A tip for getting 6 flight modes without using up 2 radio channels on your radio.

On some radios (eg JR X2720 7-channel) you can mix the 3-position flap channel
with itself, rather than mixing with gear or aux which would prevent you from
using the gear or aux radio channel for something else. The mixing switch isn't itself a
radio channel so by careful setup of the mixing offset and percentages it’s
possible to get the six positions required just using the one radio channel
(the flap channel) and the mixing switch.

To find whether you can do this on your radio, you just need to check whether it can mix flap with flap, and if so then it should be possible. Start by setting the flap positions with mixing off, for modes 0, 2 and 4, and then with mixing on for modes 1, 3 and 5. 

I posted detailed instructions for doing this on a JR X2720 as a comment on this page:


but the webmaster asked for the info to be posted here so it could be linked to, so here it is:


Here is a guide for setting up 6 flight modes on a JR Propo X2720 seven
channel radio. I have achieved this while only using one of the active channel
inputs (the flap channel) leaving gear and aux free for other purposes. The
flap switch on the right shoulder is 3-position and the mixing switch on the
left shoulder provides the cut over to the other three modes. By setting the
mix function to FLAP -> FLAP it can be done without losing the aux or gear

Here are the settings: In the Function select mode, go to Program Mix 1
Set it to FLAP -> FLAP +rate=100% -rate=-50% offset = +10 SW = MIX

In the Function select mode, go to FLAP System Set FLAP Norm = UP 46%
FLAP Mid = DN 8% FLAP Land = DN 100% ELEV Norm = 0 ELEV Mid = 0 ELEV Land = 0
Auto Land Inhibit

In the System Select Mode, go to Input Select Set D/R switch to Com Aile
(Aileron dual rate switch does all 3 dual rates, leaving mixing switch free)
Set Aux 2 switch to Aux2, Trim inhibit Set FLAP to System, Trim Inhibit

This will give you six positions for pulse widths corresponding to six
flight modes. With the Mix switch off (backwards) you get flight modes 0,2,4 on
the flap switch, and with the mix switch on (forwards) you get flight modes

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  • I have a JR X9503. I tried it the way Harry suggested and it sort of worked. Some of the positions were off a little so I only got 4 or maybe 5 modes. Actually because of the position of the switches, I would prefer to use matt's technique since the Elev/DR is just to the left of the flap switch.

    But my radio is not a DX7 and I'm not having luck finding the various options. This is what I've located:

    DeviceSEL - I know I need to set something here but which column? Do I use the FLAP column and how would I set it?

    D/R & EXP - Here I have Pos-0 and Pos-1. It looks like I just need to adjust this until I get it right or does someone know the settings?

    Flap Sys - Here I set the FLAP to U46, U3, D61 but probably not necessary since I want to use the D/R switch instead of mix switch. Or do I need to change something here also?

    Thanks for the help!



  • Developer

    A simple solution for those who have a transmitter with one or more Gyro channels : Use a gyro channel for APM mode control.

    Then simply use flight mode conditions on your transmitter to program a different gyro channel gain for each transmitter flight mode.

    Using two or more switches, you can switch flight modes. I'm using 4 switches.

    Simple, no mixing, only one channel, and you can even organize your modes priority changing the flight mode conditions order. More you have each mode name printed on the transmitter LCD screen :) That's very nice if you did forget wich button is wich mode !

    Another advantage is that you can change transmitter parameters at the same time as you change flight modes (dual rates, throttle curve...).

  • Hi, tried this on my JR DX9, with a few minor tweeks managed to get it working :)

    First in Function List Mode

    Prog mix 1 option

    Set flap -> flap

    sw select to mix

    thro stick inh

    exp off

    set point 0 to -50

    and left everything else alone

    Flap system option

    set auto land inh

    flap norm to u46%

    flap mid to u3%

    flap land d61%

    now in System Mode

    DeviceSEL option

    couldn't find d/r switch to com aile so ignored this

    under flap, trim on, out sys

    Thats it.

    Back to Mission Planner I'm now getting...

    mix pos 1, flpa pos 1, pwm 1322, flight mode 2

    mix pos 1, flap pos 2, pwm 1499, flight mode 4

    mix pos 1, flap pos 3, pwm 1744, flight mode 5

    mix pos 2, flap pos 1, pwm 1140, flight mode 1

    mix pos 2, flap pos 2, pwm 1480, flight mode 3

    mix pos 2, flap pos 3, pwm 1864, flight mode 6

  • Wiki Ninja
    Hi. I'm wondering if this setup can also be applied to DX7 as it has the same number of channels.
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