RE: Eagle 50 with Alpha 400 Brushless Motors
I dont think the other servo outputs on the eagle 50's 4 in 1 receiver(RX-603) are operational. you could test with a servo to see if moving the transmitter throttle makes that servo move on channel 4 5 or 6. I dont have a spare servo to test it nor do I know if it will work. If your test servo gets a throttle signal on 4 5 or 6 then thats where u plug in your speed control.
I have read about other people do brushless mods but they typically upgrade all of the other electronic components and move away from the 4-1 altogether.
How are you gonna power the new brushless speed controller you got with the motor? Are you gonna use a Y adapter to power the rx-603 and the ESC from the battery?
Hope I was helpful