Design 20: ROCKET PROJECT
Name _________________
Date __________________
It suddenly struck me that
that tiny pea, pretty and
blue, was the Earth. I put
up my thumb and shut
one eye, and my thumb
blotted out the planet
Earth. I didn't feel like a
giant. I felt very, very
small.
-Neil Armstrong
Introduction:
Design, speed, acceleration, gravity, wind…..we mix it all up in this project with a 2-liter
pop bottle. Once we fill it half way with water and take it up to 30 psi….it will fly
through the air (perhaps…). Our task on this project is to test how to make a bottle fly
through the air. What do you think it will need to fly smoothly through the air; weight
(ballast), fins, paint??? And return to Earth safely with an egg-o-naut aboard.
The Project:
The rocket project is a time to gather together to make something happen. This is a
project to launch your egg-o-naut into the air and get it into the air higher, farther, longer,
and return home safely. We will view a test launch (you can look on the WWW for this),
plan and construct a rocket, and then launch.
Expectations:
Each participant will plan, design, launch, a rocket made from one or two plastic 2-L
soda bottles. Do not become emotionally attached to your invention as it might not look
the same after a launch. An uncooked egg will be tucked into the rocket and checked for
survival upon landing.
Materials:
Each student will need to collect 2 or 3, 2L "Coke/Pepsi" bottles
(these are the only ones that will fit the launcher), some duct tape,
an uncooked egg (make it look cool), parachute material, and fin
material.
Awards:
Points will be awarded for the following categories:
Rocket Design and Integrity, Rocket Craftsmanship, Flight Characteristics, Height of
Flight, Time of Flight, Egg-o-naut survival
Helpful Information:
Try this web site to test fly your rocket before you begin your design:
http://www.ag.ohio-state.edu/~rockets/index.html
Some sample launches and images of designs:
http://www.mrwaynesclass.com/ProjectWaterRocket/index.html
CONSTRUCTION BEGINS:
Task
1. Build a water bottle rocket.
2. The body of the rocket must consist of 2 liter soda bottles.
3. The rocket must have fins, a nose cone, and a parachute.
Fins

Fins should be firm: if they flop around they are useless

Fins should be adequately secured: duct tape works ok, PL premium construction
adhesive is best, but it takes hours to harden, so the fins must be held in place
with a fixture.

The best fins are made of hollow plastic street advertising sign material (like
election placards). Plastic, old cd's may work for fins, cardboard may also be
used.
Nose cone

