Step 1: What You Need.
You will need the following items.
2- 3" PVC pipe 15" long
3- 3" PVC Clean outs with caps
1- 1/2 12" long plastic threaded pipe
1- 3" PVC pipe cap
1- 3" PVC pipe coupler
1- 2" PVC 90 degree
1- 14" piece of 1/4" copper tubing
1- primer bulb
1- on / off / on momentary switch or off / on momentary if you use a piezo igniter.
1- coil , condenser , relay or piezo igniter.
1- 12 volt portable air compressor
1- can PVC glue
1- roll solder
1- small tank for gas 1/2 to 2 oz
1- small one way valve
1- pressure gauge minimum 50 PSI (air pump may include gauge and air T ) .
1- air T
1- 4 feet tubing 3/8 OD 1/4 ID for air
1- 4 foot small gas tubing that will fit in the big tubing , the smaller the better.
1- 4 foot spark plug wire
1 7.2 to 12 volt stick pack battery, available at hobby shops.
Step 2: Introduction to Assembly
You will need various other parts: Super glue, wire, battery connectors, nuts and bolts,etc.
If you decide to build this project you may need to improvise on various parts and construction.
All the parts I used may not be available to you, or you may have a better idea about how to construct this project . Either way , you need some building skills and good old fashioned rigging. good luck.
WARNING :this project has the potential to be dangerous as you will be igniting compressed gasoline vapor and using a high voltage coil which could result in shock. If you make this gas powered soda bottle rocket, please use your head ,wear safety glasses and protect your hearing.
I have shot the rockets for years and have yet to get hurt, but if you're careless , someone could easily get hurt.
Step 3: Construction: Step 1
Glue both clean out caps on the pipes
Make sure they're pressed on all the way.
DO NOT glue the other caps on yet.
Step 4: 2
Drill a small hole through both the clean out fittings .
Make sure the fittings are lined up and you don't drill where the caps thread in.
Bolt the two sides; together finger tight , you will have to loosen it later.
Step 5: 3
Place the front caps on the pipe. You may have to shorten the capped bottom pipe by an inch to make it easy enough to remove. Lay the pipes on their sides on a level surface and drill a hole for a nut and bolt. Make sure the hole is as far forward as possible. You have to glue the bolt in the bottom cap.
After the framing is done, bolt or screw the bottom cap on.
Do Not Glue The Cap - You may need to fix it later.
Step 6: 4
Make sure the two pipes are bolted together. With a hole saw drill a 2" hole in the back of the top pipe. Make sure that you have clearance for the elbow pipe.
After the hole is drilled, glue the elbow pipe in.
Step 7: 5
Remove the air pump from its housing.
Step 8: 6
Place the air pump in the front of the bottom pipe; you may have to cut a hole for the air pump head in the PVC pipe if it won't fit. The air line should run out the back of the bottom PVC pipe. The power wires should run out the front.
Step 9: 7
If you're using a piezo igniter you can skip step 8 and 9. Note: piezo igniters don't work as well as a coil.
You will need a coil that will fit in the PVC pipe; a motorcycle coil will work best.
Step 10: 8
Place the coil in front of the air pump. The high voltage lead/ spark plug wire should run out the back. The low voltage wires should run out the front.
Step 11: 9
Relay and all wiring in front hooked up according to chart 1.
If you're using a piezo igniter you don't use a relay.
The relay is used to make continuous spark.
Step 12: 10
Drill 3 holes about 2" apart for pressure gauge, switch and primer bulb.
If your using a piezo igniter drill a another hole for it.
Make sure you have room in the pipe where you're drilling.
Step 13: 11
Fuel tank: you need to find a fuel tank small enough to fit in the PVC pipe.
I used a small 1/2 oz car vacuum chamber.
1/2 oz will give you about 40 to 50 shots.
Step 14: 12
Install your fuel tank wherever you have room.
Remember you have to fit a battery in later.
You should have your coil and air compressor wiring coming out the back of the bottom PVC pipe.
Depending upon where your fuel tank is mounted now might be a good time to install it. Make sure you have a way to fill it.
Step 15: 13
Install gauge, switch, primer bulb and, if used, piezo igniter.
It may be easier to wire up the switch before installing it. The same goes for the gauge and primer bulb.
Step 16: 14
Due to how different the parts you may be using are, you're on your own on this step .
The main goal is to run the fuel and the ground line through the air line to the launcher.
Make sure you run the ground, fuel and air line 3 feet.
