How to Build a Soda Pop Bottle Rocket Launcher

How to Build a Soda Pop Bottle Rocket Launcher

So we were having a work picnic and we wanted to have some kinda geeky fun ... a Soda Pop Bottle Rocket Launch was suggested....problem is we didn't have a launcher and the picnic was coming up soon!! Never fear, master builder Wireb to the rescue...he designed and built the launcher described here. I built some rockets, we tested things a bit...we brought some supplies to the picnic for others to try building and yay! the rocket launching at the picnic was a success, rockets launched over 100 feet powered just by water and compressed air (approx 100psi) ...laughs and fun were had by all...pretty cheap, no misfires and no injuries! (And while the Aquapod Soda Bottle Rocket Launcher is available for $40 on ThinkGeek .com we made this system ourselves! (and we know it's sturdier, easier to use and more powerful))

NOTE: Use caution! Although we had no misfires, we've heard from other rocketeers that these bottles can blow even under the 100 PSI or so needed here, thus a long launch string is necessary. Be aware of the launch area as well, these can fly >150 feet high and at least that far in any direction, we don't want to take out any passers byl

This Instructable contains the design of our bottle launcher and describes how you can build one and some rockets for yourself and then have some kinda geeky fun too!

Test Flight Video:
First enjoy a video of one of our test launches using the "Patriotic Minion Soda Pop Bottle Rocket" with on rocket camera, minion and parachute! Frog Eye View included!

Here's the view from that launch from the on-rocket camera:

(This Instructable has been submitted by The Rabbit Hole Maker Space group as part of the Instructables sponsorship program)

Step 1: Supplies Needed for the Launcher and Rocket:

To Create a Soda Pop Bottle Launcher you need the following parts:

Launcher:

• 1 1/8" OD x 2 1/2"stock aluminium 
• 2 1/2" long 1/2" x 1/2" square aluminum bar stock
• 9 1/2" of 1/2" PVC pipe
• 3 7/8" OD x 1/8" O rings
• 3 8-32 screws by 3/4" long
• 2 8-32 nuts
• 3 8-32 washers
• 3 8-32 lock washers
• 1 8-32 x 3/8 flat-head screw
• 1 1/4" x 1 1/2" pipe nipple
• 1 1/4" pipe tee
• 1 5" pipe nipple
• air compressor hose connectors (or connectors for tire pump)
• air compressor hose or tire punch
• 1" x 1.75" x .01" thick iron bar stock 
• Pipe thread tape
• pull ring/ key ring
• string

Tripod Base:

• 1/2" pipe nipple by 4 1/2"
• 3 chunks of 1" iron angle iron by 16" 
• 3 scrap pieces of flat bar stock ~ 4 1/2" x 2 1/2"
• scrap piece of iron 2 x 1
• 3 5/16" x 1" bolts
• 3 5/16" washers
• 3 5/16" locknuts
• 3 tent stakes or large 11" landscaping nails to stake tripod down.

Tools Required:

• Metal lathe
• Drill
• Hacksaw or bandsaw
• Welder (for the tripod pieces)
• screwdriver
• wrench
• 1/4" pipe tap
• Air compressor or Tire pump
• (optional) Pressure gauge 
• (optional) 2 port Value 

Soda Pop Bottle Parts and Tools Needed:

• 1 - 1 Liter Soda Pop Bottle
• 1 More 1Liter Soda Pop Bottle OR a 20 Ounce bottle OR whatever you like for the top half of the bottle
• Duct Tape
• Scissors or Xacto Knife
• Sturdy plastic or cardboard for fins
• Counterweight - the top needs some extra weight, you can experiment with things such as modeling clay, sand, golfball
• (optional) Parachute with strings and weight to deploy (for example a golf ball)

Step 2: Build the Business End of the Launcher

First Step Build the Business End of the Launcher:

We've included Wireb's the Google Sketchup .skp file with this Instructable. It's drawn to scale, so you may want to refer to it as we go through the launcher build process.

1. Lathe the shoulder of the launcher by cutting the stock aluminum down to the .74" diameter required for the pop bottle to fit just right (refer to sketchup for dimensions)
2. Drill through the aluminum core
3. Thread the core so the pipe will thread in
4. Lathe three slots for the O-Rings
5. With the O-Rings in place you should find a very tight fit for the 2 Liter pop bottle

Step 3: Finishing Touches on the Launcher Mechanism

Continue Assembling the Launcher Tripod

1. Connect PVC pipe to the top end of the launcher with a set screw.  
2. Connect threaded pipe to the lower end of the launcher (use pipe thread tape for a good seal)
3. Connect a tee with the compressed air connector on the side of it and another pipe on the bottom (the pipe on the bottom allows the launcher to easily be removed from the tripod when loading or unloading a rocket.
4. Fashion the tripod from the angle iron, Note the bracket welded in place to keep the rocket from twisting when the launch ring release is pullled

Step 4: Create a Few Soda Pop Bottle Rockets

Creating a Soda Pop Bottle Rocket, our recommendation: - Create a few variations of rockets, Why? 1. experiment with different flight characteristics. 2. One of mine is still up in a tree :-)

Some good tips and design options for creating a Soda Pop Bottle Rocket
http://mdavenport.net/Physical%20Science/Rockets/Rocket%20Design%20Info.pdf

1. We used 2 2-liter bottles for most of our rockets. Turn one bottle upside down, that's nozzle that we'll fill with water and air. Cut the other bottle into two pieces and use your imagination for the shape and dimension of the top section...in general though fill it with some counterweights and foam and then tape it to the bottom half. It may seem counter intuitive that the center of gravity of the rocket should be towards the top half of the rocket, but counterweights are truly necessary (see the pdf link above for detalis)
2. Fins will improve the flight of the rocket, fashion two or three of them out of thick plastic (I used an old thick plastic folder for the fins of the Minion Rocket)  
3. Optionally add a parachute. These rockets are very resilient, especially if you add some foam to the top section. But once I put the minion in my rocket it seemed too mean to not at least try to add a parachute :-) Parachutes are described in the attachment listed above, but basically cut a hole in the very top of the rocket (I cut the nozzle off of the top bottle for mine) attach a string to both the bottle and the parachute, and attach a weight like the golf ball to the string...when the bottle fires off, the ball will stay in the rocket, but once the rocket begins to head earthward, it will fall out of the rocket, causing the parachute to follow and then deploy...fun! 

Step 5: Let's Fire It Up!!

Ready, Set, Fire!

Again, use caution, we used a string that was > 20 ft long and put caution signs around the likely landing site.

Make sure the compressor (or tire pump) gets the pressure up to the proper level 90 to 100 PSI
Open the value to release the pressure into the bottle.
Pull the release string....and zoom!!

Here's one of the launches, using a rocket that was actually built at the picnic.



Thanks for checking out our instructable, and good luck with all your Projects!