Rockets are a demonstration of Newton's Third Law on dynamics: "Every action has an equal and opposite reaction". The first rocket may have been a steam-powered wooden pigeon invented by Archita of Taranto in the 4th century BC. Steam allowed the development of the gunpowder tubes of the Chinese and liquid fuel-powered rockets, imagined by Konstanin Tsiolkovsky and conceived by Robert Goddard. This article describes five ways to make a rocket, from the simplest to the most complex. Finally, a section explains some of the guiding principles for its construction and operation.
Steps
Method 1 of 5: The Balloon Rocket
Step 1. Tie one end of a piece of string or fishing line to a holder
It could be the back of a chair or the handle of a door.
Step 2. Thread the string through a straw
The wire and straw will serve as a guide system to control the path of the rocket balloon.
Model building kits often contain pieces of straw attached to the rocket's body. A metal rod attached to the launch pad is threaded into the straw to keep the rocket upright before it is launched
Step 3. Tie the other end of the twine to another support
Make sure the thread is taut before tying it.
Step 4. Inflate the balloon
Close the end to prevent it from deflating. You can use your fingers, a paper clip, or a clothespin.
Step 5. Using duct tape, attach the balloon to the straw
Step 6. Open the end of the balloon to allow air to escape
The rocket will travel from one end of the guidance system to the other.
- You can try making the rocket using a round balloon instead of an oval one and straws of different lengths to see how the balloon rocket's motion changes. You can also increase the launch angle to see how this affects the range from the rocket.
- A similar device you can make is the jet boat. Cut a milk carton in half lengthwise. Drill a hole in the bottom and insert the mouth of the balloon into the hole. Inflate the balloon, place the boat in a partially filled tub of water and leave the balloon to let the air out.
Method 2 of 5: The Rocket Shooting Straw
Step 1. Cut a rectangular strip of paper
The strip should be three times its width: the suggested dimensions are 12x4cm.
Step 2. Wrap the strip tightly around a pencil or stick
Start rolling the paper strip at the tip or end rather than the center. Part of the strip should protrude free above the tip of the pencil or the end of the stick.
Make sure you use a pencil or stick that is slightly wider than a straw, but not too much
Step 3. Tape the edge of the paper strip to prevent it from unrolling
Put the tape lengthwise, over the entire length of the strip.
Step 4. Bend the protruding end of the strip to form a point or cone
Secure with masking tape so it holds its shape.
Step 5. Remove the pencil or stick
Step 6. Check for air leaks
Gently blow into the open part of the paper rocket. Make sure that no air escapes from the side by running a finger along the entire length of the rocket. Tape off any leaks and try again until you are sure you have fixed the problem.
Step 7. Add ailerons to the open end of the rocket
Since the rocket is quite narrow, it is advisable to cut pairs of ailerons that will be easier to attack, rather than three or four single ailerons.
Step 8. Insert the straw into the open part of the rocket
Make sure the straw protrudes far enough that you can grab it with your fingers.
Step 9. Blow hard into the straw
The rocket will fly through the air, propelled by the force of your breath.
- Always aim high, not against someone.
- Build the rocket differently to see how the changes affect its flight. Also, vary the intensity with which you blow into the straw to see how the distance reached by the rocket changes.
- A paper rocket-like toy consists of a stick with a plastic cone attached to one end and a parachute attached to the other. The parachute is folded onto the stick, which is placed in a cardboard tube. By blowing into the tube, the plastic cone collects the air and throws the stick. When this reaches its maximum height, it begins to fall causing the parachute to open.
Method 3 of 5: The Rocket Made with a Roll Holder
Step 1. Decide how long / tall the rocket should be
A good size is around 15cm, but you can make it longer or shorter as well.
A good diameter is between 3.5 and 4 cm, but the actual diameter of the rocket will be determined by the size of the combustion chamber
Step 2. Get a roll holder
It will serve you as the rocket's combustion chamber. You can find it at a photo studio that still uses film.
- Check that the lid of the roll holder closes the container by means of a protrusion inside the mouth of the container itself and not by an external edge.
