Excited after finding the instructions for making a compressed air rocket on the Internet, I printed the parts list and rushed out to buy everything. I tried Home Depot, Lowe’s, and a local hardware store, but couldn’t find all the needed PVC parts. So, I decided it wasn’t worth starting if I couldn’t finish.
With my thinking cap on and a bottle of cold beer to help free the mind, it occurred to me that a garden hose should work as a pressure chamber. A 20-foot hose of 1/2 inch diameter has about the same internal volume as the 2-inch diameter PVC pressure chamber in the Internet article, and just a few parts would be needed to make it work. It took only a few hours to make, the steps were easy, and the launcher works great.
Also, there’s an easy way to make it shoot wine-bottle corks at targets.
To use the launcher, you pump air into it with a bicycle pump, slide the rocket onto the tube, and quickly open the valve. A paper rocket will shoot over 100 feet up. The basic physics of an air rocket are described on the following website.
The launcher is shown above with four types of rockets beside it (water-bottle, Perrier-bottle, paper, and foam rockets):
This project description is in seven parts:
- Water bottle rockets
- Paper rockets, foam rockets
- Add-on to shoot wine-corks
- Modification to add a pressure gauge to the launcher
- Modification for push-button control of the launcher
Step 1: LAUNCHER
- Garden hose, about 20 feet long
- Car-tire valve
- Hose clamp, size #6 (5/16 inch width, 5/16 to 7/8 inch diameter)
- Plastic riser pipe for sprinkler systems, threaded ends, 1/2 inch diameter, 18 inches long
- Hose adapter, 3/4 inch MH male to 1/2 inch MIP male
- Ball valve, 1/2 inch female ends
- Teflon thread seal plumbing tape
- Bicycle pump and a tire pressure gauge (not shown in photo)
TOOLS (not shown)
- Utility knife
- Leather work gloves
- Pot, water and stove
- 2 adjustable wrenches
- Slot screwdriver
- Cut the male end off the garden hose using the knife. For safety, wear work gloves.
- Pour some water into the pot, about 3 inches deep, and heat it to boiling.
- Wearing a work glove, push the cut end of the hose into the boiling water for maybe half a minute to soften it, and force the fat end of the car-tire valve into the hose. It should go in far enough to have about 3/8 inch of hose past the fat part, for the clamp (see photo).
- Take the plastic riser pipe and wrap teflon plumbing tape around one end. Make sure you wind the tape in the same direction you will be screwing the pipe into the ball valve. Do about 3 or 4 wraps of the tape.
- Screw the riser pipe into the ball valve, in the end where the handle is pointing when the valve is open. Hand-tighten firmly.
- Wrap teflon tape around the smaller end of the hose adapter.
- Screw the hose adapter into the valve. Tighten with adjustable wrenches.
- Do not screw the hose onto the adapter yet.
Step 2: STAND
- Plywood, 1/2 inch thick, 16x16 inches
- Wood 2x4 inch, about 15 inches long
- Wood 1x2 inch, about 6 inches long
- 2 wood screws, size #8, 2 inches long
- 1/4 or 5/16 inch hex-head bolt, 2 3/4 or 3 inches long; metal washer; wing nut
- 2 hose clamps, size #32 (1 1/2 to 2 1/2 inch diameter)
- 4 zip-ties, about 12 inches long
TOOLS (not shown)
- Drill bits: 3/32, 11/64, 1/4 and 5/16 inch
- On the plywood base, measure and mark where to drill holes. (Please refer to the photo shown with the parts.) At the midpoint of each side, make a mark 1/2 inch from the edge and at 2 1/2 inches. In the middle of the plywood, mark 1 1/4 inches from the center in both directions, for the two screws to hold the 2x4 vertically. Measure the end of the 2x4 and mark its outline on the plywood.
- Drill 11/64 inch holes in the middle two marks, and 1/4 inch holes in the eight edge marks. Turn the plywood over and use a 5/16 inch drill gently to countersink the two holes in the middle.
- Take the 2x4 and 1x2. Mark 3/4 inch from one end on each of them, in the middle. (Please refer to the photo shown with the parts.)
- Drill a 1/4 inch hole or 5/16 inch hole, depending on the size of your bolt. I don’t have a drill-press, so I clamped the two pieces of wood in a vice and drilled as straight as I could. Move the drill back and forth a few times to enlarge the hole slightly.
- Push the bolt through the hole in the 1x2. Supporting the wood on something, whack the head of the bolt with a hammer a few times to sink it into the wood slightly. Push the 2x4 onto the bolt, slide the washer on, and screw on the wing nut.
- On the other end of the 2x4, make marks in the end to match the holes in the plywood, and drill 3/32 inch pilot-holes for the screws.
- Place the plywood horizontally (good side up) on supports at both sides, leaving the middle clear. Flow wood glue onto the outline of the 2x4, place the 2x4 there and screw it into place from underneath. Leave it overnight to cure.
- Put the coiled hose on the plywood in such a way that the female end will reach the bottom of the 1x2 easily. Leaving the female end of the hose free for one turn (to have some slack for when the launcher tube is swung horizontally in order to shoot corks at targets), attach with zip-ties through the eight holes, but not very tight yet.
