In the Custom Data Converter for Display Parameters (I/O:n) - Below the DataRef selected to display, there's a textfield where you can enter Optional parameters. The label states: "Display Format (if not the same as SimVim default, and it's not offset) ". What is meant to be entered here? Is it like stdout::format in c/c++ eg.: "%5.3f"?

My goal here is to make the AP-SPD_Cmd display the double as 4 digits instead of only 3 (one dot and 2 decimals) - so like: ".723"
1 month ago in Custom Aircraft by

1 Answer


This field was added  for the custom display format, but it  is "not documented" feature now.

In short - you can try this (if you need Mach as .777 ) :


But, in this case the KTS output will be in the 509.8  format ... :(

Or, we need to write SimVim custom function for this "double-output" type Spd display (as it's done for b737-like (AP_Speed_Disp)

1 month ago by
Thanks. It works!
The custom function would be nice :-) As commented in another thread before:

The AP_SPD_Cmd for the Rotate MD88, depends on 3 custom Xrefs. The standard Xref: (sim/cockpit/autopilot/airspeed) is for some reason actually holding the display value for the AP_VS_Cmd when the AP IAS pitch mode is selected - showing the current knots- or mach value. This IAS function is similar to the levelchange (where speed is controlled by pitch).

The 3 parameters for AP_SPD_Cmd are:

XRef -- Value -- Simvim Parametername

'Rotate/md80/autopilot/spd_is_mach' -- 0,1 --  AP_IAS_Mach_On

'Rotate/md80/autopilot/at_target_mach' -- 0.5-1? -- AP_SPD_Mach?? (new parameter suggestion - if necessary)

'Rotate/md80/autopilot/at_target_speed'  -- 100-500? -- AP_SPD_Kts

The output to show depends on the spd_is_mach value: When this xref is 1 the display must show the mach value, else the Kts value. I've looked at the Conditions function - but it doesn't seem to allow every simvim-parameters as input condition parameters.  Are this kind of logic allowed in simvim? The above intermediate values does not necessarily have to be public disposed if you have another solution for this implemented.

"The standard Xref: (sim/cockpit/autopilot/airspeed)"
I recommend always to look for the datarefs under the /cockpit2/  prefix, not the old /cockpit/  which is mostly deprecated

Correct standard dataref (that is used for default SimVim parameter is sim/cockpit2/autopilot/airspeed_dial_kts_mach

I'm sure the numbers there are the same as in your plane custom datarefs (depends on the mach/kts setting)

I will add the custom display for Mach +Kts   format soon.

Ok Thanks. I wasn't aware that cockpit/.. is deprecated. The /cockpit2/.. seems to hold the same numbers as /cockpit in this case. So these values are reflecting the ias-pitch-mode (levelchange) value as well.

Best Regards