Introduction: MiG-21 From a Monster Can
This is the "sequel" to my Aeroplane from an aluminium can Instructable
( https://www.instructables.com/id/Aeroplane-from-an-Aluminium-Can-and-it-flies-too/?comments=all )
This one took me about the same amount of time (and can) as the first one. Unlike the last one, this one is based on a real aircraft which I chose for its simplicity and "Tin Can Practicality" as well as the fact that an aircraft with most of its wing surface area further back requires minimum ballast. This configuration is also more practical than the previous one because of its inherent stability, and it lacks an open front end which causes unpredictable flying patterns.
To build one like mine you'll need
1X Monster can
Tin snips or scissors
Some form of ballast; paperclips, wire, Prestik, putty etc.
Optional: -Fireworks in the form of a small rocket
-Add a hook under the nose to rubber-band launch it.
Step 1: Cut the Can
This is a very simple thing to do and the pictures definitely explain what to do better than I could. The most important thing to do is keep as much of the can usable as you can. Make sure you cut directly down from the top to the bottom and cut even, straight lines as this will make planning where to cut parts out of it easier later on.
Once you have a sheet of aluminium cut from the can, roll it "inside out" to make it more flat.
Step 2: Mark and Cut the Wings
In the first picture you should see the outline of the wings in the bottom-right corner. Do NOT cut along the lines shown, they are the lines which we will fold along. The sweptback angle of the wings is 60 degrees. The shape which will be cut is a rectangle with the sides originating from the back corners of the wings and the top of the rectangle being cut from the top (front) edge of the wing.
Step 3: Folding the Wings
This is also a fairly simple step, just fold the front parts of the rectangle down, with the folds along the pencil lines.
Clip one of these pieces along the wing's centre line. Fold the other one up into a sort of " /""""\ shape. this keel will be used for holding the aeroplane while throwing it.
Glue both of the folded down-wing pieces to the inner wing surface.
Bend a curve into the middle part of the wing, making a sort of channel. This will house the fuselage. This is shown best in the third-last picture.
Step 4: Rolling the Fuselage
Your aluminium sheet should look like this: ________
| _ _ _ |
| /"'\ |
|___/ \ |
The dotted line forms the fourth side of the rectangle that will become the fuselage. Cut it out, fold about an inch of it to what will become the inside of the tube. This will add some strength to the nose.
Keep on rolling the sheet around a pencil or small piece of dowell to give it an even bend.
Once it looks like a decent tube with the right diameter (mine turned out to be about 1.5 cm across) Add some glue to the edge of one of the sides and glue the other side to it. This works best when you roll one side into the tube to get more strength.(overlap the sides.)
Also shown here, bend the "channel" in the wing to fit the curvature of the fuselage tube.
Step 5: The Tail Surfaces
To make the horizontal stabilizer, cut a rectangle about 3 finger widths wide and about 4 long. Along the centre line of the tailplane (only about 1 finger length long) from the back edge of the rectangle cut a slit.
Fold the leading edges over as shown. I just guessed the angle and bent it until it looked right. Do the same thing to the trailing edges, but with the "inside corners" instead of the corners of the rectangle. See pictures If you are confused. Picture 7 shows what the complete tailplane should look like from the underside.
The vertical stabilizer is simple, cut a pentagon like the one shown in picture 8 and fold it in half. Trim it to look like one of the horizontal stabilizers. Bend the bottom of it to fit the back of the fuselage and remember that it has to "lean back" when considering the angle of the base where you start this bend.
Cut the slits in the sides of the back end of the fuselage and make sure they are opposite each other. These slits should be about 2 finger widths long.
Glue the horizontal stabilizer between these 2 slits and ensure that it is in the centre.
From some tail offcuts or a bit of leftover can, cut 2 shapes like the ones shown in the second-last picture and bend them in half. They will support the horizontal stabilizers.
Step 6: Finishing the Tail and Adding the Cone
Glue the two supports under the horizontal tailplane and glue them firmly to both the tailplane and the fuselage. Glue the vertical stabilizer to the top of the back of the fuselage.
To make the Nose cone/axis mount I cut about 2 finger widths off the front end of the tube because it was the right size for the cone and because the fuselage was too long. I basically cut it into an "almost triangle" and glued the edges together the same way as the fuselage tube.
Glue this cone inside of the nose end of the fuselage and make sure a lot of it is sticking out. If you think it looks unusual, do a quick google image search for the Mikoyan and Gurevuch (MiG) 21 and you'll see what I'm talking about.
Step 7: Put It Together
Glue the wings to the fuselage. The trailing edge of the wing should be about one finger width from the furthest-forward part of the tail surfaces.
To make the cockpit, cut the shape shown in the first picture out of the left over piece of sheetmetal. I chose to make the cockpit "inside out" compared to the rest of the aeroplane because of the nice contrast between the two. Bend it into the shape shown, trim it and glue it on top of the fuselage wherever it looks right.
It is now complete! Try to fly it, if it just stops in midair and falls down, add some ballast to the nose.
To fly it, hold it by the keel under the wings and throw it forward. This is definitely a dangerous thing to throw around since it is basically an all-metal dart, so be careful.
Step 8: Some Pictures and Extras
If the aircraft appears unpredictable or unstable, bend the wings up slightly to form a sort of " V " Shape. This is usually referred to as dihedral.
Note: these make it more dangerous, but add speed and therefore distance.
1- Just add a stiff piece of wire bent into a "J" shape under the nose and launch it by elastic.
2- Add rocket power! I can't try this since I don't have any rockets on me, but this modification will definitely give your aeroplane some thrust. This involves gluing a rocket into the back end of the fuselage, adding an angled launchpad, lighting it and running away.This does however mean you have to change the horizontal stabilizer to be attatched in the same way as the wings so that the tailplane doesn't cause any obstruction for the rocket. If you are considering building one for the purpose of being rocket-propelled remember this because you will have to make an all-new tail.