Effects of Control Surfaces


The new radio systems are proportional control meaning that the control surfaces move in proportion to the amount of movement of the stick. If the stick is moved half of its total travel in one direction, the corresponding control surface will move half of its total travel in the corresponding direction. A beginner must first know the effect that a stick movement has on the model. During normal flight, the throttle is set so that a constant speed is maintained. This means that thrust is equal to drag and lift is equal to weight. From this stable condition, the effects that the stick movements have on the trainer are described.

Right Stick Back

When the right stick is pulled back, the elevator moves up. This causes the nose to pitch upward increasing the angle of attack of the wing and increasing drag. If power is not applied, the airplane will slow down and eventually stall. This means that the air passing over the wing becomes turbulent and lift decreases until weight exceeds lift and the airplane will begin to drop.

Right Stick Forward

When the right stick is pushed forward, the elevator moves down. This causes the nose to pitch downward reducing the angle of attack of the wing and reducing drag. As the airplane descends its speed increases until drag and thrust are again in balance.

Right Stick Right

When the right stick is moved right, the left aileron moves down and the right aileron moves up. This causes the airplane to roll to the right meaning that the left wing moves up and the right wing moves down. It will continue to roll as long as the stick is held in the same position. When the roll takes place, lift is no longer oriented vertically so the effective lift decreases. As the angle of the roll increases, effective lift continues to decrease and the airplane will begin to drop.

Right Stick Left

When the right stick is moved left, the left aileron moves up and the right aileron moves down. This causes the airplane to roll to the left meaning that the right wing moves up and the left wing moves down. It will continue to roll as long as the stick is held in the same position. When the roll takes place, lift is no longer oriented vertically so the effective lift decreases. As the angle of the roll increases, effective lift continues to decrease and the airplane will begin to drop.

Left Stick Right

When the left stick is moved right, the rudder moves to the right. This causes the airplane to swing or yaw to the right. This causes the left wing to move slightly faster through the air causing an increase in lift. The combination of the yaw and the lift increase on the left wing results in a gentle turn to the right as long as the stick is held in position.

Left Stick Left

When the left stick is moved left, the rudder moves to the left. This causes the airplane to swing or yaw to the left. This causes the right wing to move slightly faster through the air causing an increase in lift. The combination of the yaw and the lift increase on the right wing results in a gentle turn to the left as long as the stick is held in position.

When the left stick is moved forward, the throttle is opened resulting in an increase in speed of the airplane. This causes an increase in lift and results in a tendency for the aircraft to climb. When the left stick is moved back, the throttle is closed resulting in a decrease in speed. This causes a decrease in lift and results in a tendency for the aircraft to descend.

It is obvious from the descriptions of the effects of stick movement, that any movement can adversely affect the flight of a model. These effects can be overcome by using a combination of control surfaces to achieve the desired results. For instance, the right stick can be moved back when it is moved left. The result of this action would be that the nose of the airplane would be raised to overcome the loss of lift resulting in a banked turn without a loss of altitude.

In order to understand how to properly use the controls, a change in thinking may be required of a beginner who has some basic knowledge of control surfaces. A beginner must remember the forces acting on a model in flight and how they affect the model.