Model Forum / Radio Controlled / Air Models / January 2004

The short answer is, it is the effect of the prop making the air behind it
spiral and hit the rudder on one side.  That is what usually causes models
to veer left when they first start their takeoff roll.

  Air coming back from the prop is swirling. As it hits the aircraft, most
importantly in this case, the rudder area, it causes an opposite reaction,
ie. the plane wants to swirl the other way. To get the idea think of the
plane being in a tub of water and you open the drain, the water starts
swirling down and the plane would start spinning about on the water, similar
but different, this gives you an idea as to the invisible effect being
applied to the plane from the airflow through the prop. This is an
aerodynamic force trying to make the plane go left.
  Another bit going on is mechanical, torque as has been mentioned in the
prior thread. Imagine if the propeller at the front were held in a vise and
the motor turned up, the propeller assembly would remain stationary and the
body of the plane would go spinning round. Air does not prevent the
propeller from moving, but the rotation action causes a reaction in the body
of the plane, also to the left. Because the wing is much larger than the
propellor it counteracts the force when air flows over it and or with a
small amount of 'trim' from it's shape or control surface adjustment,
aileron. On the ground these forces cannot make the plane tilt because it is
touching the surface. The forces are still in action however and the result
you observe is the plane going to the left while moving.
  If your plane came with instructions that indicate where the center of
gravity should be, check that. In any case, the center of gravity, the place
from front to back where the plane will balance like a seesaw, may be too
far forward. Think of the plane as a stick with a heavy stone on one end,
the engine. If you pick up the stick at the end with the stone you can flail
it about like a sword or what have you with ease. If there is some weight at
the other end of the stick you would find it more difficult to change
directions as you swoosh the thing about. A small, "toy" electric airplane
may be prone to such an imbalance as in the first part where you end up with
the engine flying the plane as opposed to the plane flying under control. In
conjunction with the glide tests or even beforehand, hold the plane at the
wingtips with a finger lightly and see if it hangs flat from front to back.
About one quarter to one third of the way back from the front edge of the
wing is where it should hang flat. If it tips one way or the other tape some
washers or similar to the body at the end until it will hang about level.
You want it to make a shallow glide down to the ground from your hand after
you toss it gently into the air, kinda like a proper paper airplane. Do this
where it will land on something soft and start out low perhaps squatting so
you dont end up with a torn up plane before you get it right to fly ;) Be
careful, don't do anything you are unsure of, and take your time. As an
aside, the writeup I found about this plane says the radio operates on
40mhz. You will want to be cautious about using that outside of your own
property or around other R/Cers.

Good luck ! hope to hear you got in some good flying :)