Propeller Car Helpful Hints

Helpful Hints:

Helpful Hints Logo Construction Hints and Tips

There are many possible directions that a student may wish to take with this project. The following are directions for constructing a basic propeller car that can serve as a starting point for student investigation. These plans are modified from the Lou-Vee AirCar published in February 1988 issue of The Science Teacher Journal.

Materials (per car):

1 sheet of paper
18 gauge wire
1 standard paper clip
2 soda straws
2 large note cards (12.7 cm x 20.3 cm)
masking tape
rubber bands
fine sandpaper

Construction:

Body

Roll the piece of paper lengthwise into a small tube. Tape the tube to prevent it from unwinding. This tube is the body of the car. Set the body tube aside.

Propeller and Propeller Mount:

Cut one of the large note cards in half to create two 12.7 cm by 10.2 cm rectangles.

One of the two halves will be used to construct the propeller mount, the other half will be used to make a propeller. To construct the propeller mount, take one of these rectangles and fold it in half so that you have a doubled 5.1 cm by 12.7 cm rectangle.

Fold this rectangle in half so the 5.1 cm edges touch. The resulting rectangle should be 5.1 cm by 6.4 cm.

Measure .5 cm from the fold down and make a pencil mark on both sides of the fold.

Open up the rectangle slightly so it forms two rectangles . Fold one rectangle backwards on the .5 cm mark. This should make the mount look like a z when viewed from the side.

Fold the other rectangle backwards on the .5 cm mark. This should make the mount look like a M when viewed from the side. (The shallow groove that is formed is the top and is where the propeller shaft will be attached later in the assembly process.)

Measure 1 cm from the end of the top portion of the propeller mount and mark with a pencil. Draw a diagonal from this mark to the bottom corner. (Note: It is vital to do this on the unfolded edge.)

Measure 1 cm from the end at the bottom portion of the propeller mount and mark with a pencil. Draw a diagonal line from this mark to the front bottom corner.

Trim away the diagonal areas. (Before cutting, double check to make sure the cut is on the unfolded edge.) Set the propeller assembly aside.

Take the remaining 12.7 cm by 10.2 cm card and cut it in half so you have two 12.7 cm by 5.1 cm rectangles. These rectangles will be the propellers.

Using a drawing compass, pierce a small hole in the center of the rectangles and set them aside momentarily.

Wheels:

Using the drawing compass, draw two 4.5 cm radius circles in opposite corners of the remaining large note card. These circles will be the back wheels. (Pierce the center of each circle with the compass.)

Draw two 2.1 cm radius circles in the remaining spaces of the card. These circles are the front wheels. (Pierce the center of each circle with the compass.)

Carefully cut the circles out.

If the circles appear to have rough spots or appear uneven, sand them lightly with fine sand paper. Hold the two small wheels together and the two large wheels together as you do this.

Axles and Propeller Shaft:

Cut the soda straw in half.

Set one piece aside--it is the rear axle tube. Cut the remaining tube in half. One of the short tubes is the front axle tube; the other is the propeller shaft tube.

Cut and straighten a piece of wire to extend 2.0 cm beyond the ends of both sides of the front and rear axle tubes.

Using a pair of needle nose pliers, bend one end of each wire to form a double L. (See picture)

Slide the wires through the axle tubes and bend the remaining end into a double L. The axle should have some play in it. If the bends are too close to the straw the axle will not turn.

Cut and straighten a wire that is 3.0-5.0 cm longer than the propeller shaft tube.

On one end bend the wire to form a double L.
Stick the wire through the tube and bend the remaining end into a hook.

Assembling the Car:

Slide the ends of the front and rear axles through the holes of the wheels and tape the L to the wheels. Make sure the entire L is through the hole in the wheel.

Tape the axles to the body tube. The front axle should be 2.0 cm from the front of the body. The back axle should be 6.0-7.0 cm from the back of the car.

Attach the propeller to the propeller shaft in the same fashion as used for the wheels.

Tape the shaft to the propeller shaft mount as shown in the picture. Make sure the shaft sticks off the back of the mount before taping it to the mount. (Note: The propeller needs to be attached so it is on the unfolded side of the mount.)

Tape the propeller shaft mount to rear of the car. The back of the mount and the rear of the body should be flush.

Pull apart a paper clip so that the two loops form a 30 degree angle. Widen one of the loops slightly and slide it into the front opening of the body tube. This is the front hook for the rubber bands.

