Can not transition to forward flight VTOL convergence airframe

https://review.px4.io/plot_app?log=8554b463-dfb5-4373-847f-03394dfd041d

Hi,
I am at a loss, please help!
I am having a problem while transitioning to forward flight. The plane is simply uncontrollable when switched to forward flight. After I made the adjustments below and test flew the plane. Hover ok. Upon transition the plane flipped uncontrollably and I was able to save a crash by switching to hover mode.

After tilt the rear motor is still running. causing yaw therefore the plane rolls over and crash. vt_tilt_Trans: .3 to .5 is the PARAM during transition.

I noticed that I have no throttle control during translon. tried stabilized mode, manual mode but nothing. until the rear motor stop looks like the plane is stuck in transition mode.

Param: FW_ARSP_MODE = Airspeed Disable
Made a the difference. now the tail rotor shuts down after 5 sec.

Param: VT_Trans_P2_DUR: default = .5
Time in seconds it should take for the rotors to rotate forward completely from the point when the plane has picked up enough airspeed and is ready to go into fixed wing mode.

VT_F_TR_OL_TM: 2.2 to default 6
looks like rear motor during transition is controlled by this parameter.

I’m no expert but I’ll try to assist. Could you please post your .params file? You seem to have changed some default parameters.

  • The one that stood out to me at the moment, and not really looked much into the rest is your transition airspeed is at 8m/s (18 mph) which seem to be way too low for your aircraft.
  • Did you bench test the transition to see the motor angles at the end?
  • You normally don’t have THR response during transition as it’s being controlled by the FC to meet the parameters set.
  • At best, it looks like it was only able to achieve 10 m/s (22.4 mph) which is probably at or below the aircraft’s stall speed. As a rule of thumb, I use 1.3 of stall speed for a minimum transition airspeed.

Good luck.