Request: Propeller overspeed governor

As I’m working on the P&WC; PT6 engine, a somewhat advanced feature that is
missing is the propeller overspeed governor. In simple terms, it is a second,
fallback governor that kicks in if the primary governor fails and allows you
to still run the propeller. This link explains the basics about overspeed
governors: <
components/article/10388997/propeller-control-for-turboprop-engines> And this
is from a propeller manufacturer, MT: <> The overspeed governor comes with a “test”
pushbutton that runs the OS Governor at a specific RPM (94% in our aircraft)
to make sure everything is working well. It is done before the first flight of
the day. So to sum it up:

  • OSG is a fallback system to the basic governor
  • It might require its own set of PID controllers
  • Assuming oil pressure remains the same, it will work based on the following basic properties
    • The base governor should be able to somehow fail or turned off for the OSG to work (i.e. test mode)
    • A test would need to achieve a given overspeed_governor_test_rpm value
    • In normal operation, the Overspeed governor will allow you to run the engine at a higher than normal value, overspeed_governor_max_rpm
    • The gearbox ratio will be the same as before, you are just allowed to go to higher Ng % with this.
    • The max N1 would have to either be increased in the engines.cfg file, or a new property should be introduced for the overspeed state limit, i.e. max_n1_overspeed. That property, if blank, could default to the max N1 value that’s present anyway

Hello Alex. There are no plans to implement this feature yet. I’ve added it to
our backlog so it gets reviewed on a regular basis. I suggest you create an
idea about this so people can upvote it and we have an idea of how many devs
need that feature. Regards, Sylvain