I am a full scale 172 driver N318RC p factor is involved in all prop aircraft. As the engine rotates counterclockwise the load on the prop is huge. P factor is the uneven force from the blade rotating forward and then back. You apply rt rudder always on to. A trike setup is easier to handle on the ground whereas a tail dragger requires a delicate balance of elev. rudd. and power. I have been flying rc for 30 yrs and full scale for 5. Ive heard the nextstars are not all they say they are ive never flown one as i fly WWII fighters mainly. my current proj is a pcm tristar turbine. about 10,000.00 in that project.
Maybe his plane is out od trim or the wing is not on straight. Use thread to see if wing is square on the fuse good luck