Lemon Rx User Manual
Contents
1. In the transmitter tail type if available is set to Normal this ensures that separate not mixed elevator and rudder signals are sent to the stabilizer In the receiver DIP switch J4 elevons is OFF and DIP switch J5 V tail is ON thus activating on board mixing The setting of DIP switch J6 depends on the aileron configuration The tail servos are plugged into channels 3 and 4 Elevon Delta Wing This arrangement is generally used for a tailless aircraft such as a flying wing or delta in which the wing control surfaces elevons are used to control both pitch elevator and roll aileron The elevons move up or down together for pitch and in opposite directions for roll In the transmitter wing type is set to Normal In the receiver DIP switch J4 elevons is ON to activate mixing DIP switches J5 V tail and J6 flaperon are OFF The elevon servos are plugged into channels 2 and 3 Flaperons dual aileron servos The flaperon arrangement enables the ailerons not only to move in the usual opposite directions to produce roll but also to move together downward to produce flap action and possibly upward to produce spoiler action thus controlling lift and drag This dual function capability requires that each aileron servo have its own channel normally channel 2 for right aileron RAil and channel 6 for left aileron LAil The stabilizer passes the control inputs sent by the transmitter through to the two aileron channels T2. On some transmitters entering bind mode requires holding the Bind or Trainer button switch while powering up Others require opening a menu to enable bind mode If appropriate continue to hold the switch button until the receiver LED stops flashing Release it at that point and the bind process will complete A solid green or green and red light indicates a successful bind Some transmitters will display on screen and or announce the type of bind DSMX DSM2 and the frame rate If a successful bind is not achieved remove power from the receiver and repeat the whole process with the transmitter at a greater distance Avoid trying to bind in close proximity to large metal objects such as chain link fences vehicles or a furnace Step 3 Power down and test Remove power from the receiver remove the bind plug and switch the transmitter off If you didn t use servos while binding plug in one or more now to channel 2 3 or 4 Turn the transmitter back on then apply power to the receiver Check that the receiver is operating properly and that servos respond to the transmitter controls Check that the Gear switch turns stabilization on green light only and off green and red lights Failsafe It s important to note that the Lemon stabilizer unlike some other Lemon receivers does not use preset failsafe Instead on loss of signal the pulses for all channels stop completely The speed control ESC after a brief delay shuts down the
3. 3 6ft 1 2m or the transmitter may swamp the receiver Occasionally it may be necessary to have as much as 10ft 3m separation to achieve binding Generally you should only need to bind once unless you change transmitters and after binding normal link up should not require more than 2 3 feet 1m of separation Step 1 Power up the receiver in bind mode Put the bind plug on to the Bind Aux2 pins see picture on page 1 Connect the plug from a suitable power source to any of the receiver servo outputs The power source can be e Areceiver pack battery 3 45 7 2v or e A stand alone BEC battery eliminator circuit or The throttle connection from an electronic speed control ESC with built in BEC If using a speed controller as the power source and it is installed in a model make sure the motor is unplugged or the propeller is removed for safety If you are using a satellite with the stabilizer then binding must be done with the satellite connected Binding can be done with or without servos Servos plugged in the wrong way round may prevent binding so check this if you have difficulty The LEDs on the receiver and satellite if used will flash rapidly to indicate bind mode If they don t you have a problem such as a reversed power connector Don t go any further until you get rapid flashing Lemon DSMX 7 Channel Stabilizer Instructions v 2 1 3 9 Revised July 17 2015 Step 2 Turn on transmitter in bind mode
4. The purpose of this section is to explain further how all this works The key point to understand is that the Lemon stabilizer only recognizes and corrects for movement in the three standard flight axes shown in the diagram on page 5 Consequently the stabilizer expects the transmitter to provide the conventional pure inputs roll aileron pitch elevator and yaw rudder Any processing mixing needed to turn these inputs into servo commands for a non standard control arrangement such as elevon or V tail has to take place in the stabilizer itself NOT in the transmitter By contrast flaperon mixing takes place in the transmitter What is mixing In a simple control setup each axis has a dedicated control surface or pair of surfaces in the case of aileron Each axis is controlled by a separate channel passed from the transmitter through the receiver and its integrated stabilizer and on to the servo that moves the control surface For the Lemon receivers channels 2 3 and 4 are used respectively for the three basic controls aileron elevator and rudder Mixing is the process of combining transmitter inputs to provide the servo output s required for control For many purposes the mixing is done in the transmitter For example throttle can be mixed to elevator so that as power is increased a small amount of down is added to the elevator signal in order to counter the model s tendency to climb Another common mix couples a
