Hobbies And Interests
Purpose
If the propeller is not adjusted at these angles, when the operator tries to fly the plane straight at a constant altitude, it will instead climb and turn to the left. If the propeller is adjusted at these angles, it will fly straight and horizontally. This is because the propeller produces spiraling airflow that hits the tailfin while the plane is in flight. This spiraling airflow causes the undesired upward and leftward movements. You can achieve the proper thrust line only if the model you are using has been trimmed to neutral and the engine is well run-in.
Right Thrust
To establish whether your plane has the correct right thrust, or side thrust, fly the plane straight into the wind at its highest speed and pull it up into a vertical climb. If the model continues to climb vertically, the right thrust is correct. If the model veers noticeably to the right, there is too much right thrust. If the model veers noticeably to the left, there is not enough right thrust.
Down Thrust
To establish whether your plane has the correct down thrust, fly the model straight into the wind horizontally and at full throttle. Close the throttle for a couple of seconds and then open it again. If the plane slowly arcs down when the throttle is closed and continues toward the ground when the throttle is reopened, the down thrust is correct. If it arcs up when the throttle is closed and arcs down when the throttle is reopened, there is too much down thrust. If it arcs down when the throttle is closed and up when the throttle is reopened, there is not enough down thrust.
Changing the Thrust Line
You can change the thrust line by adding washers to the top, bottom, left or right of the engine mount. Increasing down thrust, decreasing down thrust, increasing right thrust and decreasing right thrust are achieved by adding washers to the top, bottom, left and right of the engine mount, respectively.