- If you can't find a camera roll container, you can use an empty medicine tube with a snap lid. If you can't find one with this type of lid, you can easily carve the lid out of the cork, so that it fits snugly into the tube.
Step 3. Mount the rocket
The easiest way to build the rocket body is to wrap a strip of paper around the roll holder, like you did for the rocket shooting straw. Since the roll holder will launch the rocket, you may want to attach the paper to the container with tape or glue before wrapping it around it.
- Make sure you have the open part of the roll holder or tube facing outward when attaching the rocket frame. The opening will serve as a nozzle.
- Instead of folding the remaining part of the paper strip to form a cone, you can prepare the tip of the rocket by cutting out a circle of paper and folding it to form a cone. You can stick the tip with tape or glue.
- Add the ailerons. Since the rocket is thicker than the one prepared for straw launch, you may want to cut out individual ailerons. You can also only attack three ailerons instead of four.
Step 4. Decide where you want to launch the rocket from
It is best to be outside in an open space, since it can reach considerable heights.
Step 5. Fill 1/3 of the roll holder with water
If the water source is not close to the launch pad, it may be necessary to carry the rocket upside down or carry some water and fill the container near the launch site.
Step 6. Break a fizzy tablet in half and drop one of the two pieces into the water
Step 7. Cap the container, flip the rocket and place it on the launch pad
Step 8. Move to a safe distance
When the tablet dissolves, it produces carbon dioxide. The pressure will increase until the lid of the container opens, launching the rocket.
Instead of water, you can use vinegar to fill about half of the roll holder. Instead of the fizzy tablet, you can use a teaspoon of baking soda. Vinegar, an acid (which is called its own acetic acid), reacts with baking soda, a base, to produce water and carbon dioxide. However, vinegar and baking soda are more unstable than water combined with the fizzy tablet so you have to get out of the drop zone pretty quickly. Also, an overdose of the two components could break the container
Method 4 of 5: The Matchstick Rocket
Step 1. Cut out a small triangle out of tinfoil
It should be an isosceles triangle with a base of 2.5 cm and a height of 5 cm.
Step 2. Take a match from the box
Step 3. Place a pin next to the match
Make sure that the tip of the pin does not rise above the thickest part of the match head.
Step 4. Wrap the head of the match in aluminum foil, starting at the tip
Wrap the aluminum as tightly as possible, without moving the pin. When finished, the wrapper should be about 6mm below the head of the match.
Step 5. Press the foil wrap around the tip of the pin using your thumb nails
This will help the foil adhere better to the match and will shape the small channel created by the pin under the casing.
Step 6. Carefully pull the pin out of the package
Be careful not to break the foil.
Step 7. Bend a paper clip to form a launch pad
- Fold the outer part at a 60 ° angle. This will form the base of the launch pad.
- Fold the inside up and then slightly outwards to form an open triangle. This is where you will place the match wrapped in foil.
Step 8. Bring the ramp to the chosen launch location
Again, better on the outside because the match rocket can reach considerable distances. Avoid particularly dry places as the rocket could cause a fire.
Make sure the surrounding area is clear before launching the rocket
Step 9. Place the match rocket on the launch pad, upside down
The rocket should be tilted approximately 60 ° to the ground. If the slant is less, you will need to bend the paper clip a little more.
Step 10. Launch the rocket
Light another match and bring the flame close to the head of the foil-wrapped match. When the phosphorus in the package catches fire, the rocket should launch.
- Keep a bucket of water handy to dip the worn out match rockets in and make sure they are completely extinguished.
- If a match rocket lands on you, stop, throw yourself on the ground and roll until the flames are completely extinguished.
Method 5 of 5: The Water Rocket
Step 1. Prepare a 2 liter plastic bottle that will serve as a pressure chamber
Because bottles are used, this type of rocket is often called a rocket bottle. It is not to be confused with the firecracker called by the same name because it is often thrown from inside a bottle. In many areas, it is illegal to launch that type of rocket bottle; the water rocket on the other hand is legal in most areas.
