Rotor speed control and (H_RSC_MODE set to XX ) behavior

ArduCopter Traditional Helicopter
21

About 6 month ago I was just testing a new FW release.
After switching from Stabilize into Poshold immediately my Servo 3 = Elevator, had a problem and the Heli got unstable. Before I had a chance to switch back into stabilize the Pixhawk disarmed the Heli at a altitude of 8m. In the onboard video later-on I clearly could hear the motors cut out. The log file showed a crash detection in mid-air. The Heli landed very, very hard.
Because this servo had not a total stop I would have landed the Heli without damage in stabilize, I believe. This servo had been in a minor crash before. There was a little visible damage to the metal gears. I did not know that before this ‘crash’. With a now new servo the Heli is back flying.
From now on I will always have in param: FS_CRASH_CHECK = 0 ( disabled ) with my Helis.
Just a note regarding disarming in flight.

22

Indeed. And I also disable the auto disarm param. Mainly for starting piston engines which need to idle to warm up a bit so they don’t cough and quit when load is applied. But also to enable the other servos (besides cyclic and rudder) on the helicopter, and I want those servos to remain enabled until I manually disable them.

23

Hmmm, I wonder if I ever disabled that? Got me thinking now, going to have to check parameters. I don’t see any situation where I would need it enabled anyhow as I fly LOS and if it’s going down I would manually hold. Unless I am missing something here? Thoughts Chris?
Tim

24

Auto disarm is more for multi’s I think where if you arm it and are working around it and accidentally move the collective lever (or “throttle” on a multi) they start up. Kind of a safety feature I guess so it disables itself unless it’s flown right away. Helicopters don’t do that, so I don’t use it.

I also don’t use that safety button, or whatever it is. Never saw the usefulness of that either. I’m sure the thought was to protect you from yourself. But flying any aircraft is an exercise of checklists and procedures. And the more “foolproof” you try to make it, eventually you end up like so-called child-proof caps that only a child can figure out how to get open because those of us over 50 need reading glasses to read the fine print instructions on how to open it.

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