Principles of Rocketry

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Principles of Rocketry

• Design and Drawing for Production
• Mr. Herrling

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Outline

• Newtons Third Law
• Solid Fuel Rockets
• Liquid Fuel Rockets
• Water bottle Rockets
• Forces on Rockets
• Rocket Stability

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Isaac Newtons 3rd law of Motion

• For every action there is an equal and opposite
  reaction

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What is the Action?

• Solid Fuel Rockets
• Fuel in solid form burns and is converted to hot
  gasses.
• Hot gasses expand and create high pressure.
• Pressure escapes out nozzle, pushing against air
  and rocket body equally.
• Reaction Rocket moves forward, as gasses move
  backwards

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Gasses RocketAction Reaction
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More on Solid Fuel Rockets

• Solid-fueled rockets use a fuel and oxidizer in
  solid form. The fuel and oxidizer are in a
  powdery or rubbery mixture known as the grain or
  charge. Once a solid-fueled rocket is ignited, it
  burns completely. There is no way to stop the
  combustion or to change the amount of thrust.

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Liquid Fuel Rockets

• Work on same basic principles as solid fuel.
• Carry liquid fuel and oxygen.
• Unlike solid fuel, liquid fuel can be regulated
  to control thrust.

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Liquid Fuel

• Used for launches and interplanetary travel,
  liquid fuel rockets are more versatile than solid
  rockets because the amount of thrust can be
  controlled, but they are less reliable than solid
  rocket engines.

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Space Shuttle

• Liquid Fuel and Oxygen tank feeding Engines
• Solid Fuel Rocket Boosters

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Propulsion

• All spacecraft need to reach about 17,500 miles
  per hour to get into orbit.
• Thrust is used to push the spacecraft this fast.
• Thrust is produced by burning a rocket fuel with
  oxygen.
• If there is not enough thrust the spacecraft will
  fall back to earth due to gravity.

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Our Water Rockets

• Instead of hot gasses creating pressure, we use a
  bike pump and store pressure.
• Action Expelling water from engine bottle
  (water is forced down)
• Reaction Water resisting against rocket body
  (Rocket is forced up)

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Water Rockets Work Like Real Rockets
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Thrust

• Forward motion or thrust can best be described by
  observing a balloon filled with air. When air is
  released from the balloon, forces inside the
  balloon cause it to move to the left.

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Weight

• Weight is the force generated by the
  gravitational attraction on the rocket.
• We are more familiar with weight than with the
  other forces acting on a rocket, because each of
  us have our own weight which we can measure every
  morning on the bathroom scale.
• We know when one thing is heavy and when another
  thing is light

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Drag

• We can think of drag as aerodynamic friction, and
  one of the sources of drag is the skin friction
  between the molecules of the air and the solid
  surface of the moving rocket.
• Because the skin friction is an interaction
  between a solid and a gas, the magnitude of the
  skin friction depends on properties of both solid
  and gas.

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Lift

• The lift force (the aerodynamic force
  perpendicular to the flight direction) is used to
  overcome the weight.
• On a rocket, thrust is used in opposition to
  weight.
• On many rockets, lift is used to stabilize and
  control the direction of flight.

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Stability During Flight

• The purpose of putting fins on a rocket is to
  provide stability during flight, that is, to
  allow the rocket to maintain its orientation and
  intended flight path.
• If a typical amateur rocket was launched without
  fins, it would soon begin to tumble after leaving
  the launcher, due to the way that aerodynamic and
  other forces (such as wind) act upon the rocket,
  in relation to the forces that are exerted upon
  the rocket by the motor and by gravity.

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Stability During Flight

• Think about a dart

• Fins or feathers in the rear act like wind veins
  and trail behind.

• Heavy mass made of metal carriers the momentum.

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• The End