How many channels do I need?

First it is important to realize that you should be able to fly almost any
plane with a standard four channel radio. That is enough to control rudder,
elevator, ailerons and throttle. If this is a sailplane, then four channels
will allow you to handle R/E/A and flaps or spoilers to help with precision
landings. With four channels you can fly an indoor plane, an electric park
flyer, a sailplane or a giant high powered plane. Jets might require more
than 4.

With a 6 channel standard radio, with no computer mixing, you can add control
for landing gear and flaps to the R/E/A/T functions mentioned above. However
you can't mix them together in the radio. You have to do it manually. A
coordinated turn requires you to add rudder to the ailerons. When you
deploy flaps you will have to push and hold the elevator forward to keep the
plane from
ballooning up. If you deploy spoilers, then you probably need to pull and
hold some up
elevator or the plane will go into a dive.

These are complex things to handle. I know I could not get a good balance
between the up elevator and spoilers when I was trying to do them manually.
Most people find them easier to do with a computer radio which can coordinate
more than one servo from a single input. It made a world of difference for
me.

Computer radios let you do things that a standard radio can't do no matter how
many channels it has. So we start to see that our answer to, "how many
channels"
it is more than just the number of channels.

If you have more channels AND a computer radio, you gain flexibility. For
example, you can put two servos on the ailerons and control them individually.
That is something the 6 channel standard radio can not do. It has enough
channels but it can't mix them the way a computer radio can. If you are going
to beyond the standard 4 channels, you should be looking at a computer radio
where you can really take advantage of the extra channels.

Here is a typical channel breakdown, how many and what they are used to
control. These apply to electrics, glow and gliders.

Rudder - 1
Elevator - 1 or 2
Ailerons - 1 or 2
Spoilers/Flaps - 1 or 2
Motor 1
tow hook 1
landing gear - 1

That makes 4, 5, 6, 7, 8, 9 or 10 depending on what kind of plane you have.

Could you use 12? Sure, if you have the money? Bomb drops, smoke, lights,
and other stuff, all take channels.

I am not pushing a given number of channels, just trying to help establish
what they are used for.

In my opinion, many sport flyers will be well served with a 6 channel
entry level computer radio, like the the Futaba 6EXA, that
can handle two aileron servos with some special mixing. They can
automatically mix rudder with ailerons for coordinated turns. They can
usually add some elevator compensation mixed with the flaps or spoilers to
keep the plane level when the flaps/spoilers are deployed. These may be all
the channels and all the mixing many flyers will ever need. These entry level
6 channel radios may not be able to do all of these things at once, but
they can do some of them and you can choose which is the most valuable for
you.

If we step up in computer sophistication with 6 or 7 channels we find radios
like the six channel Hitec Optic 6 or a seven channel Futaba 7C. I consider
these advanced sport computer radios. With this class of radio and channel
count, you have about all you need to fly almost any sport plane. The Optic 6
and 7C can do some pretty sophisticated mixing. More importantly they add
more custom mixing that allow you to select what you want to mix and can
handle more mixes at once.

For most of us, a six or seven channel advanced sport computer radio would be
all we would likely ever need. You typically don't have spoilers and flaps on
the same plane, a motor and a tow hook then six or seven is enough. While
landing gear is very rare on sailplanes it is common on power planes. Most
sport planes and mid level sailplanes don't need two flap servos. So six or
seven will still usually do it.

Four servo wings

Here we see radios like the Hitec Eclipse 7, the Futaba 9C, the Multiplex Evo
9 and other advanced radios. I call these midrange radios which handle
complex planes and may carry you into serious competition. These have seven
or more channels but more importantly they have much more powerful computer
software to handle all the servos and how they are mixed and how the mixes can
be changed while the plane is in flight.

If you step into the world of full house sailplanes, now you are into some
complex mixing requirements as much as the number of channels. These planes
have 4 servos in the wings which must each be controlled on their own channel.
That's four channels. Rudder and elevator and you have a full house
sailplane needing 6 channels and sophisticated mixing to allow the pilot to
reshape the wing while the plane is in flight. Normally you want at least 7
channels for a full house sailplane as some of them have motors for launching
or tow hooks for being towed up into the sky.

For aerobatic power planes, you can add two elevator servos that can follow
the ailerons in their function. Each needs its own channel so now we are up
to eight channels and, again, sophisticated computer mixing to fully utilize
all those servos. For the aerobats you may want a nine or more channel radio
so you can handle smoke, lights and other things.

It is worth noting that we are not yet into the professional radios yet which
can have 10 or more channels.


Summary

So, back to the original question of how many channels. The answer is not as
simple as we might have thought. Four is adequate to fly. A computer radio
with 6 can do a lot. I feel 7 channels on an advanced sport radio should
carry most flyers for most or all of their flying career.

If you have your sights on full house sailplanes or advanced aerobatics then
it better be at least 7. For people with their eye on scale sailplanes, I
would say 8
or more channels and a very sophisticated computer radio to
handle it all.

Hope these posts have been helpful.