Introduction: Model Rocketry
Hello, This is my first instructable, showing you how to make model rockets out of simple household materials.
If your new to model rockets, you can find lots of info at the NASA website: http://exploration.grc.nasa.gov/education/rocket/r...
Model rockets are a fun and amazing hobby, and all you need to get started are a few simple materials, which can all be found in your house or at a store like Hobby Lobby.
Sorry for the bad pictures, I didn't have a very good camera.
Step 1: Materials
Most of these can probably be found around your house.
-1 sheet of blank paper
-1 note card
-1 eye hook
- the model rocket engine size you want to use. https://www.google.com/webhp?sourceid=chrome-insta...
-something circular, should have a diameter of about 1/2-2 inches (this will be the mold for the body of your rocket) I used a 1/2 inch pvc pipe.
-1 cork (should be slightly wider than the circular piece you are using for the body tube mold)
-1 roll of gummed brown tape (at art stores or online) you can use paper mache (glue water and newspaper ) but it wont be as smooth or light. http://www.dickblick.com/items/24118-1002 (cheapest place online)
-thin cardboard (like cereal box cardboard) -large rubber band or thin elastic
-wood glue or Elmer's glue, but wood glue works better.
-plastic bag (grocery store bag works fine)
-a large rubber band, or chain of rubber bands about 1.5 feet long.
To launch the rocket:
-launch pad (could be Estes launch pad, but I use a Christmas tree stand with a kite pole taped to it!) https://www.google.com/webhp?sourceid=chrome-insta...
-launch control: its best to use an official rocket launch control because they have safety features you are going to want. I used this $12 one: https://www.google.com/webhp?sourceid=chrome-insta...
-fire extinguisher or bucket of water just in case
-igniter the rocket engines you purchase should come with igniters, but usually at least one of them is faulty, so be sure to buy a pack just in case: https://www.google.com/webhp?sourceid=chrome-insta...
Step 2: Design
Now it's time to figure out the design of your rocket. This includes the engine size, rocket size, length, fin shape, recovery system, and diameter of the body tube.
Make a simple sketch of your rocket, including all of these things:
For your rocket body (or bodies) you will need a cylindrical object to mold the gummed paper on to. PVC or any other pipe works just fine, as this will not actually be a part of your rocket.
Engine: when you launch a rocket, the igniter sets the propellant off, activating the engine. Then there is a part in the engine that burns very slowly and delays the firing of the ejection charge. The ejection charge is a small chunk of clay the engine fires upwards, into the rocket. The ejection charge pushes the nose cone off the rocket and allows for the recovery system to open up and slow down the rocket's fall.
I used size B 6-4 engines -the letter in front means the amount of propellant in the engine (B engines burn longer than A engines etc.) The first number is the average thrust (newtons) the second number is the delay between when the engine cuts off and when the ejection charge fires(seconds). Engines also come in different diameters, but the standard engine size should work best. here is a pdf on model rocket engines: http://www2.estesrockets.com/pdf/Estes_Model_Rocke...
The recovery system is something that slows the rockets fall. It can be either a streamer or a parachute. A streamer doesn't slow the rocket down as much, but a parachute is more susceptible to wind and requires enough space in the rocket body for it to fit.
The fins should be large enough to help the rocket fly straight, but not so large that they weigh the rocket down.
for my rocket, I chose a B 6-4 engine, delta shaped fins, 11 inch long body (size of a piece of paper), streamer recovery, and a 1/2 inch body tube.
Step 3: Body Tube
First put glue on most of one side of the paper. wrap the paper tightly around the mold you are using with the glue facing out. you don't want to glue the paper to the tube.
Then dampen the paper towel. Measure your gummed paper to 18 inches(for a 11 inch body tube) and cut one end of the gummed paper at about 90 degrees. Wet the gummed paper and wrap it along the body. there should be a small strip of paper visible, which is fine. If your mold is much bigger than 1/2 inch in diameter, add another strip of gummed paper for support.
then take another strip of gummed paper about twice as long as your tube. cut one end at more than 45 degrees. IMPORTANT: make sure the paper overlaps itself before gluing it down. If not, make the angle of the edge shallower. Wet the gummed paper, then with the cut edge parallel to the edge of the paper, wrap it around in a spiral until you get to the other side. Then trim off the excess.
Step 4: Engine Mount
Next for the engine mount. Take the rocket engine you are using, and cut a strip of paper that is about as long as the engine and can wrap around it twice. glue the paper around the engine fairly tightly - but not glued to the engine.
then do the same thing as the body tube, put a piece of gummed paper parallel to the tube, then another one wrapped around it in a spiral.
