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Project Summary

Difficulty	6
Time required	Average (about one week)
Prerequisites	None
Material Availability	Readily available
Cost	Very Low (under $20)
Safety	No hazards

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Sponsor

Sponsored by a generous grant from Northrop Grumman Foundation

Weightless Flights of Discovery Program for Teachers

www.northropgrumman.com/ community/weightless.html

Objective

The objective of this project is to explore the aerodynamics of flying rings. What effect do various design modifications (e.g., increasing weight near perimeter, increasing weight near center, curving the leading edge, decreasing the size of the center cut-out) have on flight distance?

Introduction

In this project you will come up with a hypothesis to explain why flying rings travel farther than flying disks and make your own flying models from paper plates (or Bristol board) to test your hypothesis. If you have more than one hypothesis, it's easy to expand your project. The materials are inexpensive, and flying disks and rings are not hard to make.

Your background research should help you to come up with a hypothesis to test. The experimental procedure section has some suggestions on construction methods for building flying rings and disks. There are also tips on test-flying and measurement.

Terms, Concepts and Questions to Start Background Research

To do this project, you should do research that enables you to understand the following terms and concepts:

• lift,
• drag,
• weight.

• What forces act on flying rings and disks in flight?
• What is (are) the major difference(s) in these forces between flying rings and disks?

Bibliography

• The Exploratorium, 1997. "What effect does the rim of a frisbee have on its flight?" Sport! Science [accessed February 10, 2006] http://www.exploratorium.edu/sports/ask_us_sports_october.html.
• NASA has a great reference site on Aerodynamics. Even though there is not anything specific on frisbee flight, you can still learn a lot about how frisbees fly by learning about aerodynamic forces on other types of airfoils. Check out the Gliders section, and the Lift Simulator program.
  http://www.grc.nasa.gov/WWW/K-12/airplane/guided.htm.
• For information on the science behind Aerobie flying rings, see:
  "The Science of Aerobie Sport Toys," Aerobie, Inc. [accessed February 14, 2006] http://www.aerobie.com/Science.htm.
• For making rings from paper plates, you'll need to know how to find the center of a circle. This link tells you how:
  Dr. Math, 1996. "Finding the Center of a Circle," Ask Dr. Math Forum, Drexel University [accessed February 14, 2006] http://mathforum.org/library/drmath/view/54822.html.

Materials and Equipment

To do this experiment you will need the following materials and equipment:

• Bristol board (smooth surface, not vellum surface; available at art supply and stationery stores),
• or paper plates,
• white glue,
• compass and pencil for drawing circles,
• scissors,
• tape measure,
• string,
• tape,
• marking pen,
• helper.

Additional items that may come in handy:

• pennies (or washers) for weight,
• tools for forming curved or shaped edges: silverware, plastic cutouts.

Experimental Procedure

Developing a Hypothesis

1. Do your background research and learn about the forces on flying disks and rings in flight. How do the forces differ between the two? How do you think this will affect flight distance?
2. Carefully examine commercial flying ring and flying disk products and note differences between them. For each of the differences, think about the forces acting on these objects as they fly, and try to predict the aerodynamic consequences.
3. For example, an obvious difference between the disks and rings is the open space in the center of the ring. What aerodynamic effect(s) result from opening up the center of a disk?
4. Test your hypothesis by building a series of rings (3–5), which systematically vary the design element of interest. To continue with the example above, you could build a series of rings with successively smaller open diameters in the center.

