Ah ya know...I just spent some time finding the actual post...the guy didn't actually use the rudder, but he made motors mix so that they'd act as a ruder, check out this setp-by-step.

It looks a bit over my head atm but I'd love to try it when I get a better understanding of the electronics one day.

Btw, I'll have a 6 channel Futaba 6exa and matching 6 channel receiver.

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My Tx is a Futaba 7CH (same procedure applies to the 7CA, and probably the 9C's as well). For other brands, the procedure should be similar...

1. Use the normal channel 1 (and a Y-connector) for ailerons, or turn on the flaperon function and use channels 1 and 6 for right/left aileron plus flap capability. The following throttle setup has no effect on this part.

2. Nosewheel servo goes to channel 4, as always.. again, unaffected by the following throttle setup.

3. Use a programmable mix to slave channel 5 to channel 3, 100% mixing. This in effect creates two separate throttle channels (3 and 5) for the two ESCs.

4. Use a second programmable mix with channel 4 as master and channel 3 as slave, using +50% mix to start.

5. Use a third programmable mix with channel 4 as master and channel 5 as slave, with -50% mixing to start.

In this manner, channels 3 and 5 (ESCs) follow the throttle stick in unison, and when the rudder stick is moved, you effectively 'add' throttle on one side and 'subtract' throttle on the other. NOTE the following considerations:

An ESC cannot be 'overdriven' like a servo, so there's no problem if the combined throttle signal goes above 100% or below 0%. The ESCs simply ignore the 'excess'.

It's important to use ESCs that have a "Fixed Throttle Range" parameter so that the two ESCs retain their settings for channels 3 and 5. This is why Castle doesn't recommend using Thunderbird ESCs for multi-engine, although it seems to me that any variance could be corrected with rudder trim, which in this setup really becomes 'engine RPM synchronization' in addition to nosewheel centering.

The initial setting of 50% mix is just a starting point, and will probably have to be adjusted for the in-flight effectiveness. My initial tests 'on the floor' showed that 50% provides enough throttle differential to yaw the plane sideways in your hands. This will likely NOT be the case at flying speed when the fixed rudders take effect.

You may have to swap the ESC plugs in channels 3 and 5 (or swap the plus and minus mix settings) so that the proper motor accelerates when moving the rudder stick. LEFT rudder should cause the RIGHT motor to increase RPM.