Great Planes PT-40 MkII Kit - GPMA0118 - Manual (Page 60)

Roll Axis – The airplane axis controlled by the ailerons.
Roll is illustrated by holding the airplane by the nose and
tail. Dropping either wingtip is the roll movement. This is
used to bank or turn the airplane. Many aircraft are not
equipped with ailerons and the Roll and Yaw motions are
controlled by the rudder. This is one reason why most
trainer aircraft have a larger amount of dihedral.
Root – See “Wing Root.”
Rudder – Hinged control surface located at the trailing
edge of the vertical stabilizer, which provides control of the
airplane about the Yaw axis and causes the airplane to Yaw
left or right. Left rudder movement causes the airplane to
Yaw left and right rudder movement causes it to Yaw right.
Servo – The electro-mechanical device which moves the
control surfaces or throttle of the airplane according to
commands from the receiver. The radio device which does
the physical work inside the airplane.
Servo Output Arm – The removable arm or wheel which
bolts to the output shaft of a ser vo and connects to
the pushrod.
Shot down – A “hit” that results in a crash landing.
Sometimes caused by radios miles away.
Slop – Unwanted, excessive free movement in a control
system. Often caused by a hole in a servo arm or control
horn that is too big for the pushrod wire or clevis pin. This
condition allows the control surface to move without
transmitter stick movement.
Also, see “flutter.”
Solo – Your first totally unassisted flight that results in a
controlled landing.
Spinner – The nose cone which covers the hub of
the propeller.
Sport Airplane – A model which possesses some attributes
of many of the specialty airplanes and are best for general
flying as they are the most versatile and durable.
Stall – What happens when the angle of attack is too great
for the wing to generate lift regardless of airspeed. When
the wing cannot generate lift, the model “falls out of the sky”
until sufficient airspeed is gained. Then, you can get control
of the model – this takes altitude and should be avoided
upon takeoff! (Every airfoil has an angle of attack at which it
generates maximum lift – the airfoil will stall beyond this angle).
Tachometer – An optical sensor designed specifically to
count light impulses through a turning propeller and read
out the engine RPM.
Throw – The distance a control surface (such as elevator,
aileron, rudder) can travel. Throw is measured at the trailing
edge of the control surface.
Tip stall – The outboard end of one wing (the tip) stops
developing lift, causing the plane to roll suddenly in the
direction of the stalled wing. This situation is not fun when
you are only a few feet off the runway trying to land.
Track – The path the model takes through the air or on
the ground.
Trainer Airplane – A model designed to be inherently
stable and fly at low speeds, to give first-time modelers time
to think and react as they learn to fly.
Trailing Edge (TE) – The rearmost edge of the wing
or stabilizer.
Transmitter (Tx) – The hand-held radio controller. This is
the unit that sends out the commands that you input.
Touch-and-go –Landing and taking off without a pause.
Often confused with a good bounce.
Vertical Fin – The non-moving surface that is perpendicular
to the horizontal stabilizer and provides yaw stability. This is
the surface to which the rudder attaches.
Washout – An intentional twist in the wing, causing the
wing tips to have a lower angle of attack than the wing root.
In other words, the trailing edge is higher than the leading
edge at the wing tips. Washout helps prevent tip stalls and
helps the “PT” family of trainers recover, hands-off, from
unwanted spiral dives.
Wheel Collar – A small, round retaining device used to
keep a wheel from sliding off an axle.
Wing Loading – This is the amount of weight per square
foot that has to be overcome to provide lift. It is normally
expressed in ounces per square foot. This specification can
be easily calculated as follows: If you know the square
inches of the wing, simply divide by 144 to obtain square
feet. Divide the total weight (in ounces) of the airplane by
the wing area (in square feet). This information is valuable
when deciding on which airplane to build next. Planes with
high wing loading numbers must fly faster to stay in the air.
These are generally “performance” airplanes. Conversely,
planes with lower numbers do not need as much air flowing
around the wing to keep it flying. Gliders and trainer
airplanes fall into this category because slow, efficient flight
is desirable.
Wing Root – The centerline of the wing, where the left and
right wing panels are joined.
Yaw Axis – The airplane axis controlled by the rudder. Yaw
is illustrated by hanging the airplane level by a wire located
at the center of gravity. Left or right movement of the nose
is the Yaw movement.
Z-Bend – A simple Z-shaped bend in the wire end of a
pushrod, which is used to attach the pushrod to a servo
output arm.
Z-Bend Pliers –A plier type tool used for easily making
perfect Z-bends.
60