Introduction: Propeller Plane
In the past, my propeller plane prototypes always end its flight with a less-than-graceful nosedive. This design solves that issue by implementing lightweight skids that act as a sort of landing gear. This project is only suitable if you have access to an outdoor area or are using a large, open room.
Fold and cut sheets of cardstock in half lengthwise.
Tell your students that they will be designing a plane that can take off from the ground or table, fly at least 15 feet, and land upright. Since this project is reasonably simple to build, I recommend partially constructing an example in front of your students and explain key design features along the way. There are many steps to completing a successful plane, so try to keep digressions to a minimum. Key features and explanations are written on steps 2-6.
By means of verbal lecture, students will understand four key aviation concepts: lift, thrust, stability, and weight.
Students will consult with the teacher as they test their planes and observe the results. The teacher will help students identify the cause of any problems and offer an explanation. Students will use this new information to modify their design and repeat this process.
Once students have a successful plane, they will apply what they learned to intentionally create new flight patterns such as loops or turns.
Step 1: Materials
2 1/2 sticks
2 milkshake straws
1 sheet of cardstock
Pens for decoration
Propeller can be purchased here
Step 2: Build the Propeller Shaft
Explain important design aspects as you build an example in front of your students. The propeller shaft simply holds and stretches the rubberbands, which will be used as a power source. Be sure to firmly tape the paperclip on!
Once the rubberbands are added, the propeller shaft will provide thrust for the plane. In this case, thrust is what pulls the plane forward. Imagine you are sitting in a chair with wheels. If you push against a wall, you will roll in the opposite direction. The same thing is happening here. As the propeller spins, it pulls air toward the plane and pushes air toward the back of the plane. By pushing air backwards, the propeller creates an opposite reaction that moves the plane forward.
Step 3: Wings, Tail, and Stabilizer
The most important thing that a plane needs in order to fly is lift. Lift happens when air pushes against the underside of the wing. The bigger the wings are, the more lift it will have. The paper is folded in half and cut at a diagonal angle because we want the wings to be bigger near the middle of the plane since that is where the plane is heaviest. If the wings were a rectangle, there would be too much lift on the wingtips, which can cause the plane to lift up too much on one side and crash.
Cut the remaining folded paper in half. These pieces will be used to make the tail and stabilizer.
Step 4: Attach the Wings, Tail, and Stabilizer
Use long pieces of tape lengthwise to secure the wings to the propeller shaft.
Tape the two triangular pieces together to form the tail. The tail is attached in the same manner. Be sure to tape it on securely!
The stabilizer is taped to the tail, then bent toward the middle and taped together.
The purpose of the tail is to provide a little bit of additional lift to the back end of the plane. The stabilizer is important because it helps keep the plane from turning or tilting.
I like to explain the importance of the stabilizer like this: Hold a piece of paper in front of you (like the other half of the sheet of cardstock). Use your breath to blow against the edge of the paper. You'll notice that the paper doesn't move much. This is because the air easily goes around the paper since it is so thin. Now try holding one end of the paper and blowing against the surface. The paper will quickly bend away from the airstream because the air can't go around it as easily. It's easier for the air to push the paper out of the way until the paper is bent in the same direction as the airstream.
A stabilizer works the same way. When the plane is moving straight, the air easily around the stabilizer. But if the plane begins to turn, then the side of the stabilizer will be exposed to the airstream. The oncoming air will push against the stabilizer until it straightens out. This keeps the plane on a steady course.
The stabilizer in this design is triangular. A single flat piece of paper is too wobbly and may just bend against the oncoming air. Be sure to attach the rubberbands before making the stabilizer.
Step 5: Make and Attach the Skids
The skids allow the plane to be launched from a surface since it elevates the propeller enough so that it doesn't hit the ground. However the skids also serves another important function: it adds weight to the bottom of the plane.
Why is this important? It's not obvious. When the rubberband is wound up and then released, it is actually unwinding on both ends. One end of the rubberband turns the propeller, and the other end is trying to turn the rest of the plane! Of course the plane is much harder to turn since it is bigger and heavier, but it still experiences some of the force exerted by the rubberband. If there is too much force, the plane may tilt to one side, become unstable, and take a nosedive.
The weight from the skids helps keep the plane upright. Since the bottom of the plane is now significantly heavier than the top, the plane will be much more resistant to tilting or flipping over.
Step 6: Fly!
To fly, hold the propeller shaft near the propeller. Make sure that the user is not accidentally smooshing the wings or other paper parts. Face the propeller toward the user, then begin turning the propeller clockwise. Once students are familiar with the direction the propeller needs to be turned it, they should turn the plane away from themselves in case it accidentally is realeased.
Experiment with different amounts of energy and adjust the number of rotations to achieve the desired outcome.
When ready to launch, place the plane gently yet firmly on a flat surface facing away from the user. Starting on a surface that is elevated above the ground is recommended.
Hold the back of the plane with one hand and hold the propeller with the other hand. Release the propeller first, then let go of the back of the plane a split second later. The timing is important and can take a little bit of practice. The time between releasing the propeller and releasing the plane is about the same as the amount of time it takes to say "tick tock." This is a good auditory cue for students to use. Release the propeller when saying "tick" and the back of the plane on "tock"
Once students master the basic flight technique, they can begin experimenting with ways to produce new effects like loops, turns, or rolls!
Step 7: Safety, Tips, and Troubleshooting
- Symmetry is key! Make sure that mirroring pieces are as close to being identical as possible. Be sure to attach the propeller shaft along the center line of the wings.
- Knowing how much to wind up the propeller shaft and learning to fly the plane can take practice. Give plenty of encouragement to students who are having trouble. Let them know that it's very common for students to struggle with flying the plane, and that there is nothing to worry about - it just takes a little practice.
- If a plane is tilting to one side and taking a nosedive, check for: wingtips that are too large; floppy or damaged wings; asymmetrical wings or tail; skids placed too far from the plane's center.
- If a plane is not achieving a desired distance, check for: only one rubberband instead of two; not enough energy stored in the rubberband, excessive weight; wings that are too small
- If a plane is flying sharply upwards, then stalling and crashing, check for: wings that are too large/wing width is too uniform; lack of skids; warped or bent wings