5. large stick excursions However the balance between on board stabilization and transmitter control is a compromise There is always some stabilizing effect whenever the stabilizer is active Consequently if you need maximum airborne response to stick inputs the stabilizer should be turned off using the Gear stabilization switch It s important to understand that the 7 channel Lemon stabilizer unlike some more complex and costly units does not contain any accelerometers or other sensors to establish an absolute level or direction The Lemon stabilizer does not for example provide heading hold like the Eagletree Guardian or a panic button like Spektrum SAFE technology its action is more like that of Spektrum s basic AS3X technology The Lemon does just what most people need smoothing out flight while leaving the pilot fully in control If you want a more sophisticated stabilizer with auto leveling and a GPS sensor that enables the plane to return to the launch site automatically be patient as Lemon plans to have such technology available in future receivers Number of Transmitter Channels The minimum number of transmitted channels required to use the stabilizer with a conventionally configured electric powered three axis plane is five That covers the four flight channels Throttle channel 1 Aileron channel 2 Elevator channel 3 and Rudder channel 4 plus Gear channel 5 to switch the stabilizer on and off in flig
6. motor and all servos simply stay where they were when signal was lost Control is quickly restored when the signal returns This is a satisfactory arrangement for electric powered models such as those for which the Lemon stabilizer is intended One advantage is that unlike other failsafe arrangements it doesn t rely on the operator to ensure that the throttle is set correctly at bind time It does however make the unit unsuitable for use in fuel powered models where the throttle servo must be driven to a preset safe position low on loss of signal Note that a few very old ESC designs may not shut down when pulses are removed This unsafe behavior makes them unsuitable for use with the Lemon stabilizer and most other systems Be sure to test failsafe for any new setup Orientation of the Receiver Unit The most common arrangement is to mount the stabilizer level and upright aligned with the center line of the fuselage with the connector pins toward the tail The stabilizer can however be flipped 180 on any of the 3 axes A common arrangement that presents no problems is mounting the stabilizer upside down for access from the bottom of the model The stabilizer will not work properly if rotated 90 on an axis This means that with normal channel assignments you cannot fasten it to the flat side of a profile aircraft Nor can you mount it across the fuselage It must align with the matching aircraft axes 11 Transmitters and mod
7. next to the connectors are on indicating that the receiver is operating properly in non stabilized mode Temporarily plug a servo into each of the Ail Ele and Rud outputs and check that they operate normally in response to the correct transmitter sticks Power off 4 Test the receiver in stabilized mode Set switches J4 and J5 to the ON position Power on the transmitter and receiver Check that the green LED is ON and that the red LED goes OFF when you move the Gear switch The stabilizer is operating when only the green LED is ON i e red LED ON stabilizer OFF Power off HINT For troubleshooting plug a servo into the Gear pins channel 5 on the stabilizer The servo should move through about 80 90 when the Gear switch is toggled 5 Mount the receiver in the plane Install the stabilizer flat in the fuselage aligned with the center line and with the pins at either back or front The bottom of the stabilizer should be mounted firmly to the aircraft using the supplied double sided tape If using a satellite mount it away from the stabilizer with the antenna wires straight and at right angles to the main receiver antenna see page 11 If using the dual antenna diversity version of the stabilizer ensure that the active portions of the two antennas the silver section about 31mm long are approximately at right angles to each other Take care not to kink the cable Make sure you can access the three gain pots on the receiver a
8. see page 13 They also assume you are using a transmitter with seven channels or less and thus do not have access to Master Gain channel 8 Stabilization will work normally but without the ability to adjust gain in flight See page 12 for information on Master Gain 1 Set up the transmitter If using a computer transmitter set up anew model Disable any elevon delta or V tail mixing if these mixes are required they must be done in the stabilizer see page 13 Make sure control throws end points limits are set to 100 80 for open source firmware transmitters see page 13 2 Bind the receiver Bind the receiver to the transmitter in the normal way If you are using a satellite it must be connected during this process Completion of the bind is indicated by solid lights on the receiver and satellite if used Be sure to turn off both receiver and transmitter and remove the bind plug after binding For details see page 9 1 The picture shows a v3 or v4 4 5 receiver The v2 Stabilizer is physically different and lacks the plastic case See page 17 for version details A very similar end pin version is also available as well as a dual antenna diversity version Lemon DSMX 7 Channel Stabilizer Instructions v 2 1 3 2 Revised July 17 2015 3 Test the receiver in non stabilized mode Check that all stabilizer switches are in the OFF position Turn on the transmitter and then the receiver Check that both green and red LEDs
9. stabilizer Unscrew the two retaining screws and carefully pry the case apart with a modelling knife Do not bend the case back as doing so will break the two small plastic pins which fit tightly into sockets in the end of the case away from the screws Short the two pads shown in the photo below with a pair of tweezers or forceps or Provide power for the stabilizer Make sure the gyro does not move It must experience absolutely no vibration or movement The green LED will flash 3 times to indicate the beginning of gyro calibration After 1 second the green LED will again flash 3 times to indicate gyro calibration complete Remove the short circuit connection Power cycle the unit and test operation If the offset problem is not solved repeat steps 3 7 and make sure there is no movement or vibration of the unit Even a tiny invisible movement will prevent proper calibration Recalibrating v4 5 Receivers green flashes only at power on For this version opening the case is unnecessary 1 2 3 4 5 6 7 Unplug any power source for the stabilizer Connect two bind plugs as shown in the photo below Provide power for the stabilizer Make sure the gyro does not move It must experience absolutely no vibration or movement The green LED will flash 3 times to indicate the beginning of gyro calibration After 1 second the green LED will again flash 3 times to indicate gyro calibration complete Remove the two bind p
