FlySky FS-IA6B with Hobby Eagle A3 Pro (not v2) tip - Sbus single wire connection

Foamforce

Well-known member
I had previously tried connecting my Hobby Eagle A3 Pro gyro to my FlySky FS-IA6B receiver using the single wire PPM connection but it didn’t seem to work because when using PPM, all the PWM outputs were disabled. That includes the throttle, and since the Hobby Eagle A3 doesn’t have throttle pass-through, it meant there was no way to get a throttle signal using PPM, so I had to give up on using PPM and pass all the channels through to the gyro on separate PWM wires, which is a mess of extra wires (five wires from the receiver to the gyro instead of one).

Today I realized that it CAN be done using sbus instead of PPM. Previously I thought that if using PPM disabled all the PWM outputs, then the other digital options must too, but that’s not the case. When using sbus (and presumably ibus), all the PWM channels are still enabled. So that means I can run the single sbus wire from the top right port of the FS-IA6B (labeled servo, under the I-bus heading) to the PPM/Bus/G input on the gyro. Then on the transmitter, under System/RX Setup/Output mode, set serial to s.bus. Now connect the ailerons, elevator, and rudder to their respective ports on the gyro, and connect the ESC to port 3 on the receiver, and it all works. There is no wire for either gyro mode or gyro gain, because both of those are also handled on the sbus wire.

Caveats:
  • Some FS-IA6Bs don’t seem to be able to send sbus. Maybe they’re older ones, I’m not sure. I have two identical looking ones and one works and the other doesn’t. I also have another one rebranded as Turnigy and that one works too.
  • None of this particularly matters for the Hobby Eagle A3 Pro v2. It has throttle pass through, so you can use PPM on that if you want and connect your esc directly to the gyro. That’s even better, because it means there is only a single wire connected to your receiver, so you can place it anywhere on the plane, kind of like a satellite, and only run one wire out for it. It also means that the power for all of your servos isn’t passing through from the receiver to the gyro on the sbus wire.
  • Also, on the v2, you could go with ibus instead of sbus if you wanted, since the v2 also supports ibus. The original (non v2) only appears to support sbus though, so that’s why you need to select that.