Soda Bottle Rocket Launcher

by NightHawkInLight

100K1.1K85

Intro: 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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64 Comments

ozh 7 years ago

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

jonas4321 8 years ago

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 8 years ago

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 8 years ago

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 8 years ago

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

alexeicharkham 8 years ago

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 8 years ago

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

NightHawkInLight 8 years ago

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.

alexeicharkham 8 years ago

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

AndrewM214 8 years ago

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

psitthipol 8 years ago

Great my kids have a lot of fun with this

psitthipol 8 years ago

Great my kids have a lot of fun with this

psitthipol 8 years ago

Great my kids have a lot of fun with this

alexeicharkham 8 years ago

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

ClintJ1 8 years ago

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

fraser02 8 years ago

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

thanks for sharing.

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