How to Do It: Mastering Straight Lines and Course Adjustments-2011/12

INTRODUCTION: When most people
learn to drive a car, they work hard at
keeping the car going straight. This is
mostly because of holding in the steering
wheel corrections too long and trying to
“steer” the car straight.
After a while, we’re able to keep the car
straight with little effort because we start
appreciating that most deviations can be
corrected with a simple little nudge upon
the wheel, and we’re confident that if one
nudge doesn’t do the job, we can always
apply another. Thus, applying small nudges
to the steering wheel produces straighter
lines and reduces the number of corrections
we have to make.
Small, brief (not held in) bumps of
aileron or rudder have precisely the same
effect, helping us fly straighter lines, as
well as making small course changes
without overcontrolling.
Bump Applications: Proficient pilots use
small bumps of aileron to keep the wings level
to maintain straight lines. Bumps are also used
to bank the wings slightly and cause an
airplane to drift to the left or to the right
(Figure 1). As long as the bumps are not too
large or held in, the airplane won’t lose
altitude after a bump, so there is no need for
elevator when making small course changes.
(Note: If the airplane features a
symmetrical airfoil wing, the course change
after an aileron bump will tend to be more
gradual. To affect a more deliberate course
change with a symmetrical wing airplane, the
pilot must also pull a little up-elevator, and
perform a mini procedure turn [Figure 2].)
Because the bump is small, it must be
applied and returned to neutral smoothly to
give the airplane time to respond. Quickly
jabbing the aileron will likely produce little or
no response.
Keep in mind that the slight wing bank and
gradual course change after a smooth, small
bump may not be immediately obvious. You
must pause for a few moments after each
bump to be certain whether another bump is
needed.
Often, a single bump is enough.
Remember, overcontrolling is usually not
caused by aggressive inputs at first, but is the
result of holding an input in too long, and
occurs most often when pilots hold in their
inputs waiting to see an obvious reaction of the
airplane. As a rule, it’s better to make two
separate bumps, rather than holding in the
aileron.
Bumping the rudder on airplanes without
ailerons works as well; however, rudder
bumps must be applied smoothly to have the
desired effect. The bump technique works
great for gradual course changes up to 20° or
30°. A larger course change requires a
Figure 1
Straight lines are maintained using small (brief) aileron
bumps to keep the wings level.
46 MODEL AVIATION
Bump
Figure 2
Small course changes with symmetrical-wing airplanes entail briefly bumping
the aileron (in-out) to bank the wings slightly and then holding in a small
amount of up-elevator to effect a gentle turn.
Symmetrical wing
Figure 3
To improve your consistency and ease of flying, picture where you want the plane to be when it passes in front of
you, then project that distance to your left and right parallel with the runway and pick some ground references to
use as parallel turnaround points.
Turnaround
Point
Turnaround
Point
Figure 4a
ABOUT THE
AUTHOR
Dave Scott is a winning full-scale aerobatic competitor,
founder of 1st U.S. R/C Flight School, and author of several
RC flight-training manuals. His books and articles feature the
accelerated training techniques that he developed instructing
more than 1,300 pilots during his school’s four- and five-day
courses.
Dave is best known for teaching pilots to control what the
airplane does instead of reacting to it and presenting each
lesson in a logical “crawl, walk, run” format that makes
learning easier and more fun.
More information about his books and flight school can be
found at www.rcflightschool.com. MA
deliberate turn
involving aileron and
elevator.
As pilots (like
drivers) become more
relaxed, they start
noticing deviations from the intended path the
moment they occur, and the corresponding
bumps become so small that anyone watching
won’t be able to tell that corrections are being
made. That’s one of the main reasons why
good pilots make flying look so easy.
Flying Better Straight Lines and a Parallel
Foundation: If you have ever watched
proficient pilots fly (you can tell by their
ability to perform one maneuver after another),
you may have noticed the absence of visible
corrections between their maneuvers—often
referred to as “being smooth.” The primary
reason for their smooth flying is that they
possess a solid foundation of flying consistent
lines parallel with the runway.
