Propeller-Powered Zipline Racers




Introduction: Propeller-Powered Zipline Racers

About: I'm a writer, maker, and educator who's on a mission to better the world through hands-on engineering projects. Check out my work:

If you enjoy this project, please consider pledging on Patreon.

Please message me to report broken links. All of these materials are used in my other Instructables for kids, so your purchases can be used across multiple projects.


How It Works
It's simple. Winding the propeller will store energy in a rubberband by twisting it. When released, the propeller rapidly unwinds and generates thrust, which pulls the craft along a low-friction zipline. However, the torque from the unwinding propeller can cause the entire racer to flip upside down. To counter this force, another force is introduced: drag. By attaching a paper cutout, drag perpendicular to the side of the racer is created, which helps prevent inversions.

Safety and Tips

  • CAUTION! Pulling downward on the racer while it is hooked onto the zipline may cause it to be flung off the line upon being released. This can be dangerous when the propeller is rapidly unwinding. Be sure to directly supervise each student at least once as they attempt to launch their racer for the first time. Be sure to correct anyone who pulls on the zipline before a launch.
  • Make sure the zipline is either highly visible or above everyone's head.
  • Young students (grades 1-3) may need extra guidance while bending the paperclips, attaching the rubberbands, and properly launching the racer.
  • Encourage your students to experiment, especially if they're in grades 4 and up - I'm always amazed by their innovations and improvements.

5 People Made This Project!


  • Water Contest

    Water Contest
  • Fix It! Contest

    Fix It! Contest
  • Creative Misuse Contest

    Creative Misuse Contest

15 Discussions

I made it for a science project.

My friends pictures are above me!!!!


Wow!That's Great

Hi there! I'm an Elementary Ed student and I'll be using this to present a lesson on push and pull to my peers. You have some really great ideas and I'm sure we'll have a blast! Thanks!

as a shop teacher of 14 years i have to say what a GREAT job you've done! i am already in the process of stringing a line in my shop! thanks!

2 replies

Much appreciated :) I've admired many of your projects from the teacher contest - keep up your superb work and imagination!

oh, and if you can, please post some photos if you try out this project. Thanks!

I don't build any of your project (Nothing personal :P), but I still watch the tutorials all the way through.

Your voice is brilliant and your instructions are super clear and easy to follow. I would follow you, but I already am :D

1 reply

Wow, thanks for the feedback - It's always hard to judge one's own Instructables, so it's great to hear that it's working :)