Engine torque, and airflow from the prop will push you to the left while rolling in most of these high performance planes. If you wish to take off manually, you need to use rudder to keep the plane rolling straight.
Without knowing what flight controls you are using, Id suggest allowing the "auto take off" function to get you in the air while you become familure with AH's flight model. "Auto take off" will stay engaged until you move your controls.
You could also try the P-38 which has counter rotating props, and does not have this problem on take off.
To answer your other question, the q and w keys operate the flaps.