Instructables

Paper and soda bottle rocket launcher

Picture of paper and soda bottle rocket launcher
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This is a simple and inexpensive alternative to estes rockets. I wanted to do something to allow my kids to play with model rockets, my concerns were that estes rocket motors are highly flamable and the kids could only play with them if my wife or I were around. Another factor was the cost. The smallest Estes motors run about $5 for 3 motors, not a lot of fun with a yard full of kids.

We made a paper rocket launcher that used compressed air. This meant that rockets were cheap (1 piece of paper for the body and part of a piece for the fins) and safe. After several weeks of playing with the paper rockets one of the kids grabbed a soda bottle and stuck it on the launch tube and the rest is history. For hot summer fun soda bottles and water make this a real blast of wet wild fun.
 
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Step 1: The parts list

Picture of The parts list
1 - 1" inline sprinkler valve
2 - 2" PVC pipe 18" long
1 - 1/2" PVC pipe 18" long
4 - 1" PVC Pipe 2" long
2 - 2" PVC Elbow
2 - 2"X1" PVC reducer
1 - 1" PVC T
2 - 1" slip to 1" Male Thread PVC fitting
1 - 1/2" slip to 1/2" male thread PVC fitting
PVC Glue

Lauch handle parts list
1 - 1.5" PVC pipe 4" long
2 - 1.5" PVC Cap
6' 2 conductor 18 or 20 AWG wire
1 - Momentary switch
1 - 9v battery connector
1 - 9v battery

Total cost around $40
DanTDM1 month ago

Use a QEV and steel pipe.

DanTDM1 month ago

Never use PVC pipe. Use galvanized or copper pipe (black iron works too) and use a manual gas ball valve with a handle.

-copper tube-3 months ago

Use a modified sprinkler valve for faster opening.

Love this project! I made a slight change to the paper rockets. I used 8 1/2 x 11 card stock for the body and 3/16 foam board for the fins. I cut it with a standard box knife and attached the fins with wood glue. For the nose cone I took 1" poplar dowel rod cut to 2 1/2" long and turned it on a wood lathe. I used the wood glue to attach the nose cone also. The rockets balance nicely and weigh 1 oz total. We shot the first one a dozen times so far, it flies great and lands undamaged. Lands straight on it's nose every time, as you can see from the grass stains! I made a little fixture out of the leftover launch tube to help glue the fins on straight. I misread the instructions and used plastic wrap (food wrap) on the tube I use to roll the rocket bodies. About 6 turns worked great! I used 3" PVC for the reservoir, but only because I had some left over from a previous project. I added a gauge and cut a groove for an o-ring so we can launch water bottles too. On mine, I had to put two 9v batteries in series because one 9v would only work up to 25 psi. With two, it operates quite a bit higher. We made a clinometer also so we could estimate the maximum altitude.
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profgizmo2 years ago
there are several variations of this. Makezine has instructions at http://blog.makezine.com/archive/2008/12/compressed-air-rocket.html

And Kipkay has instructions at http://www.youtube.com/watch?v=eNFfK5uo6D0
I bult this instructable awhile ago. Recently the piece from the sprinkler valve to the holding tanks gave way while it was pressurized. I think the cause of this is because that same piece is really long, so whenever it launches it moves up and down alot. Thought I'd let you know. MonkeyBoy
JimKelleher3 years ago
I built a similar launcher for paper rockets. We use 8.5 x 11 copy paper for the rocket body and nosecone and card stock for the fins. We stuff the nosecone with a half of a paper napkin so it holds up better to the landings. I've tested launches from 10 psi to 70 psi in 10 lb increments and found 30 to 40 psi to be the best. My launch tubes have threaded fittings on them so I can change them out easily. I have 1/2" and 3/4" X 18" and 38" versions. Best performance seems to come with 1/2" X 11" body tubes at 30 to 40 psi. A rocket made with 36" wrapping paper launched at 40 psi makes an impressive sight going up but crumples when it lands. Also, I use 3@9V batteries in the launcher and after hundreds of launches the original set is still going strong. One more thing, I used a compressor during testing, but a bicycle pump when the kids are building and launching. Gives them some feedback when they are supplying the 'energy' for the flight.
ghostWolf595 years ago
I have just built this according to your instructions - Unfortunately I don't have a compressor so I had to rely on a bike pump - and as such I am buggered if I can get enough pressure to make the bottle fly high. Seem that the pressure not is released all in one hit - feels almost like the valve could be to blame. I have used a off the shelf mainstream valve suitable for retic. Any suggestions - or is it that I simply cant provide enough pressure using a bike pump ? Difficult to say how much pressure I have, but its gets really heavy to pump after a while so I guess the pressure have built up. I have also made sure the valve is aimed in the correct directions as well as made sure there is no leaks. Would appreciate any suggestions - Dont have the $$$ to buy a compressor though
davemcp (author)  ghostWolf593 years ago

We have had other people use this design with the bike pump and it has worked fine in it's current configuration.  You could use larger diameter pipe for the accumulator legs or jus make them longer if you wish.  If your valve seems to be opening slow or incomplettely you could add a second nine volt in series with the one on the plans giving you 18v to open the valve.  This should give you a good solid voltage to open the valves.  Most sprikler systems work on 24v so this could really help.

