Programming the JR-8103

for a Six Servo Wing

by Ben Diss

This document explains how to program the JR-8103 for a six servo wing such as these sailplanes:

Jaro Muller Escape (available in the US from Aero-Model)
Roedelmodell Discuss 2A (available from Roedelmodell)
NSP Fusion (available from Northeast Sailplane Products)

These instructions assume a thorough knowledge of the JR-8103 transmitter. I offer no assistance navigating the various menus. If you need help programming your JR-8103 for gliders take a look at Sherman Knight's, "The New JRXP8103 Computer Radio". If you’re looking for information on programming a Futaba 8U for a six servo wing, David Wenzlick has an excellent tutorial called How to Program Your Futaba 8U Super for the Jaro Muller Escape.

Throughout this document I refer to the programming pages of the JR-8103 by using this font. This document is formatted for printing.

Servo Connections

The trick to operating all the control surfaces is to think of the inner ailerons as flaps, and the flaps as spoilers. The flaps are controlled with two servos. One servo is reversed internally by swapping the positive and ground leads on both the circuit board and the pot. The two servos are then joined with a y-connector. There are products available that allow this to be done without modifying the servo, but they are costly both in terms of dollars and weight.

Here is how the servos connect to the receiver.

Ch	TX func	Airplane func
1	Spoi	flaps
2	Ail 1	right outer aileron
3	Elev	left v-tail
4	Rudd	right v-tail
5	Ail 2	left outer aileron
6	Flap	left inner aileron
7	Aux 2	right inner aileron
8	Aux 3	battery

Start by selecting the following:

Type Select: Glider

Wing Type: V-tail Active, Dual Flap Active

Flap Input: Flp.SW+P6

Basic Programming

Here is the basic template. I’ve included the Travel Adjustment pages for your reference. Your values will certainly be different, but these may be a good starting point to obtain the control surface throws recommended by the distributor. I’m using the recommended throws with the exception of the elevator where I increased UP travel and decreased the DOWN travel.

	Spoi	Ail1	Elev	Rudd	Ail2	Flap	Aux2	Aux3
Reverse	NORM	NORM	NORM	NORM	NORM	REV	REV	NORM
Travel Adj	+135%	L110%	D80%	L120%	L110%	U06%	+100%	+100%
	-135%	R110%	U120%	R80%	R110%	D20%	-100%	-100%
D/R		100%	60%	100%
Exponential		+35%	+35%	Lin

Notice that the Elevator is programmed with 60% dual rate. This is how you get the rudder throw to move the surface more than the elevator throw. Not mentioned in the chart above is the programming of differential. Some people prefer to program differential by adjusting the servo travel. That is certainly possible, but I chose to do it on the differential page by setting it to 50% (see below).

Advanced Mixes

The mixes are where the complication begins. We have a number of programming goals. I’ve listed them here in no particular order:

Three position flap switch for reflex and launch.

Reflex (switch up) should move all three control surfaces up about 1/16”.
Launch (switch down) should move all three surfaces down to your desired launch preset.

Crow (butterfly, or landing mode) switch. This can be programmed to be ON with the switch in either direction. In my case I desired to have the ON mode with the switch pulled forward toward the face of the transmitter.

Crow engaged causes the flap lever to deflect flaps a maximum 90° and deflect inner ailerons up maximum 45°.
Crow disengaged and the flap lever deflects flaps a maximum of 45° and inner ailerons a maximum of 35°.

Mix switch

Mix on causes the inner and outer ailerons to work together and couples the aileron and rudder together.
Mix off causes the inner aileron and rudder to no longer respond to aileron input.

I’ve listed each of the mix pages in the order they appear as you scroll through them in the transmitter.

Elev -> Flap OFF

Aile -> Flap +120%

SW: MIX

This couples the inner ailerons to the outer ailerons when the Mix switch is on.

Differential 50%

This sets up the aileron differential. Note that this differential value is passed to the inner ailerons when they are active. This is why it’s easier to program differential with this page instead of the travel adjustment setting for the individual control surface.

Flap -> Elev OFF

Flap -> Aile Rate: +50%

SW:F-U&D

Offset Flap 0

This directs the inner ailerons to move half the distance of the flaps when reflex or launch mode is engaged. You’ll probably end up adjusting the rate to suit your tastes.

Aile->Rudd +50%

SW: MIX

This couples the rudder to the ailerons when the Mix switch is on.

Butterfly		0	1
	Spoi -> Elev	-40%	0
	Spoi -> Aile	-15%	0
	Spoi -> Flap	-50%	+70%
Offset +166

This is where it starts to get tricky. This page mixes the flap handle (the JR-8103 thinks of this as the Spoiler handle) to the various control surfaces. Remember, position 0 is Crow engaged in this template. The first mix adds some up elevator when crow is engaged and the flap handle is pulled. The second mix causes the outer ailerons to go up slightly when crow is engaged and the flap handle is pulled. The third mix causes the inner ailerons to go up when crow is engaged and down when crow is not engaged and the flap handle is pulled.

Prog Mix 1,2,3 OFF

Prog Mix 4 Spoi -> Spoi

Rate: +8%

SW: Flp-U

Offset: 0

This causes the flaps to go up slightly when reflex mode is activated.

Prog Mix 5 Flap -> Spoi

Rate: +100%

+125%

SW: Flp-D

Offset: 0

This causes the flaps to go down slightly when launch mode is activated.

Prog Mix 6 Aile -> Flap

Rate: -0%

-50%

SW: Btfy1

Offset: +230

This causes the flaps to go down only 45° instead of 90° when crow is not active. To program the offset, select the offset line, move the flap handle all the way up and press clear.

That’s it. Please e-mail me with any questions, comments or corrections.