1) Download the application from RealFlight (Unfortunately, this is no longer available, see forum).
2) Optionally but preferably, add a new Windows XP bottle and name it something like winxp (for identification).
3) Select the "Control Panel" tab in the new bottle and launch "Wine Configuration" to set up a virtual desktop.
4) Go to the "Drives" tab, select "Show Advanced" near the bottom and enter "1" (any number other than zero) in the "Serial" field.
5) Apply all changes then close the Control Panel.
6) Open Crossover and click the "Install Windows Software" button or alternatively:
7) Locate the G6 file downloaded from RealFlight, right click and select "Open with..."--> "Crossover (Install)."
8) Click "Browse Available Applications..." button, select "Unlisted application" then click the "Continue" button.
9) Click "Choose Installer File", browse, select the RealFlight Demo application file then click the "Open" button.
10) Click the "Select Bottle" tab and select your newly created bottle then click the "Continue" button.
11) Click the "Install" button.
12) Crossover will open your preconfigured bottle and the RealFlight application will commense the install process.
13) Follow the RealFlight installer prompts and accept the default installation directories or select your own if desired.
14) At completion of the install, uncheck the "launch application" box and click finsh.
15) Crossover will then complete the istallation.
16) Launch the application and the Great Planes logo will appear in your virtual desktop.
17) A message box will then appear with the following information:
Error: E_NOTIMPL
File: .\DXControllerG2Interlink.cpp
Line: 97
18) Click ok to dismiss this error.
19) The application will then open for your enjoyment using the keyboard as the controller.
Edit: Completely rewritten to reflect the newer Crossover user interface version: CX 16.2.5 date: 9/29/2017