All electric motors and electronic switching devices generate electrical noise, some more than others. In radio control systems this often results in 'glitching'. This is when the servo’s operate the control services without input from the pilot.
To minimise this risk there are a number of precautions that can be taken.
1. Keep the leads from the speed controller (ESC) to the motor to less than 100mm (4 inches).
2. If using a brushed motor fit additional noise suppression capacitors. There should be three, one from each terminal to earth (case) and a third across the two terminals. The largest value capacitor is the one fitted across the two terminals.
3. The lead from the ESC to the receiver should be fitted with a torrodial or noise suppression choke. The lead is wound around the choke at least 4 times close to the receiver connector. The more turns the better the noise suppression.
4. If using a UBEC instead of the ESC onboard BEC (battery eliminator circuit) fit noise suppression chokes as above and carry out a range check. Some makes have been known to significantly reduce output therefore range when a choke has been fitted.
5. Where possible install the receiver as far away as practical from the motor / ESC.
6. If you are experiencing 'glitching' in flight then it is recommended that by changing the receiver to one of a higher specification may resolve the issue. If single conversion try a dual conversion one. If dual conversion try either a PCM Rx or an Rx with IPD. Both have built in signal verification systems i.e. they check the information the Rx has received is not corrupted before passing it to the servos.
7. If 6 fails then try a different make speed controller or try one with an higher current rating.
8. If 7 fails then try a separate Rx battery but remember to disable the BEC by removing the positive lead from the ESC.
9. Finally if after trying all the above you still have problems try changing the battery, possibly for one of a higher capacity, and by a process of elimination try and identify the noisy component.