Construction Tips for Paper Rings and Disks

1. You can use Bristol board (recommended) or paper plates to make your flying rings/disks. (If you use paper plates, see the Bibliography for a way to find the center of a circle, so you'll know where to put your compass point.)
2. Use your compass to draw circles for your rings. Building up your rings from multiple layers will make them stiffer, and they will fly better (see below).
3. If you want to add weight to your rings, try extra laminations of the appropriate diameter, or glue pennies or washers in between layers. (Sobey, 2000, 55)
4. When building your flying models, change only one design variable at a time. For example, if you are investigating the effect of the diameter of the open center, all of the rings should have the same outer diameter, mass, edge curvature, etc. Only the size of the center opening should change.
5. How can you keep the mass constant but still have more material covering the center opening? The key is to build your rings out of more than one layer of paper (laminated construction). Laminated construction has multiple advantages.
   1. Your design can redistribute the material between different layers to keep the mass constant. For example, as you add material in the center of one layer (to decrease the open diameter), you remove an equal area of material from another layer (or layers). (It's easy to calculate how much mass you are adding. Since the paper has uniform thickness, the mass will be proportional to the area. The area of a ring is just the area of the outer circle minus the area of the inner circle.)
   2. You can explore how the distribution of mass (e.g., more mass towards edge vs. more mass towards center) affects flight performance.
   3. By gluing together two or more layers (laminated construction), you will end up with a stiffer ring or disk, which will fly better.
   4. A way to further increase stiffness is to compensate for the "grain" of the paper by rotating the disks relative to the original orientation before gluing them. Most papers bend more easily in one direction than the other (usually there is more resistance to bending in the long axis of the paper). If you systematically rotate the strong axis of the separate layers, your finished ring will be stronger. For example, with a two-layer ring, rotate one layer 180°/2 = 90° before gluing. For a three-layer ring, rotate each layer 180°/3 = 60° relative to the previous layer.
6. Glue the layers together carefully with white glue. Spread the glue evenly and make sure all edges are glued down tight.
7. Wait for the glue to dry (overnight is best) before test-flying.
8. If you want to curve the edges of your flying rings/disks, you can use the a piece of silverware (like the curve on a spoon where the bowl meets the stem). Work at the edge of a table, with the edge of your disk sticking out. Carefully bend the rim of your ring with the spoon. Rotate the ring and bend a uniform curve all around the edge. (Sobey, 2000, 57–58) Alternatively, make a curve-forming tool by cutting a plastic lid in the desired shape.

Test-Flying and Measurement

1. For measuring your flights, you'll need a tape measure and a helper.
2. If your tape measure is not as long as your typical throw, make a longer tape measure using a piece of string. Mark off regular intervals with tape labels and a marker, and you're in business.
3. Do your best to keep the conditions for all of your test flights constant. Try to throw with the same arm motion and speed for each ring.
4. Do at least 10 test flights for each ring. Record the results in your lab notebook.
5. Make one or more graphs to show your results. In this example, you could graph flight distance vs. center open diameter.

Variations

• For a flying disk project, see: The "Ultimate" Science Fair Project: Flying Disk Aerodynamics.
• Think about other flight characteristics you can test. For example, think about curved flight paths. The drag component is very different between the two designs, what affect does this have on tendency of disks and rings to curve in flight? (See The "Ultimate" Science Fair Project: Flying Disk Aerodynamics for suggestions on throwing and measuring curved flight paths.)
• Laminations on top vs. underneath. If you curve the edge of your rings downward, would you expect more drag from ring laminations added to the top or to the bottom surface?

• For more science project ideas in this area of science, see Aerodynamics & Hydrodynamics Project Ideas.

Credits

Andrew Olson, Ph.D., Science Buddies

Sources

• Sobey, E., 2000. Fantastic Flying Fun with Science: Science You Can Fly, Spin, Launch, and Ride., New York, NY: McGraw-Hill.

Last edit date: 2006-02-21 18:15:16

Career Focus

If you like this project, you might want to think about career opportunities in Aerodynamics & Hydrodynamics.

Humans have always longed to fly and to make other things fly, both through the air and into outer space—aerospace engineers are the people that make those dreams come true. They design, build, and test vehicles like airplanes, helicopters, balloons, rockets, missiles, satellites, and spacecraft. Learn more about this career: Aerospace Engineer.