Frame Plus: Loiter mode copter not straight when forward/backward

ArduCopter Copter 3.3
1

Hi,
When I tried with Frame Plus (AC3.3.3), loiter mode is ok when static point, but when I push pitch up and down ( forward & backward), the copter doesn’t fly as a straight line, it always toward to right when forward, meanwhile to left when backward, I’ve tried with TRIM_X/Y but seems no help with this issue. Here is my log file, does anybody can give me a hint because for now I’ve no idea with dealing this issue, tks!
Here’s my log bin file: http://pan.baidu.com/s/1qXN0Hp6 (sorry, I’ve to put it in webdisk for it’s too big)

2

Are you sure your frame is a plus? It almost sounds like you’ve set up the frame as a plus when it likely should be an X.

3

Tks for reply. The param ‘frame’ is 0，should be plus, right?

4

Not sure. What does your frame look like in relation to the FC orientation? How is it wired?