GRAUPNER mx-24s, Programming Manual

Page: 83 / 216

83
Program description: Transmitter controls
Note:
Later, after setting up the throttle curve to suit the mo-
del (see page 124), it should not be possible to af-
fect the throttle servo with the throttle / collective pitch
stick when the throttle limiter is set up in this form and
closed.
The throttle servo now responds to the position of the
C1 trim lever only. You may need to adjust the settings
until a clean transition occurs. After starting the motor
you should check that you can actually stop it again
reliably using the C1 trim lever.
At the fl ying fi eld, move the throttle limiter s l o w l y
to the forward end-point, to avoid a sudden opening
of the carburettor. At this setting the throttle servo can
be controlled in the usual way using the throttle / coll-
ective pitch stick.
This variable “limiting” of throttle travel certainly pro-
vides a convenient method of starting and stopping
the motor, but it also offers the possibility of recording
the fl ight time. To accomplish this all you have to do is
program a control switch close to the full-throttle point
of the throttle limit slider, and then assign an On / Off
switch to the timer.
At the same time the throttle limiter provides an addi-
tional level of safety. For example, just imagine what
could happen if you were carrying the helicopter to
the take-off site with the motor running – but without
the throttle limiter set – and you accidentally moved
the C1 stick …
That is why the software alerts you if you switch the
transmitter on with the carburettor too far open: you
will hear an audible warning, and the following mes-
sage appears on the screen:
CAUTION:
Setting the “Throttle limit 12” input to “free” does
not switch the throttle limit function off; instead it
sets the limiter to “half-throttle”.
Notes:
• You can use the »
Servo display « menu to ob-
serve the infl uence of the throttle limit slider. This
menu is accessed by pressing the
HELP button
whilst holding the rotary control pressed in. Pres-
sing the
ESC button or the rotary control returns
you to your starting point.
• Bear in mind that servo output 6 controls the
throttle servo on the
mx
-24s.
• If you connect a servo to output 12, it can be used
independently for other purposes by means of mi-
xers, provided that you separate the servo from
the transmitter control at function input 12 in the
»
MIX only channel « menu; see page 142.
• The throttle restriction set by the throttle limiter is
shown as a horizontal bar in the graphic represen-
tation of the throttle curve on the second display
page of the “Channel 1
throttle” option of the
» Helicopter mixers « menu (see page 124). The
output signal of the throttle servo cannot be
higher than that defined by the position of the
horizontal bar:
The appropriate graph was anticipated here: in the
above example the throttle limit control is set to
-60%, and therefore restricts the travel of the
throttle servo to around -60% of full travel.
Time delay for the throttle limiter
0% +100%+100%
+125%
offset
SEL ASY SYM ASY SYM SEL
–time+
0%
0%
0%
+100%+100%
+100%+100%
0.0 0.0
0.0 0.0
0.0 0.0
«normal »
9 +125% +85% 0.0 4.0 Thr.l
–
Input
Input
Input
Cnt.
free
free
free 9
10
11
12
The throttle limiter could cause an abrupt opening
of the throttle, and to avoid this it is advisable to as-
sign an asymmetrical time delay to the throttle limiter
(Input 12) when the control is moved towards its for-
ward end-point. This applies in particular if you intend
to use a switch to control the throttle limiter instead of
the side-mounted proportional control, CONTROL 9.
This is the procedure for defi ning a delay time: move
the throttle limit control forward towards full-throttle,
then use the rotary control to select the
ASY fi eld un-
der the “-time+” column. After a brief press on the ro-
tary control you can enter an appropriate time delay –
e. g. four seconds – by rotating the control. A further
brief press on the rotary control concludes the entry
process.
Point ?
m
OU
T
P
U
T
– +
1
10
0
-60%
-60%
«normal »
Channel 1
Input
Curve
off
Output
Throttle
Throttle limiter position
Thr
too
high!
Modme
SPCM20
nner
0h K62
28100 0
Stop
Flight
0 00
0 00
Marker line indicates the last C1 trim position
(idle setting)
Throttle limit slider
Trim position at which the motor was stopped
Centre point