Then take a piece of cereal box cardboard cut about 1/4 inch wide and slightly longer than the circumference of the engine. take the engine out of the tube, then glue this piece right at one end of the tube. This piece needs to be able too hold up to the force of the engine.
Then flange the opposite end by making small cuts right next to each other all along the edge. bend these pieces back against the tube and tape them down.
Step 5: Assembly
To mount the engine onto the body tube, first make sure your engine fits in the tube. take a strip of cardboard about 1/4 inch wide and glue it down to the engine tube. see if it fits snugly into the body tube. If it does glue it into the tube, if not put as many layers of cardboard strips as needed then glue it down. If the engine is still wobbly, stick another ring of cardboard in the space between the engine and body tube.
Make SURE your engine mount is completely parallel to the body tube.
Step 6: Nose Cone
To make the nose cone, Take the index card and cut a 60 degree angle on one side. then put glue on a third of one side and wrap it into a cone with the 120 degree angle at the top of the cone. Take the cork and screw the eye hook into it. glue the cork to the nose cone. Then tie the long rubber band or chain of rubber bands to the eye hook.
take the remaining triangle of note card and cut off the point. glue the rubber band right at the edge, then put glue on top and fold it over. then do that again so you have the end of the rubber band wrapped. cut off the excess.
Step 7: Recovery
First decide what recovery system you want.
I developed three simple recovery systems made with a plastic grocery bag.
Parachute Take the plastic bag and cut off the handles. tape the ends of two strings to two corners of the plastic bag. then pass them through the eye hook. Then tape the other ends of the string to the two other corners.
Half parachute same as the parachute, but then you cut six inches off the bottom, so you are left with just the very top part (the very bottom of the plastic bag). This parachute takes up less space, which is important.
Streamer take the bag and cut it into strips about an inch wide and two feet long. I used two of these for this rocket. This recovery system takes up the least space.
Step 8: Final Parts
Now we will put on the final parts of the rocket.
Cut out the fins you designed in step 2, and glue them on. if the fins aren't evenly spaced, it won't really matter. What will matter is if the fins aren't parallel to the rocket body.
Then take your straw, cut it to 1 inch to make your launch lug. if your rocket is more than 8 inches long, I suggest two launch lugs. Glue these on along the body, and make sure they are parallel to the rocket body. Also make sure there is a clear space from the bottom of the rocket to the top for the launch rod to fit.
Step 9: Pre Launch Test (opt.)
If you want to make sure your rocket flies straight, and doesn't go haywire, you should follow this step.
First put a full engine in your rocket and tape it around the side so it stays in.
Try to balance your rocket on your finger to find the center of gravity. then take a string about three feet long and tie it around the center of gravity of the rocket. Then spin the rocket around your head by the string.
What you are trying to do is make sure the rocket's center of gravity ahead of its center of pressure.
If the rocket flies evenly, you are ready to launch.
If the rocket flies unstably, you probably need to move either your center of pressure back, or your center of gravity forward.
Doing either of these will help:
To move your center of pressure back, Make your fins bigger, and further back on the rocket.
To move your center of gravity forward, add weight to the nose until it flies evenly. Sticking clay in the nose cone works well. You can cut a flap in the nose cone, put clay inside, then tape it shut.
Step 10: Launch!
now that you're finished with your rocket, find an open space with low grass or pavement, and set up your launch pad. I recommend at least 200 accessible feet in every direction, to make it easier to recover your rocket.
to launch your rocket, you need:
-your rocket (duh)
-a launch pad
-a launch controller
-igniters - bring least 1 extra! It took two tries to launch this rocket, because of a faulty igniter.
-end plug, that goes in the back of the engine to hold the igniter in (should come with your engines)
-bucket of water or a fire extinguisher just in case.
-just ordinary tape
First: I am not responsible for any injuries to you or anyone around you.
Rockets are fun, but they can be dangerous if you are not safe with them. Don't angle the rocket more than 40 degrees above the ground, to avoid hitting people. stay at least 10 feet away from the launch pad when launching your rocket. Make sure younger children have adult supervision when launching. Make sure you don't have tall grass near the engine when launching, and use common sense.
To launch the rocket, set up your launch pad. Then take the igniter, put the black end into the hole in the bottom of the engine. then take the end plug and put it securely into the engine. Then insert the engine into the engine mount and tape the engine in place.(it doesn't take much tape) Then you are ready to connect the igniter to the launch controller and launch your rocket. It's best not to launch on a windy day so your rocket falls straight down.
In the video, I lost the rocket in someones backyard because I skipped step 9.
Anyway, Hope you enjoy!