Yep, you can just drill a hole in the bottom of the tank and use it as a
propellant tank. You need to make sure that the tank is FULLY empty and
purged before any drilling, and also now any rating on the tank is
completely gone. I would certainly suggest hydrotesting to above your
operating pressure to make sure that your machining wasn't structurally
detrimental, and then only testing remotely.
Also some aluminum tanks are stamped with the material, so double checking
that the material is 6061-T6 to verify it works with LOX is worthwhile.
An better solution might be, If you are only using this on a test stand,
you could also make a threaded fitting with a dip tube and a gas fitting
that screws onto the current port, allowing for gas and liquid withdrawal
with the existing port. I think the standard port is a 3/4-16 UNF for the
small industrial bottles, so you could have one 1/4" tube with a thru
fitting and a 1/4" NPT drilled out to 7/16" thru the fitting, and another
fitting drill in radially past the NPT for the other port.
Lloyd
On Tue, May 24, 2016 at 4:23 AM, Wensberg, Dana A. (2018) <
dana.wensberg@xxxxxxxxxxxx> wrote:
Does anyone know if an old aluminum gas cylinder (AT size, 1.7 ft^3) can
be modified into a propellant tank for an inert-gas pressurization liquid
fueled rocket. The maximum regulator delivery pressure to the tanks is
going to be 800 psi and the pressurizing gas is Helium. Fuel is kerosene,
oxidizer is LOX.
?Can I simply drill a hole in the bottom of the tank and fit it with the
necessary connections as the propellant inlet/outlet? Should I use the body
(tube) and cut off the top and bottom and replace them with hemisphere
caps? Or is it a better idea to get a completely new tank fabricated.
It would work wonders for my budget if I could in any way "recycle" an old
gas cylinder, no matter how minimal. Any input would be greatly appreciated.
Cheers,
Dana