Introduction: Soda Bottle Water Rocket

Picture of Soda Bottle Water Rocket

In a couple of hours (or less) you could make this water rocket! Water rockets use water and pressurized air to launch a soda bottle(s) 100's of feet into the air. This instructable will NOT cover the launcher. I hope to later come back and write up an instructable for a launcher. There are many websites with water rocket plans (and launchers) part of the fun is to experiment and come up with your own designs. Feel free to modify, improve, experiment with this instructable and post your results in the comments. The original inspiration for this rocket was from the magazine called "MAKE Magazine" (makezine.com). Issue #5 has full instructions also.

Step 1: Materials

Picture of Materials

List O Materials...

> 2 Soda Bottles (empty)
- Note: There are slight differences in the openings of the bottle depending on the soda brand. Pepsi is just a tad smaller than Coke. -
This Instructable is set up for 2 liter sized bottles - feel free to adjust for any size though.

> 1 sharp knife (kids get your parents help here!) I prefer X-acto brand for cutting foam core.

> 1 Large sheet of Foam Core (I prefer Black, but any color will do). Foam Core can be found at almost any arts and crafts supply store. To learn more about foam core try wikipedia: http://en.wikipedia.org/wiki/Foamcore

> 5 Min Epoxy (This stuff is nasty! Do not inhale, and use in a well ventilated area. Do NOT get it on your skin or eyes, or hair, etc... read all safety warnings before using.) Feel free to experiment with other glues. This can usually be found at any hardware store - kids, ask your parents for help with this glue.

> 2 (or more) Markers - I used Sharpies, one black and one Silver

> Clear Shipping Tape - It's thicker than regular scotch tape and about 2" wide.

> 2 (or more) cans of spray paint - Pick your own favorite colors!

Step 2: Step One - Cut Bottle

Picture of Step One - Cut Bottle

Peel all labels off of the bottles.
Measure up from the bottle about a Third and cut the bottle. Try to keep your cut line as straight as possible. It may help to mark a straight line around the bottle first. Be sure to recycle or reuse any scrap pieces.

Step 3: Bottle Merge

Picture of Bottle Merge

Take the cut bottle from the previous step and insert it directly over the bottom of the other bottle - this becomes the nose cone of the rocket. Try your best to keep everything straight. If you put the nose on crooked, your rocket will fly crooked. Place the nose cone on loosely at first, then gently press down until firm. Turn bottle upside down and let it drop on a hard surface several times. If you press the nose cone on too hard, you'll start to get "crinkles" in the plastic. Crinkles are bad.

Step 4: Tape Bottles Together

Picture of Tape Bottles Together

Once the nose cone is on tight (but not too tight) use the clear shipping tape to tape the seams. Try to keep tape smooth.

Step 5: Cut the Fins

Picture of Cut the Fins

Next you gotta cut some fins to keep your rocket flying straight. I will attempt to upload a PDF file here, so that you can use it as a template. I used a Pepsi bottle, so again, you may need to adjust the curves to fit your bottle. Kids - this is the step that you will need your parents help. Parents... cutting foam core can be tricky. The key is to cut one time all the way through in a smooth motion. You'll need to press hard to make sure the knife is all the way through the foam core. If you feel more comfortable using a utility knife by all means. Be Careful!

Please! Experiment with your own fin designs. I chose a more squared off design, but you can use curves if you like, etc... I chose 3 fins. You'll need a minimum of 3, no more than 4 (unless you really really want to!). If you do 3, you need to split your bottle into 3rds, which equals 120 degrees. I'll try to upload a second PDF file with a 120 degree template. 4 fins, you'll just need 90 degrees.

Step 6: Fin Supports

Picture of Fin Supports

This step may not be needed, but I figured better safe than sorry...
Using some of the scrap pieces of foam core, I cut 6 small triangles. (approx 1" x 1.5"). These will be added to your fins later for extra support.

Step 7: Attaching the Fins

Picture of Attaching the Fins

Ok, this is the tricky part. Open your adhesive (or glue of your choice). Squeeze out a small amount (enough to do one fin). Mix the epoxy with a scrap piece of foam core (this will be your "brush" too). PRE-Mark your bottle (with the marker) where you want your fins to line up. Make sure the fins fit your bottle BEFORE putting any glue on them. Trim, or adjust if needed. Apply the Epoxy to your fin, and attach it to the bottle. WARNING: This step requires patience! 5 minutes is a LONG time. If you can figure out a way of setting up some clamps, more power to ya. While holding the fin, don't let it shift... you will be able to move and adjust the fin while the epoxy is drying, but once it starts to set, it gets difficult to adjust. You'll feel it start to set. Once it gets to the point where you can't really adjust it anymore, you can place the bottles and fin, on the table to set without holding it.
Prepare your next "glob" of glue for the next fin. REPEAT for all of your fins.

