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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. In the Configuration Manager go to Tab 5 and select Item 19 - click the Update_Mode button. Then set the Heli Trim Button field and click Save to save your settings.

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 aircraft.      

Important Pre-requisites:

1. Driver card 20x2 chip firmware version 33 (or later) is required.
    
2. CL software v1.120 (X-Plane version) and background process v1.293 (or later) are required.
    
3. BFF CL Setup V1.10 (or later) application is required.
    
4. The CL software and BLDRV-12/24 driver cards MUST be set for Potentiometer-less mode. This is the default for the new CL_SPU + BLDRV2 cards.
    

Configuration Settings: Run the BFF Setup application......

1. Use Tab 5 Item 19 to set the Heli Trim Mode and Button to specify the button on the pilot station joystick card to be used to toggle cyclic trim on/off.
   
   Then for BOTH elevator Tab 1 (pitch) and aileron Tab 2 (Roll) axes.....
    
2. Set Items 28 & 29 to set the breakout force level and rate to be used to lock the cyclic in position when cyclic trim is engaged.
    
3. Set Items 11 & 12 to 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.
    
4. Use Item 5 to set the Min. Spring Constant to set a fixed modest return to mid force if it is required.
   
   IMPORTANT: ALL other Aerodynamic loading settings should be disabled when helicopter trim mode is in use.
    
5. Set Item 25 (Balanced tick box) is ticked to remove any fixed or variable control surface weight effects.
    
6. Selecting Tab 5 Item 19 Heli-Cyclic mode and clicking the Update Mode button should automatically make the following settings.
   
   Tab 5 Item 3: Position Reporting Method = 1 (for pot-less mode)
   Tab 5 Item 25: Fixed x10 resolution enable = 1
    
7. Tab 7 Item 8: Alt trim joystick no. -buts can be set to specify the joystick card used for the trim hat switch buttons used for local trimming when cyclic trim is engaged. Items 9 to 12 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 Tab 7 Item 3 can be used for that axis - please read the pop-up help tips for more information.
    
8. Tab 5 Item 15: 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.
    
9. SAVE your new background process settings.

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.

Auto-Pilot: If A/P is active the system will move the cyclic to follow the pitch and bank A/P control actions. These movements are read from custom XPUIPC offsets 0x66DA and 0x66DC as set in the XPUIPCOffsets.cfg file.

Note this is X-Plane specific.

Tab 4 Items 2 & 3 would usually be set = 1.0 to apply the full A/P movement action to the cyclic.

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