Making a propeller car is a
mechanical engineering challenge used as a competition for
students from 5th grade up to the second year college. It can also
be used as an experimental science project to test the effect of
propeller size in the speed of the car. Students may also decorate
the car or provide an aerodynamic shape to it in order to reduce the
air friction and increase the speed. All these are possible using
construction papers, glue and water based paint.
|The chassis of this car is
a 2" x 6" wooden board. Mark the location of the axles
by drawing a line parallel to the front side or backside.
Insert the eye screw axle holders on the axle lines about
one centimeter or 3/8 inch away from each side. Make sure
the screws enter in a right angle and they are not slanted
to one side.
pieces of 1/2 inch straw and keep them ready to be used as
spacers in the next step.
Insert the axle in one
wheel. Then add a spacer and a metal washer onto it. Insert
the axle in the front or back axle holders and then insert a
washer, a spacer and the other wheel onto it.
|After installing the front
and back wheels and axles test the car and make sure that it
can roll smoothly. Test all the wheels. Make adjustments if
necessary. If the straw spacers are very long, replace them
with shorter spacers.
This image shows the under
side of the car.
Turn the car over and test
it on a smooth flat surface.
|Use additional wood pieces
and wood glue to build a stand on the car similar to the one
shown on this picture. Space the wood dowels or pillars
about 1/4" apart. The plastic strap that will secure the
motor must be able to pass trough the space between the
dowels. The height of the stand must be 2.5 inches (5
centimeters) or more so that the spinning propeller will not
touch the car chassis.
Allow the glue to dry at
least for 4 hours.
|Insert the shaft of the
motor into the hole at the center of the propeller.
|Place the motor-propeller
combination on the stand and secure it in place with a
plastic strap that is included in your kit.
Mount the battery holder with
batteries on the car. You may use Velcro tape or double
sided tape to attach the bottom of the battery holder to the
Locate the two metal
connectors in the back of the motor. Each connector has a
hole in the center that will be used to hook the connection
|Connect one of the wires
on the battery holder to one of the connectors o the motor.
(Pass the wire trough the hole and twist it to keep it in
Place the batteries in the battery holder (if they are not
Hook the other wire of the
battery holder to the second connector. The propeller will
start turning. Place the car on a flat and smooth surface so
that the car can move.
If the car moves backward,
you can change the turning direction of propeller so that
the car can move forward.
To change the turning direction you
must switch the position of two wires in the back of the motor.
Simple Electric Circuit
The battery and the electric motor used in
this project will form a simple electric circuit. Connections are possible
in many different ways. If you need to install the switch for your car, you
can decide on the location of the switch as long as it does not block the
movements of the propeller.
|In the simplest form, you connect
the two wires of the battery holder directly to the electric
contacts at the back of the electric motor.
|In a standard design you will use
one battery holder, one switch and one electric motor. One wire from
the battery holder connects to the electric motor directly. The
other will connect to the switch and then another wire from the
switch will connect to the electric motor.
|In a more complex design you may
use two battery holders and install the switch between the two
Note: The electric motor is
able to spin in two different directions. You can reverse the direction of
spinning by switching around the wires connected to the motor.
|If you don't
have this kit, you can order it now! It is
available both as a single pack and class pack.