Programming the JR XP8103

Step - by – Step

By Ron Richardson © 2000

Birmingham, AL

 

The following step-by step instructions will program the JR XP8103 radio to control a full-house sailplane.  These instructions assume you can readJ, have the above radio (charged) with 6 servos, and the instruction book turned to the picture on page 100.  All wing servo output shafts should be pointed towards the wing tips.  The servo arms for the flaps should be angled as far back (towards the TE) as possible.  The servo arms for the ailerons should be angled forward (away from the TE) about 45 degrees.

The basics:  We begin with a fresh “model memory space” with all settings at factory defaults,  set to transmit to your Rx, and set for a six-servo sailplane.

 

1.     Press and hold both the UP and DN buttons while turning on the Tx to activate system mode “[SYSTEM M.]”.

 

2.     Press the UP or DN button until the triangle cursor is next to “Model SEL” (it should all ready be there).

 

3.     Then press the UP and DN buttons together to choose the “Model SEL” option.

 

4.     Press the L/+ or R/- button until you come to an empty model memory, or a model memory you can erase.

5.     Press the UP button three times to cycle through the options till you see the “[MDL Reset]” option.

 

6.     Press the Clear button to erase (clear) the selected model memory and return all settings to the factory defaults.

 

7.     Press the DN button once to reach the “[Type SEL]” option.  Press the L/+ button until the little arrow points to “GLID”.  This is where we activate all the neat sailplane stuff.

 

8.     To name that “model memory”, press the DN button again to access the “[MDL Name]” option. Scan through the available letters (and numbers) with the L/+ or R/- buttons.  When you get the desired letter, press the CH> button move the little up arrow to the next position.  When done naming the model memory, precede to the next step.

 

9.     Press the DN button twice to reach the “[FLAP IN.]” option.  Press the L/+ button so “FLP.SW+P6” is displayed at the  bottom of the screen.

 

10.  Press the DN button once more to select the “[Wing Type]” option.  Press the CH> button so the little arrow points to “DUAL FLAP”.  Press the L/+ button to change from inhibit (“INH”) to active (“ACT”).  If you have a V-tail, this is where you activate that feature as well.

 

11.  To set the TX modulation, press the DN button three more times till “[MODULAT.]” is displayed.  The L/+ button  cycles through the three available options.  If you have an FM RX, select PPM.

 

12.  Last, press the UP and DN buttons together again to get to the main display screen and turn off the TX.  You have completed the basic set-up of a model memory J.

 

Yes, we skipped the “[TRANSFER]” and “[TRIM STEP]” options on purpose.  They are not required at this time. 

 

As soon as you make material progress, you should copy your settings to have a back up in case of accident.  In this case accidents include messing up your program so bad you can’t remember what you did.  At that point you’d give your left arm just to get back where you were when it worked.  So, to copy your settings from one model memory to another:

Follow “The Basics” steps 1 through 3.

 

1.     Press the L/+ or R/- button until you come to the model memory you want to copy.

2.     Press the SELECT button which will change the word displayed on the screen from “Select” to “Copy”.  The destination “MODEL #” will the appear below the selected model memory.

3.     Press the L/+ or R/- button until the destination “MODEL #” displays an empty model memory or a model memory you can copy over.

4.     WARNING: Copying over a good model memory will erase it!

5.     Press the Clear button to copy the selected model settings to the destination model memory.

 

The functions: In addition to the basic functions of rudder, elevator and ailerons, we will also set up camber, crow, launch and speed modes.

 

1.     Hook up the servos and battery to the Rx as shown below:

 

Airplane Servo Function

Radio System Functions

Standard

Tail

V-Tail

Rx Channel Label

Tx Channel #

Tx Channel Function

empty

empty

Thro

1

Spoi

Right Aileron

Right Aileron

Ail

2

Ail 1

Elevator

Left Ruddervator

Elev

3

Elev

Rudder

Right Ruddervator

Rudd

4

Rudd

Left Aileron

Left Aileron

Gear

5

Ail 2

Left Flap

Left Flap

Aux 1

6

Flap

Right Flap

Right Flap

Aux 2

7

Aux 2

Gyro Rate

Gyro Rate

Aux 3

8

Aux 3

empty

Empty

Aux 4

 

N/A

Battery

Battery

Batt

 

N/A

 

The chart above is read from left to right.  For example, The right aileron servo is plugged into the “Ail” slot on the Rx.  This Rx function is controlled by Tx channel #2 which is shown as “AIL1” on the Tx display screen.

