Mini plane collectin series. . Mini Aermacchi MB-339.

I am having 2 problems which I can't seems to find where is the fault. Hope someone can help me.

1. During take off run, the plane tend to veer to the left. If you put the flap down before power up, you will be able to lift off before it hit the grass. You can also use the yaw to make it stay straight on the runway. And it will also tend to correct itself without interfering from the user.
2. During flight, it tend to roll to the right.

Hope someone can help me find out what could be the problem. Thank you in advance.

Flight
1. Flap down to bottom arrow.
2. Power up.
3. After lift off, retract gear.

Have a pleasant flight. .