drag in aircrafts
TRANSCRIPT
The force against the thrust is drag
OR
The force acting in the direction of relative airflow is drag
OR
During flight all parts of an aircraft exposed to the airflow
experiences a resistance as aircraft moves through the air,
the force is known as drag
Drag
Parasite Drag
Profile Drag
Interference Drag
Induced Drag
Skin Friction Drag
Form Drag
The parts not contributing to lift are called parasite
and the drag they produce is called parasite drag
The sum of skin friction drag and form drag is
known as profile drag
Skin friction drag is the reaction to the retardation
of the airflow within boundary layer, it depends
upon the rate at which the air trying to slide
adjacent to the aircraft surface
Directly proportional to square of speed
Roughness
Irregular Shape
Cruise at optimum efficiency speed
Polishing
Aerodynamic shapes
When streamline air flow passing over an aircraft
separates from the surface and becomes
turbulent, this phenomena is known as form drag
Directly proportional to square of speed
Hindrance (e.g. undercarriage)
Irregular shapes
Roughness
Aerodynamic shapes (even, smooth,
well cambered)
Fairing on undercarriage
When two differently directed airflows interfere
they produce interference drag e.g. joint between
different aircraft parts such as wing and fuselage,
lights, stabilizers and antennas
Aerodynamic Joints
The force that occurs when the aircraft redirects the
airflow coming at it, this drag force occurs due to wings
OR
Pressure difference from top to bottom of wing (span-
wise flow) causes vortices along the wings particularly
wing tips
It is a by-product of lift
Increases with increasing angle of
attack
inversely proportional to speed
increases
Increase wing span (Aspect ratio)
Wing-lets
Washout
Fuel tank on wing tips
Tapered wings
Wing tips modification