard zone around the helicopter.
You must never switch abruptly from idle to the fl ight
setting by suddenly increasing system rotational speed.
Conversely, if the model hovers below the mid-point,
correct this by reducing the pitch angle again.
You may fi nd that it is also necessary to correct the
throttle opening at the hover point (Point 3) in the “Ch 1
¼
throttle” menu.
This diagram only shows the
change in the hover point, i. e. col-
lective pitch minimum and maxi-
mum have been left at -100% and
+100% respectively.
+100%
-100%
OUTPUT
2 3 4 5 1
Control travel
Continue adjusting these settings until you really do
achieve constant main rotor speed over the full control
range between hover and climb.
The descent adjustment should now be carried out from
a safe height by fully reducing collective pitch to place
the model in a descent from forward fl ight; adjust the col-
lective pitch minimum value (Point 1) so that the model
descends at an angle of 60 … 80°. This is done on the
“Collective pitch” graphic page by moving the vertical
line to Point 1 using the collective pitch stick, and adjust-
ing the value accordingly using the rotary cylinder.
As an example, this diagram
shows only the changes in the
collective pitch minimum value.
+100%
-100%
OUTPUT
2 3 4 5 1
Control travel
Hover
point
Once the model descends reliably as described, adjust
the value for “Throttle minimum” – the value of Point 1
on the graph of the “Ch 1
¼
throttle” mixer – so that
system rotational speed neither increases nor declines.