10. BINAINE ce Sap nce ec a eee ata ued 9 Failsafe prn aa araia Eea a EEr od aden E E RS 10 Orientation of the Receiver Unit ee seesnssssrrrnsnrnrrnnnreennnnnonnnnnnnnnnnnnennnnnnnnnnnennnnnnennnnnnnnnnnnnnnnnnennnnnnnnnnnnnnaan 10 What the LEDs mean in more detail ssssssssscsssssesssssssesssssssessesassessesassaeacsassasssssseacsaesseacsasseeseaseaeeses 11 Aerials Satellites and Range Checking ssssssssssssssssssnnrnnsnrneessssensssnnnnnnnnnnnnntnnneennnnnnnnnnnnnnnnnnnnntnenennnnnnns 11 M ster Gain Cont O lsssnennncnsrngennnnann E A 12 Using an Open Source Transmitter Taranis 9XR etc ceseessssecsesseesteeseeeneessentessesntesneestesneeateeateeaes 13 Mixing and the Lemon Stabilized Receiver ssssssssssssssssssrrrsssnsssssssssusnnnunnnnnnnnnnnnnenennnnnnnnnnnnnnnnnnnntnnnnennnnnnnns 13 Recalibrating the GYrOS ss sss sssssssssssesssssnsnnnnnnnnnnnnsnnneennnnnnnnnnnnnnntnnnnnnnnnnnnnnnaannnnnnnntnntnentnnnn anan nannnnnnnnnntneen annn aat 15 Versions of the Lemon Stabilized Receiver scssssssscsssssesssssssessesessessssassessssacsassessseacsaesssessarsseseeacsaeeses 17 Lemon DSMX 7 Channel Stabilizer Instructions v 2 1 3 1 Revised July 17 2015 The Lemon DSMxX Receiver with Integrated Stabilizer The Lemon 7 channel stabilized receiver shown above is expressly designed as a simple integrated full range DSMX receiver and rate gyro stabilizer for electric models This receiver is not
11. Revised July 17 2015 Lemon 7 channel Stabilized Receiver Instructions J1 J2 J3 set the direction of each axis stabilisation response J4 is ON for Elevon Delta mix J5 is ON for VTail mix Both ON Normal wing tail x r J6 is ON to enable Dual aileron DOME tee connector or Flaperon Requires ailerons set to Dual Aileron or Flaperon J4 J5 J6 all OFF Stabilisation disabled Signal pins NE 5 Volt pins i Individual gain adjustment for Gnd pins a each flight axis Bind Aux2 L Throttle Aileron RAL Rudder This channel is used to switch For Spektrum transmitters stabilisation ON OFF and is not this is done in WingType menu Elevator normally available for anything else ie Aux1 LAL Gear not normally connected Contents The Lemon DSMX Receiver with Integrated Stabilizer eesceessesssesseesssstssseesesseeseesteeseesteestesteesteentesneeaes 2 Basic Instructions for Using the Lemon Stabilized Receiver oon ees eestesstessesstesseestteseeesteeteesteeeesteentesneeaes 2 A More Detailed Look at the Stabilized Receiver and its Use c csesesssssessessesessesesssseessesssssseesssssseesseeseees 8 What a Rate Stabilizer DOes cssssssssssssssssssssssssssssssssssessessssacsessssssatssssssaeesssasscsaesassesacsassatacsassasseeatsassaeaceaseass 8 Number of Transmitter Channel s ccccssssssssscssssssssssssssssssssssssssssessessssnssesseeassussesassassnseseassassceassacsneeseassneess 8
12. abilizer Instructions v 2 1 3 3 Revised July 17 2015 Conventional controls with aileron servos on separate channels Channels 1 THR 2 R AIL 3 ELE 4 RUD 5 XXX 6 L AIL Switches J4 ON J 5 ON J6 ON Wing type Dual Ail or Flaperon Elevon Delta wing control configuration Channels 1 THR 2 R ELEV 3 L ELEV 4 RUD 5 XXX Switches J4 ON J 5 OFF J6 OFF Wing type Normal NOT Delta V tail control single aileron servo or Y cable Channels 1 THR 2 AIL 3 R TAIL 4 L TAIL 5 XXX Switches J4 OFF J 5 ON J6 OFF Wing type Normal Tail type Normal NOT V V tail control separate aileron servos Channels 1 THR 2 R AIL 3 R TAIL 4 L TAIL 5 XXX 6 L AIL Switches J4 OFF J 5 ON J6 ON Wing type Dual Ail or Flaperon Tail type Normal Important safety warning Leave the motor unconnected or remove the propeller when testing or programming Electric models can bite Summary of the Settings for Various Control Configurations ch veel i Stabilizer annel Assignments Win Model Type g Switches Type 4 5 6 8 Conventional 7 Master N i orma one ail channel Gain Conventional Master Dual Ail two ail channels Gain Flaperon Elevon Master RElev LElev Normal Delta Wing Gain V Tail Master Normal T one ail channel Gain V Tail Master Dual Ail RAil RTail two ail channels Gain Flaperon Use of Chann
13. ally direct those channels or you may be able to use mixes from other channels for this purpose but these channel assignments within the receiver cannot be altered It follows from all this that you cannot on a conventional powered model have all three of dual ailerons and independent flaps and independent gear even with an 8 channel transmitter There are simply not enough channels available in the Lemon receiver Lemon do provide Gear channel 5 output pins on the receiver But to use that option for flaps or retracts you would have to accept stabilization being turned on and off as the flaps or gear are deployed or retracted Not very practical To summarize practical arrangements for a powered plane using a seven or more channel transmitter and v4 receiver include e A single Aileron servo or two servos on a Y cable on Ail channel 2 with Flaps on Aux1 channel 6 and Retracts on Aux 2 channel 7 e Separate Aileron servos on Ail channel 2 and Aux1 channel 6 with Retracts OR flaps on Aux 2 channel 7 this arrangement would allow use of the flaperon function Binding The stabilizer is bound just like any regular DSMX DSM2 receiver Lemon or other Binding is the process of locking the receiver to the transmitter so that it ignores any others Binding is the first step in setting up any receiver and is most easily done on the bench rather than in the model Ensure that the transmitter and receiver are separated by