 

2.     Turn on the Tx and verify the rudder and elevator servos are plugged into the right connections.  If V-tail, then rudder stick should move both ruddervators in opposite directions.  The elevator stick should move both ruddervators in the same direction.

3.     To verify the right and left aileron servos are plugged in correctly, you  must use the differential function as follows (do not let reversed servos confuse you here):

 

·       With the Tx and Rx switched ON, press both the DN and the SELECT buttons to access the “[FUNC. LIST]”.

·       Press the UP button until the triangle cursor points to “DIFFEREN.”

·       Press both the UP and DN buttons to access the differential option.

·       With full left aileron stick at the Tx, observe the right aileron servo while pressing the L/+ button.  The right aileron servo arm should move towards the neutral position (i.e. give less throw) as the differential percentage is increased. 

·       If so, press both the UP and DN buttons to exit the “function mode”.   Then, continue to step 4. 

·       Otherwise, swap the left and right aileron servo plugs at the Rx and do step 3 again.

 

4.     To verify the left and right flap servos are plugged in correctly, use the “Flap Mixing Switch” as follows:

·       Remove the servo arms first because of the damage that could result from servos thrashing from side to side.

·       With the Tx and Rx switched ON, move the “Flap Mixing Switch” to the “LAND.” (down) position.  The flap servos should move the flaps downward. 

·       If so, continue to step 6. 

·       Otherwise, swap the left and right flap servos at the Rx and do step 4 again.

 

5.     Disable the three trim knobs (because they’re just accidents waiting to happen) by performing the following steps:

·       With the Tx and Rx switched ON, press both the DN and SELECT buttons to activate the “[FUNC.LIST]”.

·       Press the UP button until the triangle cursor is next to the “D/FLAP T.” option.

·       Press both the UP and DN buttons to select that option.

·       Press the R/– button so that “POT.5” is “INH” (inhibited).

·       Press the CH> button once so the little arrow is pointed to “POT.6” and press the R/– button so it too is “INH”.

·       Repeat the last step above for “POT.7”.

 

6.     To reverse servo rotation so control surfaces move in the right direction,  access the “[REV.SW]” function in the following manner:

·       With the Tx switched ON, press both the DN and SELECT buttons to activate the “[FUNC.LIST]”.

From now on, the step above will be referred to with the phrase Activate the “[FUNC.LIST]”.

·       Press the UP button until the triangle cursor is next to the “REV.SW” option.

·       Press both the UP and DN buttons to select that option.

From now on, these two steps will be referred to as select the “????” option.  The question marks will be replaced with the correct option name.

·       With the CH> or <CH buttons move the little downward pointing arrow to the channel needing reversal.  The servo hook-up chart can help with this process.

·       Use the L/+ button to change from normal to reverse rotation.

·       Repeat the last two steps for each control surface that moves the wrong way.

 

7.     To center the control surfaces, first use the mechanical linkages to get them as close as possible, then use the “Sub Trim” function.   Don’t worry about the flaps right now!

·       Remove and realign any servo arms that were changed due to servo reversal.

·       Adjust the control linkages so the control surface is nearly centered.

·       Activate the “[FUNC.LIST]” and select the “Sub Trim” option.

·       Only four channels are displayed on the screen at a time.  The SELECT button will change the display to show the second set of  four channel functions.

·       With the CH> or <CH buttons move the little rightward pointing arrow to the channel needing adjustment.

·       Use the L/+ or R/- buttons to fine tune control surface centering.

·       Repeat the last three steps for each surface (except flaps) that needs centering.

 

8.     To center the flaps, we start with the “Sub Trim” function, then adjust the linkages, and finally return to the “Sub Trim” function for fine tuning.  It is necessary to perform all these steps to get full 90 degree motion from the flaps.

·       Remove the flap servo arms, activate the “[FUNC.LIST]” and select the “Sub Trim” option. 

·       Press the SELECT button until the “FLAP” channel is displayed.  Then press the CH> button to move the little rightward pointing arrow next to the “FLAP” channel.

