Successful VTOL Transition! Would like help tweaking!

Today at 11:53AM Local Time I completed by first VTOL transition! Then I landed, swapped batteries and did it again! WOOOTT!!

Here are the telemetry and apm logs location.

VTOL 2.1.param (17.0 KB)

What I’ve learned about VTOL:

  1. The BR2205 2300Kv racing motors, while light and delivering a whopping 1.53 lbs of thrust with a GEMFAN 6x4.5x3 prop burning 12 amps at hover, well, THEY BURN UP. The racing motors will tell you that they can handle 27-30 amps continuous but that is NOT true. They will burn up the insulation around the windings and can take out your ESC with them. It’s already happened.

  2. Despite following directions and using calibrated mulitmeters and power meters put inline with the battery and motors I still cannot get the voltage to read correctly (look at the logs and tell me that can be right).

Need help with:

  1. The aircraft seemed sluggish at 28mph and it should not of been, FBWA mode was checked on ground and servo throws seemed spot on
  2. I could hear the VTOL motors on the whole time even though the threshold was surpassed. Do I have a setting wrong? Should I just turn off Q Assist? Were they just windmilling?

I have chosen a different VTOL motor for this project that is 1400kv and will report back the stats on it in case anyone else wants to know.

If anyone sees anything they would tweak, please tell me! I’d rather have the advice and take it rather than learn from a crash!

Pic of the VTOL:

Did you try running a couple of PID tuning flights? AUTOTUNE may help you if you haven’t. I do notice from the logs that the roll behaviour is rather sluggish.

The motors were almost certainly getting activated due to Q_ASSIST:

All the “Transition Airspeed” messages getting thrown out while in FBWA mode is a giveaway, together with the fact that your quad motors are actively spooling up. Moreover, notice that Q_ASSIST is kicking in even though you are at 60% - 70% throttle.

This suggests that either:

  • Your Q_ASSIST speed is too high, and is interfering with what could have been your cruise speed. I suggest you recheck what is the stall speed of your aircraft and set Q_ASSIST_SPEED accordingly.
  • Your Q_ASSIST speed is fine, but your motor is underpowered and is consistently bringing your aircraft under stall speed. If that is the case, then you should look to upsize your forward motor; a motor that can provide level flight at 60 - 70% throttle is good.


I will turn off Q Assist for the next round of test but I want to put the more powerful VTOL motors on because the little racing ones I currently use overheat within a minute.