- Take one of the large hose clamps, put it onto the 1x2, put the bottom of the valve in it, check that there’s a washer in the female end of the hose, and attach the hose tightly, holding the valve with a wrench. Tighten the clamp loosely.
- Put the other hose clamp onto the top of the valve and 1x2, and tighten loosely.
- Align the valve handle opposite the 1x2, the clamp tighteners behind the 1x2, and the top of the valve slightly below the end of the 1x2. (Please refer to the photo above.) The clamps should hold the ends of the valve against the 1x2.
- Tighten the clamps.
- Tighten the zip-ties.
- When pumping air into the launcher, it would probably be wise to keep it below about 50 psi. The paper rockets fly more than 100 feet even at 35 psi. The other types of rockets fly less than half as high as the paper ones.
- When launching, the valve should be opened as quickly as possible.
Step 3: WATER BOTTLE ROCKETS
A small water-bottle rocket and a Perrier-bottle rocket are shown in the photo. My Perrier-bottle rocket flew higher than the water-bottle one.
- Plastic water or soda bottles. Perrier bottles have a cool shape, and two are needed to make the rocket shown above.
- For the Perrier bottle rocket: a plastic wine-cork and a small screw: #4, 1/2 inch long
- For the water or soda bottle: a small weight such as a bolt 1 inch long and 1/4 inch diameter
- Thin cardboard
- 3/4 inch clear tape
TOOLS (not shown)
- Utility knife
- Metal straightedge; e.g., a metal ruler
- Cloth or flexible-plastic measuring tape
- Grease pencil or Sharpie
- 3/4 inch clear tape
- For the Perrier bottle rocket: a green Sharpie, screwdriver, drill and 1/8 inch drill bit
STEPS FOR A WATER-BOTTLE OR SODA-BOTTLE ROCKET
- Cut three fins from thin cardboard. For a small water-bottle, cut three rectangles 4 1/2 inches long and 3 1/4 inches wide. Turn the fins good side down, and mark lines lengthwise at these distances from one side: 3/8 and 1 5/8; and 3/8 from the other side. The 1 5/8 line should be right in the middle. Bend the bad side upwards at the middle line, with the aid of a metal straightedge. Bend along the 3/8 lines toward the good side.
- Glue the bent wide sides of each fin together, taking care not to glue the narrow parts.
- Please refer to the photo above. The following instructions may seem more complicated than figuring it out from the photo. Measure and mark 1 3/4 inch from one end along the folded side, and 1/2 inch along the 3/8 part. Mark a line to join these two. Cut along that line and along the 3/8 part, to end up with tabs 1/2 inch long.
- At the other end of the fin, measure and mark 1 1/4 inches along the 3/8 part. Mark a line from the folded end to the mark. Cut along this line and along the 3/8 part, to end up with tabs 1 1/4 inches long. Cut 3/4 inch off these tabs, to end up with 1/2 inch tabs.
- Tape the fins to the open end of the water bottle or soda bottle, taping the tabs first and then along the length. My bottle happened to have a repeating pattern three times around, making it easy to place the fins.
- Tape a weight to the other end. I used a bolt, 1 inch long and 1/4 inch diameter.
STEPS FOR A PERRIER-BOTTLE ROCKET
- Get two plastic Perrier bottles. Cut one partway from the top, such that it will fit nicely onto the bottom of the other bottle. Tape it in place.
- Cut four fins from thin cardboard. For one-liter or one-quart bottles, make the rectangles 6 inches long and 3 3/4 inches wide. I used a green file folder to match the green bottle. Turn the fins good side down, and mark lines lengthwise at these distances from one side: 3/8 and 1 7/8; and 3/8 from the other side. The 1 7/8 line should be right in the middle. Bend the bad side upwards at the middle line, with the aid of a metal straightedge. Bend along the 3/8 lines toward the good side.
- Glue and cut the fins as described in steps 2 to 4 in the water-bottle section above.
- Tape the cloth or flexible-plastic measuring tape temporarily around the uncut bottle, about 6 inches from the open end. Divide the circumference by four and mark where the fins will go, using a grease pencil or a Sharpie.
- Tape the fins to the open end of the bottle, taping the tabs first and then along the length. Tape the fins at a slight angle, so the rocket will spin in flight.
- Drill a 1/8 inch hole about 1/4 inch from the top of the rocket. Use a utility knife to carve one end of a wine-cork into a cone shape. Insert the cork halfway into the top, such that the cone is sticking out, and secure with a small screw. Color the cone of the cork with a green Sharpie.
Step 4: PAPER ROCKETS, FOAM ROCKETS
A paper rocket and a rocket made from 1/2 inch foam pipe insulation are shown above. I used green masking tape for the paper rocket and ordinary duct tape for the foam rocket. The foam rocket is faster to make, but mine flew less than half as high as the paper one, which went over 100 feet with 35 psi pressure.
Instructions for making paper rockets and a template for 8 1/2” x 11” paper are shown on:
The rocket template for 8 1/2” x 14” paper (which can be printed on two 8 1/2” x 11” pages on some printers) on:
Detailed instructions for making paper rockets, as well as a PVC launcher, are shown in several Instructables and also in some projects on http://makezine.com. Search for “air rocket” on either website.
