GRAUPNER MC-22S, Programming Manual

Page: 94 / 180

94 Program description: Mixers
Roll throttle and pitch-axis throttle
Increasing collective pitch requires a corresponding
adjustment to the throttle setting, and the same ap-
plies if a substantial cyclic command is given, i.e. if
the swashplate is tilted in any direction. In the softwa-
re of the mc-22s you can adjust the degree of throttle
following for roll-axis and pitch-axis separately.
These mixers offer particular advantages in aero-
batic fl ying, e.g. when fl ying a roll: collective pitch va-
lues are only moderate, and the throttle therefore
only about half-open, but the roll requires major cyc-
lic commands, and these require a much higher po-
wer input.
The mixer values can be varied within the range 0 to
+100%. The program automatically sets the correct
direction of mixing.
In the auto-rotation fl ight phase this mixer is auto-
matically switched off.
Roll tail rotor and pitch-axis tail rotor
Increasing collective pitch requires a corresponding
adjustment to the tail rotor setting, and the same ap-
plies if a major cyclic command is given i.e. if the
swashplate is tilted in any direction.
In the software of the mc-22s you can adjust the deh-
gree of tail rotor following for roll-axis and pitch-axis
separately.
This function can eliminate a problem which is en-
countered primarily in extreme aerobatics which invol-
ve very large control defl ections in the pitch-axis con-
trol system, e.g. the “Bo-turn” (vertical pull up followed
by tipping over around the pitch-axis) and tight loops.
If the torque changes are not corrected by a mixer,
the model tends to rotate to a greater or lesser extent
around its vertical axis, and this spoils the appearan-
ce of the manoeuvre.
These two mixers provide static torque compensati-
on when the swashplate is tilted in any direction. The
mixers work by always increasing tail rotor thrust,
starting from the centre point of the roll and pitch-
axis sticks, i.e. they always affect tail rotor pitch in
the same direction, regardless of the direction of the
command.
The mixer value can be varied within the range 0 to
+100%.
The mixer direction is automatically determined when
you defi ne the direction of main rotor rotation in the
»
Helicopter type « menu, page 53.
In the auto-rotation fl ight phase this mixer is auto-
matically switched off.
Gyro suppression
Right at the outset we should mention that this func-
tion should not and must not be used if your model
is fi tted with a modern gyro system. However, ple-
ase read the operating instructions supplied with your
gyro. This menu has been retained so that the pro-
gram can still cater for all requirements and all pilots’
preferences.
In this program segment the effect of the gyro sensor
(“gyro”) varies according to the tail rotor stick position;
this assumes the use of a gyro system whose gain
can be controlled from the transmitter via an auxilia-
ry channel – this is channel 7 for
GRAUPNER/JR mc
radio control systems. The gyro suppression function
reduces gyro gain in a linear progression as the tail
rotor stick defl ection increases, the rate of suppressi-
on varying according to the mixer value you have set.
Without gyro suppression, i.e. with a mixer value of
0%, the gyro effect is constant, regardless of the tail
rotor stick position.
However, gyro gain can also be varied proportional-
ly between minimum and maximum by means of a sli-
der assigned to the “Gyro 7” line in the »
Control ad-
just « menu (see page 60). This could be transmit-
ter control 7, which in the standard transmitter confi -
guration is connected to socket CH7 on the transmit-
ter circuit board. In this case gyro gain is maximum
at full defl ection of the slider, and zero at the opposi-
te end-point. Of course, the software of the mc-22s al-
lows you to limit the gain adjustment range by alte-
ring the setting for transmitter control travel to both si-
des of neutral.
At any position of the slider, gyro gain at full defl ec-
tion of the tail rotor stick is:
“current slider position minus
gyro suppression value”,
i.e. when the slider is at the neutral position, a gyro
suppression value of 100% will reduce gyro gain to
zero with increasing tail rotor defl ection, and a value
between 100% and the maximum 199% suppresses
the gyro completely well
before full defl ection of the
tail rotor, depending on the slider position; see the di-
agram on next page.
If you are using the GRAUPNER/JR NEJ-120 BB
gyro, Order No. 3277 , the bottom and top values are
adjusted using separate rotary potentiometers: adjus-
tor 1 sets the
minimum gyro gain in the bottom positi-
on of the slider; adjustor 2 sets the maximum gain at
the top end-point of the slider; the transition between
these two values occurs roughly in the middle of the
slider travel.
In contrast, the PIEZO 900, PIEZO 2000 and PIEZO
3000 gyro systems feature proportional, infi nitely vari-
able adjustment of gyro gain; see below for typical di-
agrams.
An example of using fl ight phase-dependent (static)
gyro gain would be to exploit maximum stabilisation
for normal, slow fl ying, but to reduce gyro gain for fast
circuits and aerobatics.
1. Linear gyro suppression: 0% to 199%.
At the centre position of the tail rotor stick the gyro
gain is defi ned by the position of the slider control
“7”. It can be adjusted proportionally by moving the
slider 7 from zero (“min”) to maximum (“max”), un-