- Remove the bottle label, cutting it where it is not stuck. Be careful not to cut or scratch the bottle during this process, as this could weaken it.
- Reinforce the bottle by wrapping it with strong adhesive tape. New bottles withstand pressures of up to nearly 700 kilopascals, but repeated launches reduce their resistance. You can wrap several strips of duct tape around the center of the bottle or cover both the center and both ends. Each strip should go around the bottle twice.
- Mark the points where you will attach the ailerons. If you plan to use four ailerons, draw lines 90 degrees apart. If you plan to put only three, draw lines at 120 ° from each other (use a protractor). It is advisable to wrap a strip of paper around the bottle to mark the points, and then transfer them to the bottle itself.
Step 2. Build the ailerons
Since the rocket body is relatively strong, even if you have had to reinforce it, the ailerons will have to be too. Cardboard will be fine for a while, but the ideal solution is to use plastic, like the one that rigid folders or ring binders are made of.
- First you will need to draw the ailerons and create a paper model to use as a cutting guide. Whichever way you decide to design the ailerons, they must be designed so that the actual aileron is folded back (doubled) to increase drag, and reaches at least the part where the bottle shrinks.
- Cut out the template and use it as a guide to cut the actual wing.
- Shape the ailerons and attach them to the rocket body using strong tape.
- Depending on the shape of the rocket launcher, it might be better if the ailerons don't extend beyond the mouth of the bottle / rocket nozzle.
Step 3. Create the rocket tip and cargo section
You will need another 2-liter bottle.
- Cut the bottom of the bottle.
- Place a weight at the top of the cut bottle. It could be a piece of modeled clay or a handful of rubber bands. Slide the top of the cut bottle into the bottom one, so that the mouth of the bottle is facing the bottom of the bottom. Secure the modified bottle with adhesive tape and attach it to the first bottle (the one that acts as a pressure chamber) always with adhesive tape.
- The tip can be anything from a 2-liter bottle cap to a piece of PVC tubing to a plastic cone. Once you have decided what the tip will be and assembled, it should always stick to the top of the cut bottle.
Step 4. Check if the rocket is well balanced
Keep the rocket balanced on your index finger. It should be balanced by placing it on your finger roughly at the height of the top of the pressure chamber (i.e. the bottom of the first bottle). If not, remove the load section and adjust the weight.
When you've found the center of gravity, weigh the rocket. It should weigh between 200 and 240 grams
Step 5. Prepare the valve / cap
There are several devices you can use to launch the rocket. The simplest is a valve-cap that fits perfectly into the mouth of the bottle that acts as a pressure chamber.
- Get a cork that fits perfectly into the mouth of the bottle. It may be necessary to file the edge slightly.
- Get a valve of the type used in a car tire or bicycle tube. Measure its diameter.
- Make a hole in the center of the cork that is the same diameter as the valve.
- Clean the valve and put a piece of tape over the threaded part and opening.
- Insert the valve into the cork and seal the components with silicone. Let it dry completely before removing the tape.
- Check that air passes through the valve smoothly.
- Test the cap. Put a small amount of water in the rocket's pressure chamber, put the cap on and turn the rocket upside down. If you notice any leaks, reseal the valve and try again. Once you have blocked any leaks, test to see what pressure is causing the bottle to uncork.
- To build a more complex launch system, follow the instructions you find here
Step 6. Choose the launch site
As with the rocket built with a roll holder and the match rocket, it is advisable to choose an outdoor location. Since the water rocket is bigger than the others, you will need a wider and flatter space.
A raised surface such as a picnic table is a good idea around small children
Step 7. Launch the rocket
- Fill about a third / half of the pressure chamber with water (you could add some food coloring to make the launch more spectacular). It is possible to launch the rocket even without putting water, but in this case the limit pressure value could change.
- Insert the valve / plug into the mouth of the pressure chamber.
- Attach a pump of the type used to inflate bike wheels to the valve.
- Turn the rocket over and put it upright.
- Pumps air until the limit pressure is reached which will uncork the bottle. There may be some delay between the release of the cap and the launch of the rocket.
