From the Middle Point RC Flyers, Murfreesboro, Tennessee
Airplanes for Flying in Windy Weather
by Ivan Cankov
All too often, on an otherwise
nice but windy day, folks just don’t fly. Obviously,
for a beginner, that’s common sense—but for someone
who has some experience, the wind can be a challenge
that adds some spice to flying.
While it’s easy to see that experience level has a
lot to do with how much wind is too much, it may not
be quite as apparent that the type of model you’re
flying also can have a great effect on your ability
to handle winds.
Let’s go through some airplane design features to
see which ones give us the best flying
characteristics to handle winds and the resulting
turbulence:
Size: In general, the larger the airplane,
the better it will handle winds of all kinds; large
models don’t “flop around” as much!
Dihedral: The more dihedral in a model’s
wings, the more they are going to be affected by
crosswind gusts; it is hard to keep the wings level,
therefore lineup to the runway is difficult in a
crosswind situation.
Wing Loading: The higher the wing loading,
the less an airplane will be affected when hit with
a gust.
Aspect Ratio: Lower aspect ratio (stubby)
wings will be less bothered by gusts; there is less
leverage for side forces to upset the airplane, and
lower aspect ratio wings have a greater tolerance to
changes in angle of attack caused by gusts.
Power: Having the power to overcome the force
of wind is necessary. The same thing goes when you
get into a sticky situation.
Lateral Control: Ailerons are beneficial in a
crosswind landing and takeoff phases. The ability to
dip a wing into a crosswind without changing heading
is essential, as is the ability to rudder the
airplane parallel to the runway heading while
keeping wings level with ailerons while landing.
Landing Gear: Models with tricycle landing
gear are easier to land and take off in a crosswind
than tail draggers; in addition, the wider the
spread on the main gear, the better.
Maneuverability: This one is a bit harder to
quantify. You want a model with stability, yet you
do need good maneuverability to cope with gusts.
Therefore, you want a model that is stable, yet
responsive.
Wing Mounting: Generally, a low-wing airplane
will handle crosswinds better. This is because the
center of gravity of the airplane is nearer, in a
vertical sense, to the aerodynamic center of the
wing.
Therefore, a side gust does not roll the model as
easily. Moreover, by mounting the main landing gear
on that low-wing model, they can be spread wider.
It’s unfortunate that almost every preceding item is
in direct opposition to the characteristics found in
many popular trainers. The main exception is the
requirement for tricycle landing gear. But even with
trainers, there are differences. Compare a Seniorita
with the Kadet Mk2. While the Seniorita may be a bit
slower and a bit easier to fly, the Kadet, with its
ailerons, higher wing loading, lower aspect ratio,
and lower dihedral, is a far better airplane when
flying in windy conditions. Going a step further
with the same kit manufacturer, the Cougar
(.40)/Cobra (.60) kits embody all the right
characteristics for windy flying.
In closing, I offer Confucius’ only known saying
about RC flying: “To learn to fly in wind, one must
fly in wind!” Q
|
|