·       Press the L/+  or R/- button to rotate the servo output shaft in the direction that raises the flap.  You want to use up nearly all the adjustment. 

·       On early radios the target is UP 100 out of an adjustment range of +/- 125.  For later models the target is UP 200 as they have an adjustment range of +/-250.

·       Reattach the servo arm, adjust the linkage, and fine tune the centering.

·       Repeat the four steps above for the AUX2 channel.

 

9.     Instead of using the travel adjustment to limit control surface throw, we are going to use the dual rate function.  This approach, learned from Sherman Knight, accomplishes the task of adjusting surface throws in fewer steps because both the high and low end points are set at the same time.  Travel adjustments will be made later, but only on an exception basis.  To set the dual rates, perform the following steps:

·       Move the rudder, aileron and elevator dual rate switches down to position one (1).  This will be normal flight mode.  Reduced throws will be accessed when the dual rate switch is in the up (0) position.

·       Activate the “[FUNC.LIST]” and select the “D/R & EXP” option.

·       With the CH> button, cycle through the three control functions; rudder “RUDD”, elevator “ELEV”, and aileron “AILE”.  Stop when you arrive at the rudder “RUDD” function.

·       Move the rudder stick on the Tx all the way to the right or until the servo gets in a bind.  If you see there won’t be enough surface throw, increase the servo arm length or whatever it takes. Proper set-up and free movement of control surfaces is a topic unto itself and won’t be covered here.

·       If the servo is binding, find out why and fix it.  There are three major causes of servo binding; bad hinges, push-rod drag, and excess servo throw.  Two of the three causes won’t be covered here, excess servo throw will.

·       At this point the triangle cursor should point to the “D/R 100%”.  At the top of the display you should see “[D/R & EXP]” “RUDD” and “Pos-1”.  This means you are setting the dual rate for the rudder in primary flight mode (position 1).

·       Press the L/+ or the R/- button until the measured throw at the surface agrees with the design specs.  The dual rate has a range of 0 – 125% so you can increase the throw a little or reduce it to nothing.

·       As you move the Tx control from full right to full left you should notice that the throws are nearly the same.  Fine tuning will be accomplished with the travel adjustment function.

·       Before you continue, flip the dual rate switch to position 0 (“Pos-0”).  The percentage throw displayed next to the “D/R” should change back to 100%.  Press the L/+ or the R/- button until the percentage displayed for “Pos-0” is at least the same as for “Pos-1”.  If you want reduced throws, the percentage for “Pos-0” will be less.

·       If you want exponential throws, this is where you set them.  You do so by pressing the SELECT button so the triangle cursor is next to “EXP”.  Then you press the L/+ or the R/- button to soften or sharpen control response around neutral.

·       Once the rudder is complete, repeat the steps above for the elevator “[ELEV]”.  DO NOT adjust the aileron dual rates yet.  You must first adjust the aileron differential as described below.

 

10.  To set the aileron throws, use both the differential and the dual rate functions.  First, set the differential so there is no downward throw.  Then adjust the dual rates for position 1 so the upward throw matches the specs.  Then go back to the differential function and increase it until the desired amount of downward throw is achieved.  Then go back to dual rates and set the throw for position 0.  Below is the exact programming sequence.

·       Begin by activating the “[FUNC.LIST]” and selecting the “DIFFEREN.” option.

·       Press the L/+ button until the display reads “SPLIT 100%”.  Aileron stick movement should produce only upward control surface deflection.

·       Activate the “[FUNC.LIST]” again and select the “D/R & EXP” option.

·       With the CH> button, cycle through the three control functions until you arrive at the aileron “AILE” function.

·       As before, move the (aileron) stick on the Tx all the way to the right or until the servo gets in a bind.

·       At this point the triangle cursor should point to the “D/R 100%”.  At the top of the display you should see “[D/R & EXP]” “AILE” and “Pos-1”.

·       Press the L/+ or the R/- button until the measured throw at the surface agrees with the design specs.

·       Before you continue, flip the aileron dual rate switch to position 0 (“Pos-0”) and press the L/+ or the R/- button until the percentage displayed for “Pos-0” is at least the same as for “Pos-1”.  If you want reduced throws, the percentage for “Pos-0” will be less.

