 Some people
consider a glider as the obvious
choice for the first model.
Although a glider normally flies
slower and is supposed to be
more forgiving, I think that's
just a matter of taste. Being a
skilled glider pilot doesn't
necessarily mean being also a
skilled powered aircraft pilot
and vice-versa.
Assuming
that a powered model was chosen,
the beginner is advised to start
with a so-called trainer. This
type is usually a high wing
aircraft model with nearly flat
bottom airfoil that produces
high lift, permitting slow
landing speeds without stalling.
It also has some dihedral angle
to give a good lateral
stability.
However,
a flat bottom high wing with
dihedral is more sensitive to
crosswind gusts, so the first
flights should be done during
calm weather.
 A
beginner should avoid wings with
too sharp leading edges, as it
will worsen the stall
characteristics.
A
well-rounded leading edge is
therefore preferable, as it
better conveys the airflow onto
the upper wing surface allowing
higher angle of attack at low
speed.
A trainer
model should not be too small,
as it would be difficult to
assemble and maintain and would
be more sensitive to strong
winds.
It
should not be too large either,
as it would be difficult to
transport, require a larger
flying field and would be more
expensive.
A
reasonable size is about 150cm
wingspan (60 in) with a high
aspect ratio, which means the
wingspan being about 5.5 times
the wing chord. A square wing is
advisable, as it distributes the
weight of the aircraft evenly
over the entire surface of the
wing. In order to allow a
reasonable low landing speed
without stalling, the wing
loading should not be greater
than about 60g/sq.dm (19-oz/sq.
ft). Wing loading is the
aircraft's weight divided by the
wing area. Some degree of wing
washout also improves the stall
characteristics.
The basic
parts of a trainer model:
Engine
- provides the power to rotate
the propeller.
Propeller - (also Prop)
is attached to the engine's
shaft to convert rotational
motion into thrust and speed,
which depends on the Prop's
diameter, pitch and the Engine's
power.
Spinner - streamlined
part that covers the end of the
Prop shaft.
Fin - (also Vertical
Stabilizer) provides directional
stability (stability in yaw).
Rudder - moveable part
fitted to the Fin's trailing
edge, is used to change the
aircraft's direction.
Stabilizer - (also
Horizontal Stabilizer or Stab)
provides longitudinal stability
(stability in pitch).
Elevator - moveable part
fitted to the Horizontal
Stabilizer's trailing edge, is
used to make the aircraft climb
or dive.
Ailerons - movable parts
on both sides of the wing, are
used to make the aircraft roll
about its fore - aft axis. When
one aileron moves up the other
moves down.
Wing - provides the
aircraft's main lifting force.
One may
build a model aircraft based on
drawings (plans). This requires
some building skills and also
time and effort to find out and
gather the materials needed for
the construction. An easier
approach (albeit more expensive)
is buying a kit of parts. There
are many kits on the market with
different levels of
prefabrication depending on
their price. The cheaper kits
have most of parts included, but
some pieces come either pre -cut
or printed on sheets of wood, so
the builder is expected to do
some extensive job, such as to
cut out the fuselage formers and
wing ribs, glue the parts
together, apply the covering
material, etc. For those who are
not so keen on construction,
there are almost ready to fly (ARF)
kits with an extensive
prefabrication, requiring one or
two evenings to assemble. There
are also ready to fly (RTF),
which normally come complete
with the power plant and some of
them even with the radio
preinstalled. |
