RC Radio Electrics and Power Systems


General notes for WMAC talk.

Limited to general purpose glider and low to medium performance electric power. Excluding high speed and high power. Excluding motor/prop selection. Divisions: low power indoor, medium power outdoor, high power outdoor.

Will need a Whiteboard. Briefly touch on each of the following points….


Keep it tidy and safe. Mains voltages kill.

Keeping connections and layout tidy will go a long way towards making your system reliable.

Test Equipment: a reasonable multimeter (cautions), RC watt-meter and servo tester.

RC Transmitters and receivers

Long wire vs 2.4G. Crystal Vs synthesized. Antennas

Transmitters and heat. Sun. Lipo batteries. Power output. Long-wire power output vs voltage. Antenna efficiency and orientation. Control recovery, 2.4G bind delay.

2.4G is synthesized. FH-SS-DSSS. Cheap sets are OK for some uses but the signal more likely to be interfered with as it uses less of the band.

Motors, speed controllers and servos

In-runner, Out-runner and brushed. KV rating vs Power rating. Connectors, wires, stranded-flex vs enamelled copper.

Servo current draw. Linear vs Digital. Noise generated.

Speed controllers. Current and voltage rating. Heat and cooling.

Batteries, wiring and voltage regulators

Lipo. Dangerous if mistreated. Store and charge in safe container.  3V to 4.2 V/cell. Storage at room temp or cooler at 40% charge. Balance charge at 1C, never above 4.2V/cell. Stay above 3.3V/cell. Puffy means damaged, at own risk. Discharge and throw out. Use largest C rating for best life. Loss of capacity with age; voltage sags.

Power supplies. PC power supplies.

Wire sizes and volt drop. Suitable connectors for current.

Voltage Regulators, BEC, UBEC, SBEC. Linear vs Switching. Overheating.

Misc extras

Testing stuff. Current limits and safety. Damage due to testing procedures.

What are LEDs. Voltages and resistor values.

Typical problems

Battery failure. C rating. Indoor small battery, high draw for size = hard life.

Current draw. BEC heating and shutdown.

Vibration and receiver reliability (crystals).

Radio interference. Range. Failure.

Overheating pre-launch.