Project 4.2.8b Propulsion Systems – Rocket Fuel

Introduction

Propulsion is the way in which aircraft and spacecraft are moved forward. It is a combination of factors such as thrust (forward push), lift (upward push), drag (backward pull), and weight (downward pull). In order for an aircraft or spacecraft to achieve forward motion, it must have enough thrust and lift to overcome drag and weight. Different propulsion systems produce thrust in different ways.

The aerodynamics of aircraft flight is based on the effects of Earth’s gravity and the availability of oxygen in the atmosphere. Flight in space is much different since it must break through the gravitational pull and oxygen is absent in space. Therefore, engineers had to develop an alternative type of propulsion that could develop thrust without burning oxygen.

The rocket that launched Deep Space 1 on October 24, 1998, had four different kinds of engines. Some pushed the rocket off of the ground; others helped the rocket continue its climb into space. Others gave the Deep Space 1 spacecraft its final push away from Earth. All of the engines forced a gas to shoot out of the rocket, thus pushing the rocket in the opposite direction.

In this project you will work with a team member to design a new rocket propellant.

Equipment

  • Gateway notebook
  • Pencil
  • Propellant materials
  • 35mm film canisters with internal sealing lids (usually the clear canisters); these can typically be obtained from a film developing shop that recycles suchcontainers
  • Paper towels (for clean-up at launch site)
  • Eye protection
  • Stop watch
  • Meter stick
  • Calculator
  • 100 ml graduated cylinders
  • Measuring spoons

Procedure

Space Journey has a new job opening.They are interested in hiring you. There are other candidates for the job, so they have created a challenge to help them decide who to hire. The challenge, should you choose to accept it, is to work with a partner to design the best propellant for launching rockets. Space Journey’sdecision will be based on how much money you spend (less is better), how high your rocket goes (higher is better), how long it takes your rocket to liftoff (quicker is better), and how well you work with a teammate.Below is a list of materials available for you to use and the cost of each material.

Water fuel / $5 per milliliter
Vinegar fuel / $30 per milliliter
Diet Coke fuel / $100 per milliliter
Tums (crushed) / $5,000 per ½ teaspoon
Alka Seltzer (crushed) / $7,000 per ½ teaspoon
Baking soda powder / $900 per ½ teaspoon
Salt / $150 per ½ teaspoon
  1. Experiment and determine what happens when you mix (react) different materials together. This process will allow you to choose the best propellant for your rocket. Record your results in the table below.
  2. Place 30 ml of the liquid fuel into the 100 ml graduated cylinder.
  3. Add ½ teaspoon of the solid fuel into the graduated cylinder.
  4. Using the stopwatch, measure the amount of time it takes for the foam to reach its maximum level. In the chart below, record time and net volume of foam (Net volume of foam = Final volume – 30 ml). Record your net volume in ml.

Vinegar / Water / Diet Coke
Tums
Alka Seltzer
Baking Soda
Salt
  1. Choose and record in the chart below your team’s 1st choice for the best rocket propellant.Things to remember:
  2. You have a limited amount of resources.Use your materials wisely.
  3. Be sure to list the quantity of liquid and solid materials, as well as your choice of materials.
  4. A film canister holds approximately 32 ml of material. Besides the liquid portion of the fuel, you must also consider the amount of solid that is contributing to the total volume:
  5. 1 teaspoon = 5 ml
  6. ¾ teaspoon = 3.75 ml
  7. ½ teaspoon = 2.5 ml
  8. ¼ teaspoon = 1.25 ml
  9. Do not overfill your canister! You must leave room for the reaction between liquid and solid fuels to take place.
  10. Calculate the total cost of your fuel propellant mixture.
  1. Gather your rockets, propellant materials, a stop watch, a meter stick, a pencil, and this activity to take to the launch site. Launch your rockettime and record all information in the table below.
  2. Turn rocket upside down and fill with liquid fuel.
  3. Add the solid fuel and quickly snap the lid on tight.
  4. Turn the rocket upside down (cap down), and stand back.
  5. Note the height the rocket travels, as well as the time of flight, starting from when the solid fuel was added to the liquid fuel.
  6. Calculate the propellant cost per unit of height by dividing the propellant cost by the maximum height.
  1. As with most engineering projects, adjustments, known as “tweaks” must be made to optimize performance of the product. In the last row, explain the tweaks you plan to make for your second and third flights.
  1. When finished with your flights, answer the conclusion questions at the end of this project.

1st Flight / 2nd Flight / 3rd Flight
Propellant Mixture
Propellant Cost (total cost of materials)
Maximum Height Obtained during Flight
Time of Flight
Propellant cost per unit of Height
What do you want to improve in your flight? (What changes are you making in your propellant mixture, and why?)

Conclusion

  1. Explain what you would do to further improve your results.
  1. All three of Newton’s laws of motion are demonstrated when a rocket lifts off. Describe the law and how it applies to the rocket liftoff.

Newton’s first law:

Newton’s second law:

Newton’s third law:

© 2011 Project Lead The Way, Inc.

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