Trex500 with Copter 3.5

For those wondering if Copter 3.5 is good with TradHeli, I maidened a Trex500 electric with copter 3.5 today.

Pilot was Greg, heli owned by Alastair (both from CanberraUAV)
It flew very nicely. Only changes needed were:

  • Raised ATC_RAT_PIT_ILMI to 0.1 from default of 0, as the heli is a little tail heavy and needed some integrator when close to the ground
  • reduced VEL_Z_P and POS_Z_P by 30% to fix a height oscillation in ALT_HOLD.
    Running on a 6S 2850mAh battery

Hi Tridge,

Would you mind posting a few photo’s of the build?
It’s interesting to see where the PixHawk is located.
A parameter file would also be great!

I’ve sometimes managed to use some hover I gain for auto-trim. But helicopters can carry a variety of payloads, including tethered loads, and it doesn’t always work. With a normal (non-ArduPilot) heli the common thing to do is add elevator or aileron trim on the radio to compensate for issues with CG being shifted. And that works with ArduPilot until you switch to Loiter and the helicopter then takes off on a nice cruise all by itself.

So I’ve gone to using two methods to compensate for CG problems with various payloads. If I’m going to be flying it manually I use radio trim to trim it. If I’m going be using Loiter at all I just compensate it for it in manual flying by fighting it with the stick until I switch to Loiter or Auto and then it takes care of itself.