Lemon RX Stabilizer PLUS Receiver –Essential Instructions
Lemon Stab Plus Essential Instructions 2017 v.1a.doc Page 6
Preparing to Fly
Always remove the propeller when working with the battery plugged in.
1. With the receiver already bound, power up first the transmitter and then the receiver (i.e, transmitter
should be FIRST ON, LAST OFF). The Stabilizer PLUS will calibrate its sensors automatically any time the
model remains stationary, with no vibration, for 2 or 3 seconds during power-up of the receiver. This
calibration is seldom needed, so making sure it happens every month or two will be adequate.
2. With the stabilizer mode set to OFF (Indicator 2: Red/Green ON steadily), verify that all control surfaces
travel in their correct directions when the transmitter sticks are moved. If necessary, change the
relevant Reverse settings in the transmitter. At this time check that all control surfaces are centered.
Note: If using a Transmitter with two-position Gear switch, skip step 3 or step 4, as appropriate.
3. Set the stabilizer mode to Autolevel (Indicator 2: Red and Green lights alternately flashing slowly).
Rotate the model about the pitch and roll axes and watch for the ailerons and elevator to deflect and
stay deflected when it is not level. Rotate the model about the yaw axis and watch for a momentary
pulse of rudder deflection followed by a return to neutral.
The directions of this stabilizer action on each axis MUST be as follows:
Model rolls to the right, the right aileron goes DOWN and the left UP to counter the motion.
Nose of model pitches down, the elevator goes UP to restore the model to level flight.
Model yaws (rotates) to the right, the rudder pulses LEFT momentarily (as in Gyro mode –see
Step 4) to resist the displacement.
If any response is incorrect, change the appropriate switch J1, J2 or J3 to reverse the travel.
4. Set the stabilizer to Gyro mode (Indicator 2: Green ON, Red OFF) and test the stabilizer action on each
of the control axes. Directions of movement should be as above, except that this time what you are
looking for on all three axes is a pulse of movement of the control surface which occurs while the
model is starting to move from stationary.
For example, when you roll the model sharply to the right, the right aileron should for a moment go
DOWN and the left UP (to oppose the displacement), then they should return to neutral. Note that if the
direction of stabilization movement for aileron and elevator is correct for Autolevel mode it will also be
correct for Gyro mode.
If the stabilizer motion is hard to interpret, turn the gain pots fully clockwise (or turn up Master Gain, if
available). Note that it is often easier to feel the direction of deflection with your finger on the control
surface than to see it. Additional information on stabilizer response is provided in the Complete Guide.
5. Carefully recheck the directions of control movement and stabilizer action –a mistake here can have
serious consequences!
6. Check that the three gain pots on the receiver are set to 12 o’clock.
7. If available, set Master Gain to the midpoint (0% on the transmitter’s monitor screen). If your
transmitter has less than eight channels, Master Gain is fixed at 1 and you can skip this step.
8. Check that the flight control trims are set to zero. If necessary, use Sub-trim to align the servo arms at
right angles to the pushrods. Finally, adjust the mechanical settings to center the control surfaces.
9. Test failsafe by turning off the transmitter with throttle well above zero (make sure your prop is
removed or the model is restrained). The motor should stop within a second or two. Turn the
transmitter back ON and it should restart.
