Read an Excerpt
Soda-Pop Rockets
20 Sensational Projects to Make from Plastic Bottles
By Paul Jarvis Chicago Review Press Incorporated
Copyright © 2009 Ivy Press Limited
All rights reserved.
ISBN: 978-1-55652-960-3
CHAPTER 1
PART 1
ROCKET BASICS
This section takes you through a few straightforward rocket designs and shows you how to build two sorts of launcher: one very simple and one sturdy enough to take even the heaviest and most ambitious models from the second and third sections of the book.
Unless you're already a seasoned rocket engineer, try the most basic rocket first. Not only is it easy and quick to make, but it can also achieve surprisingly impressive results at the firing range. Then build your skills and confidence by adding the features that will make your creations look more like real rockets: fins, nose cones, and even a working parachute.
1.1 A BASIC
ROCKET AND LAUNCHER
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This starter project is made with a simple improvised launcher that guarantees fast and satisfying results. When you have successfully fired your first rocket, you can try a slightly more elaborate setup using the heavy-duty launcher described in project 1.3 (see pages 22–25).
You will need:
• 2-liter plastic soda-pop bottle
• Duct tape
• Scissors
• Pliers
• Inner tube from a bicycle tire
• Cable tie
• Two wire clothes hangers
• Ball of strong string
• Bicycle pump. A pressure gauge is useful but not essential.
1. Cut the valve stem off the inner tube, cutting it as close to the tube as possible. Cut a strip 1 inch (2.5 cm) wide and 24 inches (61 cm) long from the remainder of the inner tube.
2. To make the stopper for the bottle, wrap the strip of rubber from the inner tube tightly around the valve stem until it is the correct size to stop the opening of the soda-pop bottle; it should fit it very snugly. Cut off any excess rubber and secure the rolled stopper with a cable tie. Wrap a layer of duct tape around the stopper. This will improve the seal and make it easier to insert into the bottle opening.
3. Fill the bottle so that it is from one-third to one-half full with water and stop the mouth with the wrapped valve.
4. To make the stand, take a wire clothes hanger and bend it as shown in the diagram. Carefully measure lengths A and B. Length A allows the trigger (see step 5) to fit neatly over the rim of the soda-pop bottle, and length B is the exact distance between the rim of the bottle and the top of the rubber wrapped around the valve. The legs of the stand should about 8 inches (20 cm) long.
5. To make the trigger, straighten out a length of wire approximately 12 inches (30 cm) long from the second clothes hanger and cut it with pliers. Bend it to create a U shape that fits around the neck of the bottle, but under the loops of the stand. Tie a length of string about 13 feet (4 m) long to the center of the trigger's rounded end.
To Set Up the Stand
Push the stand into soft ground. Place the bottle in the stand with the valve pointing downward through the loop in the stand. Hold the bottle steady with one hand, then push the trigger into the stand so that it is wedged between the top of the stand and the rim of the neck of the bottle. This will prevent the rocket from launching prematurely while air is being pumped into it.
To Prepare for Launch
Attach the bicycle pump to the valve and pump air into the rocket. If you have a pressure gauge, a pressure of about 60 psi (pounds per square inch) works well. If you don't have a gauge, you will need to experiment to find the optimum pressure. Keep a record of the number of pumps that were used to pressurize before a flight, and then try repeat flights with more or fewer pumps to find the optimum pressure for each rocket.
To Launch Your Rocket
Now that your bottle is pressurized, you are ready to fire. Stand clear and pull sharply the string that is connected to the trigger to release the rocket. When the trigger is released, the pressure inside the bottle forces the stopper out of the neck of the bottle, leaving the stopper behind as your rocket launches into the air.
1.2 A ROCKET WITH FINS
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Three sleek fins will not only make your rocket look smarter, they will also help to stabilize it in flight. The model shown here has fins of the classic 1950s-style triangular type, but you can modify the designs according to taste–you'll find another variation to inspire you on pages 44–45. We've used the basic rocket described on pages 10–13 as the foundation for this project. You'll find the fin template on page 108.
