Lemon 7 Channel Stabalizing Receiver

If you haven’t heard about the Lemon Stabilizing Receivers, here’s my experience using them last year in my ef1 and c40 racers. They are compatible with Spektrum radios DX8, DX9, DX6i and DX7 and work with DMSX and DMS2 technology. Why would you want to use a stabilizer on your ef1 racers?  1st, it helps with rudder function on high power takeoff. 2nd  it will help you fly smoother with stabilization on aileron and elevator.  I have 12 of these little jewels and they have performed without a glitch. They can be found on the WEB, search Lemon RX and I think the company is XENON out of China, cost $19. I have been using the remote antenna on my C40 planes which will cost another $8.  Shipping through usps air mail is $3 and it will take about 2 weeks to get them. EBAY also has them available from a vender in Australia. I would suggest that you also down load the instructions that are available on their WEB site to help with the setup. Bye the way, RC universe has a thread with valuable info.  

RECEIVER INSTALLATION: The receiver needs to be mounted with the servo plugs to the rear (towards the tail) and mounted securely on a flat surface.  The black mounting foam that comes with the receiver is very strong, but makes it very difficult to remove the receiver without damaging the case, so I prefer hot glue on the corners of the case to hold it securely. The case needs to be mounted so that it doesn’t move or the stabilizer will not function properly.  Also, the receiver needs to be mounted as close to the “CG” as possible, but I have one mounted in a Proud bird 2.5” aft of the “CG” and it works great.  I recommend on some airframes you make a plywood platform that allows easy access to the receiver for fine tuning. For instance, on my club 40 racers, I make a platform just in front of the throttle servo to have easy access with the wing off.

DIP SWITCHES (6 each): These switches are used to configure the receiver with on/off positions. Don’t use an Exacto knife to move the switches, they can be damaged, I found that a small jewelers screw driver works best.

  1.  Switch #1 (aileron), #2 (elevator), and #3 (Rudder). These switch are used after you have established the correct servo direction on your transmitter,  next , the stabilizing direction needs to be set on the receiver. This is where you need to look at the diagrams in their provided instructions to set these switches to give the correct stabilizing response. Some pilots prefer using stabilization only on the rudder, which is beneficial, however, I use all three, and find it helps me fly smoother. If you elect to not use the stabilizer on any of the control surfaces just leave the pot in the 10 o’ clock position as described in “GAIN POT ADJUSTMENT “ below..
  2.  #4 and #5 should be on for fixed wing configuration. If you’re going to use 2 wing servos then read the instructions for wing configuration (flaperons) setup in the Lemon instructions, however, a “y” harness will not require any additional programming. The #4 and #5 can also be used for delta wing and v-tail operation per there instruction sheet.use all three to include aileron and elevator and I must admit it makes me a better smoother flying racer.
  3. #6 should be in the off position; it turns the master gain off on the receiver  (aux3 knob) DX8/DX9 trans.  I strongly recommend you not use the master gain function,  just use the gain pots on the receiver to adjust the gain , which we will discuss more in detail. If you are using a DX6i or DX7 this Aux3 channel isn’t available and there is no master gain function.

GAIN POT ADJUSTMENT (3-EACH): Now that you’re sure that you have the stabilizing function moving in the correct direction, per the instruction sheet, the gain pots need to be pre- flight adjusted. In the instruction sheet they refer to the pots being at 50 percent, which was a bit confusing to me because they don’t have any percent markings, so this is my recommendation. Remember that the servo plugs needed to be installed towards the tail for proper stabilizing function, so, I used the plugs as a 6 o’clock position, the tail of the aircraft.  Now, with a small jewelers screw driver rotate the pots in the counter clockwise direction and you will see that they stop at about a 10 o’clock position; nose would represent 12 o’ clock.  Caution! , don’t apply too much pressure these pots are small and can be damaged. Now that you have a 10 o’clock position set, turn each pot clock wise to the 1 o’ clock position.  I found that this is the sweet spot and usually works on all my aircraft. One other thing, the stabilizer doesn’t like exponential in the transmitter setup, so I usually have one rate setting that has none for stabilized flight and use the other rate settings for normal flying.

IN-FLIGHT TRIMING: Be sure that the stabilizer is off utilizing the retract switch and preform a preflight to include range check. After takeoff, trim your aircraft, full throttle for racers, then get at a comfortable altitude into the wind and flip the retract switch on/off rapidly, 2 times in the length of a second per instruction sheet. This locks the stabilizer on to the trim settings you have established. Caution! This is where you find out if you made a mistake and got the DIP switches, 1, 2, and 3 in the correct/wrong  direction?  If not you could lose your plane!  Now, your first reaction is that all the control functions have slowed way down, this is normal and takes some getting used to, however, with some aircraft I have gone back and set more end point travel on elevator/aileron on the transmitter. Rudder authority is important, you want to have as much as possible, so, I go back and start putting more gain on the rudder pot say 2 to 3 o’ clock. If you get too much gain you will notice the tail will fishtail at high speeds, if this happens just reduce the gain as necessary.  Remember smooth is fast!

Sometimes I think that this is way too much detail in my instructions, however, I look back at how long it took me to figure it out and hope it reduces your learning curve. My email: fredfrench18@gmail.com if I can help.

Fast Freddy 



Exceptional article Freddy!  Thanks for all the great information!

Thanks Fred!  This is just what I was looking for.  It should be applicable to the Orange FASST 3-axis receivers too!