Introduction: (Initial Observation)
How is it possible for something that weighs thousands of pounds to fly through the air? It’s not easy, that’s for sure.
People dreamed for thousands of years of flying. It wasn’t until 1903, however, that the dream came true. Two brothers, the Wright brothers, created a very simple airplane and flew only a matter of yards. It was the start of something more incredible than they could have imagined.
EXPERIMENT 1: (Source: http://www.allstar.fiu.edu/aero/Experiment1.htm)
- Strip of notebook paper or newspaper, about 2 inches wide and 10 inches long
- Paper clips
The force that lifts an airplane and holds it up comes in part from the air that flows swiftly over and under its wings.Make an airfoil (wing) by placing one end of the strip of paper between the pages of the book so that the other end hangs over the top as shown in diagram A. Move the book swiftly through the air, or blow across the top of the strip of paper. It flutters upward.Hold the book in the breeze of an electric fan so the air blows over the top of the paper.
Bernoulli’s principle works with an airplane wing. In motion, air hits the leading edge (front edge) of the wing. Some of the air moves under the wing, and some of it goes over the top. The air moving over the top of the curved wing must travel farther to reach the back of the wing; consequently it must travel faster than the air moving under the wing, to reach the trailing edge (back edge) at the same time. Therefore the air pressure on the top of the wing is less than that on the bottom of the wing.
Following are some additional links:
If you are participating in an aviation competition or if you need to test and compare multiple model airplanes, you will need a system to ensure all models are ejected with the same force and angle.
To do this you may construct a special catapult for ejecting your models.
Get a strip of wood about 2 feet long and 2 inches wide. One side of this will be the runway, must remain smooth and clean. In the other side glue a wood block in the center to be used as a handle and glue a small wooden block on one end to be used as the anchor for the rubber band.
The picture in the right shows how it will be used.
If you need more information, click on help above to contact your project advisor.
The purpose of this project is to see how does the shape of wing affect the the fly of an airplane.
We will not need to define variables for this project. However, if we wanted to study the effect of wing curve on the lift, then the wing curve would and the lift would be our variables.
My hypothesis is that if with any method we be able to slow down the movement of the air under the wings, or speed up the movement of the air above the wing, that will create a lift force on the wings that can in turn lift the airplane. My hypothesis is based on collected information that indicates faster movement of air on a surface, will reduce the air pressure to that surface.
Design an experiment to test each hypothesis. Make a step-by-step list of what you will do to answer each question. This list is called an experimental procedure. For an experiment to give answers you can trust, it must have a “control.” A control is an additional experimental trial or run. It is a separate experiment, done exactly like the others. The only difference is that no experimental variables are changed. A control is a neutral “reference point” for comparison that allows you to see what changing a variable does by comparing it to not changing anything. Dependable controls are sometimes very hard to develop. They can be the hardest part of a project. Without a control you cannot be sure that changing the variable causes your observations. A series of experiments that includes a control is called a “controlled experiment.”
In this experiment we will make a wing model that one side of that is flat and the other side is curved. Then we place it in a wind tunnel (actually we hold it in front of an electric fan) to see if the lower air pressure on the curved side will push the wing toward the curve side.
In order to see the result better, we make two wings with opposite curved sides. This should make our plane to spin.
Get a heavy letter size paper and draw cutting and folding lines for your double wing model. Draw 3 lines along the length of paper, First line is 2 inches away from the edge of paper, second line is 3 inches from the edge and the third line is 5 inches away from the edge.
Draw three lines along the width of paper. one 3 inches, one 5.5 inches and one 8.5 inches from the edge. Cut the paper over the 3rd line in each direction, so you will have a 5 x 8.5 rectangle, divided in 9 smaller rectangles. Cut two of small rectangles from two opposite corners. Notice that the 2 x 2.5 rectangles will be the flat side of each wing and 2 x 3 rectangles will form the curved side of the wings.
Make additional cuts like shown in the image such that you can fold 3 x 2 rectangles over 2.5 x 2 rectangles.
Fold the one inch strip to give it some form and strength. You will later use this area to insert a wire or pin as axis. So tape it to be solid and strong.
Carefully use a pin to make holes for entry point and exit point of the axis that can be a longer pin or a thin steel wire.
Fold the curved surfaces over the flat surface, align the edges and staple them. When you align edges, the fold that is 3 inches will be curved while the 2.5 inch fold will remain straight. Staple tow folds together close to the edge. Remember to fold them in opposite direction for this experimen
Insert a 5 inch pin in the center part and place it over a straw. Hold it faced to an electric fan. What happens?
Wings will spin, showing that air pressure on the flat surface is more than curved surface.
In this experiment we will make a wing model that both sides of that are flat, but one side is not as smooth as the other. The rough surface is supposed to slow down the air current on that surface (So air pressure will increase). Then we place it in a wind tunnel (actually we hold it in front of an electric fan again) to see if the lower air pressure on the smooth side will pull the wing toward that side.
In order to see the result better, we make two wings with opposite smooth sides. This should make our plane to spin.
Start from an empty box or any other thin card board or thick paper that you can find.
Cut two small pieces of cardboard about 2″ x 5″ each. Later we will connect these two together to make on wing, so each piece will form one side of the wing. The surface of cardboard is smooth, to make it rough, we punch some holes on that.