Step 8: Glue Your Fin Supports

Picture of Glue Your Fin Supports

This is the added step for extra support. Glob out another dab of Epoxy and glue your triangle to the bottle and the fin. Glue the Supports on each side of each fin. Wait approx 10-15 minutes to be sure Epoxy has set.

Guess what... Your done all of the assembly at this point!!
You could take this rocket to the launcher at this stage and let it rip!
BUT... it's kinda messy looking isn't it?
One more step...

Step 9: Paint and Details

Picture of Paint and Details

This is where the spray paint comes in.
I used BLACK and a Bright Green so that the rocket would be easy to spot while up in the air!
Decorate your rocket any way you like! Flames, spots, checkers, glitter, etc...
Use your extra markers to add any fine details or words (I put H20 on mine so everyone would know this is a water rocket). Add some pin stripes, etc...

(note: as you can see from this photo, I also added some additional tape to the fins for extra support. Do this BEFORE painting.)

Perhaps, I should have mentioned this before, but this rocket has no parachute! What goes up, must come down.
WORDS OF CAUTION:
DO NOT launch this rocket near people, a crowd, small animals, streets or cars or houses... in other words... take your rocket out to the middle of nowhere and launch it in a safe place. Make sure everyone knows there is no parachute and that this rocket will be crashing to earth at a high rate of speed. I wouldn't want to get hit by it! The rocket will probably fly higher and farther than you think.

Step 10: Links and Video

Here are some additional links that may help...
http://www.youtube.com/watch?v=kRUt5I-pNuU
Youtube video of my rocket and a group of others from the MAKE:PHILLY Bar-B-Que. (I'll try to embed this video also).

Links:
http://www.MakePhilly.com/
http://www.water-rockets.com/
http://en.wikipedia.org/wiki/Water_Rockets
http://makezine.com/05/rocket/

Zine:
Make Magazine - Issue #5

Video:


Comments

thomasl264 (author)2017-10-12

can this bottle rocket stay in the air for more than a minute or two

cyenobite (author)thomasl2642017-10-23

Did you watch the video at the end? You can see exactly how long these water rockets fly.

Mystery_Kid (author)2017-09-30

Can this hold an egg?

brs2 (author)Mystery_Kid2017-10-23

It can, but its flight will be shortened a bit

Mystery_Kid (author)Mystery_Kid2017-09-30

not to rush or anything but I need an answer before tuesday... launch day is on wednesday

cool_girl10 (author)2017-06-01

About how many feet up in the air will this type of rocket fly?

cyenobite (author)cool_girl102017-06-12

Not sure exactly, but if you watched the video you should be able to see it went higher than the oak tree(s).

TandemDwarf3410 made it! (author)2017-06-11

took more than an hour, but great instructions! Here's mine:

Looks Cool! Thanks for posting!

ksau6038 (author)2017-05-05

can this be launched on a launch pad or nah?

democnptn426 (author)2017-04-23

That seems like a pretty fancy launchpad you guys had there! Do you have any instructions for those (especially how to set it up so you can trigger from afar)?

LakenT1 (author)2016-02-11

I have to make a rocket for my 7th grade project, would a water rocket be a good choice?

PranavA14 (author)LakenT12016-11-04

Same Question, Same Grade

eddyred (author)2016-05-18

for extra power you can use a heavier liquid which has a greater density than water, like syrup or you can use carbonated water which is easier to pressurize so faster launches

CriderA (author)eddyred2016-09-14

really

it does how high does it go

CriderA (author)2016-09-14

hi how do make a bottle rocket

dahlias8799 (author)2015-06-04

Hello, this is a really cool rocket design. I wanted to know how far it travels because I have to make one for a school project and we are graded on the distance. Thanks so much!

ipodsie (author)dahlias87992016-08-03

the design is stable and honest. to extend distance traveled try using a more dense liquid, syrup(s), or a liquid that already has a noticable amount of gas dissolved in it like sparkling or carbonated water as they do partially(sort of) compress when pressurized. water is an easily available and stable liquid and even dissolving stuff in it like different salts could effect the distance traveled(hint, hint) but it is something you should experiment with yeah? kero syrups, different waters etc try lots of stuff. also make sure the cap is on rocket nose and possibly sand or abrate the lip that catches the cap. anything that might effect the aero-dynamics even use some of the stiff foam to make a cone( cone would be better than pyramid) and cover the top part of the rocket. foam is good because it is light, you could use a heavier material like balsa wood or the like but remember weight is not your friend if you want to go the distance

SpARkS A (author)2016-02-08

how many mil. water do you put in it

1XxaveryxX1 (author)SpARkS A2016-05-12

1 liter

BexiLee (author)2016-04-28

Can I launch this rocket on a dry launcher (without water)?

dondon12345 (author)2016-03-21

Thanks for the design it really helped me

HamsterP (author)2015-10-25

are the soda bottles 1 liter bottles?

