The first video segment, in the pitch axis both the model had an error and the LQR regulator bandwidth was too high. The combination was barely stable. It was the first run with this compensator for the pitch axis and forward backward velocity control using RC control.
In the second segment we reduced the LQR regulator BW as well as the large error in the model. There is still some error in the model on small items.
We are upgrading to a dual rotor system right now so we have better yaw/steering control. Yes we can steer with one rotor but it is not trivial to do, nor is it very robust.