arducopter v3.5.5 TradHeli problem

Hello guys. I have a problem. I have a t-rex 600 helicopter and a pixhawk px4 helicopter. When I change flight mode from stabilize to althold then the swashplate goes down to -3 degrees just like I have set the bottom range of the swashplate movement. The same happens in the loiter mode. Does anyone know what it is caused by?

Please post a param file so we can look at your setup. Thanks!

setup.param (13.5 KB)

It is normal to statically test the swashplate in several flight modes on the ground. After takeoff, there will be barometer data to determine the position of the collective pitch.

I thought so too and after take off I turned on the althold mode, then the helicopter went down to the ground and did not react. In the althold mode, I tried to pick him up from the ground and the swashplate did not react.

Everything in your set up appears to look normal. I am a little concerned with the 115 PWM between H_COL_MAX and H_COL_MIN. This is typically over 200 in most setups I’ve seen. What is the min and max collective angle associated with these parameters. I assume by your first post the H_COL_MIN is equal to -3 deg collective angle.

Do you have a log file for this flight? I’d be interested to see it. It might better explain what is happening.

Min collective angle is -3 deg, max collective angle is +11. In the althold mode, should I not be able to move swash plate the top down even if the helicopter is on the ground? I can control from side to side and back and forth, but the swash plate does not rise even when I give the stick to the top.

I dont have log file, unfortunately. I dont know why nothing is written down.

I think it depends on whether the aircraft is armed and if the motor interlock is enabled. Remember that you are no longer controlling the blade collective pitch angle in Althold. You are commanding climb or descent rate. So doing a ground test really requires you to disconnect the engine, then arm and enable the motor interlock.

I’m not sure what ground control software your using but connect to your heli and download the dataflash log. It should be on the pixhawk unless you don’t have an SD card installed. What is your log_bitmask parameter set to?

Yesterday I made two short flights. Here is the link to logs. Perhaps one of them will be able to find out why the helicopter does not maintain altitude.

Could anyone try and help me solve this problem? Please.

From what I see in the log it looks like you’re just flying the heli on VFF and haven’t tuned the PID’s.