Lanetron (author)HamsterP2016-01-05

the are 2 liter bottles

Erika Rich (author)2015-12-02

Is there a video to this? So I can see how much pressure the rocket is?

Lanetron (author)Erika Rich2016-01-05

You should probably use 45-60 psi

soldiersweeney2 (author)2015-11-18

that is an awsame idea! i Love rockets

lol

TheKandiKidPLUR. (author)2015-10-31

what exact foam core did you use?

HamsterP (author)2015-10-22

how do you keep the cut in the middle so air-tigh?

HamsterP (author)HamsterP2015-10-25

It makes so much sense now! I cut the bottom of each bottle ant tried to tape them together.

cyenobite (author)HamsterP2015-10-22

If I understand you "Hamster" :)
the cut in the middle is mostly for just the way the rocket looks. It's to put the second soda bottle over-top of the "primary" soda bottle. This gives the rocket some extra length.
ALL of the pressure is stored in only the First Soda Bottle.
Hope that made sense.

Hamsterplays (author)2015-10-16

Does this rocket work if you use vinegar and baking soda instead of water pressure?

cyenobite (author)Hamsterplays2015-10-16

Hmm, I'm going to say "maybe"... I'm not sure what sort of pressure can build up by the reaction of the vinegar and baking soda. When we launched these (almost 10 years ago!) I think we were pumping up the internal pressure to around 70 or 80psi (if memory serves).
Sorry I can't give you a better answer.
Try it - and post your results!

HamsterP (author)cyenobite2015-10-21

thanks

kevinw15 (author)2015-06-10

yes

jamesisamazing (author)kevinw152015-09-15

thanks great idea

Dk1213 (author)2015-05-31

Can I add a parachute on this and if so how?

There are lots of ways you can attach a parachute to a water rocket. I would recommend something like an air flap or timer system, or if you're willing to spend some money, a flight computer or magnetic apogee detector.

Here is a very reliable timer based version:https://www.youtube.com/watch?v=bVpJqoHQBm0

Here is a magnetic apogee detector version:http://www.aircommandrockets.com/construction_7.htm

another one: http://www.uswaterrockets.com/documents/LaunchPad_AlTImeter/manual.htm

he is actually right that's a couple of wayz

Flashdance5 (author)Dk12132015-07-11

yes u can and I will make an instruct able in about a month on how so keep posted!

cyenobite (author)Dk12132015-05-31

You can try. I didn't feel the need, as it is fairly durable (unless it crashes onto pavement or hard dirt, the nose might get caved in, but with mine, I just pulled it, and the nose popped back fine. You can *not* tape the nose portion of the rocket to the main body, and loosely attach it (with tape and string) to the body, then the parachute could be stored in that loose nose section. In theory, when it hits the apex, the nose will 'fall' off and the parachute will deploy. I won't guarantee this will be a good plan. But feel free to experiment. If it works, please post back here and let us know! Good luck!

Flashdance5 (author)2015-07-11

guyz I made the rocket don't have pic because I used a launcher and it broke cause it went really high.

Simo245 (author)2015-06-17

GhostWolf76 (author)2015-06-12

pics of my soda bottle water rocket i made for 2 of my nephews. tried to make it look like Iron Man

cyenobite (author)GhostWolf762015-06-12

Looks Great! Always cool to see photos!

GhostWolf76 (author)2015-06-09

hey cyenobite, i was wondering what type of tape did you use to give extra support for the fins before you painted the rocket?

cyenobite (author)GhostWolf762015-06-10

hi ghostwolf76, I actually did not use any tape at all when it came to the fins. I just glued them on using the epoxy, and they I added the small triangles for the extra support (also epoxy). The only place I used the shipping tape was to seal the one bottle top onto the other bottle. Hope that helps.

GhostWolf76 (author)cyenobite2015-06-10

it step 9 it shows the tape and you said you put tape for extra support on the fins before you painted it.

cyenobite (author)GhostWolf762015-06-10

Oops sorry, you are correct. (I built this almost 7 years ago! :)
If memory serves, I just used the same shipping tape, cut into smaller pieces. I think the shipping tape was good and strong, and didn't stretch much (like masking tape or duct tape would be too flexible). Hope this helps. Good Luck!

GhostWolf76 (author)cyenobite2015-06-10

ah thanks. i used electrical tape but as soon as i painted over it, the edges and corners curled up lol

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