The radio set.
The radio control (R/C)set consists of a transmitter (the bit you
hold) and in the model are a receiver, servo's and a battery. As you
move the stick on the transmitter (Tx) it sends a signal to the receiver
(Rx), which sends a signal to the servos, which then move the arm
on top of the servo in response to you moving the Tx stick. This arm
is then connected to the control surfaces on the model via some sort
of pushrod. Please see the pictures below.
The most popular manufacturers of radio control radios are Futaba,
Spektrum, JR, Multiplex, Sanwa and Hitec. The cheaper R/C sets are
usually 2 channel (meaning you can only control 2 functions on the
model, e.g. rudder & elevator) and the more you pay, the more
features you get.
A 2 channel set will cost about £80, however if you can afford
it you are MUCH better off spending a bit more and getting a 4 or
6 channel set with a few extra features. Useful features include servo
reverse and "rates". These make it easy to set up your model
so that the controls work in the right direction. Another very useful
feature is extra model memories. This enables you to easily use the
same Tx with several models.
R/C sets are available on 4 radio frequency "bands":
The newest is the 2.4Ghz band
The 35Mhz band - reserved for aircraft only.
The 40Mhz band - purely for ground based models, i.e. cars and
boats, NOT airplanes or gliders.
And finally the 27Mhz band - for use by anyone, i.e. planes, boats,
The best choice at the current time (2010) would be to a 2.4Ghz radio.
The main reason for this is that 2.4Ghz sets are pretty much interference
free, because they work on a totally different principle to the other
3 types of sets. The 2.4Ghz radios constantly monitor the whole of
the 2.4Ghz band and automatically set and change frequencies, meaning
frequency clashes are impossible. Typical manufacturers include Spektrum,
Futaba, JR, etc and the radios can easily be identified by a short
aerial (approx 4" long)
Second choice would be a 35Mhz radio set. These were "the standard"
radio sets for airplanes/gliders until the recent introduction of
the 2.4Ghz radios. They operate on a number of fixed frequencies,
which are controlled by swapping crystals (or by moving small switches)
in both the transmitter & receiver. Please see below for more
info on crystals.
The 35Mhz band has frequencies designated by numbers i.e. 57, 58
.......84, 85, 86 ...90. Only 1 person can fly on any individual frequency
(or number) at any one time, but you can have 1 person on 84, one
on 86, etc. As long as you use a different number to the other people
flying at that time, that's ok.
Most clubs operate an "even frequencies only" or an "odd
frequencies only" rule to reduce the chances of interference
- so it's best to check what rule applies in the club you are thinking
of joining. The SCSA operates an even frequencies only rule.
The disadvantage of using crystals to control frequencies, is that
it's possible to get interference and lose control of your model if
someone switches their transmitter on using the same frequency (or
number) as you. This is impossible with 2.4Ghz radio sets. Having
said that, the 35 Mhz radios have been in use for probably 20 years
or more, with no major problems (apart from the occasional accidental
interference) so they are still perfectly acceptable.
The advantage of 35Mhz is that the radio sets tend to be cheaper,
as people are tending to buying 2.4Ghz sets nowadays. Typical manufacturers
include Futaba, JR, Hitec etc. The radios can be identified by having
a much longer telescopic aerial (approx 30" long when extended)
You can also use the 27Mhz band radios, but nowadays these
tend to be very much "budget" radios and can't really be
recommended for flying airplanes/gliders.
This photo shows a typical 35Mhz receiver (Rx), servo and battery
The Rx is the black box on the right, the blue object is the battery
pack and a servo can just be seen within the red fuselage (It's the
small black thing on the left with the white L shaped arm)
In the bottom RH corner of the receiver you can just see the top of
This photo is about 2/3rds full size.
Picture of a crystal. (as can be seen from the label, this crystal
is channel 80 on the 35Mhz band..actually = 35.200Mhz)
NB: this photo is at roughly double actual size.
A typical 2.4 Ghz radio transmitter (Tx).
This particular set is an ideal beginners set, the Spektrum Dx6i
Note the short 2.4Ghz aerial
A typical 35 MHz radio transmitter (Tx).
Note this is a mid-range Futaba FF8 and has lots of extra knobs &
The typical beginners Tx is usually much more simple than this.
These sets come with a telescopic aerial, which is completely retracted
in this photo.