DC-3 Mixture always on auto-lean / fuel flow / levers inop

:wave: Thank you using the Bug section, using templates provided will greatly help the team reproducing the issue and ease the process of fixing it.

Are you using Developer Mode or made changes in it?


Have you disabled/removed all your mods and addons?


Brief description of the issue:

There is currently no code for engine mixtures (also stated by the developer). Therefore the plane always uses Auto-Lean. To get the fuel flow on takeoff correct there is just a multiplier applied leading to a way off fuel flow cruise.

Provide Screenshot(s)/video(s) of the issue encountered:

Detailed steps to reproduce the issue encountered:

  1. Start a flight
  2. Measure FF on MT/METO power
  3. climb to 10k’
  4. Set cruise power
  5. Measure FF: should be ~ 45gph/engine → is over 100gph

PC specs and/or peripheral set up if relevant:


Build Version # when you first started experiencing this issue:

:loudspeaker: For anyone who wants to contribute on this issue, Click on the button below to use this template:

Do you have the same issue if you follow the OP’s steps to reproduce it?

Provide extra information to complete the original description of the issue:

If relevant, provide additional screenshots/video:

I have the same issue, I have tried to fin the Auto rich/Auto lean option in the panel but i couldn’t.

If the Mixture lever is not pushed all the way forward, the motors do not start, which corresponds to reality. An “auto rich” function is not useful for starting, or is it?

I have a problem with the assignment of the mixture levers to the available controls. I have assigned the propeller speed control to the only free analog slider which my throttle unit has. As consequence I don’t have a free analog slider anymore and I have to assign the full-forward position of the mixture levers to a key combination. But none of the keyboard assignment options in the mixture section of the control options work. Who has an idea?

It’s the opposite way (or should be, at least) in the DC-3: fuel mixture was set to Auto Lean when starting the engines in order to not flood the engine.

Ok, to minimize (my) confusion I studied the original “DC3 operation procedures”. Here it is required that the MIXTURE lever must be in IDLE-CUT-OFF position before starting the engines. As soon as an engine fires, the corresponding MIXTURE lever must be moved to “AUTOMATIC RICH”. At this moment the engine only gets fuel it needs for ignition through careful priming.

From my own real experience with SEP I know that an engine can only be overprimed by priming too long (e.g. in winter), not by the position of the MIXTURE lever. The MIXTURE system is a valve, the primer is a small fuel pump (often driven manually). It bypasses throttle and mixture and injects fuel directly into the intake areas of the cylinders, regardless of throttle and mixture lever position.

1 Like