Establishing a parallel foundation starts
with picturing where you want the airplane to
be when it passes in front of you, otherwise
known as “show center.” Then, project that
distance out to your left and right parallel with
the runway and pick some ground reference
targets on the horizon to use as parallel
turnaround points (Figure 3). Guiding your
airplane toward these points will improve your
consistency in the air.
Crosswind Positioning Basics and Objects as
a Whole: As a rule, an airplane will fly in a
straight line whenever the wings are level.
When a crosswind exists, the airplane will crab
(point) into the wind a bit, but as long as the
wings remain level it will continue to track
straight.
From the ground, the position of the wings
can be difficult to judge. Rather than relying on
the positions of the wing or fuselage, proficient
pilots concentrate on where the airplane is
traveling (Figures 4a and 4b).
It is easy to see deviations when guiding the
airplane as a whole toward a distinct target on
the horizon. It’s trickier on the return path to
show center. Early detection of deviations from
parallel, after turning around, is accomplished
December 2011 47
Pilot
Figure 4b
An airplane will fly in a straight line when the wings are level.
Flying in a crosswind causes the fuselage to crab into the wind,
yet as long as the wings remain level, the plane as a whole will
continue to fly in a straight line. Pilots, therefore, need to pay
attention to where the airplane as a whole is traveling, not
where it is pointing.
Figure 5
When the airplane as a whole is neither veering in or away from you
approaching show center, the airplane will be flying generally parallel
with the runway.
with an eye on where the airplane is traveling
relative to you.
Ask yourself, “Is it drifting away from
me?” (Bump it in.) “Is it drifting toward me?”
(Bump it out.) When neither a deviation in or
away from you is detected, the airplane will
track parallel with the runway (Figure 5).
While wind is often blamed for deviations,
it mainly exaggerates deviations and mistakes
that pilots can otherwise get away with in
calmer conditions. For example, when a
crosswind exists, amateur pilots often make
the mistake of completing their turns when the
airplane points where he or she wants it to go,
then inputting a crab into the wind after
detecting wind drift.
The correct method is to finish turns a bit
early or late so that the required crab angle into
the wind is already in place. That way, the
airplane never gets blown in the first place
(Figure 6). How early or late this happens
depends on the strength of the crosswind.
A note to beginners regarding left/right
confusion when the airplane is approaching
show center: Consider the fact that a person
driving a car doesn’t have to think about
whether to apply a left or right input. Because
the driver is facing in the direction that the car
is traveling, all he or she has to do is move the
steering wheel in the direction he or she wants
the car to go.
Rotating your body to face in the direction
the airplane is traveling, and thinking in terms
of bumping the control stick in the direction
that you want the airplane to go, helps reduce
left/right confusion when learning to fly
(Figure 7).
48 MODEL AVIATION
Note that body rotation will naturally start
disappearing within a few days as you shift
from thinking about your own orientation to
thinking about guiding the airplane as if you
were in it.
Conclusion:Most RC pilots continue to fly
using the techniques they learned early on,
including the habit of making constant
corrections. Most pilots make three to four
times more control inputs than what’s necessary
Figure 6
When turning into a crosswind, exit the turn a little early to establish
the necessary crab angle and prevent getting blown. Or, overshoot
the turn a little when turning with the wind.
Figure 6
When turning with a crosswind, overshoot the turn a little to establish
the necessary crab angle into the wind and prevent getting blown.
when the airplane is flown correctly, but they
are simply too busy making corrections to
realize it.
Not only does learning to bump one at a time
improve consistency and reduce overcontrolling,
it significantly improves landing because of the
importance of making small inputs when low to
the ground. Happy landings! MA
—Dave Scott
[email protected]
Figure 7
To reduce left-right confusion, face in
the general direction that the airplane is
traveling so that your left and right
match that of the plane.
Actual flight path when the fuselage
is mistakenly pointed toward show
center in a crosswind.
Wind
Wind
“Right turn,
Left correction.”