paper and soda bottle rocket launcher

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.

Step 1 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

Comments

[profgizmo]

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

[MonkeyBoy3217]

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

[JimKelleher]

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.

[ghostWolf59]

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]

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

[heathbar64]

 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]

Another suggestion I have received is to add a second 9v battery making the valve open better. Dave

[BigMac96]

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]

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

[DJDeegee]

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]

try this launcher. I am building it tomorrow. I built a rough version today.

[archimeech]

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]

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]

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.

[thedolb]

a 9 volt battery wont trigger the valve. am i doing something wrong

[carl87gt]

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!

[rock climber]

Wouldn't the wires get wet when the water came out of the bottle

[carl87gt]

yes and . . . water doesn't hurt wires. Won't make any difference when running the low current from a 9 volt battery.

[kgunmaker]

how much did it cost?

[davemcp]

I believe the total cost was somewhere around $30-$40. If you build two it drops your per unit cost to around $25. --Dave

[MonkeyBoy3217]

Here are the pictures!

[MonkeyBoy3217]

P.S. I know the launcher looks like a bomb. Better not bring that to school! lol MonkeyBoy3217

[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

[ihart]

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!

[maxpower49]

about how much was everything

[explosivemaker]

.....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]

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.

[bmichaelis]

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]

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.

[pleasedontspamme]

Nice addition with the sprinkler valve. I always use quarter turn valves.
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[Mr. Rig It]

Cool little project.

[davemcp]

Thanks, We have had a lot of fun with it over the past 3-4 years.