·       If you want exponential throws, this is where you set them by pressing the SELECT button so the triangle cursor is next to “EXP”.  Then you press the L/+ or the R/- button to soften or sharpen control response around neutral.

 

11.  Now that most of the control throws have been set, we can use the travel adjustment function to correct any minor differences in movement.  For example, we set the travel adjustment to get both the left and right ailerons to move up exactly the same amount.  If you paid attention to detail when constructing the control linkage geometry,  there may be nothing to change here.

·       Activate the “[FUNC.LIST]” and select the “TRVL ADJ.” option.

·       Only four channels at a time are displayed on the screen.  The SELECT button will change the display to show the second set of  four channel functions.

·       With the CH> or <CH buttons move the little rightward pointing arrow to the channel needing adjustment.

·       By moving the Tx stick, you can get the little arrow to move between the left and right (or up and down) settings.

·       If the rudder moves more left than right, hold full left rudder stick on the Tx.  The little arrow will be pointing the “L 100%”

·       Press the R/- button until the left rudder throw is equal to the right throw.  You may want to revisit the dual rates and check full throw again.

 

12.  Another Sherman tip is to use travel adjust to give extra down elevator for topping off those zoom launches.

·       Activate the “[FUNC.LIST]” and select the “TRVL ADJ.” option.

·       Use the SELECT button to display the set of  channel functions with “ELEV”.

·       With the CH> or <CH buttons move the little rightward pointing arrow to “ELEV”.

·       Move the elevator Tx stick to the down elevator position, so the little arrow  points the down setting.

·       Press the L/+ button until the display shows “D 125%”.  You now have 25% more down elevator available at the top of the zoom.

 

13.  Aileron to rudder mixing is useful during launches, landing and anytime low airspeed reduces aileron effectiveness.  Follow the steps below to couple the rudder to the aileron stick.

·       Activate the “[FUNC.LIST]” and select the “AIL->RUD M” option.

·       Use the CH> or <CH buttons to move the little rightward pointing arrow from “Rate:  %” to “SW: MIX”.

·       Press the L/+ or R/-  buttons to cycle through the available switches that may be used to activate the mix.  See chart below for a full listing of mixes and available switches.

·       Notice that if a selected switch is not on, “SW OFF” will be displayed in the upper right area of the screen.  You must turn the switch on to change the rate.

·       Press the CH> button to move the little arrow back to “Rate: %” and press the L/+ button to increase the percentage mix from 0% to as much as 125%.  This means full aileron stick will make the rudder servo will move as if the rudder stick were deflected by the “Rate: %”.

 

14.  Camber (for thermal flight) is where the ailerons and flaps all move down together, changing the airfoil in flight. Crow (a.k.a. butterfly) is when both ailerons move up as the flaps move down.  Crow  is useful for landing and descending from high altitudes quickly.  Primary access for both functions is through the “Butterfly” function.

·       Activate the “[FUNC.LIST]” and select the “Butterfly” option.

·       Use the CH> or <CH buttons to move the little rightward pointing arrow to each of the three mixes (i.e. “SPOI->ELEV, SPOI->AILE ).  Stop when you get to the “SPOI Offset” function.

·       With the spoiler stick at the top or the bottom (which ever you prefer) , press the CLEAR button.  A  value such as –174 or +163 should appear next to “SPOI Offset” depending whether you like to start with the flap stick at the bottom or the top.

·       With the crow switch forward (normal flight mode),  the little arrow should be pointing to the “0:” next to each mix.

·       To set camber control, press the CH> button so the arrow is next to “SPOI->FLAP”.  With the spoiler stick in the full camber position, press the L/+ or R/- buttons to achieve the amount of flap deflection required for full camber.

·       Press the CH> button so the arrow is next to “SPOI->AILE”.  With the spoiler stick still in the full camber position, press the L/+ or R/- buttons to achieve the amount of aileron deflection required to match the flap deflection.

·       The “SPOI->ELEV” function is used to mix in some down elevator as the airfoil camber is changed.  Start out with 3% and adjust at the field.

·       To set Crow/Butterfly control, flip the crow switch back so the little arrow points to the “1:” beside each mix.