14. an autopilot or self leveling device It will not fly the plane for you It is designed simply to smooth out flight and thus make flying in wind and turbulence a pleasure rather than a risk The Lemon stabilizer is very small and light Despite its low cost it offers both high quality and high performance A Lemon DSMX satellite receiver can be added to further improve performance A dual antenna diversity version is also available The unit automatically switches from DSMX to DSM2 and so will work with any Spektrum or compatible transmitter of five channels or more including the basic DX4e and DX5e units as well as computer transmitters such as DX6 DX7 DX8 and DX9 It can also work with open source transmitters such as Taranis and Turnigy 9XR using an add on DSM2 or DSMX module The unit provides mixing capability for elevon delta and V tail and supports dual aileron and flaperon functions The first part of this document provides basic instructions for installing and adjusting the Lemon stabilizer For many users the Basic Instructions section should supply all necessary information The second part of the document provides more detailed information on various aspects of operation and should be consulted as necessary Basic Instructions for Using the Lemon Stabilized Receiver NOTE These basic instructions assume you are using a Spektrum transmitter If you are using an open source firmware transmitter such as a Taranis or 9XR
15. and forth twice quickly within 1 second to store the neutral positions of the controls This double toggle should be done before each flight if any of the trims and or subtrims are far from zero If little trim subtrim is used this step can be omitted 6 If using a DX4e or DX5e the built in D R switch gives 100 and 75 rates Lemon DSMX 7 Channel Stabilizer Instructions v 2 1 3 6 Revised July 17 2015 Check that the stabilizer is turned OFF Take off and fly around adjusting trim as necessary Make sure the model flies properly without stabilization If you make major trim adjustments do a double toggle to enable the stabilizer to store the new neutral positions At a safe height use the Gear switch to turn the stabilizer ON If the model rolls dives or turns suddenly at least one of the gyro direction switches J1 J2 J3 is incorrectly set Switch OFF the stabilizer immediately Land and fix Likewise if you encounter major oscillation land and reduce gain in the axis axes involved Assuming the model does nothing scary continue flying to explore the action of the stabilizer Do a shallow dive to pick up speed and watch for oscillation on one or more axes If it happens just throttle back and slow down oscillation is quite different from control surface flutter and is generally not destructive Notice how the model handles with the stabilizer turned on It may be less responsive on one or more axes Experiment with d
16. by a double flash of both the red and green LEDs at power up V4 5 released in July 2015 is identical to V4 except it allows the gyros to be easily recalibrated by the user without opening the case This version is distinguished by a double flash of only the green LED at power up All versions of the Stabilizer have been available in top pin configuration Lemon released an end pin version of the V4 stabilizer in May 2015 see photo at right In addition Lemon released a dual antenna diversity version of the stabilizer in July 2015 NOTICE This manual is provided to help you understand and use the Lemon 7 Channel Stabilized Receiver The authors are not associated with Lemon Rx and this is not a Lemon Rx publication You can freely quote from redistribute and or modify this manual in doing so please acknowledge the source and any changes The manual is distributed in the hope that it will be useful but WITHOUT ANY WARRANTY without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE See the GNU General Public License for more details In using this manual you agree that you accept all responsibility For more information see http www rcgroups com forums showthread php t 2164243 http www lemon rx com shop index php route common home JJ604 and Daedalus66 July 2015 Lemon Stab7 manual REV 05d Jul 2015 Lemon DSMX 7 Channel Stabilizer Instructions v 2 1 3 17
17. e Transmitter Taranis 9XR etc The Lemon stabilized receiver can be used with a transmitter other than Spektrum provided it has a DSMX or DSM2 module installed Transmitters such as the FrSky Taranis Turnigy 9XR and 9XR Pro and FlySky Turnigy 9x with Er9x all use open source firmware that can be easily programmed to emulate the output of a Spektrum transmitter including such functions as flaperon mixing While the programming steps are slightly different for the various transmitters the following suggested setup can be applied to any of them e Channels 1 4 set up as a simple four channel model with channel order TAER e Channel 5 set up to give 100 in response to a suitable two position switch e Channel 6 is available for dual aileron flap or gear as required e Channel 7 is available for dual aileron flap or gear as required v4 receiver e Channel 8 set up to provide 100 in response to a knob slider or lever Set limits of 80 on all channels to match Spektrum 100 pulse width Reverse channel 2 aileron and channel 4 rudder to match Spektrum This will give you a transmitter that works very much like a DX8 and that provides a good basis for setting up the stabilizer according to the Basic Instructions provided earlier Mixing and the Lemon Stabilized Receiver Step 6 in the Basic Instructions page 3 should give you the information you need to set up elevon V tail or flaperon mixing with the Lemon Stabilizer
18. els 7 and or 8 requires a transmitter with more than six channels 7 Verify control directions adjust centering and servo throws Power on Use the Gear switch to turn the stabilizer OFF green ON red ON b Ifyou wish to change the switch direction reverse the channel in the transmitter Make a note of how it works so you can switch stabilization OFF quickly if necessary c Adjust transmitter reversing so that all servos work in the correct direction in response to the sticks Note that where elevon V tail or flaperon mixing is involved it may be 3 Only used if the model has a separate vertical rudder 4 On a transmitter like the DX9 assign channel 5 gear to a suitable switch Lemon DSMX 7 Channel Stabilizer Instructions v 2 1 3 4 Revised July 17 2015 necessary to interchange the two servo connectors and or reverse controls to get the correct action d With trims in neutral adjust servo arms and linkages to align your control surfaces Use only a minimum of subtrim on the transmitter for fine tuning Servo arms should be at right angles to push rods to ensure equal movement in both directions e With end points limits and control rates at 100 check that control surface throws are at the recommended maximums for the model and adjust linkages if necessary Note that adjusting throws in the transmitter will not affect stabilization so throws need to be set mechanically to give the stabilizer enough control the exact amou
