Independent Design and Build Activity

Objective:

This is an open-ended activity where you will assemble a propeller-based propulsion system and explore different ways of improving the propulsive performance of the system.

Materials:

• Small electric motor [e.g., the vibrator from an old pager, motor from a small fan used for cooling]

• Panasonic 2.5V 3.3F Gold Capacitor

• Nylon propeller

• AA battery holder

• Four quick disconnect plugs (2 male, 2 female)

• 4 AA batteries

• Soldering gun and solder

• 2 3" lengths of wire

Assembly:

Begin by soldering the capacitor to the motor terminals. Also solder two three-inch wires to the capacitor terminals on one end and to the header pins on the other end. Attach the propeller to the electric motor's shaft. The motor/capacitor assembly is shown in the right photograph below.

Photos of plane motor assembly.

To operate the motor, install four AA batteries into the battery holder and connect it to the quick disconnect plugs to begin charging the capacitor. This assembly is shown in the left photograph above. When the propeller is spinning at its maximum rate, quickly disconnect the motor from the battery holder. The motor should run for several seconds until the charge in the capacitor has run out. You can recharge the capacitor as often as you like.

What do I do now?

Now that you have a functioning propulsion system, you can mount it to different vehicles and/or modify it to improve performance. Remember, you are the propulsion engineer for this activity, so try different things and see if you can get them to work as well as you expected. And just as important, learn from your failures. If something didn't work, try to figure out why so you can make a better design next time.

Suggested Activities: These activities will require additional materials and assembly as necessary in order to construct/modify the vehicles.

1. Supercharge a Paper Airplane: This activity was published in Popular Science magazine and step-by-step instructions can be found here.
2. Build an electrically-powered propeller car: Modify the Doc Fizzix Aero Racer so you can mount your electric motor to it.
3. Build an electrically-powered propeller boat: Mount your propulsion system to a plastic hull boat. Make sure to keep the motor and capacitor out of the water!

Whichever you choose, see what propeller designs or modifications give the greatest vehicle speed or allow the vehicle to travel the farthest on a given charge. Have a competition to see who can design a vehicle with the greatest range.

For the car and boat options, you can rewire the motor to be powered directly from the battery. You can also try connecting it to solar cells to see if you can build a solar-powered vehicle.

Just remember to be creative and have fun!