The nose cone must have a higher mass to surface area ratio than the body of the
rocket. The nose cone must go through the air easier than the body of the rocket.
4. All energy put into the rocket must originate from the water/air pressure
combination.
5. Timing of the rocket stops when the first part of the rocket hits the ground or
when the rocket disappears from sight or when the rocket impacts or gets
entangled in an object.
6. All rockets will be launched at a pressure not to exceed 80 pounds per square
inch.
7. See drawings and diagrams on the next pages to help with construction.
DETAILS OF CONSTRUCTION:
Egg-o-naut
Details of Construction
Rocket with parachute and egg-o-naut
Rocket with parachute
and egg-o-naut
1. MAIN BODY/PRESSURE CHAMBER
The main part of your rocket is the body or PRESSURE CHAMBER.
We will be using a 2 liter bottle for our project. Almost any 2 liter bottle
will work, however, some bottles have a mouth or opening (nozzle) that
is too large to accommodate the launch tube. The launch apparatus only
fills and holds one type of 2 liter bottle.
Please use Coke 2-L bottles, other brands do not fit the launcher.
Peel the label off your bottle and try to clean the glue residue the best that you can. Be
careful not to use hot water on the bottle because it might shrink the sides and deform the
bottle.
Don't use any knives or sharp instruments when cleaning your bottle. Even the smallest
of scratches or cuts in the pressure chamber can result in an explosion. Besides the risk of
physical injury, an exploded rocket will not fly.
Some people have tried to use chemical solvents to remove the glue residue on the bottle.
This might alter the walls of the bottle and make them too brittle or soft. Therefore we
don't recommend it.
After cleaning
When launching, the tremendous pressure inside the bottle will cause the
walls to expand. This expansion leads to a loss of energy and will make for a
lack luster performance. To solve this problem take some wide strapping tape
(the best), packing tape, or duct tape and pre-wrap the center of the pressure
chamber. One and a half times around should do the trick. You don't want the
tape to be too bulky and watch for wrinkles. This will strengthen the walls of
the bottle without adding too much mass and launch altitude will increase
overall.
2. Nose Cones
Nose cones and fins are not only for performance but add character and style to your
rocket. Be sure to take some time thinking out the design of your rocket before
committing to a plan of action.
Here are several types of nose cones and the methods used to make them. These are only
a few examples, so don't be afraid to be creative. The fins have been removed, in the
illustrations below, for clarity.
A cardboard nose cone is the easiest to make but lacks flight stability. The cone
is made from poster board or tag board. You can make the cone by simply
cutting a large circle out of the poster board (about a 6 inch radius). Cut a line
from the outer edge of the circle to the center on the radius.
Overlap the cut edges and turn the circle while holding one edge
stationary until you get the desired cone shape. Secure the cone
with staples or tape. Attach to the bottle with tape or similar
adhesive.
Overall this nose cone lacks flight stability. This can be fixed by
pressing a small lump of clay inside of the nose cone (we’ll place
our egg-o-naut here). This will add mass to the cone and keep
your rocket from flipping end-over-end while in flight. Dress the
nose cone to be more aerodynamic.
The "Bertha Series" nose cones are easy to make as well but require a little attention to
detail. The "Bertha" nose cones are made by cutting the bottom off a spare bottle and
attaching the top portion onto the pressure chamber. One strip of tape should be enough
to hold the cone on. (Note: Never cut the pressure chamber) Using this method you
can even make your "Bertha" rocket two or three nose cones tall! Within one of these
bottles you can add your egg-o-naut. Pay attention to keep all the cones in a straight line.
A curvy rocket will not be safe coming off the launcher.
3. Fins
Fins are the guidance system for your rocket. Without them a rocket would tumble end
over end. Fins can give your rocket life and beauty. Fins can portray aggressive power or
aerodynamic grace. However, fins tend to be the single greatest downfall of many young
rocket builders. With the incredible speeds and frightful acceleration generated at launch,
many fins get ripped off the rocket body within a fraction of a second
Materials: (remember lightweight but sturdy)
Hollow plastic message board, (used to advertise elections on street corners) THIS
IS THE BEST MATERIAL AND WORKS BEST WHEN USED WITH PL
PREMIUM ADHESIVE
Index cards
Clear packing tape
Cardboard (cheap, plentiful, soggy when wet)
Gray cardboard (cereal boxes)
Foam core (a little tougher but more $, some water damage)
Sturdi-board (like plastic cardboard, great stuff, $$, no water damage)
Balsa wood (might be a little heavy, fragile on impact)
Styrofoam sheets* (cheap, low mass, fragile on impact, use PL Premium Construction
adhesive)
