Airfield Models - Radio Control Systems

Radio Control (RC) Equipment for Model Airplanes  Overview

May 05, 2015

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Back to Model Airplane Radio Control Systems


Airfield Models ( of Radio Control Equipment

When you purchase your first set of radio controls, all the pieces in the box can all seem kind of confusing.

At their most basic, radio control systems are very easy to understand and use and require no knowledge of electronics or radio transmission theory.


Before You Purchase a Radio Control System

Be sure to talk to members of the local club to find out if any frequencies are known to have interference problems.

Also be sure to ask if any of the frequencies are crowded.  Only one person can use any given frequency at a time, so if a lot of guys have the same frequency then there is sure to be a wait before you can fly if you're using the same frequency.

Radio brands are another thing pilots like to argue about.  There seems to be this Futaba vs. JR war.  I don't get it, but I don't care to.  All major brands work well.

One thing you should do is make sure your radio is compatible with the instructor's who will train you.  If it's not then you probably won't be able to use a buddy cord.  Buddy cords are discussed under Transmitters.


Getting Started

The first thing you should do is consider reading the instructions.  Every set I have ever purchased indicated the batteries should be charged for approximately 12-16 hours before attempting to use the set.

Get the batteries on charge as soon as you've read the instructions.  You can not have any fun with your radio when the batteries are dead.

After the batteries are charged, plug the switch harness into the receiver and the battery into the switch harness.

Next, plug in all the servos starting with Channel 1 and working your way up.

Channels 1 through 4 are the basic channels for most airplanes.  I can't say for certain that channel designations are consistent from one brand to the next, but I believe that they are.

Note that these channel designations apply to Mode 2 transmitters which are used in the United States.  I don't know how Mode I transmitters are set up.

  • Channel 1 = Aileron
  • Channel 2 = Elevator
  • Channel 3 = Throttle
  • Channel 4 = Rudder

Tip: Always turn on the transmitter first and receiver second.  Always turn the receiver off first and the transmitter second.  The idea here is that the receiver should never be on when the transmitter is off.

This is an old rule that came about prior to dual conversion receivers.  Older receivers would go nuts when they were not receiving the correct signal and send commands to the servos that could make the servos rotate beyond their limits resulting in stripped gears or other damage.

It's much less likely to happen now, but still a good habit to get into.

With the system on move the sticks and watch the servos.  Now it all starts to make sense.

The rest of the stuff in the box is extra servo arms, servo extensions (usually one), servo trays, mounting hardware and maybe a neck strap.

The term Channel has two distinct meanings!

Apparently someone decided this hobby should be more confusing so he decided to recycle words already in use and give them additional meanings.

Definition 1: Channel = Frequency.  For example, Channel 25 is the frequency 72.290.

Definition 2: Channel = control function.  Each function on the transmitter is a channel.  For example, aileron is a channel, elevator is a channel, rudder is a channel and so on.  A 4-channel radio has 4 functions.  A 9-channel radio has 9 functions.

Note that the transmitter and receiver do not need to have the same number of channels.  You can use a 9-channel transmitter with a 4-channel receiver or you can use a 4-channel transmitter with a 9-channel receiver.

At most you will have available the lesser number of channels, however.  In both examples above, you will only have 4 channels available.


Components of a Radio Control System

Transmitter (abbreviated as Tx)

The box you hold that has sticks and switches that you move to tell the model what to do.  It takes your commands and sends them in a radio signal to the airplane.

Battery Charger

These are pretty much what they say they are.  They range from simple wall mounted transformer types that are included with many systems to expensive multi-function chargers that can simultaneously charge several packs.  Some can save data from charge to charge to graph various information about the state of the battery.


Flight Pack

These items are mounted someplace on or in the aircraft.  Collectively, these items are knows as the Flight Pack.

Receiver (abbreviated as Rx)

Receives the signal from the transmitter and sends it to the servos.  A receiver must have a channel for every function that you want in the model.  For example, a 4-channel radio is designed for a simple aircraft having ailerons, elevator, throttle and rudder.  If you want to add additional functions such as flaps, retractable landing gear, bomb drops, etc. then you will need a system with more channels.


An Electro-mechanical device that does the work inside the plane.  A servo moves a control surface or other device mounted to the model such as retractable landing gear, throttle, bomb drop, camera or whatever.


Both the transmitter and the receiver need a power source.  Most R/C equipment uses rechargeable batteries although some use regular dry cells.  Rechargeable batteries are much more economical in the long run.  All R/C systems worth buying come with rechargeable batteries.

Battery switch

A switch mounted to the model that allows the onboard radio to be turned on and off.

Servo Extensions

These are plugged in between the servo and the receiver when the servo lead is not long enough to reach the receiver.


There are miscellaneous other items that are designed to be used with radio control equipment such as gyros, auto-pilots, telemetry devices, etc.  These items go beyond the scope of this series of articles.



Radio Control Systems for Model Airplanes
Transmitters for Radio Control Model Airplanes

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Copyright 2004 Paul K. Johnson