19. enced RC pilots check stick directions before the first flight of the day so a pilot using a stabilizer should check that the surfaces move correctly in response to a disturbance 5 If you are using channel 8 for Master Gain set it to the middle of its range see page 12 Lemon DSMX 7 Channel Stabilizer Instructions v 2 1 3 5 Revised July 17 2015 9 Set dual rates and expo in the transmitter You should already have the control surfaces set up to move in the correct directions and with the full throws recommended for your model Now you should adjust the response to transmitter inputs by setting dual rates D R and expo A good starting point for D R is to set High Rate at 100 and Low Rate at 65 75 for each axis Expo of 20 30 softens response around neutral and can make smooth flying easier Stabilization settings also affect the response of the model to the transmitter sticks typically reducing sensitivity with an expo like effect To achieve your preferred response you may need to adjust your rates and expo once you find out how the model reacts Note that the dual rate and expo settings determine stick feel but don t affect how the stabilization works That is entirely done within the receiver 10 Adjust the stabilizer gain pots Set the three gain pots at about the 10 o clock position This is a good conservative starting point that will produce noticeable stabilization For most models at least one or two gain set
20. ether the stabilizer is on or off Note that it may be necessary not only to use channel reversing in the transmitter but also to interchange the plugs of the two servos involved in the control mixing For example if both V tail surfaces move sideways when the elevator stick is moved interchange the plugs in channels 3 and 4 Then use channel reverse in the transmitter to adjust the direction When all control settings and mixing are completed and the control directions are correct the direction of the stabilizer s response to a flight disturbance must be set for each axis Checking must be done with the stabilizer turned ON and in accordance with the instructions provided earlier see page 5 To change the direction of response for an axis use the appropriate DIP switch J1 aileron J2 elevator or J3 rudder Recalibrating the Gyros The stabilizer as supplied is fully calibrated and normally requires no further adjustment A problem in manufacturing or a situation such as operation in temperatures far from the nominal 25 degrees Celsius 77F might require recalibration of the gyros to avoid control surface offset when stabilization is turned on What causes the problem The stabilizer reads gyro values and multiplies them by the gains set by the potentiometers this creates output values used to generate corrections that drive the servos Every gyro has an inherent offset that is calibrated out when the stabilizer is manufactu
21. he inputs can include not only flaperon mixing but also differential aileron more up than down to compensate for adverse aileron drag Unlike V tail and Elevon where the mixing happens in the stabilizer aileron flaperon mixing takes place in the transmitter For the stabilizer to apply corrections to both ailerons in response to wind gusts etc switch J6 must be ON If it is OFF only the right aileron CH2 will have stabilizer action In the transmitter wing type should be set to Dual Aileron or Flaperon as appropriate If flaperon is used then Flap mixing must be applied this usually includes mixing to the Lemon DSMX 7 Channel Stabilizer Instructions v 2 1 3 14 Revised July 17 2015 elevator channel to compensate for the pitch effects of flap action Also differential aileron can be applied if required In the receiver DIP switch J6 flaperon is ON to enable stabilization on the second aileron channel DIP switches J4 and J5 are ON except for a model with a V tail when J4 must be OFF The right and left aileron servos are plugged into channels 2 and 6 respectively Reversing Controls and Corrections The direction of response of the control surfaces to the transmitter inputs must be checked and corrected if necessary AFTER any mixing is set up for V Tail Elevons and Flaperons To avoid distracting control surface motions stabilizer action should be turned OFF with the Gear switch during this process mixing occurs wh
22. ht All full range Spektrum transmitters have at least five controllable channels and thus can be used with the Lemon stabilizer The computer transmitters offer the following possibilities With a DX6i or DX6 Aux1 channel 6 can be used to control one of three main possibilities 1 retracts or 2 flaps or 3 a second aileron servo as in a dual aileron or flaperon setup A DX7 or DX7s enables the use of Aux2 channel 7 for a v3 receiver this channel only works when stabilization is OFF but for a v4 or 4 5 receiver Aux2 is available whether stabilization is ON or OFF see page 13 A 7 channel transmitter enables any two of the above three possibilities A DX8 or higher transmitter enables internal use of Aux3 channel 8 giving Master Gain control on a v3 or V4 receiver It does not provide an additional free channel 8 Gear channel 5 is operated by the ACT Aux switch on a DX4e and the Ch 5 switch on a DX5e 9 The new DX6 introduced in 2014 not the old one from 2006 which is not compatible 10 Either the old DX7 from 2007 or the new one for 2015 Lemon DSMX 7 Channel Stabilizer Instructions v 2 1 3 8 Revised July 17 2015 Note that no amount of transmitter mixing can change the receiver s use of Gear channel 5 or Aux3 channel 8 These channels are permanently committed within the receiver to stabilizer ON OFF and Master Gain respectively You can on some transmitters adjust which switches knobs or sliders actu
