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When setting combustion to OFF using the A:var (reciprocal engine), engine RPM instantaneously goes to 0 on the next frame. When combustion is stopped through "regular means" such as turning the magnetos to OFF, the combustion flag goes to 0 but the engine smoothly decelerates.
Is it possible to make the propeller behaviour consistent?
Hello @SWS-AlexVletsas
I think you will have this behaviour if you write to GENERAL ENG COMBUSTION EX1 instead of GENERAL ENG COMBUSTION
Regards,
Sylvain
Setting the combustion to 0 by code freezes it. Setting Combustion EX1 doesn't do anything and it resets back to 1 on the next frame.
SWS-AlexVletsas can you be more specific about your sequence, so I could reproduce it? There is no SimVar called A:var. I'm guessing your aircraft is on the ground during this test. Can you reproduce this with a stock aircraft, e.g. the Cessna 152? If so can you let me know the simplest plane? I think you have an issue with the ENGINE behaviour, not the propeller behaviour, although I accept those things appear bolted together in the model.
You can try with the Asobo TBM. Writing 0 to GENERAL ENG COMBUSTION will instantly stop the propeller while writing 0 to GENERAL ENG COMBUSTION EX1 will have it decelerate smoothly.
I've realised this thread assumes the plane is on the ground, so my hope someone might have found a way to stop the propeller rotating more generally (i.e. including in the air) doesn't apply.
Raccoon is that a typo in your comment? i.e. your "1" would be a zero hence 0 (>GENERAL ENG COMBUSTION:1, Bool).
@SWS-AlexVletsas Some additional details:
The GENERAL ENG COMBUSTION EX1 simvar depends on other factors.
On turbines, if auto_ignition is enabled and ignition_auto_type is set to always on (empty string or omitted parameter), the combustion will logically be reset to 1 instantly.
On piston engines, if you set the simvar to 0 but magnetos are on and engines are running fast enough to restart, combustion will be set to 1 as well.
May I ask what are you trying to achieve?
If you're trying to stop combustion on a piston engine, I'd say using the magnetos simvars is more appropriate.
Regards,
Sylvain
To explain a bit further: the plane with said problem is the RV-14 which is equipped with P-MAGs and a test switch for them. Setting the switch to TEST will disconnect the P-MAGs from the electrical system. If the engine has sufficient speed to maintain a combustion it will, but if it drops below 1000rpm the engine will stop, regardless of the magneto position.
As I cannot set the rpm threshold through the engine file and setting the magnetos triggers the animation, turning off the engine with one of the combustion flags is the only way I can think of to shut down the engine.
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