Hi!
Is it possible, to use 4 quad engines instead of ailerons?
Hi,
I assume by VTOL you are referring to a quadplane? Also, to rephrase your question, are you asking whether you can use your VTOL quad motors to replace your aileron control surface?
There is the option of turning on Q_ASSIST_SPEED and Q_ASSIST_ANGLE (see ArduPilot Documentation). So if you want to use the quad motors in place of the ailerons, set Q_ASSIST_ANGLE to slightly above zero. The controller will read your transmitter roll input, and tell the quad motors to assist in providing the necessary roll so as to match the desired input.
Hi!
Thank you for your answer.
Yes, I was referring to quadplane and to use my motoris instead of ailerons.
If I use it this way, Then after transition to “plane mode”, is the PID settings I used for copter, still used, or I also have to tune any other plane PID settings?
It is an heavy 8kg skywalker X8, and is only used for autonomous flights.
Hi Hans,
I’m not very sure about this, but from what I see from the documentation page (in the link I posted earlier), there is a warning about tuning with quad assist:
“…it is not a good idea to use AUTOTUNE mode with a high value of Q_ASSIST_SPEED as the quad assistance will interfere with the learning of the fixed wing gains.”
From this I infer that the motors are responding according to the copter PIDs, thus while the fixed-wing PIDs are still being tuned they will get interference from the quad. So while your quad motors are responding to the copter PIDs when performing a roll, your other plane control surfaces (elevator, rudder) will still need to be tuned separately.
Of course, if there is anyone else out there who understands the quadplane control architecture and sees that I am wrong, please correct me 
Finally, if you’re comfortable with sharing, I’m curious to know why you intend to use your motors to replace your ailerons. I understand that the Skywalker series uses elevons instead of ailerons/elevators, but why do you choose to use your motors instead of turning on elevon mixing?
Hei,
So yeah, there was no plan to use autotune.
Actually I’m just curious myself that how it will affect aerodynamics and is flying like this using more or less battery.
I dont have much experience with planes or copters. It’s my secound built. First was Sw X8 plane, there were many servo glitches so I’m somehow trying to avoid them.
Also not using them wins me about 400g…
Hi,
Using the quad motors in flight will definitely use more battery; you are supplying power to 4 extra motors rather than just a couple of servos. As for the aerodynamics, having the props spinning during forward flight will affect the airflow around your wings. How much do they affect I am not too clear.
Did you face problems with elevon mixing? Maybe you could also open a new forum post regarding the issues you faced with your servos, and seek help from the community.
All the best with your new build!