Transcript How Airplanes Fly

How Airplanes Fly
Jonathan De La Cruz
Quan Nguyen
Physics Related Concepts
 Vectors – Concepts such as thrust, drag, lift and weight all
have direction and magnitude.
 Forces – The above mentioned concepts are all forces that
help or oppose motion in the directions.
 Newton’s Laws
 Gravitation – The forces of gravity and weight play a big
role in maintaining flight.
 Energy – Engines must use potential and kinetic energy to
actually form motion. Heat is also a key component in
engines to start combustion and create thrust.
Intro: Fluid Mechanics
 Physicists’ definition of fluids includes both liquids
and gases.
 They are classified under the same mathematic
relationships.
 Our atmosphere contains enough fluid for it to be
considered under fluid mechanics.
Forces: Thrust and Drag
 Thrust
 Can be caused by a
propeller or engine.
Pushes an object towards
a desired location.
 Drag
 The “friction” of flight,
opposes movement of an
object in motion in a fluid.
 For flight to take place,
thrust must be equal to or
greater than drag. An
increase in drag causes the
plane to slow down
Forces: Weight and Lift
 Weight
 Product of both mass and
acceleration due to
gravity.


 Lift
 Opposes weight through
the use of wings, or
airfoil.
 Exists only in presence of
a moving fluid.

Occurs when a moving fluid is
deflected by any solid object.
Wings are designed so that air
over the wing travels faster
than air under the wing,
allowing for an increase in
speed.
Newton’s Third Law supports
the idea that if wings create a
force, there is an equal force on
the wind.
Landing and Take Off
require a drastic change in
speed.
 Greater angles = more lift,
smaller angles = less lift.
 Wings must divert enough
air to create sufficient lift.
 Landings and take off
 Flaps on wings are released
to create more lift.
(Increases drag though, so
take off requires more
thrust.)
 Slats perform the same
task, but are located on the
front, not the rear.
Lift and Power
 Lift requires power, as the air below the wings is
given energy. Power is supplied by the planes engine.
 The power needed to lift the plane is proportional to
the mass and the vertical velocity of the air.
 “Induced” power is used to overcome weight,
“parasitic” power Is used to overcome drag.
Engines
 To create the necessary thrust, plane engines must consider
Newton’s Third Law.
 Air enters and is compressed and forced into combustion
chambers where fuel is added to the mixture and
combustion occurs, creating thrust.
 Fans may be used to add additional thrust to the object,
creating more motion.
Insight
 We now grasp the difficulty of applying several aspects
to flight that must be accounted for to maintain flight.
 We understand the effect of forces on our everyday life
and how they account into our travels.
 We understand that every part of the plane is vital and
useful and necessary for safe take offs and landings.
 We know that a powerful engine plays a huge role in
creating the necessary thrust.
References
 http://science.howstuffworks.com/transport/flight/m
odern/airplanes.htm
 http://inventors.about.com/library/inventors/blhowaje
tengineworks.htm
 http://www.allstar.fiu.edu/aero/fltmidfly.htm
 http://www.allstar.fiu.edu/aero/airflylvl3.htm