Operation Manual

Static Mixer Dynamic Mixer
(access via Set-Up Menu) (access via Set-Up Menu)
Helicopter 77
DYNAMIC TORQUE
COMPENSATION
STATIC TORQUE
COMPENSATION
Using this option the static torque compensation
(Pitch Î Tail) can be adjusted, separately for the
climbing, indicated "STH", and descending flight,
indicated "STL" representing above and below the
collective pitch control stick central position.
It is the goal of this option is to find settings to
compensate for the change in torque, compared to
that for hovering flight, to prevent the helicopter
turning during climbing and descending flight. It is
not intended to trim for hovering flight which is
carried out exclusively with the tail rotor trim lever.
Required for a useful setting of torque compensation
is that the pitch and gas curves were correctly set,
ensuring a constant rotor speed through the entire
range of collective pitch (see page 70).
The mix direction depends on the direction of the
main rotor rotation: For anti-clockwise rotating
systems (anti-clockwise as seen from above, e.g.
HEIM-system) positive values are to be set, for
clockwise rotating rotors use negative values.
Set-Up
:
A separate setting is made for both directions of stick
movement, which swap as the control stick is
brought into the relevant position, using the INC or
DEC buttons, in a range from -125% to +125%.
CLEAR puts the mix proportion back to 0%.
Using switch 6 this mixer can be turned off at the
same time as the dynamic torque mixer.
Note
:
During autorotation the static mixer is automatically
turned off, which is indicated by the flashing
announcement "STL" or "STH".
With the dynamic mixer Throttle Î Tail momentary
torque fluctuations can be compensated for, which
are caused by acceleration delay in the drive.
It is mainly intended for older helicopters without
collective pitch and RPM controls lift, however, it can
be used with helicopters that, although equipped with
collective pitch control, do not maintain constant
system RPM, but with the collective pitch control
change the RPM at the same time. This applies
particularly to older models, for example the BELL
212 TWIN JET.
The mixer limits the tail rotor adjustment temporarily
and thereby compensates the brief torque changes.
The size of overshoot is set using INC / DEC .
CLEAR puts the mix proportion back to 0%.
Using switch 6 this mixer can be turned off at the
same time as the static torque mixer.
The mix direction depends on the direction of the
main rotor rotation: For anti-clockwise rotating
systems (anti-clockwise as seen from above, e.g.
HEIM-system) positive values are to be set, for
clockwise rotating rotors use negative values.
With modern helicopters, which are flown with
constant RPM throughout the entire collective pitch
range, this mixer is not needed and therefore
should not be activated.
Note
:
During autorotation the dynamic mixer is turned off
automatically, which is indicated by the flashing
announcement "DYN.