An
Exercise in Rocketry at Vanderbilt
Dyer Observatory
Rocket Valve
My local Ace Hardware keeps the following accessories.
I came up with this on a whim as I was
running out of time for our camp. The valve stem is seated in the rubber tip,
(after a small hole
is punched in the tip) and then the valve is seated on the pop bottle threads.
When you seat it, the
valve will slip inside the bottle and
the tip will grab over the outside of the threads. This combination
will get you to about 65 psi. If you want to wrap the whole thing with duct
tape 2x, that will allow for an increase
in pressure to 70-80psi. As you pump and the bottle reaches these pressures,
it will blow out on its own. The valve
will require a little muscle to put on securely. Try to seat it down to the
bottle lip. Be sure to remove the
little plastic ring collar on the bottle neck.
The parts are ACE Hardware #51241
Rubber Tips 7/8” (22mm) for chair legs
and
ACE Hardware Camel Brand #30-415-2
Snap-In Valve TR 415 1-1/4” eff. length fits .625 rim hole
duct tape for more pressure