Instructions for foam rockets are on the website shown below. They are faster to make than the paper rockets. The diameter of my 1/2 inch foam pipe insulation was a bit small. Before taping, I had to slide the foam onto the launch tube and place a 3/8 inch foam spacer in the entire length of the gap. It’s important that the foam slides easily on the launch tube. I also found that I had to tape the very bottom of the rocket where the spacer fits into the gap, to prevent air from escaping down during the launching.
There’s an Instructable for making exploding rockets, with a firecracker and a small toy person with a parachute in the nose of a rocket. That’s certainly on my list of things to do.
Step 5: ADD-ON TO SHOOT WINE-CORKS
With the launch tube set at a slightly above-horizontal position, a couple of parts screwed onto the end of the launch tube will allow wine-corks to be shot at targets. Corks vary slightly in size. The best results are with corks that fit snugly in the pipe, but not jammed in tightly.
Various other objects could be shot out of this pipe or other sizes of pipe. Of course, safety is even more important when shooting hard objects or firecrackers.
I couldn’t find plastic parts, only galvanized:
- Reducing coupling 3/4 inch to 1/2 inch
- Pipe (nipple) 3/4 inch, 6 inches long
TOOLS (not shown)
- Teflon plumbing tape
- Wrap teflon plumbing tape around the end of the plastic launch tube. Make sure you wind the tape in the same direction you will be screwing the tube into the coupling. Do about 3 or 4 wraps of the tape.
- Wrap teflon plumbing tape around one end of the pipe.
- Screw the pipe into the coupling and the coupling into the launch tube.
Step 6: MODIFICATION TO ADD a PRESSURE GAUGE TO THE LAUNCHER
If you want to pump the device to a specific air pressure, you could use a pump with a built-in pressure gauge, or use a small car-tire pressure gauge, or attach a gauge to the launcher as described here.
- Pressure gauge with a female hose connector (found in the sprinkler system section of the plumbing department)
- Hose Y adapter (found in the hose section of the gardening department)
- When assembling the launcher, attach the Y adapter between the hose and hose adapter that is connected to the valve. No teflon tape is needed; the female connectors should all have washers in them.
- Attach the pressure gauge to the remaining outlet of the Y adapter.
Step 7: MODIFICATION FOR PUSH-BUTTON CONTROL OF THE LAUNCHER
An impressive way to launch rockets is to include an electric valve and a remote control push-button switch, as described below. Electric sprinkler valves typically operate on 24 volts AC, but will work on about 12 to 18 volts DC if the voltage is applied for a only short time to avoid burning it out.
An even more impressive method is to use an electronic infra-red remote switch connected to the wires instead of a push-button. It will open the electric valve when you click a TV remote control from some distance away. Some electronic hobby shops sell such a gadget or a kit to make one. There are also several websites that show the circuit for this gadget if you Google “IR remote switch.” This method is not described here.
- 3/4 inch automatic inline valve for sprinkler systems
- Hose adapter, 3/4 inch MH male to 3/4 inch MIP male
- Adapter (also called a bushing), 3/4 inch MIP male to 1/2 inch FIP female
- Two 9-volt batteries (not shown)
- Two clips for 9-volt batteries (not shown)
- Paired wire, 10 feet long (speaker wire or lamp cord) (not shown)
- Push-button momentary switch (not shown)
- Electrical tape (not shown)
TOOLS (not shown)
- Wire cutter & stripper
- Soldering iron, solder (optional)
- Fine sandpaper
- The automatic inline valve replaces the ball valve. Wrap teflon plumbing tape around the male ends of the adapters. Screw the male end of the hose adapter into the “in” side of the inline valve. Screw the other adapter into the “out” side.
- Remove the launch tube from the launcher and screw it into the 1/2 inch female adapter.
- Loosen the two hose clamps on the launcher, remove the ball valve, replace it with the inline valve, and attach the hose to it. Tighten the hose clamps.
- Strip about 1/2 inch of insulation from each end of both wires in the paired wire, and from the wires on the inline valve if not already stripped. Sandpaper all the stripped wires lightly. If you would like to see photos of these steps, please look on the following website: http://makezine.com/projects/make-compressed-air-... The website also includes a handle for the switch, which I decided not to make.
- Connect one end of the paired wire to the switch. Some switches have a screw connection; others may need to have the wires twisted around the terminals. Solder the twisted connection if you have a soldering iron.
- Connect the other end of one of the paired wire to one wire of the inline valve, by twisting the wires and soldering if possible. Wrap with electrical tape.
- Connect the black wire of one battery clip to the red wire of the other battery clip. Connect one of the free wires of the battery clips to the remaining free end of the paired wire. Connect the remaining free wire of the battery clips to the remaining free wire of the inline valve. Solder all the connections if possible, and wrap with electrical tape.
- Tape the wires to the 2x4. You may want to tape the batteries there also.
- Test the connections by pressing the switch momentarily. The inline valve should click.
This was a fun project to make, and the grandkids enjoy launching rockets and shooting corks.