A Bottled Carbon Dioxide Water Rocket Launcher

The InterPlanetary Water Rocket Society                     Gordon McDonough  12/06

    This launcher was assembled with the support of Partners In Education, a Santa Fe based organization that directly helps school teachers in the city with many of their classroom needs.
Thank you, Partners!                                           The cool wallpaper is from the Slide Rule Universe.

This launcher consists of four components:

The launch tube is 1/2" Schedule 40 PVC (white), capped on the bottom.  It was cut on the top with a tubing cutter to provide a square and smooth seat for a #94 "O" ring.  I reamed the top with an extended 5/8" spade drill bit drawn backwards into the tube, and cemented in a length of 1/2" CPVC (tan).  Dimensions depend on the intended rocket dimensions and the length of my long drill bit.  Pressure is introduced through a fitting in the side.  I have padded the bottom and  the top sections of the launch tube where it fits inside the riser with pieces of PVC so it doesn't rattle around.                                                                           Top

Cable tie release    The release is a Clark Cable Tie release system, invented by Ian Clark in Melbourne, Australia.  It is quite ingenious, and is used almost universally by serious water rocketeers.  There are details on my front water rocket page.
























  My current favorite stand is a 3' 4" (a ten foot length makes three) tall piece of 1 1/4" Sched. 40 PVC pipe. The bottom end has a block glued into it, and then I put a big spike through a hole in an end cap and glued it on, spike facing out for a ground stake. Three guy ropes attach near the top and are staked out with more spikes. The pull cord passes through a pully at the bottom and has a hook to pull on the launch tube bridle. This is the most portable launcher I have ever used.


Simple launch stand 2006


The pressure system includes, from right to left,  a bottle of liquefied CO2, an adapter to a nitrogen purging regulator (The threads and fittings are different for CO2 and Nitrogen,) a 1/2" NPT ball valve (red Handle), a hose quick release, and a 25' pressure hose (yellow sleeve on the end.)
pressure plumbing    I got all the parts from the bottle to the regulator at a welding supply shop for about US$200.  The regulator was a catalog order item.  The rest of it came off the shelf from a Home Depot for another $50.  In service, the tank valve is open, the output pressure is set on the regulator by adjusting the handle, and the rocket is pressurized by opening the ball valve.  I close the ball valve on three during the countdown.
 

    Notes: (2001)

CO2 bottle stand    And now we are ready to launch.
 

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My regulator is a Victor Medalist TPR250-500-580 (Mine says P250. . .) and is capable of output pressures from 10 to 500 psi (3500 kPa).  Liquid CO2 has a vapor pressure of about 400 psi (2750 kPa) at room temperature, and that should provide the effective limit, although I have no reason at this time to have tried going higher than about 150 PSI.  The high side gauge reads from 0 to 4,000 psi (28,000 kPa) and the low side from 0 to 600 psi (620 kPa)  The regulator was manufactured by the Thermodyne Company, and there is information on their web site at: http://www.thermadyne.com/vec/literature/pdfs/115_65-2007.pdf
    I live in New Mexico, where carbon dioxide extraction, a component of our natural gas industry, plays a major role in the state economy.   After a hundred or more launches, my bottle is still quite heavy, I am clearly not pulling my weight!