Radio Safety is the most important part of flying a radio control model aircraft.  If a student pilot cannot demonstrate an understanding of safe radio operating procedures then they would never be allowed to switch their aircraft on, let alone fly it!

The Frequency Key System

Most model clubs adopt some sort of frequency peg, or key, system to identify which transmitter frequencies are in use and which pilot’s are using them.  LMMAC is no different operating a ‘keyboard’ style system to indicate which frequencies are in use.
Your transmitter will be set to, or contain a crystal that allows it transmit on a certain frequency within the 36 megahertz band.  A sticker on the back of your transmitter will show the frequency displayed as something like 36.470.  This number tells us the transmitting channel, in this case channel 647.
When you want to switch on your transmitter you must place your frequency key into the relevant slot in the keyboard before switching on your transmitter.  Your key then stays in the board until after your transmitter is switched off and placed back into the compound.
When not using your transmitter, make sure you return it to the shelves below the keyboard and hang your key over your aerial.


It is important to get transmitters certified to ensure their safety.  The club should already have provided instructions on how to do this.  Certified transmitters use a narrow yellow key, uncertified a wider blue key to ensure a wider safety margin.  These keys will be provided by the club.

Radio Installation

As you are building your first trainer aircraft, your instructor will be able to help you with installing the radio gear correctly to ensure trouble free operation.


Use all four screws provided with standard servos and attach the rubber anti-vibration grommets correctly.  Usually this involves placing a rubber grommet over each servo mounting hole and pushing in the small metal sleeve from the underside.  Your instructor will help to explain this to you.


Check all linkages from servo to pushrod and pushrod to control horn are secure.  Short lengths of silicone tubing should be used to ensure clevises do not vibrate loose in flight.

Receiver & Battery

Plenty of foam should be used to ensure the receiver and flight battery are safe from vibration.  Make sure they are fixed down and cannot move around in flight.

Aerial Routing

Receiver aerials should be routed outside or inside the fuselage and stretched out to their full length.  They should not be in contact with servo leads or pushrods as this can cause interference.  Aerials should be taped or fixed in place so that they cannot swing forward and foul the propeller.

Switch Mounting

If mounting your receiver switch outside the aircraft, ensure to locate it on the opposite side to the engine exhaust.

The Range Check

Once your engine is started and before the first flight of the day it is important to do a range check.
With the aerial on your transmitter down, walk backwards from the pits to the edge of the runway all the time watching the control surfaces on the aircraft.  You are looking for any unexplained movement not originating from a control input.  Any movement might be a sign of a ‘glitch’, or interference in your receiver.  Once at full distance, check full throttle response and movement of your controls before coming back.  It sometimes helps to have a helper stand next to your model to give you the ‘thumbs up’ if everything is okay.


S.M.A.R.T is a useful acronym to remember.  It stands for:

  • SWITCH – Is everything switched on?
  • METER – Are your batteries fully charged?
  • AERIAL – Is your transmitter aerial fully extended?
  • RATES – Do you need high or low rates selected (if applicable) for this model?
  • TRIMS – Is the model trimmed?  Are all the controls moving freely and in the correct direction?
Do these checks before you take off – every time you fly!

2.4GHz Radio

The new 2.4GHz radio technology allows a greater safety margin than 36MHz as it seeks and locks onto a free channel before it will work.  LMMAC still requires pilots using 2.4GHz sets to place a key in a different board so that other pilots are aware a 2.4GHz set is in use.

Always switch on your transmitter BEFORE you switch on your receiver!

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