on Model Aircraft
Flaperons are a mix of
Aileron to allow these
control surfaces to improve flight efficiency or
Unfortunately, the concept of Flaperons seems to have
confused some people which has resulted in incorrect and misleading
information being passed around.
Some people believe that
mixing flaps to the
elevator is Flaperons. This is absolutely untrue.
Flaps can be mixed to the elevator, but this mix is simply called an
mix. It is not Flaperons.
The only correct definition of Flaperons is flap/aileron mixing.
The reason for this confusion is that some people create a Flaperon mix for
the sole purpose of mixing the flaps to the elevator. An elevator/flap
mix will, in most cases, allow an aircraft to perform tighter (smaller
radius) loops and related
pitch maneuvers - such as square corners.
Although any number of surfaces on the
trailing edge of the wing can be mixed to create Flaperons, it is most
common for a pair of
strip ailerons to be mixed. To create the mix, a
servo is required for each aileron. You will need a computer
transmitter or a separate mixing module.
Each servo must be on its own channel. If you use a
connect the two servos, then they can not be used as flaperons.
The way the mix works is that the ailerons perform normally when giving aileron
commands (ailerons move in opposite direction). Flaps can also be used
which will raise or lower both ailerons simultaneously. The flaps can
be used by themselves or can be mixed to the elevator as explained above.
A more efficient type of Flaperon is to have two surfaces on each wing - an
aileron and a flap. This setup is often called "Quad Flaps."
Again, a servo on each surface is required - four in total.
a variety of ways to set these up depending on the capabilities of your
transmitter and what you are trying to do. In fact, you can have
several modes programmed in for various flight conditions.
For example, you can have all four surfaces act as ailerons or as flaps.
You can also have only the two ailerons act as ailerons while all four
surfaces act as flaps. The inverse can also be used - all four
surfaces work as ailerons but the two inboard surfaces act as flaps.
Any of these mixes can also be mixed to the elevator as well. When you
consider the number of possibilities, it is easy to see that most
transmitters are not capable of having every mode available for a single
model memory, so you have to choose which ones you want to use. Of
course if you do not like a particular mix, you can adjust it, turn it off or
replace it with a different mix.
You might want all four surfaces working as flaps for aerobatics, but only
the inboard flaps working for landing.
The reason is that when flaps are lowered, it raises
angle of attack of that section of the wing which puts the wing closer
If the flaps are full-span, as when using strip
ailerons, then lowering the flaps can make the aircraft more prone to
wing tip stalls which can lead to catastrophic results - especially when
low and slow such as during a
Using four surfaces allows the outboard ailerons to assume their normal
angle of attack while the inboard surfaces are lowered. This flight
condition will cause the inboard section of the wing to create more
lower speeds. It also means the inboard section of the wing will
stall before the tips which will cause the nose to pitch down rather
than the aircraft
rolling over as in a tip stall.
Another flight condition possible with quad flaps is called Crow (aka
Butterfly). This is an extremely efficient landing configuration
because both ailerons are simultaneously raised which lowers their angle of
attack. At the same time, the inboard flaps are lowered which raises
their angle of attack and creates more lift as previously stated.
This configuration greatly increases
drag which slows the aircraft while creating a great deal of
lift allowing the aircraft to continue flying at this reduced speed.
The lower angle of attack at the tips provides an excellent safety margin to
avoid tip stalls.
As with a dual aileron setup, all four surfaces can be mixed to act as flaps
and then mixed to the elevator. Therefore, with a capable
transmitter (one having many channels and available mixes), an aircraft
can be setup to fly extremely efficiently in many different flight