GRAUPNER MC-22S, Programming Manual

Page: 153 / 180

153 Programming examples – Model helicopters
done so, adjust the mechanical linkages to the rotor
head so that all the blades are set to a collective pitch
angle of 4° to 5° positive for the hover. All known heli-
copters will fl y at this approximate setting.
Now push the collective pitch stick fully forward to the
maximum collective pitch point (we have already set
collective pitch minimum to the “back” position). The
solid vertical line in the graph indicates the current
stick position. You can now adjust this point “H” (high)
on the collective pitch curve using the rotary control,
with the aim of producing a collective pitch maximum
setting of around 9° at the main rotor blades. Point “H”
will need to be around 50%.
Note:
A rotor blade set-up gauge, e.g. the GRAUPNER
item, Order No.
61 , is very useful when setting up bla-
de pitch angles.
Now pull the collective pitch stick right back to the col-
lective pitch minimum position: point “L” (low). Set the
blade pitch angle for this setting to 0° to -4°, depen-
ding on the pilot’s fl ying ability. This process produces
a slightly “bent” line (known as the “collective pitch
curve”) at the hover point, and the graph may well
look something like this:
P i t c h
I n p u t + 5 0 %
C u r v e O u t p u t + 2 5 %
o f f P o i n t ?
-
1
At this point you should round off the curve by simply
pressing the left
ENTER button again.
If you now switch to the auto-rotation phase – you will
see the name of the fl ight phase “Autorot” at the bot-
tom of the screen – you will fi nd the “old” collective
pitch curve once more. In this phase you should set
the same values as in the normal phase, with the fol-
lowing exception: increase the collective pitch ang-
le by about 2° at “H”, i.e. the extreme forward position
of the stick. This gives slightly more rotor blade pitch
for fl aring the model when practising “autos” at a la-
ter (!) date.
Once you have set up the collective pitch curve, press
ESC to return to the Helicopter mixers menu list, and
move to the “ Channel 1 throttle ” line where you
can set up the throttle curve.
The fi rst step here is to defi ne the idle trim range by
adjusting point “L” on the throttle curve; it should be
set to around -65%.
With the throttle limiter closed and the idle trim fully
open, pull the collective pitch stick to the “fully back”
position, and move it slightly to and fro. The thrott-
le servo should not respond to this movement. This
arrangement gives you a seamless transition from
idle trim to the throttle curve. You will probably need
to make further adjustments to the throttle curve, but
this must be carried out later as part of the fl ight-tes-
ting process.
If you temporarily switch from this graphic display to
the auto-rotation fl ight phase (AR), the display “Chan-
nel 1
throttle off” appears, i.e. the throttle servo is
switched to a fi xed value which can be set up as fol-
lows:
Select ESC to return to the menu list. You will fi nd that
certain new sub-menus now appear in the list, but
only as long as you stay in the auto-rotation phase.
The new menus are:
P i t c h = >
T h r s e t t i n g A R - 9 0 %
T a i l r o t o r o f f s e t A R 0 %
G y r o s u p p r e s s i o n 0 %
S w a s h p l a t e r o t a t i o n 0 °
« A u t o r o t »
t
The important line here is “ Thr setting AR ”. The va-
lue on the right of this line should be set to either ap-
proxi125% or -125%, depending on the di-
rection of rotation of the servo. If you are not sure of
this, call up the »
Servo display « menu to help you.
This setting ensures that the motor is reliably stop-
ped in the auto-rotation phase (to cope with an emer-
gency). Later, when you have gained suffi cient expe-
rience to practise auto-rotation landings, the setting
should be changed to a value which provides a reliab-
le idle.
At present the remaining sub-menus are of no impor-
tance. Switch “AR” off, and we move back to the fi rst
menu list.
Call up the “Channel 1 tail rotor” line, in which you
can set static torque compensation for the tail rotor.
Here again, it is better to keep to just three reference
points; anything more elaborate is strictly the province
of experienced pilots. For the moment you can safe-
ly accept the pre-set values of “L” = -30% at the bot-
tom end of stick travel and “H” = +30% at the opposite
end, although you may fi nd it necessary to correct the
settings slightly later.
Now switch back to the AR phase for a moment. The
set-up curve is disabled here, with the result that the
tail rotor servo no longer responds to collective pitch
commands (when the main rotor is not powered, the-
re is no torque to be corrected). All the other sub-
points are of no importance for the moment.
If your gyro features gain control from the transmitter
– unlike the model we are using in this example – you
can safely store the standard gain value in the mo-