Introduction: Soda Bottle Rocket Launcher

Picture of Soda Bottle Rocket Launcher

Some of you that have followed me for a while might recognize this project as an upgraded version of my water bottle rocket launcher, seen in this video. While the old design was the cause of quite a few singed arm hairs, this new model is much more pleasant to use due to the new blast shield as well as the distance from the rockets that has been achieved by having the igniter on a longer leash. Even so, safety glasses are a required precaution, just in case.

I recently participated in leading some science based activities for grade school aged kids and these bottle launchers were a big hit. The kids had a lot of fun attaching craft foam fins onto the bottles with duct tape and hot glue. The launchers themselves only take about 20 minutes to put together, so it's a quick and easy project that offers a ton of entertainment.

The rockets are fueled by the combustion of rubbing alcohol, which is ignited by the spark from a barbecue igniter. I used rubbing alcohol with a concentration of about 90% in the video, but any concentration of 70% or greater should work just as well. When fueling the bottles, the most important step as shown in the video is to whip the last drops of liquid alcohol out the open end. This brings the fuel/air mixture to the proper level for a good combustion, and reduces the liquid alcohol particles expelled from the rocket upon launch that otherwise could melt the plastic blast shield or cause minor burns.

A neat trick I did not mention in the video is that once the bottles have been fueled, rather than pushing them onto the launcher the cap can be put back on the bottle to have it ready to fire later.

Parts for this project:

  • (x2) 1.5' x 3/4" PVC Pipe
  • (x2) 10" x 3/4" PVC Pipe
  • 3' x 1/2" PVC Pipe
  • 3/4" x 3/4" x 1/2" PVC Tee
  • (x2) 3/4" PVC Elbow
  • Push Button Barbecue Igniter
  • Extra Wire (about the same diameter as the wires on the igniter)
  • Solder & Heat Shrink Tubing or Electrical Tape
  • Paper
  • Hot Glue
  • Duct Tape
  • 2 Liter Soda Bottle
  • Safety Glasses & Hearing Protection!

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Comments

SammyDale made it! (author)2016-07-07

I made mine with the joystick type igniter button and it works pretty good. My 6 year old grandson loves shooting the launcher. We hot glued fins and a pointed nose on some bottles and it's a fun activity for my grandson and me. I tried both kinds of alcohol and it seems like it works better with less alcohol and more air mixture. If it doesn't fire, I just wave it around more or blow into it and then it fires. Does anybody have a suggestion for something that will provide more spark? I just can't get a good big spark out of mine. Also, I think I know the answer but would gasoline be dangerous and blow up?

Very cool setup with the joystick. For something that provides more spark you could use an 'arc lighter' or a weak stun gun and wire that into the leads. But then of course a stray shock would be more painful than from the BBQ igniter. Too much to entrust to a 6 year old. Gasoline would be a poor idea. I haven't found a fuel that works better than rubbing alcohol.

Thanks - I think I might just keep it the way it is and maybe try the spray bottle suggestion for measuring the alcohol a little better. It seems like when it doesn't fire the first time it's either because the wires are touching (grandson bumps them when loading another bottle) or because the air/fuel mixture is too rich. I'm trying to remember if their was some kind of spark igniter for the solid rockets my kids launched when they were kids. It is a great instructable that doesn't take a lot of skill to build and yields a lot of fun for kids from 6 to 60.

ProjectPlace made it! (author)2014-08-20

Great Instructable. I loved it.

I made a modification to your original design. Instead of having the igniter hanging lose, I added a three piece coupler to the main launch tube. I then added a small piece of pvc to the middle couple and then added a 90 degree elbow to the end of the small piece of pvc. Finally, I added a piece of pvc, that was long enough for the igniter to fit into, to the end of the open couple in the 90 degree elbow.

This mod created a sort-of joystick with the top button being the igniter button.

This allowed for a more stable launch as I had full control over the main launch tube.

Again, great Instructable!!! Thanks.

Btw, I voted for all three of the contests you are entered into.

Awesome mod! That looks sweet. I thought about doing something similar in my video but decided to keep it as simple as possible and leave the modding up to others. Glad to see you took up the challenge! The rockets are working well for you?

Thanks for the votes!

The rockets are great!! I'm getting a good 75 feet distance (with fins angled so the bottle spins and a nosecone) when launched at about a 45 degree angle with minimal alcohol, so it isn't as loud and scary. I don't want the neighbors to get too nervous when I launch :)

Another mod idea that the mathematically inclined might find useful, is a protractor at the bottom so an angle of elevation can be determined.

