Our knowledge of physics principles tells us that a projectile will follow a path like this:

In actual practice, the rockets experience drag, caused by air resistance. The force of drag acts in the opposite direction to the rocket's motion, changing its path. This plays a large part in the shape and design of the rocket's fins.

The wind's velocity and direction also have a large influence on the flight path of the rockets.

Is the launch angle important?... YES, it governs both distance and height a rocket will attain. In physics, the distance a projectile travels is referred to as the range. A launch angle of 45 degrees maximizes the range (see the figure below). When a projectile is launched, it has both a vertical velocity and a horizontal velocity.

(NOTE: If the wind velocity is high and coming from behind, then the rocket may go further if the angle is increased above 45 degrees. If the velocity of the wind is high and is coming from the direction of launch, an angle less than 45 degrees may maximize the distance.)

Examples of the theoretical trajectories for four different launch angles are shown below:

• 3 sheets of 8.5" x 11" paper
• Thin cardboard for fins
• 1 bottle of white glue
• 1 piece of 3/4" PVC about a foot long

What you need:

1. First you must find a flat surface to work on.
2. The only tools that are needed are one piece of doweling or PVC pipe with a 3/4" diameter, glue, scissors and regular 8.5" x 11" paper.

How to build it:

1. THE BODY: Lay out one piece of paper.
2. Spread glue on half of the paper. Roll the paper into a tube, starting at the end with no glue. Keep the paper tight and roll slowly to ensure that no wrinkles or air bubbles appear in your tube. Be sure that the paper does not stick to the doweling.



3. Place a small bead of glue along the final seam to ensure that it is completely sealed. Remove the doweling.
4. THE NOSE CONE: Cut out a circle at least 10 cm in diameter. Cut a slit along a radial line (see pattern below).



5. Holding one end of the circle, wrap the paper around your finger to form a nose cone shape. Glue the last flap down and seal the seam.



6. THE FINS: This requires some design and experimentation with regards to the shape, size, placement, and number of fins to make. Here are some examples:



7. The fins must be evenly spaced out around the tube. To measure the circumference of the tube use this formula: Circumference = diameter x 3.14, or use a ruler and a piece of string.
8. Divide the circumference by the number of fins to be placed. Mark out the fin positions, starting with the first fin on the seam of the rocket. (HINT: Three fins seem to work the best as they keep the rocket straight and weigh less than four or five fins.)



9. FIN ATTACHMENT: Replace the doweling to aid in attaching the fins. Dip the edge of a fin in glue and place it on the marked fin position on the body tube. Press down firmly into the body tube (with doweling inside) for about 15 to 30 seconds to set the fin in place.
10. NOSE CONE ATTACHMENT: Place the nose cone upside down inside the body tube. Mark the nose cone around the top edge of the body tube.



11. Trim the nose cone to where it is marked.
12. Place a bead of glue inside the TOP of the body tube with your finger.
13. Stick the nose cone up through the BOTTOM of the body tube, pushing it along with a thin piece of doweling. Once at the top position, carefully let it dry in place.



14. Coat the rocket with glue to stiffen the body tube. It is not necessary to coat the fins with glue. Let the glue dry overnight.
15. HINT: It is recommended that you re-coat your rocket several times in order to achieve a thick, solid coat of glue. This will make the rocket almost like plastic when it is dry. If this step is done correctly, the rocket should easily hold the 120 pounds of pressure used during the launching.

NOTE: This project takes several days to complete. For example, the rockets are made on day one and are coated with glue, which must be left to dry overnight. The next day a second coat of glue is applied to the rockets. When dry, the rockets are decorated and launched.