X-347/388S and Twin Engine Aircraft.

The X-347/388S transmitters can be used to control two throttle servos on a twin engine model. As described, each engine can be disabled to a high tick-over position for starting, while the other continues to be controlled by the throttle stick. Each servo has its own trim.

Channel allocation:    Left engine servo - Throttle (channel 1)
                                   Right engine servo - AUX2 (SPOI, channel 7)

Switch allocation: Flight mode switch in centre position - both engine servos operate together.
Flight mode switch in upper position - left engine servo is disabled.
Flight mode switch in lower position - right engine servo is disabled.

The three position Flight mode switch is used to direct the throttle control to the required engine servo(s) and the Pot 7 knob acts as throttle trim for the right engine servo. Please note that while the left engine servo throttle trim operates only when the throttle stick is below half, the Pot 7 knob, acting as the right engine servo throttle trim, operates over the whole throttle stick range. The Pot 7 knob can therefor be used to balance the engines on full power.

Set-up (AERO mode)

Set the AUX2 (SPOI, channel 7) travel to 30% each side of neutral to so that the Pot 7 knob acts only as a trim on the right engine servo.

Leave the throttle (channel 1) travel at the default of 100% to avoid complications.

Mix A. Operate two servos from one transmitter control.

Mix throttle (channel 1) -> AUX2 (channel 7), +100% (note the plus sign!) each side of neutral. Leave the switch selection at ON. Leave the offset at 0. Both servos now follow the throttle stick. The throttle trim operates only on the left engine servo (throttle, channel 1).

Mix B. Inhibit the left engine servo (throttle, channel 1).

Mix throttle (channel 1) -> throttle (channel 1), -100% (note the minus sign!) each side of neutral. Enable/disable the mix with the EL - F switch selection. (When the flight mode switch is in the upper position, the mix is enabled.) With the flight mode switch in the upper position to enable the mix, move the throttle stick to the required "high tick-over" position and store the position as the mix offset. (A reading of 140 is a good starting point.) The left engine servo (throttle, channel 1) is now disabled when the flight mode switch is in the upper position and takes up the high tick-over position.

Mix C. Inhibit the right engine servo (AUX2, channel 7).

Mix throttle (channel 1) -> AUX2 (channel 7), -100% (note the minus sign!) each side of neutral. Enable/disable the mix with the LAND switch selection. (When the flight mode switch is in the lower position, the mix is enabled.) With the flight mode switch in the lower position to enable the mix, move the throttle stick to the required "high tick-over" position and store the position as the mix offset. (A reading of 140 is a good starting point.) The right engine servo (AUX2, channel 7) is now disabled when the flight mode switch is in the lower position and takes up the high tick-over position.