How to Build a Bottle Rocket
By Caitlin Wayne
Rules
- No metal parts anywhere on the rocket
- The Body of the rocket must be made from soda bottles (not water or juice) 2-Liter or less in size
- Nosecones and fins can be made of cardboard, plastic, styrofoam, or other material
- No commercial or pre-made parachutes allowed
- Rockets parts may separate during flight, but must remain attached together
- Completed rockets must weigh less than 300 g
- All rockets will be launched with the same air pressure: 75 p.s.i.
- No supplemental forms of energy for launch will be allowed
- Rockets will be timed from the moment of launch until it hits the ground, falls out of sight, or becomes stuck in a tree, powerline, etc.
Suplies
- (2) 2 litter bottle (intended for carbonated drink)
- cardboard box (cereal box, granola bar box, etc.)
- electrical tape
- (1) garbage bag
- scissors
- hole puncher
- fishing wire
- spray paint (optional)
- baby powder (optional)
Main Steps
The Fins
To make the fins I made a triangle with a height of 10 cm and a length of 7 cm. Then, cut it out and trace 2 more. Next, fold over 1 centimeter on the height of the fin to make a flap so it is easier to tape to the bottle. Now, apply electrical tape to the outside edges of the fin. Finally, tape upside down to the top of the main bottle so that when flipped launch, it will be facing right side up.
The Parachute
To make the parachute we took a medium sized garbage bag and cut it in half. Then, we cut it into a circle with a diameter of 71 centimeters and a smaller hole in the middle of the parachute with a diameter of 8 centimeters. Next, we used a hole puncher to make four holes on the outer edge of the parachute and then tying about a yard of fish wire to each hole. After that, we tied all four strings together and used electrical tape to tape them to the the top of the main body of the rocket.
The Body
To make the body of the rocket we took one of the 2 liter bottles and made a small incision right below where the bottle curves for the spout. Next, use scissors and cut of the spout part of the bottle and tape it to the bottom of the rocket. Then, place the modified bottle on top of the main bottle. Finally, use the hole puncher and make a hole on the open end of the modified bottle and tie the fishing wire through the hole and tape it to the bottom of the main bottle.
Folding the parachute
First, you fold the parachute in half so it is a semi-circle. Next, fold it in half again so it is a quarter circle. Then, fold it in half again so it looks like a slice of pie, the 1/8 the original size. Now, straighten it up and fold down into thirds. Finally, put the strings to the side and place it inside the modified bottle and the modified bottle on top the main bottle.
Center of mass
To have the rocket have center of mass we took four quarter sized balls and put them in the nose of the modified rocket. We wanted our rocket to be nose heavy so it would fly straighter.
Baby Powder
Apply baby powder to the inside of the modified bottle and on the parachute to ensure that the parachute doesn't stick to the inside of the rocket or itself.
Decorations
This is an optional part. What we did was spray paint our bottle. If you decide to do this just make sure you do not get any paint below where it starts curving for the nozzle. If you want you can also decorate your rocket with duct tape, sharpies, stickers, etc.
Our Finished Result
When Hailey and I were done, this is what our rocket looked like. We did two launches and our flight times were 6.97 and 8.19 seconds. To launch we filled the body of the rocket about 1/3 way full and then the rest with pressurized air.
Our Flight
Caitlin and Hailey's launch