One of the key programming components that allows a
pilot to perform 3D aerobatics is dual rates. To perform
any type of 3D maneuver, the plane needs to have very
large control-surface movement, but this will not allow
the pilot to fly the plane smoothly during normal flight.
The dual-rate switch is a way to move between high and
low throws so that the pilot can use extreme movement
when needed for 3D and then reduce them when flying
with precision. But dual rates can also be used on other
type of aircraft; for example, on a scale bird, you might
need a little more control when slowing the plane down
for landing—using a higher rate for that could help.
On most radios, the elevator dual-rate switch is usually
in the upper left front of the transmitter, while the aileron
dual-rate switch is in the upper right front. The rudder
switch, if there is one, will be located on the upper top
right of the transmitter. Higher-end transmitters will have
triple rates (low, medium, and high) to give the pilot even
more selection. Just because all three control surfaces
start out on different switches does not mean they have
to stay there—pilots, if they choose to do so, can assign
them all to one switch. With this setup, flipping one switch
will change all control surfaces from low to high. I like to
keep them on different switches until I dial in the right
amount of throw on each one, and when I am happy with
that movement, I transfer them all to one dual-rate switch.
The purpose of these switches is to establish a limited
servo travel position when the switch is moved to either
of its two positions (three on some radios). When a switch
is in the away position, for instance, it will allow 70% servo
travel (if that is what you have programmed in for that
position). If the switch is clicked toward you, the dual-rate
setting might provide 100% travel of that same servo or
Here’s a specific example. Let’s say that you are flying
a tail-dragger, and on takeoff, you only want to input
small amounts of rudder. With the rudder rate on low,
you have 70% of the available rudder throw, which makes
takeoffs smoother. Once in the air and you want to start
performing aerobatics, you now need to have 100% of
the rudder throw, so just flip the switch to the high rates.
Of course, you, the pilot, will have to fine-tune the control
throw after many flight experimentations, by using
different percentages until you find the one that best fits
your flying style. Other factors that control the amount of
surface deflection are the servo arm and control-surface
horn lengths. The programming of the dual rates will be
one of the final steps, however, in tuning your aircraft to
fly to your liking.
All pilots should use dual rates. This feature is an
important component, provided by radio manufacturers
to help make us smoother, more accomplished fliers. The
best part is that the rates are easy to program, and even
the beginner-level transmitters incorporate dual rates.
The Dual Rate screen will allow you to program in different throw rates (attached to one switch) for a
high and low rate. This rate will generally be displayed as a percentage.
With the switch in high rates, you will have the full travel available for that control surface.
While in low rates, the same travel distance on the stick will yield a lower amount of travel on the
All pilots should use duAl rAtes.
this feAture is An importAnt
component, provided by rAdio
mAnufActurers to help mAke us
smoother, more Accomplished