Figure 2
Do not exclusively use the inboard root or tip of the control surface
to set neutral. Instead, identify and “average” any twists to set the
true neutral control surface position. Also, do not make the mistake of
lining up the forward leading edges of the rudder and elevator balance
tabs with the leading edges of the horizontal and vertical stabilizers.
Doing so with a twisted control surface won’t be truly neutral! When
the twist is averaged, the balance tab will appear askew, but the
surface overall will be neutral and therefore more favorable to early
flying success.
(Twisted elevator halves example.) Despite one elevator looking like
it is up and the other down, they are actually both neutral when the
twists are averaged.
Aerodynamic balance tab.
(Full length twisted aileron example.) Half span = true aileron neutral.
responsive by increasing travels.
Most of the advanced programming features that draw so
much attention today fit into the category of helping to fine-tune an otherwise good-flying airplane. Meaning, if you’re
unable to quickly achieve a high level of
handling comfort, you need to focus on the
basic setup, such as increasing or decreasing
control surface travels before you dive into
adding more exponential or mixes or adding
modes and flipping switches.
On the other hand, if the general handling
is good, but you want to make it better, the
answer probably lies in utilizing some of your radio’s more
sophisticated capabilities.
A common mistake is making changes in the setup to try
to improve an isolated condition or maneuver, but at the cost
of overall handling comfort. Logic dictates the “best” airplane
setup is the one that best complements the type of flying a
person does most often. For most pilots, that means setting up
their airplanes for better takeoffs and landings, precise patterns,
and smooth sport flying.
Therefore, the following setup rules of thumb are aimed at
maximizing “precision” control and handling, as opposed to
the entirely different setup required to perform extreme 3-D
maneuvers.
Maximum Resolution and Smoothness
When possible, the ideal control hookup for smooth
precision flying begins with connecting the control pushrod
to the hole closest to the center of the servo, and the farthest
out hole on the control horn, in order to achieve maximum
resolution and mechanical advantage (torque), then increasing
or decreasing the radio percentages to initially achieve the
recommended travel and later the desired handling.
If you max out the percentage in the radio and still need
more travel, you will obviously have to sacrifice some
resolution by moving out on the servo arm and/or closer to the
control surface (see Figure 1).
Resolution explained: Think of servos as moving a certain
number of incremental “steps.” Increasing and decreasing the
travel percentage in the radio increases or decreases travel
by adding or removing steps, yet the size of the steps remain
the same. Connecting the pushrod closer to the center of
“LOGIC DICTATES THE ‘BEST’ AIRPLANE SETUP
IS THE ONE THAT BEST COMPLEMENTS THE
TYPE OF FLYING A PERSON DOES MOST OFTEN.”
21 Model Aviation JULY 2017 www.ModelAviation.com sponsored by HOW-TO issue
