Thrust is the force which moves an
aircraft through the air. Thrust is used to overcome the
drag
of an airplane, and to overcome the
weight
of a rocket.
Thrust is generated by the engines of the aircraft
through some kind of
propulsion system.
Thrust is a mechanical force, so the propulsion system must
be in physical contact with a working fluid to produce thrust.
Thrust is generated most often through
the reaction of accelerating a
mass
of gas.
Since thrust is a force, it is a
vector quantity
having both a magnitude and a direction.
The engine does
work
on the gas and accelerates the gas to the rear of the engine;
the thrust is generated in the opposite direction
from the accelerated gas.
The magnitude of the thrust depends on the amount of gas that
is accelerated and on the
difference in velocity
of the gas through the engine.
The physics involved in the generation of thrust is introduced in
middle school and studied in some detail in high school and college.
To accelerate the gas, we have to expend
energy.
The energy is
generated as heat by the combustion of
some fuel. The thrust equation describes
how the acceleration of the gas produces a force.
The type
of propulsion system used on an aircraft may vary from airplane to airplane and
each device produces thrust in a slightly different way. We will
discuss four principal propulsion systems at this web site; the
propeller,
the turbine,or jet, engine,
the ramjet,
and
the rocket.
You can view a short
movie
of "Orville and Wilbur Wright" discussing the thrust force
and how it affected the flight of their aircraft. The movie file can
be saved to your computer and viewed as a Podcast on your podcast player.
Activities:
Guided Tours
-
Forces on an Airplane:
-
Propulsion Systems:
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