Thanks for the great tutorial!

Lumberjck (author)2017-02-07

Nice!

grumpyrich made it! (author)2016-08-21

This is mine: frame's made from some pallet offcuts that support a tube with the cable running up it.

Needs a coat of paint and a more cunning way of changing the elevation than "a wood chock" - but it works

Worth mentioning that it doesn't half bang when it launches - my other half came belting out of the house when I first fired it wondering what I'd done. The video seems to suggest a nice pedestrian "phhutt" as it fires... It wasn't. :o)

ozh (author)2016-05-29

Awesome and simple stuff, great to make with kids. Thanks a ton :)

jonas4321 (author)2016-04-20

More experimentation, some of this might help those that have not been able to achieve consistent ignition.

I switched to 100% ethanol and it made a huge difference. Until the sun went down and the temps dipped into the 50's. Then I was not getting any ignition even with the ethanol!

Turns out that the bottle needs some warmth to vaporize the alcohol. Putting 20oz bottles inside my jacket under my armpit did the trick, but what was even more effective was holding the bottle next to the exhaust of my car - that warmed things up nicely and I was back to booming 100% of the time.

Another "ah-ha" was that 2L bottles are MUCH more energetic than 16- or 20-oz bottles. LOTS more. Bigger bang, flew farther.

Also, nighttime launching SHOULD be done - there's a really cool flash of light as the bottle launches. No vapor trail, but a nice glow at ignition. Will be taping some glow bracelets to some bottles for nighttime fun! Just gotta remember the warm-the-bottle trick at night.

Lastly, I can get multiple launches from a single fueling if I squeeze and release the bottle after the first launch to get some more oxygen into the bottle. With 16/20oz bottles, I get one free launch; with 2L bottles, I get 2 free launches. Just need to remember to add warmth as needed.

Thank you again for this really fun design!

jonas4321 (author)2016-04-19

After many attempts with 70% and 91% rubbing alcohol, I switched to 100% ethanol and BOOM!!! Works Every. Single. Time. We just happened to have some in the shop at work. I'll be trying denatured alcohol tonight.

This is a GREAT Instructable, thank you!!!!

alexeicharkham (author)2016-04-11

Hi all. I've made this now, but to my great disappointment it doesn't work. I tried changing the bottles, adding more/less alcohol, etc.

Did anyone have a similar problem and resolve it, please??

alexeicharkham (author)2016-04-06

Hi there. It was this one, but you don't need to spend so much as you don't need the wire (just any electrical wire seems to work)

http://www.ebay.co.uk/itm/381541690186?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

That'll do you...spot on. Good luck with it and enjoy the little shocks you get before you learn how to get it right ;)

alexeicharkham (author)2016-04-05

Hi NightHawk

I'm trying to make this and have bought a piezo spark thing. It comes with a single wire which doesn't spark at the end (but gives a small electric shock). I can vaguely see that you have two wires, with one fitted on the side of the device.

Do I want to solder one wire on the end, and a second one through the gap in the side?

Thanks very muchly,

Alexei

Yes, you should have one wire coming out of the end, and there should also be a metal part higher up the igniter. If you bring the bottom wire close to the metal part a spark should jump between them when you press the button. I wouldn't solder the wires on as it might damage the igniter. I would try holding them on with tape or a crimp.

Great...thanks so much. I seem to have it now...much appreciated!

Alexei, may I ask which piezo starter you purchased? I am pretty novice when it comes to DIY.

psitthipol (author)2016-04-04

Great my kids have a lot of fun with this

psitthipol (author)2016-04-04

Great my kids have a lot of fun with this

psitthipol (author)2016-04-04

Great my kids have a lot of fun with this

alexeicharkham (author)2016-04-03

Fantastically explained...I am going to try this. Thank you

ClintJ1 (author)2016-04-03

This was very nicely done. Going to make one right away. Can you share what software you used to created your YouTube video with?

NightHawkInLight (author)ClintJ12016-04-03

I use Sony Vegas

BrookeJ6 made it! (author)2016-04-02

I tried it but I guess my ignitor is not up to par because I got a small spark but never enough to ignite and shoot off the rocket. Total buzz kill on a Saturday after ramping up my son on this project. So how strong does the ignitor need to be?

fraser02 (author)2016-03-28

very cool... about how far does it go?

thanks for sharing.

Paul-soars_JR (author)2016-03-16

C.j.'s saying it's great

Paul-soars_JR (author)2016-03-16

This worked great!

