THE REAL BOTTLE ROCKET
 

OR

MEGA FILM CAN CANNON

It started with a website that explained how to make a film can cannon, a simple device that used household items to make a nice bang.  Hair spray, a film can and a lighter (the one with a piezo igniter) was all that was needed.  My only problem was I didn’t have a film can.  I DID have some soda bottles, round plastic, O-rings, excess wood and a lathe.  I measured the inner diameter of a regular single serving size soda bottle, and machined a plastic piece that the neck of the soda bottle could slip over with an airtight seal.  I used and O-ring which fit into a groove on the plastic piece to make a nice tight connection that would slip on, and hopefully pop off with a bang.  I drilled a hole through the center of the piece to insert some wire to create the spark gap.  I then placed the piece on a block of wood.  This made my launching device.  

I used an old lighter with a piezo igniter to drive the spark gap, but the tiny spark was too weak to ignite the fuel air mixture in the bottle.  I was very disappointed and decided and good strong hot spark was needed.  I wanted a battery-powered device, which would create strong sparks.  I had known that T.V. flyback transformers were good sources of high voltage power, but I was fresh out of old monitors and T.V.’s so I was out of luck.  Then one day I happened upon an old computer monitor that had been thrown in the trash.  I took it home and tore it apart.  Inside I extracted the flyback transformer, various power MOSFETs and BJTs, capacitors (nice H.V. ones) and other such stuff.  I had hit the jackpot!  I found a circuit online to drive a flyback transformer and I adapted it to work with a power MOSFET.

The circuit is INCREDIBLY simple, one power MOSFET, and one resistor.  It worked, and created nice strong sparks.  I connected a HV capacitor in parallel with the spark gap, and I had a very SNAPPY spark that fired rapidly!  MUCH BETTER!

I mounted all the components into a black project box,   and wired up a super simple fire switch.  The result was a device, which I could easily connect to my launcher.  The system was tested and works flawlessly!  I have launched a 2-liter soda bottle with this device, and let me tell you, THIS IS FUN!!!

BottleRocket.wmv ~ 2.1 Mbytes

BottleRocketOutside.wmv ~ 4.5 Mbyte