Appendix C. Helicopter Cyclic Mode.
In V1.120 of the CL software (with v1.293 of the
background process) I've added an operating mode for simple
helicopter cyclic loading. This is active in the X-Plane version of
the CL software only.
Helicopter cyclic mode is enabled by specifying an
additional button number on the pilot station joystick card to be
used for toggling cyclic trim on/off. The BFF CL Setup v1.10
application should be
used to do this - see Elev-Tab1-Setup- Heli Trim But. A
non-zero button number will enable the mode.
In helicopter cyclic loading mode, whilst cyclic
trim is disengaged, the cyclic moves
freely without airspeed dependent loading (but with damping/friction
if set). When cyclic trim is engaged the CL system will lock the
cyclic at the position at which trim was engaged. The normal
"elevator-pitch" and "aileron-roll" axis trim buttons can then also
be used to provide position trim about the locked position. The cyclic
is held in position by an adjustable breakout force generated by the
CL system - the pilot can push out of this manually to move the cyclic
whilst trim is active if required.
Damping and friction components can be specified
to provide some tuneable resistance to cyclic movement -
particularly useful when cyclic trim is disengaged. Also a modest
fixed spring rate component can be set to give a light return to mid
if required when cyclic trim is disengaged. The normal engine vibration settings are active
in the mode.
Air-speed dependent spring and trim loading,
propwash, AoA and mass acceleration loading effects are all disabled
whilst in helicopter cyclic mode as these are specific to fixed wing
- Driver card 20x2 chip firmware version 33 (or
later) is required.
- CL software v1.120 (X-Plane version) and background process
v1.293 (or later) are required.
- BFF CL Setup V1.10 (or later) application is
- The CL software and BLDRV-12/24 driver cards
MUST be set for
Configuration Settings: Run the BFF Setup
- Under Elevator-Tab1-Setup set the Heli Trim But to
specify the button on the pilot station joystick card to be used
to toggle cyclic trim on/off.
Then for BOTH elevator (pitch) and aileron (Roll) axes.....
- Under Tab2-Feel set the
breakout force level and rate to be used to lock the cyclic in
position when cyclic trim is engaged.
- Under the same Tab also set the damping
and/or friction levels to use - this will affect the feel of the
stick particularly when cyclic trim is disengaged and there is
no air-speed dependent loading on the cyclic.
- Under Tab3-Lift-Trim set the Min.
Spring Constant to set a fixed modest return to mid force if it
IMPORTANT: ALL other Tab 3 settings should be zero
or disabled when helicopter trim mode is in use.
- Under Tab4-Weight-Accel ensure the
Balanced tick box is ticked to remove any fixed or variable
control surface weight effects.
- SAVE your new settings.
- Use the Bck_Grnd_Set button to open the back
ground process settings. Ensure...
Line 74: Position Reporting Method = 1 (for pot-less
Line 62: Fixed x10 resolution enable = 1
Line 47: Alt trim joystick no. -buts is set to specify
the joystick card used for the trim hat switch buttons used for
local trimming when cyclic trim is engaged. Lines 48-51 are used
to specify the hat switch buttons on the card.
If pot based trim input is needed for the rudder (yaw pedals)
axis then Line 57 can be used for that axis - please read the
pop-up help tips for more information.
- Line 54: Button trim rate may need to
be adjusted to give the required local trim adjustment rate when
the hat switch is operated to give local cyclic position trim.
Reducing the value will slow down the speed of response of the
resulting trim movement.
- SAVE your new background process
If the above settings are not made correctly
then the helicopter cyclic mode and/or the breakout trim hold
function may not engage properly.
The helicopter cyclic mode is intended as a simple
simulation of the cyclic behaviour in helicopters with
"power-assisted" controls which use hydraulic systems to move the
rotors and which provide a cyclic trim function as part of the
flight control system.
It may not be representative of stick loading behaviour in non-power
assisted helicopter controls.