Principles of Rocketry

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Principles of Rocketry
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Isaac Newton's 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 Rocket
Action
Reaction
Equal pressure in all directions
Pascals Principle
Hot gasses escaping
Nozzle
Burning fuel Producing hot gasses
Solid Fuel
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Space ShuttleSolid and Liquid Fuel Rockets
Liquid Fuel and Oxygen tank Feeding Engines

Solid Fuel Rocket Boosters
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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
Pascals Principle
Reaction Bottle forced up by water being
expelled down
High Air pressure is transmitted equally in all
directions and parts of the fluid.
Action
Water forced out and down by air pressure
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Other factors that make the Water Bottle Rocket
Fly
Compressed Air Water
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Mother Nature doesn't like it when things aren't
equal!
When you pull the pin on the launch pad, and the
latch holding your rocket to the launch pad pulls
back, no force will be holding that rocket down!
The unbalanced force of the High air pressure
inside of your rocket will instantly rush out of
the rocket nozzle pushing your rocket into the
sky!
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Newton's 3 Laws Explains Everything

• Newton's 3 Laws of Motion
• 1An object will stay at rest unless a force acts
  upon it.
• 2Force Mass x Acceleration
• 3For every action there is an equal an opposite
  reaction.

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How Newton's Laws Affect Our Rockets

• Newton's First Law

When you pressurize your rocket and compress all
of that air into your rocket engine, the force of
the launch pad latch equals the force of the
compressed air. Your rocket is resting, it will
go nowhere.
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Newton's Second Law

• This law tells you how much force (push) is
  going to come out of your rocket nozzle. The air
  is the accelerant, the water is the mass. You are
  limited to a 2000 ml volume rocket engine (a 2
  liter pop bottle).What ratio of compressed air
  (limited to 65 psi) and water (your choice) will
  produce the most force?

About half the bottle full of water 100mLs
Too much mass too much inertia
No mass nothing to push off of
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Newton's Third Law

• When you pull the pin, that area of High Air
  Pressure in the top of your rocket engine is
  going to force, throw, hurl, spew that "massive"
  water out the bottom of your rocket at a great
  speed. That water and air is pushing down, so
  your rocket must go up.

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Stability During Flight
The orientation of fins and distribution of mass
help make the rocket stable.
Center of Gravity
Center of Pressure
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Center of 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 in front carries the momentum
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Bring These Materials to class on Monday

• Two, 2-Liter soda bottles
• Old cds
• Duct Tape
• Manila envelopes
• Clay
• Stickers, paint, colorful duct tape for
  prettiness and other decorations are optional

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Lesson by Mr. Alex Sowyrda Cooperating Teacher
Mr. Robert Jones Kenney Middle School 7th Grade
Technology Hannibal, NY Sept Oct 2004

• http//www.hannibal.cnyric.org/TeacherWebs/Rjones/
  rockets/PowerPoint/Rocketry_files/frame.htm