·       Press the CH> button so the arrow is next to “SPOI->FLAP”.  With the spoiler stick in the full flap position, press the L/+ or R/- buttons to achieve the full 90 degree flap deflection.

·       press the CH> button again so the arrow is next to “SPOI->AILE”.  Press the L/+ or R/- buttons until both ailerons move up to achieve the crow/butterfly function.

·       Down elevator mix for crow/butterfly landing mode is best done with a programmable mix so more down can be fed into the mix at the beginning of the spoiler stick movement.  This smoothes out the pitch up tendency when flaps are dropped for landing.

 

15.  To smooth out the pitch up tendency when dropping flaps for landing, use the multi-point programmable mixing for down elevator in landing mode.  The design specs should tell you how much down elevator in inches/mm to use with full flaps.  Mark this amount on the fin as a guideline.  To program the multi-point programmable mix, follow the steps below:

·       Activate the “[FUNC.LIST]” and select the “PROG.Mix2” option.  You may need to press the SELECT button to display the screen showing the programmable mixes.

·       The SELECT button cycles the triangle cursor through the three different options; channels, mix points & switches.  Make sure the triangle cursor is on the first option, channels.

·       The CH> moves the underline between the “from/master” and the “to/slave” channels.

·       Make sure the underline in under the left, “from/master” channel.  Use the L/+ or R/- buttons to cycle through the available channels (see the chart below).  The left, “from/master” should be set to “SPOI”.

·       Press the CH> button to select the “to/slave” channel.  Press the L/+ button until the slave channel reads “ELEV”.

·       Now press the SELECT twice button to select the switch.  The triangle cursor should be next to the “SW:”.

·       Press the L/+ or R/- buttons till the switch is set to butterfly 1 (“BTFY1”).  If the switch is forward, “OFF” will appear below.  Make sure the switch is back so a number (like 0) appears next to the “OUT” below the “BTFY1”.

·       Now that the mix is set to move the elevator as the spoiler stick is moved when the butterfly/crow switch is in the landing (back) position, the direction and amount of elevator movement can be set.

·       Move the butterfly/crow switch to the back/landing position. 

·       Press the SELECT button so the triangle cursor is next to ”Point-L” on the display. 

·       Press the CH> button until “Point-L” changes to “Point-H”.

·       Move the spoiler stick to the full flap/landing position and press the L/+ or R/- buttons until the elevator moves the specified direction and amount for full flap landing mode.

·       Press the CH> button again until “Point-H” changes to “EXP”.  Press the L/+ so that “ON” is displayed below the “EXP”.

·       By now the line graph in the display should have a straight line halfway across the middle sweeping upward from the middle to the right.

·       Press the CH> button again and again until “EXP” changes to “Point-2”.  Press the L/+ so that the line graph becomes a curved line producing much of the elevator throw at the beginning of the spoiler stick movement.

·       For example, my mix 2 has 0 at “Point-L”,  33 at “Point-1”, 50 at “Point-2, (point 3 is inhibited) and 65 at “Point-H”.  These values are just an example, your mileage will varyJ

 

16.  To set the preset launch flap, use the travel adjust, the flap to aileron mix and the flap to elevator features in unison as follows:

·       Activate the “[FUNC.LIST]” and select the “TRVL ADJ.” option.

·       Use the SELECT button to display the set of  channel functions with “FLAP”.

·       With the CH> or <CH buttons move the little rightward pointing arrow to “FLAP”.

·       Move the flap mixing switch to the down position, so the little arrow  points at the down setting.

·       Press the L/+ or R/- button until the flaps move to the specified position for launch.  Returning the flap mixing switch to the middle will bring the flaps back up to neutral.

·       Activate the “[FUNC.LIST]” again and select the “FLP->AIL” option.

·       With the CH> or <CH buttons move the little rightward pointing arrow to “SW:”.

·       Press the L/+ button until the display shows “F-U&D”.  The flaps will now move the ailerons when the flap mixing switch is either up or down.

·       With the CH> or <CH buttons move the little rightward pointing arrow to “Rate:”.

·       With the flap mixing switch in either the up or down position, press the L/+ or R/- button until the ailerons move the desired direction and amount.  Mine is set to +85%.

·       Activate the “[FUNC.LIST]” again and select the “FLP->ELE” option.