Tie 2 to 3 rubber bands together and attach one end to the front hook and the other end to the propeller hook. The rubber bands should sag considerably before the propeller is wound up.

Bend opposite ends of the propeller to create pitch. When pitching the blades, remember to bend them in the same direction.
Wind the propeller and test the car!

Additional items:

Plastic washers can be cut out of milk jugs and slipped between the propeller and the propeller shaft. This will increase the efficiency of the propeller.
File folders can be used instead of note cards. This allows students to create larger components.
Try not to store the cars sitting on their wheels. This often results in warped wheels and makes the car run poorly.

Return to Propeller Cars

	Cut one of the large note cards in half to create two 12.7 cm by 10.2 cm rectangles.
	One of the two halves will be used to construct the propeller mount, the other half will be used to make a propeller. To construct the propeller mount, take one of these rectangles and fold it in half so that you have a doubled 5.1 cm by 12.7 cm rectangle.
	Fold this rectangle in half so the 5.1 cm edges touch. The resulting rectangle should be 5.1 cm by 6.4 cm.
	Measure .5 cm from the fold down and make a pencil mark on both sides of the fold.
	Open up the rectangle slightly so it forms two rectangles . Fold one rectangle backwards on the .5 cm mark. This should make the mount look like a z when viewed from the side.
	Fold the other rectangle backwards on the .5 cm mark. This should make the mount look like a M when viewed from the side. (The shallow groove that is formed is the top and is where the propeller shaft will be attached later in the assembly process.)
	Measure 1 cm from the end of the top portion of the propeller mount and mark with a pencil. Draw a diagonal from this mark to the bottom corner. (Note: It is vital to do this on the unfolded edge.)
	Measure 1 cm from the end at the bottom portion of the propeller mount and mark with a pencil. Draw a diagonal line from this mark to the front bottom corner.
	Trim away the diagonal areas. (Before cutting, double check to make sure the cut is on the unfolded edge.) Set the propeller assembly aside.
	Take the remaining 12.7 cm by 10.2 cm card and cut it in half so you have two 12.7 cm by 5.1 cm rectangles. These rectangles will be the propellers.
	Using a drawing compass, pierce a small hole in the center of the rectangles and set them aside momentarily.

	Using the drawing compass, draw two 4.5 cm radius circles in opposite corners of the remaining large note card. These circles will be the back wheels. (Pierce the center of each circle with the compass.)
	Draw two 2.1 cm radius circles in the remaining spaces of the card. These circles are the front wheels. (Pierce the center of each circle with the compass.)
	Carefully cut the circles out.
	If the circles appear to have rough spots or appear uneven, sand them lightly with fine sand paper. Hold the two small wheels together and the two large wheels together as you do this.

	Cut the soda straw in half.
	Set one piece aside--it is the rear axle tube. Cut the remaining tube in half. One of the short tubes is the front axle tube; the other is the propeller shaft tube.
	Cut and straighten a piece of wire to extend 2.0 cm beyond the ends of both sides of the front and rear axle tubes.
	Using a pair of needle nose pliers, bend one end of each wire to form a double L. (See picture)
	Slide the wires through the axle tubes and bend the remaining end into a double L. The axle should have some play in it. If the bends are too close to the straw the axle will not turn.
	Cut and straighten a wire that is 3.0-5.0 cm longer than the propeller shaft tube.
	On one end bend the wire to form a double L. Stick the wire through the tube and bend the remaining end into a hook.

	Slide the ends of the front and rear axles through the holes of the wheels and tape the L to the wheels. Make sure the entire L is through the hole in the wheel.
	Tape the axles to the body tube. The front axle should be 2.0 cm from the front of the body. The back axle should be 6.0-7.0 cm from the back of the car.
	Attach the propeller to the propeller shaft in the same fashion as used for the wheels.
	Tape the shaft to the propeller shaft mount as shown in the picture. Make sure the shaft sticks off the back of the mount before taping it to the mount. (Note: The propeller needs to be attached so it is on the unfolded side of the mount.)
	Tape the propeller shaft mount to rear of the car. The back of the mount and the rear of the body should be flush.
	Pull apart a paper clip so that the two loops form a 30 degree angle. Widen one of the loops slightly and slide it into the front opening of the body tube. This is the front hook for the rubber bands.
	Tie 2 to 3 rubber bands together and attach one end to the front hook and the other end to the propeller hook. The rubber bands should sag considerably before the propeller is wound up.
	Bend opposite ends of the propeller to create pitch. When pitching the blades, remember to bend them in the same direction. Wind the propeller and test the car!