Parts & Controls of an Aircraft
primary flight controls on any aeroplane are:
: Roll : Yaw : Throttle
following descriptions give an explanation of the effect of each control
in isolation, for a theoretical aircraft. Obviously in flight, control
are operated together, and there are also secondary effects of controls to consider.
changes raise or lower the nose of the aircraft. This effect is
caused by the operation of the elevator. As the
elevator is raised, the force of the airflow pushes the tail down,
rotating the aircraft about the balance point and raising the
is a rotation around the long axis of the fuselage. This effect
is caused by the operation of the ailerons. To
roll left, the left aileron is raised and the right aileron lowered.
The combined effects of the airflow on the controls lifts the
right wing and lowers the left wing. The operation is reversed
to roll right.
is a horizontal rotation around the vertical axis of the aircraft,
and is initiated by the rudder. If the rudder
is deflected left, the pressure from the airflow pushes the back
around and the aircraft rotates around the vertical axis. Right
rudder makes it rotate in the opposite direction. In the absence
of any other control inputs, the aircraft will carry on the original
direction of flight but with a sideways motion; it will only turn
as a consequence of the secondary effects of controls.
the amount of power the engine produces. Contrary to what you
may see at the flying field, most models are not required to be
flown around at full throttle all the time!
Opening the throttle will cause the aircraft to speed up, thus
creating more lift, resulting in a climb. Closing it will
cause the aircraft to slow down, reducing the lift and hence making
the aircraft descend.
Now you have seen how the control surfaces affect the flight path of the
model, you can read about how the radio operates the control surfaces.
Effects of Control
of these controls actually work in isolation, whenever a control is applied,
there are always secondary effects which influence the reaction of the
the elevator is used to pitch the nose of the aircraft up, this has
the secondary effect of increasing the angle of attack of the wing and
so more lift is generated which will make the aircraft climb, however
at the same time the change of attitude will increase the drag of the
aircraft which will tend to slow it down and cause it to descend. So,
provided the engine output remains the same, the secondary effects of
the elevator are to control the speed of the aircraft.
If the stick is moved
to the left the aircraft will bank to the left. As the lift always acts
at 90º to the wing, and weight always acts straight down, the resultant
imbalance of forces causes the aircraft to sideslip to the left. This sideslip causes
a flow of air towards the fuselage sides. As there will be more area
behind the Centre of Gravity than in front of it, the resultant force
will tend to rotate the aircraft causing it to yaw.
of the rudder causes the model to yaw from side to side. This yaw means
that the wing on the outside of the turn is moving faster through the
air, while the inside wing moves slower. This speed change generates
more lift from the outside wing and less from the inner, causing the
aircraft to roll in the direction of the turn. The application of rudder
then, causes first a yaw, followed by a roll. It is this secondary effect
that allows aileron-less rudder only models to be controlled.