You will need:
• 2-liter plastic soda-pop bottle
• Epoxy glue
• Heavyweight scissors or craft knife
• Cutting mat
• Soft pencil–2B is ideal
• Tape measure
• Sheet of thin cardstock, 8 × 11 inches (20 × 28 cm)
• Sheet of thin, flexible plastic, 11½ × 16½ inches (29 × 42 cm)-you can find this in hobby or craft stores
• Modeling clay (you'll need a piece the size of a golf ball or a little smaller)
• Either the launcher and the bottle stopper from project 1.1 (see pages 10–13) or the launcher from project 1.3 (see pages 22–25), and a bicycle pump, ideally with a pressure gauge. You will also need access to a photocopier.
1. In this project you'll be adding fins to a basic bottle rocket like the one you made in project 1.1. The fins must be added before you fill the rocket and insert its stopper.
2. Enlarge the fin template on page 108 to scale onto the thin cardstock, using a photocopier. Cut out the fin shape carefully with scissors or a craft knife. Draw around the cardstock template on the flexible plastic sheet. Repeat twice so that you have the outlines for three fins.
3. Cut around the outlines with scissors or a craft knife. If you are using a craft knife, do your cutting on a cutting mat.
4. Cut the slits on the fins, as shown on the template.
5. Fold three tabs going one way and three going the other on each fin.
6. Make three marks an equal distance apart around the circumference of your bottle, about 2 inches (5 cm) up from the neck where the body of the bottle is straight. Divide the circumference by three and mark it into equal thirds with a pencil.
7. Using epoxy glue, stick the first fin in place. The lowest tab should be stuck about ½ inch (13 mm) above the neck, where the body of the bottle is straight. When the first fin is stuck down, place the other two in position on the pencil marks you made in step 6 and glue them down. Prop up your rocket with books until the glue is dry.
8. After the glue has dried, fill and stop your bottle as shown in project 1.1 (see pages 10–13). Before launching the rocket, soften a ball of modeling clay about the size of a golf ball in your hands, and mold it to the top of the rocket (the base of the bottle), so that its weight is evenly distributed. This will help to balance your rocket and will encourage it to fly straighter.
To Launch Your Rocket
Although you can use the launcher found in the next project (1.3), this rocket is also light enough to work well with the more basic model you used to launch your first creation. Just push the wire into the ground, fill the bottle halfway with water, and seal the mouth with the stopper. Place your rocket on the launcher, secure with the wire trigger, pressurize, and fire.
1.3 A HEAVYDUTY ROCKET LAUNCHER
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As you get to grips with larger and more complex rockets, you'll find that you need a launcher worthy of them. This useful, all-purpose launcher is both sturdy and adaptable enough to help any rocket in this book realize its full potential. It's easy to make but will take an hour or two, so set aside an afternoon to put it together.
You will need:
• Wood saw
• Screwdriver
• Small hacksaw
• Craft knife
• Electric drill
• Wood piece, 2 × 2 inches (2.5 × 2.5 cm) square, and 20 inches (0.5 m) long
• Wood plank, 1 inch (2.5 cm) thick, 6 inches (15 cm) wide, and 4 feet (1.2 m) long
• Piece of plywood, ½ inch (13 mm) thick, 8 inches (20 cm) wide, and 12 inches long
• 1¾-inch (4.5-cm) wood screws
• 10-foot (3-m) length of 1/2-inch (13-mm) OD (outside diameter) plastic water pipe
• ½-inch (13-mm) elbow push-fit pipe fitting
• ½-inch (13-mm) straight-connector push-fit pipe fitting
• Four ½-inch (13-mm) plastic pipemounting clips
• ½-inch (13-mm) tank push-fit pipe fitting
• 1-inch (2.5-cm) to ½-inch (13-mm) reducing push-fit pipe fitting
• Wire clothes hanger
• Trigger from project 1.1 (see pages 10–13)
• Two cable ties
• Schrader-type car-tire valve
• 1-inch (2.5-cm) brass compression stop-end pipe fitting
• To test, the rocket from project 1.1 (see pages 10–13) and a bicycle pump, ideally with a pressure gauge
1. Cut the 2 × 2 inch (2.5 × 2.5 cm) wood piece in half to leave two pieces each approximately 10 inches (25 cm) in length.
