The background: Scratch-built a 3 channel Simple Cub for my third FT project. Maiden flight a couple days ago showed a left roll with power on. It was severe enough that even with it trimmed full right, it still took about 50% right rudder to keep it in the air. I adjusted the thrust angle down and to the right using some shims I made up. It helped a bit, but at full right trim, it still rolls left. Power-off glide is fairly level, though free glide slope isn't great.
The plane is balanced just like Josh shows in the video. It's ruining a B- pack motor and esc with an 1800 mah 3s battery.
Structurally, it's not perfect. The tail section of the fuselage is slightly out of square, so the tail is ever-so-slightly off counterclockwise. The rudder is parallel with the motor axis, but not perfect. Also the dihedral angle of the wing is slightly different from one side to the other, putting the left wing tip about 4mm higher than the left. Both wing halves appear to be even and symmetrical otherwise.
The questions:
Could the asymmetry of the wing be causing the roll? I would think that if it glides straight power-off, it's probably not a wing issue, correct?
Do I keep shimming the motor until it goes away? How much shimming is too much?
Is there anything else that could be causing this roll? Or is it just the torque it's fighting?
Thanks, gang!
The plane is balanced just like Josh shows in the video. It's ruining a B- pack motor and esc with an 1800 mah 3s battery.
Structurally, it's not perfect. The tail section of the fuselage is slightly out of square, so the tail is ever-so-slightly off counterclockwise. The rudder is parallel with the motor axis, but not perfect. Also the dihedral angle of the wing is slightly different from one side to the other, putting the left wing tip about 4mm higher than the left. Both wing halves appear to be even and symmetrical otherwise.
The questions:
Could the asymmetry of the wing be causing the roll? I would think that if it glides straight power-off, it's probably not a wing issue, correct?
Do I keep shimming the motor until it goes away? How much shimming is too much?
Is there anything else that could be causing this roll? Or is it just the torque it's fighting?
Thanks, gang!
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