Quad Copter Initial Flight

Quad, Pixhawk Clone (v2.4.6), MP v1.3.74 bld 1.3.756327684, Copter v4.0.5., plastic props and plastic frame, Taranis X9D+ TX, Taranis X8R RX (SBUS from RX to Pixhawk clone). Conducted the mandatory setup.

I built this quad about 2 years ago and experiencing numerous EFK / compass issues and decided to shelf the project. 1st flight I identified a few issues:

1 - When switching from stab. mode to position hold, with the throttle stick held constant, the RPM of all four motors suddenly decreased??**

2 - This is probably the oddest part, my pitch trim is reversed, that is the pitch when using the TX channel 2 stick is correct but as I say the trim is reversed.

I am attaching 1.bin file for the flight and would appreciate any comments, observations, information and/or suggestions.


It seems to be flying ok. Roll pitch tuning seems OK (I compared DesRoll vs Roll, DesPitch vs Pitch, Rate.RDes vs R, Rate.PDes vs P).

The barometer is a little noisy but not too bad. Vibrations are OK (17m/s/s average with very occasional spikes above 30m/s/s).

In general I think it is better to use Loiter rather than PosHold. They are very similar but Loiter is better supported.

It looks like the “fmuv2” firmware is loaded which is OK but has some features removed to save flash space because some older pixhawk’s suffered from the 1M flash issue. It might be good to try and load the Pixhawk firmware instead (see “arducopter.apj” file here) if the board is indeed a Pixhawk similar to the ones that mRobotics sells.

rmackay9, thanks, I will try the PX4 firmware and report back.

If the trim is reversed, but the stick works in the right direction, I think the problem must be in the Taranis setup?

I’m a bit rusty on this, but is it that you have reversed the input rather than the mix/output?

Regarding the altitude hold issue, have you tried following the tuning instructions? Specifically the part at https://ardupilot.org/copter/docs/tuning-process-instructions.html#test-althold may be relevant.