·       Again use the CH> or <CH buttons to move the little rightward pointing arrow to “SW:”.  Press the L/+ button until the display shows “F-U&D”.  Now the flaps will also move the elevator when the flap mixing switch is either up or down.

·       With the CH> or <CH buttons move the little rightward pointing arrow to “Rate:”.

·       With the flap mixing switch in the down position (for launching), press the L/+ or R/- button until the elevator moves the desired direction and amount.  Mine is set to +25% giving a little up elevator with my down flaps & ailerons on launch.

·       REMEMBER:  To adjust launch settings, control flaps with travel.  Set ailerons with the flap to aileron mix.  Set launch elevator with the flap to elevator mix.

 

17.  To set reflex mode, follow the instructions for launch mode with the following exceptions:

·       Start with the Rx turned off because the factory default travel adjust will bind the servos.

·       The flap mixing switch will be in the up position.

·       The upward travel adjustment will be small.  Mine is set to 5%.

·       You may want elevator to flap mixing so your elevator stick changes the amount of flaps.  I tend to use the reflex switch for aerobatics mode.

 


Functions Mixed

Available Switches

Always on “ON”

Mixing Switch “MIX”

Flap Mixing Switch Elev “FLP-U”

Flap Mixing Switch Land. “FLP-D”

Flap Mixing Switch Elev or Land.   “F-U&D”

Crow Switch Forward “BTFY-0”

Crow Switch Backward “BTFY-1”

ELE -> FLP

X

X

X

X

 

 

 

AIL -> FLP

X

X

 

X

X

 

 

FLP -> ELE

X

X

 

X

X

 

 

FLP -> AIL

X

X

 

X

X

 

 

AIL -> RUD

X

X

X

X

 

 

 

Butterfly

 

 

 

 

 

X

X

PROG. Mix1

X

X

X

X

 

 

 

PROG. Mix2

X

X

 

 

 

X

X

PROG. Mix3

X

X

 

 

 

X

X

PROG. Mix4

X

X

X

X

 

 

 

PROG. Mix5

X

X

X

X

 

 

 

PROG. Mix6

X

X

 

 

 

X

X

 

Available channels

Programmable Mixes

Mix 1*

Mix 2*

Mix 3

Mix 4

Mix 5

Mix 6

From

To

From

To

From

To

From

To

From

To

From

To

SPOIL

X

X

X

X

X

X

X

X

X

X

X

X

AILE

X

X

X

X

X

X

X

X

X

X

X

X

ELEV

X

X

X

X

X

X

X

X

X

X

X

X

RUDD

X

X

X

X

X

X

X

X

X

X

X

X

POT5

X

 

X

 

X

 

X

 

 

 

 

 

POT6

 

 

X

 

 

 

X

 

 

 

 

 

FPRN

 

X

 

X

 

X

 

X

X

X

X

X

FLAP

X

X

 

X

X

X

 

X

X

X

X

X

AUX2

X

X

X

X

X

X

X

X

X

X

X

X

AUX3

X

X

X

X

X

X

X

X

X

X

X

X

* Multi-point mixing.

 

Extra bonus programs:

 

By now, you should be able to program these function in your sleep.  So here are a few tips for additional programs:

 

1.     Here are the basic steps to program an auto pilot:

·       Set Programmable Mix 4 to pot5->aux3

rate:     +100%

+100%

SW:     on

Offset  +170

·       Set Programmable Mix 6 to aux3->aux3

rate:     +100%

+0%

SW:     BTFY1

Offset: -512

·       Set Servo reverse on aux3:     normal

·       Set Travel adjust on aux3:       +100%

-100%

·       Set Sub trim on aux3:              -170

 

Now I can have full in-flight adjustment of an “autopilot” or gyro device.

 

2.     I also like the aileron to rudder mix to automatically engage whenever I set up to land.  For this I program the aileron stick to wiggle the rudder whenever the BTFY switch is set to “Land”.  It’s real easy, just:

·       Set programmable mix 3 to Ail -> Rud

Rate:    +100%

            -100%

SW:     BTFY1

Offset: 0

·       Set Servo reverse on aux3:     normal

·       Set Travel adjust on aux3:       +100%

-100%

·       Set Sub trim on aux3:              +0