23. ileron and rudder to aid in coordinating turns The important thing about such mixes for our purposes is that they don t affect the basic arrangement of Lemon DSMX 7 Channel Stabilizer Instructions v 2 1 3 13 Revised July 17 2015 allocating one channel to each control axis or function Consequently they still provide the separate inputs required by the stabilizer The V tail and elevon mixes we are concerned with are different in that they involve two separate and independently driven control surfaces working together to provide a single aerodynamic function For example a pair of elevons must work in unison to produce pitch and in opposition to generate roll To achieve this the mixing MUST be done on board since the stabilizer cannot interpret inputs in the form of mixed control commands it only understands roll pitch and yaw Any V tail or elevon mixing in the transmitter must therefore be disabled Flaperon is another case where two inputs aileron and flap are involved but here the mixing is done in the transmitter Let s take a look specifically at how these three types of control setup are dealt with in relation to the Lemon Stabilized Receiver The terms J and DIP refer to the six small white slide switches on the receiver V Tail In this arrangement the functions of elevator and rudder are managed by tail control surfaces that move up or down together for pitch right or left together for yaw
24. ing the gear channel or the DIP switches Aerials Satellites and Range Checking All Lemon receivers including the stabilizer are full range This means that they have ample range for all normal visual flying as opposed to long range FPV flying In practice Lemon receivers match or better the range of other comparable DSM2 DSMxX receivers under the same conditions Modern 2 4 GHz receivers work very well indeed but under some conditions the radio link can be interrupted by factors such as nearby metal fencing or conductive objects within the model The reliability of the link for a given range is affected by the number of aerials antennas and their orientation as well as by the installation of the receiver in the model The base Lemon stabilizer has one aerial wire For the strongest and most reliable reception the wire should stick straight out from the stabilizer an aerial bent along the stabilizer case may reduce reliable range Likewise locating the aerial wire very close to motor wiring the battery or other conductive objects may reduce reliable range A satellite remote receiver enhances reliability by adding signal diversity It provides a second independent receiver that can be well separated from the main receiver thus sampling a different part of the radio transmission field From moment to moment the main receiver selects the stronger of its own signal or that of the satellite If a satellite is connected most re
25. liable reception is obtained when its aerial and that of the stabilizer are at right angles The two wires of the satellite aerial should be in a straight line The satellite should be mounted so that it cannot move around in the model The diversity version of the stabilizer has two separate antennas and an internal switch that selects from moment to moment the antenna receiving the better signal The active portions of the two antennas the silver sections approximately 31mm long should be well separated and arranged at right angles taking care not to kink the cable 13 The brownout warning will be triggered if you turn the receiver off and back on again without also power cycling the transmitter Lemon DSMX 7 Channel Stabilizer Instructions v 2 1 3 11 Revised July 17 2015 To verify a new installation or to check radio operation before the first flight of the day use the range check function on your transmitter This temporarily attenuates transmitter power so that range is reduced by a factor of about 30 With Spektrum and similar transmitters full control at 30 paces roughly 27yds 25m with the transmitter in range check mode indicates ample range for normal visual flying In many cases the receiver will show considerably more range than this but the important thing for safe flying is that it meet the 30 paces go no go standard Master Gain Control If the transmitter has eight channels or more then Aux3 channel 8 control
26. lugs Power cycle the unit and test operation If the offset problem is not solved repeat the above steps and make sure there is no movement or vibration of the unit Even a tiny invisible movement will prevent proper calibration Note It should not be necessary to re bind the receiver to the transmitter after this procedure Lemon DSMX 7 Channel Stabilizer Instructions v 2 1 3 16 Revised July 17 2015 Versions of the Lemon Stabilized Receiver The variants of the Stabilizer available to date are the following V1 was only briefly available in mid 2013 and was withdrawn almost immediately V2 was released early in 2014 It has two layers of circuit board and lacks a plastic case On off is controlled by Aux1 channel 6 thus Gear channel 5 is available for other purposes Master Gain is not available V3 issued in May 2014 has a single layer circuit board design and plastic case as shown in the picture on page 1 On off is controlled by the Gear switch channel 5 making Aux1 channel 6 available for other purposes Access to Aux2 channel 7 is available on the bind pins but the channel only works when the receiver is in non stabilized mode Master Gain uses Aux3 channel 8 Version 3 emits no flashes at power on V4 released in August 2014 is identical to V3 in appearance and function except that Aux2 channel 7 is available on the bind pins in both stabilized and non stabilized modes The version can be recognized
