We chose the Futaba 2.4GHz FASST system to control the SUMO. We have used classic Graupner/JR transmitters together with Futaba HFM12-x transmitter modules and the Futaba T6EX, T7C and T8FG transmitters. The T6EX is not really recommended as you might need to modify it to have a 3 position switch. With the T6EX we also had seen issues because of reduced transmission power at low temperatures (-28°C).
Choose your personal stick mode for the Futaba T7C or T8FG and do not reverse channels. Program the transmitter to have a 3-position switch (for manual/auto1/auto2) to appear on channel 5.
The channels at a Futaba R6107SP should then be
1 Roll 2 Pitch 3 Throttle 4 Yaw 5 Autopilot Mode (M/A1/A2)
Use the radio/t7c.xml radio file for configuration (for a Futaba R6107SP receiver).
Programming the 5th channel of the T7C for Paparazzi mode
turn on transmitter
long press Mode/Page button
press Cursor/Down 2x to get to PARAMETR
press big round Multi/Rotation button
press Cursor/Down 2x to SCH-K5 (channel 5)
turn big round Multi/Rotation button until E (3-way switch) appears
press End 2x to leave