Why Auto Land is NOT a good idea

With any sort of combustion engine helicopter. Watch what happens to the CHT (labeled EGT in the telemetry, as I haven’t changed it yet in this radio).

I got a feedforward surge from the throttle curve when the governor disengaged, as I failed to switch to throttle curve before engaging Auto Land. And the throttle curve is set for the high Idleup. But still can see what it does.

What are you trying to show/say here? It seems normal that the CHT would rise after shutting down a hot engine due to the sensor heat soaking.

No, helicopter engines aren’t at all like airplane engines because they operate at high continuous load in hover. Just shutting it off from full load results in loss of the cooling system. The internal parts of the engine are way hotter than the outside and the heat is constantly being carried away by the cooling system to keep the critical part - piston and cylinder at a safe operating temperature. So the temperature of the engine spikes, which will stick the piston rings (and valves on a four-stroke). And once you do that and score the cylinder it will seize up.

Idling the engine to let it cool down gets rid of the internal heat and dissipates it thru the cooling system at a power level that is not creating as much heat to get it to a safe shutdown temperature.

RC helicopters with combustion engines are no different than full-size. Even a Jet Ranger with a Allison 250-C20J turbine requires a minimum 2 minute cooldown at ground idle before shutdown. Failure to follow it will result in cracked combustors.

The ArduPilot system is designed for electric aircraft. So for people flying pistons or turbines and using auto land - and then can’t figure out why they got stuck valves in their four-stroke or the engine seizes up a few flights later - guess what caused it? Don’t use auto land with combustion engines. It makes the difference between getting 40-50 hours (or less) out of your engine vs 500.

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