27. nt is not critical as gain will later be used to adjust stabilization 8 Test stabilization response and direction Turn the three onboard gain adjustment pots fully clockwise maximum Switch the stabilizer ON using the Gear switch lights green ON red OFF Sharply move the plane in each of the three flight axes and check that the control surfaces move vigorously to oppose the disturbance See diagram below Direction of servo movment with changes in direction when stabilizer is enabled A A F gt rs SS C f R yiia r Y The diagram shows how the surfaces should respond to movement of the model about each axis When the model is rolled sharply to the right the right aileron should go down and the left aileron up to resist the displacement Likewise when the model pitches nose down the elevator should go up to compensate And when it yaws nose right the rudder should go left Note that the control surfaces will only be displaced while the model is being disturbed as soon as angular motion stops they will return to neutral So look for quick twitches of the control surfaces in the right directions not prolonged control offsets THIS IS VITALLY IMPORTANT If stabilization moves the surfaces the wrong way i e to increase the disturbance your model may be uncontrollable until you switch off stabilization To correct this change the appropriate switch J1 aileron J2 elevator or J3 rudder Just as experi
28. ontrols The Master Gain is the overall volume control It modifies the levels of all three channels and turns them up or down together The individual gain values are all multiplied by the value of the Master Gain controlled by Aux3 channel 8 e With the Master Gain in the center Aux3 0 the gain value is 1 and the individual gain values as set by the pots are unaffected e If Aux3 is at 100 Master Gain is very low and the individual gains become very small e If Aux3 is at 100 the Master Gain is nearly 2x and the individual gains have almost twice their usual effect To turn the stabilizer completely off with Master Gain the low end of Aux 3 must be 150 on a Spektrum or JR transmitter In practice many people initially set Aux3 at 0 middle position so that the Master Gain multiplier is 1x then as explained in Basic Instructions they adjust the individual gains to give good stabilization without any oscillation Master Gain can greatly help in this process and can subsequently be used to turn the overall gain up or down to suit changing flight conditions Lemon DSMX 7 Channel Stabilizer Instructions v 2 1 3 12 Revised July 17 2015 If your transmitter has seven channels or fewer Master Gain will default to a value of 0 8 This is a practical compromise erring on the side of safety so that the individual pots have a good range of control but are less likely to induce oscillation if set too high Using an Open Sourc
29. red Normally this initial calibration lasts for the life of the stabilizer but if for some reason it is not done correctly in the first place or things change later there will be an offset on one or more channels This will show up as control surface deflection when stabilization is turned on followed by a return to neutral when stabilization is turned off Correcting this issue requires recalibration of the gyros Recalibration is only needed if a control surface moves from neutral and stays there when the stabilizer is turned ON then returns to its previous position when the stabilizer is turned OFF Please note Gyro recalibration has nothing to do with the double toggle gesture mentioned on page 6 The purpose of that feature is to allow the stabilizer to identify the current neutral positions of the sticks How to recalibrate the gyros Stabilizers can be recalibrated by the user but the procedure has changed with the release of v4 5 A version 4 stabilizer can be recognized by a double flash of both red and green LEDs when the stabilizer is powered on and receives a signal from the transmitter while version 3 emits no flashes Version 4 5 produces a double flash of only the green LED Lemon DSMX 7 Channel Stabilizer Instructions v 2 1 3 15 Revised July 17 2015 Recalibrating v3 and v4 Receivers no flashes or red and green flashes at power on 1 2 3 4 5 6 7 8 Unplug any power source from the
30. s the overall Master Gain of the stabilizer system The Master Gain function multiplies the setting of the individual gain pots by a factor that can range from 0 to 2 In other words with Master Gain turned full up the gain setting of each individual axis will be roughly doubled If turned full down there will be little or no stabilization on any axis regardless of the setting of the pots For Master Gain to be useful it is best controlled by a knob slider or lever on the transmitter To check operation make sure stabilization is ON green LED on red off and set the Master Gain control to one end of its travel Move the model rapidly about the yaw pitch and roll axes If the control surfaces respond vigorously when the model is disturbed you have identified the full gain setting Test again with the control at the other end of its travel If nothing much happens either way make sure stabilization is turned on and the individual pots on the receiver are somewhere around middle setting or higher You can use channel reverse in the transmitter to reverse the operation of the knob slider lever controlling the Aux 3 channel Most people intuitively think of clockwise as increase for a knob and upwards as increase for a slider or lever Understanding Master Gain Think of the three stabilized channels as the three inputs of a three channel audio mixer The on board rotary controls or pots potentiometers are like the three individual volume c
31. s you will need to adjust them perhaps repeatedly Note that the receiver can be mounted upright or inverted with the servo connectors at front or back It will not work properly if mounted across the fuselage on edge tilted forward or backward or at an angle to the center line This receiver unlike many other stabilizers does not need to be mounted very close to the center of gravity of the model Both receiver and satellite if used must be firmly attached See page 10 for more detail on receiver orientation 6 Connect servos and speed control ESC set switches and wing type Plug the servos and ESC into the appropriate slots on the receiver Normally the Gear slot channel 5 will be empty as it is used internally by the receiver to turn stabilization on off Set switches J4 J5 and J6 on the receiver as indicated below For Spektrum transmitters set wing type on the transmitter as shown in all cases the tail type is Normal Note that mixing for elevons or V tail is done in the receiver the transmitter must NOT be programmed for V tail or elevons Conventional controls with single aileron servo or two servos and a Y cable Channels 1 THR 2 AIL 3 ELE 4 RUD 5 XXX Switches J4 ON J 5 ON J6 OFF Wing type Normal 2 As shipped all the switches on the stabilizer are OFF This means the stabilizer is inactive and the receiver operates as a normal unstabilized 7 channel receiver Lemon DSMX 7 Channel St
