Mixture Controller for Turbocharged Piston Engines in MSFS 2020
NOTE: If using the Working Title Technology add-on for the PMS50 GTN750 in the Carenado Seneca V, the mixture controller WASM file and the panel.cfg must be edited in the "pms50-gtn750wtt-aircraft-carenado-seneca" folder in your community folder, rather than following the procedure in the included PDF instructions. The PMS50 WTT add-on replaces the default panel in the Seneca V, and it will override the mixture controller if it is located in the official Carenado installation directory.
Microsoft Flight Simulator's fuel mixture logic for turbocharged piston engines produces excessively rich fuel mixtures and loss of power at high altitudes. The default logic appears to calculate fuel/air mixture based on ambient density. In a real-world turbocharged engine, the turbocharger compresses air before it enters the cylinders. This increases the density of air in the engine significantly above ambient density. As such, the default logic in MSFS does not properly represent the behavior of a turbocharged engine. A more detailed description of the problem, with data extracted from MSFS, is available here:
This package includes mixture controllers for four turbocharged piston aircraft that are currently available for MSFS:
- Robert Young's Turbonormalized Bonanza
- Just Flight Turbo Arrow
- Carenado Seneca V
- Flysimware 414AW
The controllers calculate a target fuel/air mixture based on the user's hardware mixture lever setting and the air density in the intake manifold (rather than the ambient density). This allows the mixture to be managed according to the POH, setting mixture at full-rich throughout the climb instead of leaning the mixture to maintain proper power.
Please see the included instructions.pdf for detailed instructions on how to install the controllers for any of the aircraft mentioned above.
DEPENDENCIES: Successful installtion of the mixture controller requires updating the layout.json file for the airplane to include a reference to the .wasm file which is added to the airplane's panel folder. I recommend using the MSFS Layout Generator for this. It is a quick drag-and-drop utility that updates layout files painlessly. See the link below for more information.
https://github.com/HughesMDflyer4/MSFSLayoutGenerator
CAUTION: Successfully installing these controllers will require copying and pasting the files to the proper folders and updating each airplane's panel.cfg and layout.json files. If you are not comfortable taking these steps, do not use this code.
These controllers are designed to work with a hardware axis (throttle quadrant, HOTAS with mixture axis, etc). If you do not have a hardware mixture axis, or if you have automixture enabled in MSFS settings, this controller will not add much value to your experience.
KNOWN ISSUES: The mixture lever displayed in the virtual cockpit will not reflect the mixture setting on your hardware axis. The virtual cockpit lever displays the mixture setting in the sim, which the controller code calculates based on your hardware axis position and the density in the intake manifold. At high altitudes, it is quite possible to see the virtual cockpit lever set to 25% mixture while the hardware axis is set to full-rich. This is an artifact of the incorrect mixture logic in the core sim. It is possible to map the virtual cockpit mixture lever to the hardware axis, but this controller currently does not implement that feature.