2. Attach the two pieces to the center of the longer plank in an L shape as shown, using a screwdriver and three wood screws to hold the pieces in place.
3. With the plywood, make a brace to strengthen the L shape, using screws to hold it in place.
4. Using the hacksaw, cut two lengths from the ½-inch (13mm) water pipe. The first should be 2 inches (5 cm) shorter than the length between the end of the plank of wood and the central upright. The second should be 3 inches (7.5 cm) taller than the height of the upright. Join the lengths of tube together using the elbow fitting.
5. Attach the straight connector to the opposite end of the longer piece of tube. Secure the resulting L-shaped piece of piping to the wooden frame using the mounting clips. The shorter piece of tube should be vertically upright against the central upright and the longer piece of tube is fixed horizontally along the plank.
6. Remove the nut from the threaded end of the tank pipe fitting and attach the fitting to the top of the upright tube. Insert a length of ½-inch (13-mm) pipe into the open end of the fitting. (You may need to trim the pipe slightly with a craft knife to make it fit well.) The piece of tube needs to be long enough for the base of the bottle to just clear it when the bottle is in position on the launcher, so use the basic rocket from project 1.1 (see pages 10–13) as a tester as you work.
7. Take the wire clothes hanger and bend it into the frame shape as shown in the illustration. You'll find it easiest to bend the wire accurately using two pairs of pliers. The dimensions of the frame will be determined by the dimensions of the tank fitting you are using. The finished frame needs to hold the bottle tightly against the rubber washer in the tank fitting when the release trigger from project 1.1 (see pages 10–13) is in position.
8. Lower the wire frame down the vertical tube so that the lower loops of the frame are just under the lip under the rubber washer, then tie one of the cable ties around two ends of the lower loops and pull the cable tie tight. Use the second cable tie to pull the opposite ends of the loops together so that the frame is held securely below the lip under the washer.
9. Measure the car-tire valve and drill a hole in the brass stop end large enough to fit it tightly. Pull the valve through the hole.
10. Insert the 1-inch (2.5-cm) to ½-inch (13-mm) reducing push-fit pipe fitting into the stop end and tighten the compression fitting, then insert the remainder of the ½-inch (13-mm) pipe into the open end of the reducing push-fit pipe fitting.
11. Push the other end of the pipe into the open end of the launcher assembly. Your rocket launcher is now ready for testing.
To Test Your Launcher
Fill the basic plastic soda-pop bottle about one-third with water. Holding the launcher at an angle to stop the water escaping from the bottle, place the neck of the bottle over the upright tube and secure it in place with the trigger. Attach the bicycle pump, pressurize the rocket, and use the string to pull out the trigger to launch. If water leaks from the bottle when it's placed on the tank fitting, try adding extra washers on top of the washer on the tank fitting.
1.4 A TWO-BOTTLE ROCKET
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The two-bottle rocket works on the same principle as the basic rocket described in project 1.1 (see pages 10–13), but is made larger and more impressive by means of a simple duct-tape joint. You can use the bottle stopper and launcher you made for project 1.1 for this rocket, too.
You will need:
• Two 2-liter plastic soda-pop bottles
• Duct tape
• Heavyweight scissors or craft knife
• Measuring tape
• Either the launcher and the bottle stopper from project 1.1 (see pages 10–13) or the launcher from project 1.3 (see pages 22–25), and a bicycle pump, ideally with a pressure gauge
• If you wish to add fins, follow steps 2–7 of project 1.2 and add them after step 3
1. Use the measuring tape to check that the two bottles are the same diameter. For your rocket to fly successfully, the joint between them needs to be tight.
