This was a solo project I completed for Cal Poly Space Systems that involved the design, construction, and testing of a nitrous oxide pressure vessel. This will be used for testing our hybrid rocket propulsion system for the 2017 IREC competition.

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JOSHUA FIRTH-SCHAEFER
Undergraduate - Physics
Nitrous Oxide Test Tank – Cal Poly Space Systems, 2016 – 2017 Academic Year
My first project of the year has been the development and construction of a nitrous oxide tank capable of holding 18
pounds of nitrous at 800 psi. The idea of this tank is to have a sturdy container to protect our nitrous oxide in the unlikely
event of a catastrophic combustion chamber failure; we don’t want a ruptured oxidizer tank releasing decomposing
nitrous. Thus, beyond the pressure and oxidizer mass requirements, I was told that the tank needed a factor of safety of
at least 5 at 815 psi, and be rated to 2500 psi. This project required that I learn how to use MatLab, and add to my
knowledge of SolidWorks. Within the next few weeks, it will undergo hydrostatic testing and receive a certification.
As one might
imagine, this isn’t
just a machining
project, it has also
been a significant
research project.
Not only have I
exceeded all of my
prior capabilities in
SolidWorks and
Excel, I have also
created my first
practical MatLab
code in order to
model the
performance of the
test tank under specific conditions. Additionally, I have
created multiple iterations of this Mat Lab code as new
and superior nitrous oxide data is found and
incorporated. This
project has
demonstrated my
ability to tackle
significant projects on
my own with
autonomy, little
instruction, and
necessary research.
As soon as I was able, I ordered my material and began
work on the tank. Pictured just above is an aluminum
cylinder that will become two end-caps for the tank. This
project has involved nearly fifty hours of work on a
manual lathe and mill, and has served as a rewarding
challenge and learning experience.
Pictured above is one of the end-plates that fits to the
very top and bottom of the tank. Being eight inches in
diameter, it couldn’t fit onto our lathe chucks, so it had
to face it on a mill.
Once completed, the tank
weighed a little over 60
pounds, just four pounds
more than what my MatLab
code predicted. The excess
threaded rod was later
removed with an angle
grinder, and appropriate
plumbing will be attached. It
is able to hold between 12
and 18 pounds of nitrous
oxide at temperatures
ranging from 20 degrees to
70 degrees Fahrenheit.