Throttle arm/servo horn positions
To achieve the correct position of the throttle/servo arm, it may be necessary to re-position the throttle arm on the carburetor. It may also be necessary to adjust the length of the throttle linkage slightly to achieve full open and closed positions of the carburetor.
It is also possible to increase/reduce the travel of the throttle servo through the travel adjust function found in most computer radio systems. If this function is used, make sure the values for the high and low positions remain equal (same value for high/low). If these values are not equal, it will create a differential, or uneven movement of the throttle, making rotor rpm adjustment and fine tuning more difficult.
CCPM servo centering with the sub-trim functionIt may be necessary to make minor servo centering adjustments with the use of the sub-trim function to achieve the desired servo arm positions. Adjust the sub-trim percentages through the radio system as necessary to make the servo wheels center properly. With proper servo arm positioning, little to no sub trim will be required.
Pitch-to-aileron mixing adjustment with travel adjust
It is very possible that the travel of each servo varies slightly, which can cause the swashplate to be tilted to the left or right when the collective is moved to the extreme high and low pitch positions. This condition is generally more common when standard-type servos are used. If digital
servos are used, the adjustment required is generally very small, if any. These variations in travel can be corrected by altering the travel value of each servo slightly through the travel adjustment function. To check the pitch-to-aileron mixing, it will first be necessary to position the collective stick in the center position and make sure the swashplate is level. Next, move the collective stick from the center position to the high pitch position while viewing the swashplate from the rear of the model as shown in the diagram below.
While moving the swashplate, look for any tendency for the swashplate to roll to the left or right as it reaches the high pitch position. Repeat this procedure several times to be sure that your observations are correct. If no rolling tendency is found, it will now be necessary to repeat this procedure from the center collective stick position to full low pitch. If no rolling tendency is found, proceed to the next step. In our example, we have shown that the swashplate has been tilted to the left as the collective has been
increased to full pitch. This would indicate that the left servo’s maximum travel is less than the right servo’s maximum travel. In this condition, we suggest that the travel value for the left servo be increased slightly (5–10%). Repeat the procedure above if the same condition occurs, but to a lesser degree. The travel value of the right servo should be decreased slightly and retested. In most cases, it will require only the adjustment of the left or right servo to correct this situation. Once this condition has been corrected, repeat this procedure for the
center-to-low collective pitch position and adjust as needed.
Pitch-to-elevator mixing adjustment with travel adjust
The total travel of each servo can vary slightly, which can also cause the
swashplate to be tilted fore and aft when the collective is moved to the extreme high and low pitch positions. This situation can also be corrected if necessary through the use of the travel adjustment function.
To check pitch-to-elevator mixing, it will first be necessary to position the collective stick in the center position as in the previous step. Next, move the collective stick from the center to the high pitch position while viewing the swashplate from the left side of the model. While moving the swashplate, look for any tendencies for the swashplate to tilt fore or aft as it reaches the high pitch positions. Repeat this procedure several times to be sure that your observations are correct. If no fore or aft tilting tendencies are found, it will now be necessary to repeat this procedure from the center collective stick position to full low pitch. If no tilting tendency is found, proceed to the next step.
In our example, we have shown that the swashplate has tilted backward as the collective has been increased to full high pitch. This would indicate that the top servo’s maximum travel is less than that of the two left/right servos.
In this condition, we suggest that the travel value for the rear servo be increased slightly (5–10%). Repeat the above procedure and decrease the value as needed until the tilting tendency is eliminated. For information on the travel adjustment function, please refer to your radio’s instruction manual for details. Once this condition has been corrected, repeat this procedure for the center-to-low collective pitch position and adjust as needed.Note: It is very important that during this step, only the travel value for the top servo (elevator) be adjusted to correct any pitch-to-elevator tendencies. If the travel value of the left or right servo changes, this will affect the pitch-to-aileron tendencies corrected in the previous step. If you feel that readjustment of the left and right servo travel is necessary, then it is suggested that the travel for each servo be increased or decreased at the same amount and the pitch-to-aileron procedure be retested.
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Information from JR VIBE 50 Manual