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Teaching Radio Control flying:
Before instruction
By MIKE LYNCH
Text from AMA News Letter September 2003
Instructors tend to get the brunt of
questions from people just thinking
about getting into the hobby. Once
someone has started learning to fly,
instructors are bombarded with
questions related to all facets of the
hobby. Even after the person has
learned to fly, if he or she has
questions (especially about aerobatics),
the instructor is the first one
approached.
This section is devoted to handling
common questions and problems a
beginner has. Even though as an
experienced pilot you already know
much of what is presented in this
section, the information should help
with your ability to relate what you
know to beginners. Also, much of this
section can be copied and given to
beginners with questions.
In this section, I do mention some
brand names and actual models, but
keep in mind I do so for the sole
purpose of offering comparisons. I am
not endorsing nor criticizing any of the
products mentioned. There are many
radios, airplane kits, Almost-Ready-to-
Fly aircraft, engines, and flying
accessories of excellent quality. In fact,
you really have to go out of your way
to find a poor product in this hobby.
Common RC questions
It has been my experience that most
beginners in the hobby tend to have
the same set of questions as they enter
into the Radio Control airplane hobby.
I’ll begin by giving a summary of these
questions and supplying brief answers.
How does the radio-control
system work? As with any kind of
radio, a transmitter (held by the flier) is
used to send signals to the receiver in
the airplane. Both are powered by
(usually rechargeable) batteries. The
radio system can have several channels.
Each channel is used to control one
airplane function. Servos (one for each
channel) are used to cause the actual
motion within the airplane to make
control surfaces move.
A good beginner’s radio
configuration has four channels. These
channels control ailerons, elevator,
rudder, and throttle. Two sticks (like
computer game joysticks) on the
transmitter allow the flier to manage
these four controls. With the most
common radio setup mode, the right
stick is used to control aileron
(left/right) and elevator (up/down).
The left stick is used to control rudder
(left/right) and throttle (idle through
full throttle). Like a computer game
joystick, the aileron, elevator, and
rudder sticks are spring loaded. When
you let go, these sticks spring back to
the middle of the control. The throttle
stick stays where you place it, from idle
to full throttle.
Keep in mind that radio-control
systems can have more than four
channels. Other controls for these
channels include retractable landing
gear, flaps, and even smoke systems.
For now, you should concentrate on
the four basic controls. Leave the fancy
stuff for when you have mastered the
hobby.
| | Within the airplane, servos receive
signals from the radio’s receiver
whenever either of the transmitter
sticks is moved. The servos respond
according to the motions of the
transmitter sticks and cause the control
surfaces of the airplane to move in
sync with stick movements (through
mechanical linkages). Instructors: If an
interested person at the flying field has
questions about radio systems, be sure
to demonstrate with your own airplane.
Other radio terminology.
Trim controls: It is not possible to
perfectly set each servo and control
surface. Say, for example, the airplane
tends to climb in a hands-off
condition. The elevator trim control
gives the flier the ability to trim in
some down elevator without affecting
the joystick for the elevator. In essence,
trim controls allow the flyer to set the
radio so the aircraft will fly straight and
level with hands off the radio. All
radios come with trim controls for the
four basic channels.
By the way, this is another reason
beginners should seek help. It is highly
unlikely that a new airplane will behave
perfectly with regard to trim settings.
An airplane that is not trimmed
properly can be difficult to fly (even for
an experienced flier). For a beginner, it
will be impossible to fly. During a new
airplane’s first flight, the instructor
should trim the airplane, causing the
centered or neutral position of each
channel to be centrally positioned.
Servo reversing: Sometimes it’s
inconvenient (if not impossible) to
mount the servos in a way to properly
control the control surface.
In many cases, the servo will come out
backwards (left aileron comes out to be
right aileron, for example). The feature
servo reversing allows you to mount
the servos in the most convenient
manner, and if one or the other comes
out backwards, the servo reversing
switch for that servo (in the
transmitter) can be turned on. Servo
reversing is a standard feature on
almost all radios sold today.
Dual rates: Though not included on
every radio, this feature allows you to
change the responsiveness of your
airplane’s control surfaces. (Usually this
feature only applies to ailerons and
elevator.) On high rates, your servos
will move full travel and the airplane
will be quite responsive. On low rates,
your servos may only move about 40 to
60 percent of their total travels. This is
a nice feature for beginners, since you
can reduce the responsiveness of your
airplane, making it easier to fly.
Mixing: This feature allows you to
have one control automatically invoke
another. For example, as you give left
aileron, the radio can be adjusted to
automatically give some right rudder
(to make for a smoother turn). While
this is a nice feature for experienced
fliers, it doesn’t help beginners learn to
fly. Don’t go out of your way to find a
radio with this feature for your first
radio.
Radio styles: AM versus FM versus
PCM—generally speaking, the most
reliable, and most expensive, radio
style is Pulse Coded Modulation
(PCM). Next in reliability and price
comes Frequency Modulation (FM).
Finally, comes Amplitude Modulation
(AM). Although almost all of these
radio styles are highly reliable, I
recommend that beginners purchase an
FM radio.
Trainer system: This feature allows
the safest manner of flight instruction.
You will see more information about
trainer systems later. Remember a
beginner should not buy a radio
without the trainer system! | |