[Space] Interested Rocket Man

James Mulroy james.d.mulroy at gmail.com
Mon Jul 11 19:00:55 UTC 2011

@Christopher--Sounds like a plan.  I'm pretty sure that I can make it out
that weekend.  Where are you guys flying out of and what time?

@Jonathan--PVC motors are somewhat popular because they are cheap and easy
to make.  Unfortunately when they blow up they make a mess and make a lot of
damage.  I was testing a non-PVC motor (it was aluminum) with a PVC test
stand, and I did it near a garage (big mistake).  When it blew up, the PVC
shrapnelled right into garage causing $300 in damage and completely
decimating the siding.  It was a grenade.  PVC motors are bad.  While I'll
never test a motor again unless I'm in the middle of a field, the point it
that they can hurt someone and they can cost you $$ in damage when something
goes wrong, and something WILL go wrong at some point.

Composites and aluminum are far superior materials because they do not
shrapnel.  You can get hundreds of dollars in high pressure composite pipe
for free if you bring a case of beer to construction workers building a gas
station.  Use that instead.  It's free, and withstand higher pressures which
means a bigger range of propellant types, and most of all--it won't kill
someone.  That's my suggestion.

Oh, and also, burning PVC is totally disgusting.  It's make cyanide and who
knows what other nasty crap that you don't want to inhale.

I suggest that if you want an "easy" motor then you make a "nozzleless
rocket motor."  This is something that I want to pursue.  They have a lot of
benefits, they're cheap, and they're awesome!  Look up Ray Goodson's
nozzleless rocket motors on Youtube.  There is a 5" and 3" version you'll


On Mon, Jul 11, 2011 at 10:28 AM, Jonathan Moore <moore at eds.org> wrote:

> On Sun, Jun 12, 2011 at 2:40 PM, James Mulroy <james.d.mulroy at gmail.com>
> wrote:
> > I don't doubt it.  There is definitely more electronics (gas control) in
> a
> > hybrid.  More machining too!  I think it would be a fun project.
> The all PVC engines seem real simple to make and use. The biggest pain
> is just hauling out the NOX to the launch sight from what I can tell:
>    http://www.google.com/search?q=pvc+hybrid+rocket+engine
> -Jonathan

James Mulroy
Student Researcher
Freelance Writer <http://www.pcworld.com/author/James-Mulroy>
james.d.mulroy at gmail.com
(920) 470-3473
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