I put the original version together in about a half an hour, and played with it for way too long to admit. Eventually it got tore up, and now I've decided to create a new and improved version. This new version boasts some new features, almost all of which are designed to add distance. Starting at the nose cone, it now allows for retractable rubber bands. This will also allow multiple rubber bands to be used where it created too much instability in the original design. The new body is a bit longer, and I figured out a way to help trim down it's circumference a bit and keep it rounder than before. The tail fins are also much larger now to create more spin and ultimately more stability. Finally, per a user comment I now also have a tool to launch the rocket with to avoid accidently thumping your finger on occasion.
Step 1: Build the Nose Cone
To get started, we'll begin with the nose cone. Cut off the neck of the bottle, leaving as much of the straight section in place as possible. Next, unscrew the cap and drill a couple of small holes (the size of the paper clip) near the top on two sides. I didn't have a drill handy, and used a small leather punch in place of the drill for now. First, remove and save (without destroying) the sealing ring, then go ahead and put the paper clip in place and screw the lid down tightly. Then you can mark the raised section of the neck for two more holes to keep the paper clip in place. Unscrew the cap and make your holes. Finally, make a hole large enough on top of the cap for at least a couple of rubber bands to fit through.
Now it's time to put it all together. Take the paper clip out, and put the rubber band(s) on. The strength, quality, and number of rubber bands you use will make quite a difference on how the rocket performs. This design is a little heavier than the original, and needs a little bit more power to fly well. The paper clip on the inside keeps them from falling down into the rocket later on, and you'll be able to dig them out with the launcher (built in the next step) if needed. I placed a golf tee under them so they wouldn't fall back through. I had to use a pair of needle-nose to get the paper clips forced through the holes further down the neck, but that will keep it from falling out. If you need to replace the rubber bands later, it's probably just best to also replace that paper clip.
Step 2: Build the Launching Tool
This is the easist piece to build, and it will help you building the body in the next step. Leave the smaller hook in the paper clip, and straighten out the rest. Take the ballpoint and cap off the pen, leaving the outer hull. Put the paper clip on the fat end, and tape it with the hook facing towards the middle using your favorite type of tape.
Step 3: The Rocket Body
You will probably want to wrap your plastic shell around something roughly the same size as what you want the finished product to be. Wrap it around twice, and make sure it is tight and even on both ends, then mark the ends with the sharpie where it meets inside the first layer. Then use the ruler to make a straight line, subtract a little bit to compensate for the PVC (what I wrapped mine around) and cut out the body. Next I used a spray adhesive on the inside of the bottle and quickly wrapped it back into a roll where it it was doubled over again. At this point grab the 2-Liter bottle tops you cut off, and use them to place over the body to hold it in place at the correct size.
Now that it's drying, you can start working on the hook that will go inside the body. Unfold a paper clip, and double it over as shown in the pictures. A little ways down, you can bend the legs back out at about a 45 degree angle. Your glue should be drying by now, so figure out how low in the body you need the hook to be and mark the rocket again. I used a hot glue gun to really hold down the outer joint from separating. From there, you can figure out where to drill two small holes for the paper clips to come out the side of the rocket. Use a pair of needle nose pliers to place it inside- think of it as working on a ship in a bottle. When you finally get it, place the hook in the middle and bend the paper clip down the sides. I then dropped in some hot glue and used a pinky finger to kind of smear where I wanted it to go. Just be careful not to burn yourself.
I used a bit of electrical tape to hold the paper clip to the sides. One last thing to do, I sawed off a couple of rings from each of the bottle lips and placed these near the ends of the rocket body (unglued). They can butt up to the fins and nose cone later, their main purpose is to keep the rocket body round instead of the oblong shape this design tries to force it to be.
Step 4: Making the Fins
Step 5: Put It All Together
Next, holding the nose cone just off to the side of the top, use your launcher to place the other end of the rubber bands over the hook on the inside. Once they are in place, slide the nose cone as far down onto the rocket as it will go, and slide the other plastic lip up to meet it. I left my hook up a little too high in the rocket, so I also cut the sealing ring we saved from before in half, and used that to make a small little half moon under the top of the rubber bands. This isn't necessary, but I think it adds to the look and helped keep the rubber bands from being so loose. They don't have to be stretched, but you don't want too much room left over or they may not retract properly. Another problem is that they may become unhooked inside the rocket.
Step 6: Add Some Decals.
This has been a re-build of my fifth instructable, and still one of my favorites. It was a winner in the rubber band contest, and part of my new design has come from suggestions in the user comments below. I hope the new directions allow you to build one that will fly even further than before. Below is also a video of the old style in use. I hope to get a new one put up soon, and to be able to start posting some new distances for you. My original "50 foot+ Rubber Band Rocket" eventually got up to 78' with some modifications, and I'm hoping this new version can make it up to 100 feet or more before I'm done with it. The only way to find out... build your own and start testing!
Step 7: Observations of the New Design
Rundown of the video:
Shot One- Trying to go through tree.
Shot Two- Trying to go under tree.
Shot Three- Trying to go around tree.
Shot Four- Accidently figuring out I can easily go over the tree instead of through it.
Shot Five- Over the tree, estimated at 78 feet. The front edge of the road is 54 feet from my doorway, the road is 18 feet across, and it was five feet past the far edge of the road.
The first thing to mention is that while the sealing ring adds a nice look to the finished rocket, it doesn't stand up very well to the crash landings. After reattaching it a couple of times, I finally gave up and just tore it off. The only other modification I made was the hook on the inside. After having problems trying to catch the rubber bands on it, I realized it was easier to just run a paper clip straight through, catching the rubber bands, and bending it back up the sides of the rocket to hold. I then used some electrical tape to secure and hide the ends of the paper clip.