How many fins do I need?
To ensure stability and safety, the minimum number of fins on a rocket is three (3). Many
people choose a 3 or 4 fin design. There is no maximum number of fins you may have
but keep in mind that the more fins you have the more drag you will create and drag
slows a rocket down.
Constructing fins
1. Be creative and cut out 3 or 4 identical fins. You can use any shape.
2. Lay the fin on a flat surface.
3. Glue and/or tape an index card onto the side of the
fin. Be sure to leave a one-inch tab on the index card.
You will later bend this tab out 90 degrees to make an
attachable area for the rocket.
4. Repeat the same for the other side of the fin.
5. Repeat with other fins.
You should now have 3 or 4 fins each with two-index card tabs on the backside.
Fin placement
The fins of your rocket can't be placed above the halfway point of your pressure cylinder.
You want to place your fins at the base of the rocket to lower or maintain the center of
gravity. If you were to place the fins above the center of gravity, the rocket would tumble
and spin out of control once it left the launch pad.
Attaching the fins
1. Apply a piece of tape to the index card tabs and then carefully tape
them to your rocket.
2. Look at your fin. Make sure it doesn't curve or it isn't crooked. It
should be in a direct line with the body of your rocket. If it isn't
perfect, take it off and try again.
3. Attach the other fins. If you are using 4 fins they should be at 90degree angles. 3 fins should be at 120-degree angles.
4. Test the wiggle of the fins. Your fins shouldn't wiggle more than a
few centimeters from side to side. Adding more tape to the top and
bottom areas of the fin might fix this problem.
NOTE – The fins must be very very rigid and have no movement
on the rocket. If the fins are flexible or if they are not securely
attached, the rocket will not fly straight.
4. Parachute Systems
By now you may have spent several hours building the rocket of your dreams. It may not
be completely obvious to you yet, but as the old saying goes, what goes up... must come
down. It's time to think about safe recovery of your egg-o-naut. Here are a few ideas to
get you started. Note: you may substitute "crepe paper streamers" for "parachute" in most
of the following examples.
Let's make a parachute. Here is a list of materials:
Tall kitchen garbage bag -orFour-grocery plastic bags
Kite string -orYarn
Baby Powder
Scotch Tape
The size and shape of your parachute can be as varied as your rocket. A good rule of
thumb is to make your chute about 12 inches across. Your chute could be larger but some
rocket styles have narrow nosecones and the chute could get stuck.
Making the Chute
Carefully cut the garbage bag along one side and the bottom seam. Open the bag along
the fold and lay it flat.
The Square Chute
The simplest chute to make is the "Square
Chute". Prepare the edges, where you will
connect the strings, with scotch tape grommets.
First apply a piece of tape to both sides of the
plastic. Then, with a HOLE PUNCH, punch a
clean hole through the center of the tape and
plastic tab. Repeat this procedure for each
location where you are placing a string.
the "Square Chute", measure two 24of string and tie each end to one of the
holes. Bring the centers of the string
together and tie them off.
To complete
inch lengths
grommet
loops
Folding the Chute
Dust the chute with baby powder to ensure that it doesn't stick to the side of the rocket
or itself. Grab the chute between two fingers, in the center, and pull it up toward the
ceiling. Let the chute fold naturally as you lift it. Once you have the chute pulled up,
fold it once in half at the center. You don't want to fold the chute too tightly but you can
fold your chute into thirds if space is a factor. Wrap the excess string loosely around the
chute.
Making an Extension
If you find that the chute area is too small to hold your
parachute, you can increase the size of container by adding
a section of another 2-L bottle around the girth of the
bottle. Remove the top and bottom of the 2nd 2-liter bottle
and tape the new cylinder into position. This tends to make
your rocket more stable by increasing the distance between
the Center of Pressure and the Center of Gravity.
The "Bertha Cone Chute" (3 out of 5 Stars)
the egg-o-naut inside and
the pressure cylinder. In
apogee (the highest point of
separates from the main body.
drag to slow down and
everything works, the
pieces float gently back down
With this chute system, instead of
taping the nose cone on, attach a
safety cord to the nose cone with
attach the parachute to the top of
theory, once the rocket reaches
travel), the weighted nose cone
The main body is creating enough
separate from the nose cone. If
parachute deploys and the two
to earth.
In practice, the nose cone can
main body causing a failure.
short and the cone can't clear
sometimes get jammed on the
In addition, safety cord can be too
the body.
Web sites with water rocket information:

http://www.h2orocket.com/

http://www.geocities.com/nolesen2001/

http://bradcalv.customer.netspace.net.au/wrbook.htm

Check YouTube out also.