I am hand-launching a model using Takeoff mode and the throttle is cutting back to idle about a second after launch. I am not sure if I have a setting wrong or if I am following the wrong process. I am doing the following when I launch:
Set model to FBWA mode with throttle at idle
Arm model (using TX switch)
Set to Takeoff mode (using TX button)
Shake to wake and throw - throttle is still at idle
I have attached my settings. There is a log at 2025-03-01 09-23-48.bin. I am not seeing any Tx input during the launch that would cancel the takeoff sequence. I would appreciate any guidance. ArduPlane.param (19.0 KB)
To me it looks like it is going to THR_THR_MAX for TKOFF_THR_MAX_T then regular TECS kicks in and goes quite a bit down before attempting to settle around 50-60% (just as you take control). I suspect you would need to tune TECS parameter to better match the performance characteristics. Airspeed sensor would make configuration a bit easier.
Ah, I see that now. I had assumed by the sound that it was bringing it back to idle, but it was still at 40%. It may just not need 90% power to meet the climb angle demand. I’ll try again and give it another second or two before taking over to see if it continues to climb to the takeoff altitude setting. Thanks.
Thanks for that feedback. The function buttons on the Frsky X20 are persistent and are programmed using a var for the six Arduplane flight mode pwm values on ch 8. I read in another thread though that entering Takeoff mode from an auto mode may cause problems, so I am also going to try switching to it from Manual mode instead of from FBWA.
Using an airspeed sensor will improve the motor/speed management 100%
Than you can force tkoff_thr_max for more seconds if you like. This way it will takeoff and climb at takeoff max throttle for the number of seconds you want.
Mike can also switch to Plane4.6beta4. For takeoff, throttle is now forced to max value until altitude is reached. Basically broke TECS controlled throttle for planes without airspeed sensor.
Thanks. My airspeed sensor and lidar are in use on another model, so I am limited to just a flight controller and GPS on this one. I have installed 4.6 beta 4 and have tkoff_options set to 0. I will report back.