Like previous experiment, our card board will actually act like two wings of an airplane. Left wing and right wing. We make the holes on one side of each card board, so when we connect them together one wing will have rough surface at the bottom and the other will have rough surface at the top.
It is good if you glue tow surfaces together, but I just stapled them together. The wire that you see in the picture is inserted between two layers and will later be used as axis. You can think of that as the body of the airplane. Frame all edges with clear tape to cover sharp or rough edges.
In order to show you the left wing has holes on one surface and the right wing has holes on the opposite surface, I have placed my wing model in front of a mirror.
Insert the axis in a straw and hold your wing model in front of an electric fan. What direction does it spin? Why?
Also visit the following links for more ideas.
Need a graph? Scientific method?
An airplane related project may be selected as an engineering project or as an experimental project. In an engineering project you often don’t need a question, a hypothesis, and defining variables; instead, you focus on improving an existing system or creating a new system. In an experimental project however, you must study one specific question and one specific variable; You also need to follow the scientific method (question, variables, hypothesis, experiment, analysis, conclusion,..)
If you need an experimental project, required to follow scientific method or have graph for your results, select the experiment number 3:
Question/ purpose:Study the effect of wing span on the distance that an airplane can glide.
Independent variable (also known as manipulated variable) is the wing span.
Dependent variable (also known as responding variable) is the glide distance.
Controlled variables are the air pressure, temperature and wind. (Do all your experiments in the same day, same temperature, same weather conditions)
I hypothesize that airplanes with a larger wingspan can glide a longer distance.
Buy or make a simple balsa airplane for this experiment. Balsa airplanes and balsa wood can be purchased from toy stores, craft stores and hobby stores. Build or make your model balsa airplane with a wide wing span before starting your experiment.
Record the wing span of your airplane in your data table.
Throw your airplane 3 times and record the maximum distance that it can fly in your data table.
Cut 1/2″ from each wing and trim the edges.
Record the new wing span of your airplane in your data table.
Throw your airplane again 3 times and record the maximum distance that it can fly in your data table.
Repeat steps 3 to 6 until there is no wing left.
Your data table will look like this
|Wingspan||Flight distance 1||Flight distance 2||Flight distance 3||Flight distance average|
Your wingspan and average flight distance are the variables that form your graph.
Materials and Equipment:
List of material can be extracted from the experiment.
Results of Experiment (Observation):
Report the result of your experiments and observations at this section. You may want to include answers to these questions.
How long did it take for you to complete each experiment?
What problems did you face while preparing and performing your experiments?
What did you learn during this project?
Not much calculation is required for this project, however if you decide to change the experiments or make different sizes of wings, you may need to do some calculations. If you do, write your calculations here.
Summery of Results:
Summarize what happened. This can be in the form of a table of processed numerical data, or graphs. It could also be a written statement of what occurred during experiments.
It is from calculations using recorded data that tables and graphs are made. Studying tables and graphs, we can see trends that tell us how different variables cause our observations. Based on these trends, we can draw conclusions about the system under study. These conclusions help us confirm or deny our original hypothesis. Often, mathematical equations can be made from graphs. These equations allow us to predict how a change will affect the system without the need to do additional experiments. Advanced levels of experimental science rely heavily on graphical and mathematical analysis of data. At this level, science becomes even more interesting and powerful.
Using the trends in your experimental data and your experimental observations, try to answer your original questions. Is your hypothesis correct? Now is the time to pull together what happened, and assess the experiments you did.
Related Questions & Answers:
What you have learned may allow you to answer other questions. Many questions are related. Several new questions may have occurred to you while doing experiments. You may now be able to understand or verify things that you discovered when gathering information for the project. Questions lead to more questions, which lead to additional hypothesis that need to be tested.
If you did not observe anything different than what happened with your control, the variable you changed may not affect the system you are investigating. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. The first thing to check is how you are making your measurements. Is the measurement method questionable or unreliable? Maybe you are reading a scale incorrectly, or maybe the measuring instrument is working erratically.
If you determine that experimental errors are influencing your results, carefully rethink the design of your experiments. Review each step of the procedure to find sources of potential errors. If possible, have a scientist review the procedure with you. Sometimes the designer of an experiment can miss the obvious.
Visit your local library and search for books related to flight, aeronautics, airplane and refer to does books as your references, in addition to on-line references.
Using a wind tunnel
One of the ways you may test a wing or an airplane for lift is using a wind tunnel.
A model of wing can be made using heavy construction paper or balsa wood. You may make different wings with different curvatures on the top and the bottom for your tests. The diagram in the right shows a wing with flat bottom and curved top.
Insert two parallel straws in the wing so they can be used as a guide for the wings to move up or down depending on the wind forces.
Pass two rods through the straws and secure the bottom part of the rods by inserting them in a wooden base. now the wing must be able to freely move up or down.
Place your setup in a wind tunnel you construct. One side of the wind tunnel may be glass or clear plastic so you can see inside. Two ends of the wind tunnel must remain open so the air generated by an electric fan will enter from one side and exit from the other side.
If you need to make measurements of the lift force, you may place masses such as coins inside the wing area or you may hang a string to the wing and hang weights such as paper clips to the string.