Is the force which opposes to the
thrust.
D
The drag acts always
parallel to the relative
wind and opposite to
the flight path
It is caused by the
airplane's movement ,
and its direction will
be always opposite to
itself.
The Total Drag (TD), application’s point
is the Aerodynamic Center.
Aerodynamic Center:
Imaginary point where all the axis meet.
100% of Drag
80% of Drag
60% of Drag
50% of Drag
30% of Drag
10% of Drag
Magnus Effect
Let's suppose there is a cylinder
immersed on a fluid and it turns
around on its own axis. The
gyratory movement of the
cylinder will cause, for rubbing,
a circular movement of the fluid
which is pulled on the same
direction of the cylinder.
Boundary Layer
Is a thin layer of air next to
the surface of an airfoil ( zero
speed) which shows a
reduction in speed due to the
air’s viscosity or stickiness
until reach the 99% o the
air’s free speed.
Boundary Layer
Inversion Point
Detaching Point
RELATIVE WIND
Types of Drags
Total Drag D
Parasite Dp
Wing's Parasite
(Airfoil)
Induced Di
Airplane’s Parasite
(structural)
Friction
Friction
Form
Form
Interference
Total Drag:
Is the adding of all of
the Drags.
DT = DP + DI
Parasite Drag:
Is caused by any interference
between the aircraft's area and
any free air stream. Briefly, is
caused by any element that
does not produces lift.
Parasite Drag of the
Wing or Airfoil.
Is caused by the leading edge
“effort” when facing up the air
particles.
Structural Parasite
Drag:
Is caused by the entire airplane's
structure (with exception of the
wings) when facing up air
particles.
Interference Drag:
Occurs when varied
currents of air over an
airplane meet and interact.
Friction Drag
Is caused by the roughness of
the airplane's surfaces. Even
though these surfaces may
appear smooth, under a
microscope they may be quite
rough.
Resistencia por Forma
Se origina por la forma de
cualquier elemento del avión y
se puede disminuir carenando
o fuselando dichos elementos.
Induced Drag.
Is generated by the airflow
circulation around the wing as
it creates lift. The high
pressure air beneath the wing
joins the low pressure air
above the wing at the trailing
edge and wingtips.
Reducing drag
Devices
They are aerodynamic devices
that face up the free air
stream, and its aim is to
imprint energy to the
boundary layer, retarding the
separation point and
decreasing drag.
Vortex Generators
Wing Fence
Dog Tooth
Trailing Edge Vortex Generators
Carenas
NACA Air Entries
Fuselage
Vortex Generators
Wing Lets
Wing Tip Tanks
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