GRAUPNER MC-22S, Programming Manual

Page: 75 / 180

75 Program description: Switches
Auxiliary switch
Switches: Auto-rotation, Auto-rot. Ch1 position
A u t o r o t a t i o n
A u t o r o t a t i o n C 1 P o s . 0 %
t
Within a given model memory the mc-22s softwa-
re enables you to program a total of four indepen-
dent settings for each model helicopter, in order to
cope with the different stages of a fl ight; these inclu-
de the auto-rotation fl ight phase which is covered by
this menu. The three other fl ight phase switches can
be defi ned in the »
Phase setting « and » Phase assi-
gnment « menus. If you are a relative beginner to he-
licopter fl ying, please start by reading the “Helicopter”
programming example on page 150; and especially
the section entitled »
Auxiliary switch « on page 152.
The meaning of Auto-rotation
The term auto-rotation describes a fl ight situation in
which the helicopter is descending under no power,
with the main rotor kept spinning at high speed by the
air fl owing through the blades, which are set at a pitch
angle designed to promote this; the principle is that of
the windmill. The energy stored in the spinning rotor
can then be converted into upthrust just before touch-
down by changing the pitch angle, enabling the model
to fl are out and land safely.
Auto-rotation is used by full-size and model helicop-
ters, and makes them capable of landing safely with
the engine stopped, e.g. if the motor should fail in
fl ight. However, an auto-rotation landing can only
be successful if the pilot is highly skilled and experi-
enced, and is thoroughly familiar with his model he-
licopter. Fast reactions, a good “eye” and fi ne judge-
ment are essential, as the rotational energy in the ro-
tor can only be exploited once for the fl are.
In a competition fl ight the motor must be stopped if an
auto-rotation landing is called. For practice, however,
it is sensible to keep the motor running at idle when
practising “autos”, so that full throttle can be applied
immediately if a critical situation should develop.
Auto-rotation
Operating the auto-rotation switch invokes the auto-
rotation fl ight phase, in which the controls for “thrott-
le” and “collective pitch” are separated, and all mixers
which affect the throttle servo are switched off. This
fl ight phase is assigned the fi xed name «Autorot»,
which appears in the basic display and all menus
which can be set separately for different fl ight phases
(see page 76 for list).
Defi ning the auto-rotation switch
Press the rotary control and assign a switch to this
function as described on page 30.
This switch has
absolute priority over all other fl ight phase swit-
ches.
Auto-rotation Ch1 position
Alternatively the auto-rotation fl ight phase can be in-
voked by means of a switching point on the throttle /
collective pitch stick Ch1. When you select this line on
the screen, the
STO (store) fi eld appears.
Move the Ch1 stick to the switching position you wish
to use, and press the rotary control: the screen dis-
plays the current value. In the right-hand column you
can now assign an activation switch.
Approach angle under
varying wind conditions.
How the “Autorot Ch1 Pos.” works
Assuming that you have operated
the activation switch, the Heli pro-
gram immediately switches to “auto-rotation” when
the Ch1 stick is moved below the set switching point,
and stays in that fl ight phase until you move the ac-
tivation switch (in this example No. 2) back to the
“OFF” position. It does this regardless of the position
to which you move the Ch1 stick.
“Auto-rotation Ch1 Pos.” always has precedence over
the remaining three fl ight phase switches, as assi-
gned in the »
Phase setting « and » Phase assign-
ment « menus.
Auto-rotation parameter settings
The following parameters
• collective-pitch servos
• throttle servo
• tail rotor servo
• any swashplate rotation
• gyro setting
are programmed in the » Helicopter mixer « menu
(see page 99).
All the other menus which apply to auto-rotation are
listed in the table on page 76.
45°
60°
75°
Approach angle:
strong
wind
medium
wind
without
wind
K 1 P o s . - 8 5 % 2
S T O
Move Ch1 stick
to the desired
position.