BFF Motion Driver v2 - Short User Guide


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10. Heave Cue Settings


The heave cue tuning settings can be made by manually adjusting the parameters in your .bff configuration file (see section 4), or by opening the heave settings window using the R button on the motion driver.

The Heave settings window includes input fields for the detailed parameters. Unlike the Pitch and Roll cues there is no settings wizard for the Heave cue; this is because the settings are fairly simple to make manually.

For details of each of the  parameters hold the mouse over an input text field and a pop-up help window will appear.

Manual Settings

The main scaling parameters to fit the required heave acceleration to the heave range of the platform are circled in blue. They are the heave acceleration magnitude to fit to the working range and the heave acceleration cap level - it is usual to make these equal. Their value depends on the magnitude of aircraft heave acceleration you wish to capture in the platform motion. I suggest values that allow reasonable general heave motion as the aircraft moves about in normal weather conditions and which gives good runway touch-down movement.

Use the Capture button to record the typical heave acceleration for your choice of aircraft and flying style.

The noise and washout filter time constants are circled in red.

1. Heave acceleration smoothing/delay filter. This controls the speed with which the platform heave reacts to changes in aircraft heave acceleration by filtering out the higher frequency components of the acceleration. Setting larger values (longer time constants) in this low-pass filter removes more of the fast changes and slows the heave response.

2. The heave cue washout filter. Increasing the value here slows the washout to mid. However a reasonably quick washout is required in the heave axis to ensure that the limited range of movement is not constantly saturated.

3. Heave cue final smoothing filter. This low-pass filter can be used to remove noise from the final heave cue. Increasing the time constant value will increase the noise filtering effect and also slow the heave cue response. Again, the heave cues need to be fairly sharp to be felt in the cockpit so a low value for the filter is usual.

Two special settings are circled in green. These are scaling factors that determine the strength of the "manufactured" light-turbulence heave motion and runway heave effects. In FS9/X especially straight and level flight can result in unrealistically low heave movement of the aircraft. The first parameter sets the proportion of a recorded light-turbulence heave motion that can be added to the live motion.

The second parameter sets the magnitude of the manufactured runway heave motion to be added whilst the aircraft is on the ground. See section 4 for details of the runway heave settings.

Click Update_Settings to calculate the detailed range and scaling settings. These are then displayed in the upper part of the window.

Use and Save

The changes you make manually to settings or changes made by the wizard will not be made active until the Use button is clicked. They will then be made active in the current driver session, but will not be saved to your .bff file. To save the changes to your file you must use the Save button.

IMPORTANT – Take great care when making changes to the cue settings as they can directly impact on the motion range. It is recommended that the adjusted cue output is viewed in the Virtual Oscilloscope and its stability assessed BEFORE the driver is put back in Drive mode and the platform made active.

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