32. tings will need to be increased or decreased during flight testing to achieve optimum stabilization As delivered the stabilizer gains are normally at the 12 o clock position Many models fly with gains between 10 o clock and 2 o clock but some may require minimum gain lt 8 o clock and some maximum oe gain gt 4 o clock on a particular channel There is p Y no hard rule and gains can only be fine tuned by eee i observing the behavior of the model at various somo omo D D Ra j speeds during flight testing E a 11 Prepare for flying pe n j Plug in the motor and or install the propeller as ios Bhs az necessary Check the control directions and stabilization functions one more time Do a reduced power range test should give at least 25m 27 yards range with full control Check that the Gear switch is operating correctly to turn stabilization ON green light only and OFF green and red lights Make sure you know which way is which Test failsafe operation by running the model well secured at about half throttle and turning off the transmitter The motor should stop after a couple of seconds and the control surfaces should stay in their current positions For more on failsafe see page 10 If you have Master Gain on channel 8 set it to the middle of its range see page 12 12 Perform a test flight Before taking off starting in the OFF position toggle the Gear stabilizer switch back
33. ual rate settings Turn stabilization off and on to get familiar with its effects 13 Fine tune stabilizer gain Now make a series of flights to optimize the individual gain settings This will involve repeated landings to adjust each pot on the receiver followed by retesting in flight but the basic job can be done relatively quickly It s a good idea to keep notes If you encountered oscillation on any axis during the initial flight turn down the gain a little for that axis Then go through the following steps e Turn Aileron and Elevator pots fully anticlockwise minimum gain and increase the Rudder pot setting by about two hours e Take off with stabilization OFF Turn ON ata safe height with the model in level flight Watch for oscillation on the yaw axis tail wag Do a shallow dive to pick up speed and again watch for oscillation e Land and adjust the rudder pot as required If there was no oscillation even when diving turn the pot up close further If there was oscillation turn the pot down a bit e Take off and retest You re aiming to set the pot to the maximum gain that doesn t produce oscillation in any normal flying e When satisfied with the rudder gain setting turn up the elevator gain pot and repeat the process e Finally follow the same procedure to set the aileron gain pot Many people find that on typical models the rudder gain can be quite high or even full while roll and elevator end
34. ules vary in how long the switch needs to be held Some may require it to be held to the end of the process while others will not complete until it is released Releasing when the flashing changes works in most cases 12 The receiver can be mounted in certain other orientations but doing so requires switching channel assignments For details see http www rcgroups com forums showpost php p 28340414 amp postcount 3 Lemon DSMX 7 Channel Stabilizer Instructions v 2 1 3 10 Revised July 17 2015 What the LEDs mean in more detail The 7 channel stabilizer has three LEDs red and green ones on the top near the connectors and ared one on the back of the PC board inside the case This single internal LED can normally be ignored as it mostly just mirrors some of the actions of the green LED There is one exception when using a transmitter on DSM2 this LED can flash a brownout warning to indicate momentary power loss Status Lights Transmitter Receiver Stabilizer Green LED Red LED Internal LED Normal Operation OFF ON x x x ON ON ON Vv x v ON ON OFF v Vv Vv DSM2 only Brownout 3 Flashing Binding ON or OFF BIND MODE Rapid Flash Rapid Flash Rapid Flash BIND MODE BINDING Flashing Flashing Slow Flash BIND MODE BOUND ON v x v Bottom line A properly bound active stabilizer will show only a solid green LED The red LED will come on when you turn the stabilizer OFF us
35. up somewhere in the range of 9 o clock to 2 o clock but the settings vary with factors such as model design flight speed and control setup HINT It s best to do the initial setup and tuning in fairly calm conditions to avoid confusing stabilizer induced oscillation with buffeting caused by turbulence Once you have things adjusted test the effectiveness of stabilization by flying in windier weather turning stabilization on and off You should see a noticeable improvement in smoothness with stabilization turned on 7 If you have an eight or more channel transmitter you can use Master Gain to help speed up the process of adjusting the individual gains See page 10 Lemon DSMX 7 Channel Stabilizer Instructions v 2 1 3 7 Revised July 17 2015 A More Detailed Look at the Stabilized Receiver and its Use What a Rate Stabilizer Does A rate gyro stabilizer compensates for external disturbances on all three flight axes pitch roll and yaw If your plane is disturbed by an external force such as a thermal or wind gust then the gyro sends out a shot of opposite control on the appropriate axis using ailerons elevator or rudder or elevons or V tail if used This will even out the flight path and make flying in turbulent conditions much easier The 7 channel stabilizer is designed to stabilize while keeping interference with normal control to a minimum To achieve this the amount of correction is automatically reduced for
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