Dave
 If I'm understanding this thing correctly, the bigger pipe is serving as an air reservoir of sorts, so that when the valve is opened the air is released all at once into the launch tube. I'm thinking that with a hand pump, the volume of the reservoir is not enough. with the compressor, it's tanks supply the air with plenty of volume. You could add an additional tank to correct it. Maybe you could connect a hose from your spare tire to serve as additional air storage on the cheap.
davemcp (author)  ghostWolf594 years ago
Another suggestion I have received is to add a second 9v battery making the valve open better. Dave
I've seen both used before. You get more exercise from the bike pump :-) I'm just never sure about the psi. Maybe I can find a meter that I can put between my pump and the luncher.
davemcp (author)  ghostWolf595 years ago
You can use a bike pump, My guess is that the valve is the problem. You may want to open it up to make sure that there are no obstructions. You could test it by taking it over to a tire store/garage and borrowing their compressor to test. Dave
DJDeegee4 years ago
Does every Bottle rocket launcher use sprinkler parts. I just cant seem to find a single easy rocket launcer without all the awesome proffesional stuff..
TOCO DJDeegee4 years ago
try this launcher. I am building it tomorrow. I built a rough version today.
archimeech4 years ago
Thanks for the Instructable, nice job.  I'm curious about what your paper rockets looked like?  Any shots of some of the simpler ones the kids made, and what was the range at 30-40 psi?
davemcp (author)  archimeech4 years ago
We just use normal 8.5" X 11" paper or construction paper to build our rockets.  if you put a piece of shrink wrap tubing over a piece of 1/2" PVC it makes a great form to ROLL your rockets.  There is also a site where you can buy them premade or buy nose cones or whatever you need.  It is not my website and I am in no way affiliated with the owner of the site.
Http://www.itsablast.com
and yes the rockets take 30-40 psi without too much problem.  if you roll your rockets to 8.5" length instead of the 11" length we have had some take 60 psi or so.  They really go at that pressure.  But remember increased pressure means increased risk.  I know someone will put the presure way up there and I am not responsible for damage or injury.  I only recommend using 30-40 psi.  Anything higher you do at your own risk.

Dave
davemcp (author) 4 years ago
I have not had any problems with using a single 9v battery but you could try using 2 in series connet the + terminal of the first battery to one lead of the sprinkler valve, connect the - lead to the + lead of the second battery and the - lead of the second battery to the other lead to the sprinkler valve. If this still doesn't work pull the solenoid on the sprinkler valve and make sure that it it pulling in the plunger when you hit the button.
thedolb4 years ago
a 9 volt battery wont trigger the valve. am i doing something wrong
carl87gt4 years ago
Here's mine (picture is before I glued it all up). I actually added a another bend upward right before the sprinkler valve. I have a screw on end cap with the tire valve on it. This is so I can replace the end cap to one with a compressor when a compressor is available. My son, neighborhood kids, nieces, and nephews have been having a blast with this!
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Wouldn't the wires get wet when the water came out of the bottle
yes and . . . water doesn't hurt wires. Won't make any difference when running the low current from a 9 volt battery.
kgunmaker4 years ago
how much did it cost?
davemcp (author)  kgunmaker4 years ago
I believe the total cost was somewhere around $30-$40. If you build two it drops your per unit cost to around $25. --Dave
Here are the pictures!
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P.S. I know the launcher looks like a bomb. Better not bring that to school! lol MonkeyBoy3217
Wow this is a great Instructable! it should win an award! Well my Dad and I are making this because I got bored one and made a rocket, but I don't have a launcher so we are building one. we have everything but the barrel and the 1in to 1/2in male piece. because it wasn't on the list. ill post some pics soon MonkeyBoy3217
ihart5 years ago
Thanks for this Instructable! I just built this with my kids and it worked great. I thought I would add some feedback: 1) I think a part is missing from your parts list. The elbow below the launch tube doesn't seem to be there. 2) I ended up using 2 - 9V batteries. I detached the solenoid above the valve and noticed that it pulled in weakly or not at all with 1 9V battery. With 2 in series, I got 18 Volts and it slammed in strongly. 3) I learned a trick for the launch tube watching a PBS This old house episode with a bottle launcher. The trick is to use a lighter to swell the launch tube so the bottle will fit snugly on the tube. Just spin the tube while holding a lighter below it and it will swell at that point. With the bottle fitting more snugly, you get more pressure at launch. You can see a darker spot on the tube in my picture where it is widened. Thanks again!
maxpower495 years ago
about how much was everything
.....fun but still can be dangerous if you are close enough to get hit or if it falls over/etc........I would still advise adult supervision.....
davemcp (author)  explosivemaker5 years ago
It is always a good idea to supervise children any time compressed air is used. I don't allow the kids to turn the regulator above ~30 psi. Which keeps the danger low. Be Safe and have fun.
bmichaelis5 years ago
How did you get the 24V sprinkler valve to fire off of a 9V battery? I have the whole thing built, but the only sprinkler valves I can find are 24V and they don't fire on a 9V battery.
davemcp (author)  bmichaelis5 years ago
I have only ever used the 24v sprikler valves and have never had a problem with them not working. test the solenoid by holding one wire to the 9V pasitive and brushing the other against the negative, you should hear a soft click. If you do your valve is working, if you don't, try a new 9v battery.
Nice addition with the sprinkler valve. I always use quarter turn valves.
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Mr. Rig It5 years ago
Cool little project.
davemcp (author)  Mr. Rig It5 years ago
Thanks, We have had a lot of fun with it over the past 3-4 years.
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