# Jet Engines

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```					Rockets
Aerospace
Today’s Topics

• History of Rocketry
• Define a rocket
• Examine the physics behind rocketry
• Define the mechanics of a rocket
• Name the 4 major systems of a rocket
History of Rocketry
   Chinese were using rockets in the early 13th
century
   As early as the 15th century rockets
constructed with gunpowder were used in
war
   Colonel William Congreve
– British artillery expert
– Refined gunpowder for rockets & created
stabilizing guides
– Increased launch range from 300 yards to a few
thousand
History of Rocketry
   Dr. Robert Goddard
– Father of Modern Rocketry
– First scientist to use liquid propellants (gas and
liquid oxygen) in a rocket (1926)
– Goddard’s research along with Hermann Oberth
was the catalyst for the German V-2 rockets used
in WWII

V-2
Newton’s Laws & Rocketry
   1st Law: A body in a state of rest and a body
in motion tend to remain at rest or in uniform
motion unless acted upon by some outside
force.
– Law of inertia
– The thrust must be greater than
the weight of the rocket
– Example: Apollo spacecraft weighted
6,000,000 lbs. & the Saturn V rocket
produced 7,500,000 lbs of thrust
Newton’s Laws & Rocketry
   2nd Law: The rate of change in the
momentum of a body is proportional to the
force acting upon the body and is in the
direction of the force.
– At liftoff a rocket seems very slow
because its mass is only slightly less
then the thrust being produced
however, as the launch progress its
speed increases because it weighs
less but is producing the same thrust
Newton’s Laws & Rocketry
   3rd Law: To every action, there is an equal
and opposite reaction.
– The thrust produced in a
rocket is a reactive force
acting in a direction opposite
to the direction of the
exhaust.
Rocket Systems
   Modern rockets consist of four major
systems
 The airframe system
 The propulsion system
 The guidance system
 The control system
Airframe System
 Contains the other systems and to
provide aerodynamics
 Must be structurally strong but
lightweight
 Capable of withstanding extreme heat,
vibration and stress.
Propulsion System
   Consists of the following:
 Propellant used
 Containers for the propellant
 All the plumbing of the system
Guidance & Control System
 The brain of the rocket
 A self-contained electronic unit that
employs a computer for tracking
 Computer is preprogrammed for the
desired flight trajectory
 Changes can be made post lift off
 Control: Follows the directions put forth
by the guidance system
Types of Rockets
   Solid-Fuel Rockets
– Solid propellant is called grain
– Composed of fuel and oxidizer mixture
– Fuel burns in the combustion chamber and exhaust escapes
through a nozzle
– Cannot stop a solid rocket once started
   Liquid-Fuel Rockets
– Stored in separate tanks
– Can shutdown engine once takeoff begins
Forces Affecting Flight
   Thrust
– Force generated by the rocket engine
   Gravity
– Downward force applied to all objects on
earth
   Drag
– Amount of resistance or friction on the
rocket as it flies
Review
   Who is the father of modern rocketry?
Robert Goddard
   What was the name of rocket used by the
Germans in WWII?
V-2
   What are the four major systems of a rocket?
Airframe-Propulsion-Guidance-Control
   What are the two types of rockets?
Solid & Liquid Rockets
Assignment
   First read ch. 12 Section A in the Aviation
Fundamentals book and complete questions 1-12 in
the workbook
   Start designing for your H2O rocket project
   Refer to the rubric for the details of the assignment

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