Ultimate model performance can only be achieved through careful trimming. Ideally the model should be adjusted until it is flying with the lines very slightly slack. It is only when this stage has been reached that the full motor power will be used for flying.
Very taut flying lines, although necessary when flying in windy conditions, indicate that much of the motor power is being wasted simply tugging at the pole. As already described, basic trimming is carried out through tether hook and elevator adjustment. In addition, most models also require some degree of rudder offset, and where flying lines over about 5 metres are being used, some ballast to the outer wing tip may be necessary.
Final trimming must be governed by flying conditions, i.e. wind, flying line length and type of model, with performance depending upon a correct balance between tether hook position, elevator and rudder adjustment. Optimum results can only be achieved through practice and experimentation with simple models. More advanced types can be tackled as skills improve.
For best flying performance models must be lightly built and capable of flying on no more than a maximum of 70% full power.