Propeller-Powered Car - Engineering Project for Kids

Fast and fun, the propeller car is a hands-on lesson in air-powered thrust and inertia. Small, lightweight wheels have less inertia than big ones, which lets the car reach its maximum speed quickly!

Just wind it up and watch it race across the floor up to 30'!

You can find the lesson plan, 1-page project sheet, and more project ideas at STEM-Inventions.com

Step 1: Materials

I created a kit that has enough supplies for 10 propeller cars here, or you can source the parts individually:

Plastic propellers (Larger pack)

Wheels

Straws

1/8" dowel

Craft sticks

Craft cubes (Bulk pack)

Long rubber bands

Paperclips

Masking tape

Hot glue gun with safety nozzle

Hot glue sticks

When you make a purchase through these links, I may earn an affiliate commission at zero cost to you.

Step 2: No-Glue Variation

The no-glue variation uses the same building system as the Geometric Shapes lesson. The low triangular frame is built by using a normal craft stick and two smaller pieces, each approximately 1/3 the length of a normal craft sticks.

The tip of the propeller is taped, which keeps the metal hook in place and allows the user to wind the propeller counter-clockwise. Winding the propeller counter-clockwise propels the car in the direction of the narrow end of its triangular frame.

Step 3: Tips and Troubleshooting

• Remove any thin strands of dried glue before operating the car. "Hot glue strings" get tangled in the axle or propeller shaft.
• Make sure the skewers (axles) are straight. These are mass produced and can be severely warped.
• More rubberbands isn't always better. Too much energy can cause the car to spin wildly out of control.
• Wide-set wheels are more stable than narrow ones. A narrow car may flip over from the torque generated by the rubber band.
• The rubberbands may become loose over time. You can breath new life into old bands by unhooking them and tying one end into an overhand knot. Now the remaining band is shorter (and tighter) than before.

Please be sure to take video or photos if you do this project with your class and post it in the comments :)
Have fun teaching!

Comments

[beekins]

Hi Lance - This is a great beginner's rubber band car. I had a hard time finding wheels, and used standard mouth mason jar lids. I drilled 1/8" holes in the dimple in the middle, and it worked great! Also, since I had a hot glue gun ready, I used cardboard straws and glued them to the craft sticks. Thanks for the Instructable.

[MargaretS110]

Having trouble finding the wheels. They are currently unavailable on Amazon. Would you have other suggestions as to where I could find them?

[beekins]

I used standard mouth mason jar lids and drilled holes in the dimple in the middle for the axles.

[27haylee_bloom]

water bottle caps

[LanceMakes]

It looks like the wheels are in stock again:

https://amzn.to/2KMqcL3

[omikentoby]

Amazon.com is out of the wheels. What is a good replacement?

[tbriley1]

3D print them.

[dillonmaurer]

but if you don't have the propeller

[27haylee_bloom]

use a water bottle propeller

[TallDwarf]

Can you please re-link the craft cubes as the link is broken.

[LanceMakes]

Thanks for alerting me. It's fixed!

[JohnS1161]

I am a premium member but the site will not let me download anything. What is going on?

[LanceMakes]

Hi - I don't know anything about that, but you can contact Instructables here: [e-mail].

You can also find downloadable files on my website, https://www.madeforsteam.com/project-plans

[kguzdial]

What did you use to trim the ends of the dowels? Thank you!

[zeeshan012]

yes i made it but without that thing..

[jazo65]

Hi. What did you use instead of the eye hook? Thanks

[Jakob8866]

ughhhh

[T0BY]

Great idea!

[ecoexplorers]

You are awesome! I LOVE your instructables and can't wait to try some of these out with my 4th graders!

[PranayC]

Please answer me . I have to make it fast