Parts of the Rocket and How They Work
1. Use the propellant to make the rocket lift and travel through the air
A rocket flies by directing a jet of exhaust gas downward through one or more nozzles. In this way it rises and moves forward in the air. Rocket engines work by mixing the actual fuel with an oxygen source (oxidant) that allows them to function both in space and in the Earth's atmosphere.
- The first rockets were solid fuel. This type of rocket includes the firecrackers, Chinese war rockets and the two carrier rockets used by the Space Shuttle. Most rockets of this type have a central hole for fuel and oxidizer to mix and burn. The rocket engines used in the model cars use solid fuels with a variety of loads to deploy the rocket's parachute when the fuel is gone.
- Liquid fuel rockets have separate autoclaves for fuel, such as gasoline or hydrazine, and for liquid oxygen. These two liquids are pumped into a combustion chamber at the base of the rocket. The main thrusters of the Space Shuttle were liquid fuel rockets, powered by the external tank carried under the shuttle at the time of launch. The Saturn V rockets of the Apollo mission were also liquid fueled.
- Many propulsion vehicles have small flares on their sides for them to be oriented in space. These are called shunting reactors. The service module attached to the Apollo command module had these types of thrusters; even the backpacks with maneuvering equipment used by the Space Shuttle astronauts were provided with them.
2. Slice the air with the tip
The air has mass and the denser it is (especially near the Earth) the more it holds the objects that try to move inside it. Rockets need to be optimized (giving them elongated and elliptical shapes) to minimize the friction they encounter while traveling through the air. It is for this reason that they generally have a pointed "snout".
- In rockets carrying a load (astronauts, satellites or explosive warheads) this is usually placed in or near the tip. The Apollo command module, for example, was cone-shaped.
- The tip also contains any guidance systems carried by the rocket to help it move in the correct direction without causing it to deflect. Guidance systems may include on-board computers, sensors, radar, and radios to provide information and control the rocket's flight path (Goddard's rocket used a gyroscope control system).
3. Balance the rocket around its center of gravity
The rocket's overall weight must be balanced around some point inside the rocket to make sure it flies without falling. This point can be called the point of balance, the center of gravity or the center of gravity.
- The center of gravity is different for each rocket. In general, the equilibrium point should be somewhere above the top of the pressure chamber.
- The load helps to place the center of gravity above the pressure chamber, but if it is too heavy it risks unbalancing the rocket making it difficult to hold it upright before launch and guide it during takeoff. For this reason, integrated circuits have been incorporated into spacecraft computers, in order to reduce their weight (this has led to the use of similar integrated circuits, or chips, in calculators, digital watches, PCs and, more recently, in smartphones. and tablets).
4. Stabilize rocket flight with ailerons
The ailerons help ensure that the rocket's flight is straight by providing resistance against changes in direction. Some ailerons are designed to extend beyond the rocket's nozzle in order to keep it upright before launch.
In the 19th century, the Englishman William Hale devised another way to use the ailerons to stabilize the flight of the rocket. He devised exhaust ports placed next to weather vane ailerons. The gas, exiting the doors, pushed against the ailerons and caused the rocket to rotate around its axis, preventing it from turning. This process is called "spin stabilization"
Advice
- If you enjoyed making the above rockets but want something more challenging, you can get closer to rocket modeling. Kits for building model rockets have been on the market since the late 1950s. They have disposable engines powered by black powder and can reach heights between 100 and 500 meters.
- If it is too difficult to launch the rockets vertically, launch sleds can be made to carry out horizontal launches (in practice the rocket balloon is a rocket-sled shape). You can attach the roll holder rocket to a toy car or the water rocket to a skateboard. You will still need to find a large enough space to launch.
Warnings
- Always wear protective goggles when launching an unguided rocket (so all except the balloon rocket). For larger free-flying rockets, such as the water rocket, it is advisable to also wear a hard hat, in case the rocket hits you.
- Don't shoot free-flying rockets at someone.
- Adult supervision is always recommended when launching rockets powered by anything more powerful than breath.