One end of the tee goes to the gauge the other two go to the pump and launcher.
Note: go heavy on the super glue!
Step 17: 15
Drill two holes in the bottom back clean out , one for the air line the other for the spark plug wire.
The other line is for filling the gas tank.
Step 18: 16
Install wiring according to chart 1.
Connect the one way valve to the fuel line entering the air line. The other end goes to the primer bulb output.
The primer bulb input comes from the bottom of the gas tank.
All the grounds and negatives are shared.
Leave room for the battery.
Step 19: 17
Cut the copper tubing about Â½ " longer than the 1/2 " plastic pipe, about 12.5 "
You can solder a barb fitting on the copper pipe for the hose, but keep the length at 12.5 "
Solder the igniter end closed (refer to chart 2). Put a small pin hole in the copper tubing right below the solder.
The black mark is how far the fuel line comes up in the copper air line.
Step 20: 18
Drill a hole in one of the caps so that the pipe can thread into.
Make sure it is centered, then glue it.
Step 21: 19
You can use less than 3 feet (2.5 feet should work) of the tubing and spark plug wire. Just make sure you have enough to unscrew the launcher with a bottle on it.
Run the fuel line up through the copper tube about 2.5 " from the top.
Connect the air line to the bottom of the copper tube. You have to cut some of the air line to do this (refer to chart 2.)
Cut the ground line the same length as the air line. Splice the wire and connect it to the copper tube.
Run the spark plug wire along the copper tube stopping about 1 1/4 " from the top
Glue the spark plug wire to the copper tube. Insert a piece of piano wire in the center of the spark plug wire sticking out about 1 1/4 " . Put a small bend at the top towards the copper tube. After all measurements are made, glue the air line to the copper tube with super glue.
Step 22: 20
Put the copper tube and spark plug wire through the 1/2 " plastic pipe.
The copper pipe should stick out about 1/2 "
Fill the end with hot glue.
Step 23: 21
Put a bottle in the PVC pipe to hold the 1/2 " pipe straight while the glue dries.
Step 24: 22
Use a hose clamp as a stopper for your bottle so it does not hit the igniter.
Step 25: 23 IMPORTANT !!!
Wipe super glue around the base of the launcher starting at the pipe clamp going up about 1.5" , LET IT DRY then check the fit of the bottle in the glued area. It should fit fairly tight and when tested with air pressure it should come off with about 50 PSI, the idea is to keep the bottle in place while being pressurized to 35 PSI. When it is fired the pressure will well exceed 50 PSI and the bottle will release. DO NOT GLUE THE BOTTLE ON THE PIPE !!!!!!
If the bottle is too tight it may explode when fired. If the bottle does explode, most of the time, it just blows the front of the bottle off with a loud bang. If it fails to fire DO NOT GET IN FRONT OF THE BARREL. Wait a few minutes and unscrew the back and remove the bottle.
Step 26: Fire !
1. Make sure there is no bottle on the launcher.
2. Fill the gas tank by turning it up side down putting the filling hose in gas and pumping the
primer bulb until all the air is out of the line and gas starts to run out of the copper tube.
3. Make sure you don't have a bottle on the launcher.
4. Run the air pump to expel any excess gas from the vaporizer assembly.
5. Now you can put the bottle on the launch tube and press down until it hits the stopper.
6. Press the primer bulb 1/2 pump you should see the fuel run into the vaporizer tubes.
7. Turn the compressor on and pressurize the bottle
to 25-35 psi.
8. Any higher is at your own risk.
10. Repeat 4-7
11. IF it does not fire, don't get in front of the
launcher. Wait a few minutes, then unscrew the launch
tube and remove and replace the bottle
(the bottle may be flooded)
Try putting a few ounces of water in the bottle, this will give you a nice boost.
You can also shoot this from the hip if you feel confident enough after a few firings,
I don't however advise shooting from your shoulder unless you devise some facial
Shielding, or other protection.
Step 27: Tray
The bottles don't carry too far (due to their weight) but they're not supposed to, the object on the front (water balloon, etc) is the payload.
You have to make a launching tray out of another soda bottle just chop the bottom off about 1/4 up.
You can also put water in the rocket bottle (about 1/4 full) for some extra kick.
Do not fire objects over 6 oz.
Wear safety glasses and ear plugs.
And Most Of All Use Your Head!!
Think about where you are and who is around when you decide to start firing!!!
Step 28: Chart 3
Step 29: Chart 1
Step 30: Chart 2