The Automatic Smoke Cannon

This project began when I was watching some youtube videos about a toy called the "Airzooka."  Basically the Airzooka is a tube with a flexible diaphragm attached on the back.  When the user pulls back and releases the diaphragm, the diaphragm pushes out a powerful vortex of air. 

Airzooka

As I searched youtube for more Airzookas I found videos of people building their own Airzooka and filling it with smoke.  The affect was amazing.  When filled with smoke, the Airzooka creates a perfect beautiful smoke ring.

Airzooka filled with smoke

Although the Airzooka is simple to construct out of cheap material, the science behind a smoke ring is truly "Weird Science."  All the science behind a smoke ring is extremely complicated and beyond the scope of my understanding of physics.  But basically when a puff of smoke leaves the circular opening of the Airzooka, the ball of smoke experiences the friction of the surrounding air flowing in the opposite direction.  This friction pulls the puff of smoke backwards from its direction of motion causing the smoke to circle and forms a vortex in the shape of a doughnut ring.  This ring remains stable until it is sheared apart by turbulence or other disturbances.

I knew then that I wanted to build my own smoke cannon.  But this was not worthy of a final project, especially with my brilliant and talented classmates.  I wanted to improve on this design.  The easiest way was to of course go bigger.  Instead of a simple hand-held smoke ring shooter, I decided I was going to build a full size cannon built on a tilting frame.  Another thing I disliked about the Airzooka was that the user had to pull back each time in order to shoot the weapon.  I'm a pretty lazy dude, and pulling back on this thing every time I wanted to use it was going to be a total waste of energy that I desperately need to sit and watch TV.  The solution?  Let's make it totally automatic.  So there it was my project, a fully automatic smoke ring shooter.

The first step was to make a smoke ring shooter.  To do this was simple.  I cut out a circle on a plastic 20 gallon trash can and taped a plastic sheet on the other end.  To generate the smoke I used the sublimination of dry ice.  Indeed after taping on the back of the plastic sheet, smoke rings were generated.  The next step was to measure how much throw would be necessary to create a smoke ring.  I figured that pushing in on the sheet about 4 inches would create a nice smoke ring.  Now the hard part, how to make it fully automatic.  I knew from taking physics the semester before that circular motion could be used to create simple harmonic linear motion, much in the same way the linear motion of a piston creates the circular motion of a crankshaft, but for my cannon this processed would need to be reversed.

I knew what I wanted to do but I didn't have the skills to implement it.  I knew I was going to need some help.  It's at this point I posted an add on craiglist for a carpenter who could help me with the project along with the power tools that I would need to build my smoke cannon.  Luckily I found Chris Ring, a talented carpenter and metal worker in East Austin that was eager to help. 

Building the crankshaft:

                   Chris bending the crankshaft                       Me trying the hand at metal work

                Crank Shaft in the making                                      Completed Crank Shaft

The crankshaft is powered by a 9.2 Volt Cordless electric drill.

The stand was simply two triangle cut out of plywood with two horizonal braces on the front and the back.  And then Tada!!! The automatic smoke cannon comes to fruition.  Look at the camouflage paint, you can barely see it right?  Perfect for this simple deadly weapon.

     Check out the camo paint.  Can you see it?                        Me aiming the cannon

Of course I couldn't do this project on my own.  I would first like to thank Chris Ring again.  Arch welding is freaking hard trust me.  Without Chris's metal working expertise and skill the crankshaft could have never been completed, and my project would have been so ordinary.  Of course I want to thank Dr. Sandy Stone and my T.A Joseph Lopez for designing a course that allowed me to explore my talents and interests.  Finally I want to thank my classmates in the ACTLAB, you guys always encouraged me and your outstanding projects pushed me to try harder.  Though I am always outshone by your projects, my projects are richer than they would have been otherwise.  Hope everybody enjoyed the projects.  

-Johnny

For more information go to:

Science Of Smoke Rings Explained     Giant Smoke Cannon     Airzooka Spoof