If you like this project, then I encourage you to get a copy of my book, Rubber Band Engineer.
Everything I make: LanceMakes.com
The rubberband-powered helicopter is a favorite of my students because of the ease of construction and the exciting end product.
Materials and Tools:
6" hook nose propellers
2 Rubber bands
Colored construction paper (or other rigid yet light material)
How It Works:
1. Energy is stored in the sport rubber by winding the propeller.
2. When flown, the sport rubber rapidly releases its energy by unwinding, which turns both the propeller blade and the paper cutout.
3. The paper cutout pushes against the surrounding air, which creates horizontal air resistance, or drag. This makes it harder for the cutout to spin. Because the cutout does not spin as easily, more energy from the sport rubber is released into the propeller, which is much easier to turn. In this way, the paper acts like the rear rotor of a real helicopter
4. As the propeller spins rapidly, it begins to create lift by pushing air downward. With enough energy, the helicopter will fly in whatever direction it is pointing.
Tips and Troubleshooting:
- The number one reason helicopters fail to fly is due to simply not winding the rubberband enough.
- The second biggest reason is caused by letting go of the whole helicopter at once. When I show students how to fly the helicopter, I say, "Let go - let go," as I release the top and bottom. Tell your students that verbalizing "Let go - let go" in one's head or out loud can help coordinate one's hands.
- You may want to tie the sport rubber for younger students during your prep time.
- Try making templates of bird wings or a helicopter silhouette. For one Halloween, I made cardboard templates of bats. For added flair, the project was renamed "Baticopters."
- In my experience, a long rectangle approximately 6" x 1.5" made out of cardstock is the most efficient shape and material.
- Cutouts which span less than 3" typically do not perform well.
- With a little practice, students can throw the helicopter as it is being released for additional height
- Spinning propellers can get caught in long hair.
- Stay far away from buildings, trees and fences!