2. Cut a section from the base of one of the bottles using either scissors or a craft knife. Cut as straight a line as possible. If you find it helpful, you can wrap duct tape around the bottle to use as a cutting guide. You can cut as much or as little as you like, but remember that the less you cut, the taller and more impressive your rocket will be.
3. Line up the base of the complete bottle with the cut edge of the shortened bottle and fit the latter carefully over the base of the former. Keep the two parts aligned so your completed rocket will be straight. Cut a length of duct tape a little longer than the circumference of the bottles and tape the cut bottle to the complete one. When you have a neat joint, add another two layers of duct tape over the first layer to ensure that the joint is firm and won't give way when you launch your rocket.
To Launch Your Rocket
Fill the rocket halfway with water and, if using the launcher from project 1.1 (see pages 10–13), seal the mouth with the stopper. Place your rocket on the launcher, secure with the wire trigger, pressurize, and fire.
1.5 A ROCKET WITH NOSE CONE AND PARACHUTE
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This model, in addition to having fins that will steady its flight on its way up, also has a nose cone containing a parachute that will help it float back down to the ground in elegant style. It's based on a two-bottle rocket like the one described in project 1.4 (see pages 28–29). The top bottle makes a store for the parachute, while the lower bottle holds the water that will propel the rocket's flight.
You will need:
• Two 2-liter plastic soda-pop bottles
• Duct tape
• Epoxy glue
• Heavyweight scissors or craft knife
• Cutting mat
• Hole punch
• Soft pencil-2B is ideal
• Measuring tape
• Large black plastic garbage bag
• Ball of thin string
• Sheet of thin cardstock, 8 × 11 inches (20 × 28 cm)
• Sheet of thin, flexible plastic, 11½ × 16½ inches (29 × 42 cm)-you can find this in hobby or craft stores
• Either the launcher and the bottle stopper from project 1.1 (see pages 10–13) or the launcher from project 1.3 (see pages 22–25), and a bicycle pump, ideally with a pressure gauge. You will also need access to a photocopier.
• If you wish to add fins, follow steps 2-7 of project 1.2 and add them after step 2
1. Use heavyweight scissors or a craft knife to cut off the top and bottom of one of your bottles. Don't cut much length off-cut just at the point where the body becomes straight below the neck and above the base, so that you are left with a long cylinder of plastic.
2. Fit one open end of the cut bottle over the base of the second bottle and duct tape the two together neatly. Use two or three layers of tape to ensure that the joint is strong and secure.
3. Make the parachute. Lay the garbage bag out flat on your worktable or on the floor and use scissors to cut off the sealed end, cutting as straight a line as you can. Straighten out the resulting tube and cut down the sides to make two panels of thin plastic. Use one panel to make the parachute and save the other for use in the future.
4. Fold the panel in half lengthwise from left to right, then fold in half again from bottom to top. Fold the left edge to meet the bottom edge and make a small cut in the plastic where the top of the left edge meets the bottom edge. Fold the diagonal edge on the left to meet the bottom, then repeat this again to leave a narrow triangle of plastic with the open edges outer-most. Find the small cut you made earlier, then cut in a slightly circular motion to the top edge. Open up the plastic to reveal the large circle.
5. Mark the plastic circle out in quarters (you can do this by eye or use a measuring tape). Cut a 3-inch (7.5-cm) length of duct tape and stick it at one of the quarter-points of the parachute, wrapping it around both sides of the plastic so that it makes a solid tab at the edge. Mark the other three quarter-points with duct tape in the same way, then add three extra tabs between each quarter-point marker, spacing them as evenly as possible. You should now have 16 tabs around the edge of your plastic circle.
(Continues...)
Excerpted from Soda-Pop Rockets by Paul Jarvis. Copyright © 2009 Ivy Press Limited. Excerpted by permission of Chicago Review Press Incorporated.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
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