Paul-soars_JR (author)2016-03-16

Most of my rockets in Minecraft didn't work as great as yours(this is because they just kept blowing up!This works WAY better then paper airplanes, too)!

#Paul' s best friend (because i'm great at building big things that is beautiful!Subscribed from masters)

lava_man made it! (author)2016-03-11

Recently I have been making rockets of my own, but not as good as these!My first rocket made from your instructions was horrible but on my brothers' laptop I saw he was doing his successfully. Confused, I tried again, and it worked great!

antech (author)2015-10-26

jk

nice project for teaching kids.... for my project

antech (author)2015-10-26

jk

nice project for teaching kids.... for my project

KyleTheCreator (author)2014-08-18

Cool! The blast shield is a great upgrade to the bottle launcher. Do you think that the distance could be improved by shooting the bottles out of a PVC mortar tube?

Thanks for sharing,
KTC

You're getting into the basic idea of one of my upcoming projects...But to answer your question, no, not really. The range of the bottles isn't increased by a significant amount by adding an exterior barrel. At least not with a short barrel which is all I've tried.

@NightHawkInLight: Is the 'upcoming project' something you have uploaded to Instructables yet or no? I know this was 7 months ago, but just curious :)

Your 'ibles are amazing by the way.

Yep, this is it: https://www.instructables.com/id/Make-A-Bottle-Rocket-Mortar-Launcher/

Ah there it is, thank you!

Am I missing something? I have bought 3 BBQ lighters and after half a dozen lights they stop working.

Sorry to hear you're having issues. Are the wires getting cut into by the blast shield? If the insulation gets cut through the spark will just jump across the cut rather than between the gap inside the bottles. The igniters should last for a long time.

JohnM48 made it! (author)2015-02-14

Have you tried using a spray bottle for adding the alcohol? I've tried this with the 91% alcohol you get at the grocery store and it works great. One or two sprays is the right amount. I also reconfigured the piping to form more of a bazooka, and the switch fits nicely inside a PVC cross.

lambdamechanic (author)2014-12-30

We tried this with a few friends i used my own design similar to yours but i hadnt got pvc pipes so i changed the design and used a hard hose. I took apart a bbq lighter and got the piezoelectric generator. Then put it in the hose. We didnt have any rubbing alcohol and used deodorant as fuel.We had a great spark but it didnt ignite. After a lot of times we got it to ignite but it just created a fireball and left me with a 2nd degree burn on my finger. Damn it hurts a lot. whatever i know that fuel to air ratio is the problem but how can we find the needed amount. Great project BTW. here is how it looka if it matters.

I use rubbing alcohol because the fuel/air ratio pretty much takes care of itself. If you're using deodorant you're going to have to find it by trial and error.

mhausler (author)2014-08-22

where did you find those BBQ ignitors?

lambdamechanic (author)mhausler2014-12-30

You can take apart a lighter and get the piezoelectric generator then solder it with some wires to increase the lengh

MattT6 (author)2014-10-18

Great instructable - FYI - this doesn't work with smaller-sized 16-oz water bottles (or I'm doing something wrong) - got a good spark but no launch. I'd be interested if anyone has had success with the smaller 16-oz bottles.

NightHawkInLight (author)MattT62014-10-18

The size of the bottle doesn't really matter. I'm using small bottles in the video also. The two things that can go wrong are the fuel mixture and the spark. You've either got too much or too little fuel, or the spark isn't hot enough and the gap needs to be adjusted or the wires shortened.

MattT6 (author)NightHawkInLight2014-10-19

Thanks for the quick reply.

I've tried adjusting both the gap and the mixture with no luck. Guess I'll try shortening the wires next.

MattT6 (author)MattT62014-10-20

Still no luck, so I'm clearly doing something wrong here.

I put about a teaspoon of 91% isopropyl alcohol in a 16-oz water bottle, shook it vigorously for about 2 minutes, then put it on the launcher only to watch it sit there while I mutter to myself clicking away on the igniter button.

I even tried igniting it using a lighter wand, and it did ignite, but burned slowly and melted the bottle without the "pop" I see in your video, which indicates to me that there's an issue with my fuel/air mixture.

Just can't seem to get it to work!

NightHawkInLight (author)MattT62014-10-20

Use more alcohol like I do in the video then pour the excess out afterwards. You should only need to shake it for 5 seconds or less. Remember to shake out the excess alcohol, which should again only take 5 seconds.

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Bio: I like turning boring things into awesome things! Usually on video.
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