From: Henry Spencer <henry@zoo.toronto.edu>
Newsgroups: sci.space.tech
Subject: Re: Ejector Ramjets (Was Re: Injector ramjet launcher?)
Date: Sun, 24 May 1998 22:11:32 GMT

In article <356224BB.1C40@primary.net>,
James A Davis  <jimdavis2@primary.net> wrote:
>> >Oxidizer?
>> N2O.
>
>Laughing gas? My Kit and Evered dismiss it with the phrase "Nitrous
>oxide has been considered for use as an oxidizer but thermodynamic
>calculations show lack of promise." I suppose for a test handling
>concerns prevailed. (Unless you meant N2O4?)

By number of launches, N2O may actually be the most commonly-used liquid
oxidizer these days... because small hybrids using N2O as oxidizer are
commercially available, and increasingly common, in "high-power rocketry",
model rocketry's big brother.  It's the only rocket-grade liquid oxidizer
that is available over the counter and is largely free of handling
problems.  (Hydrogen peroxide comes close on ease of handling, but is not
readily available in rocket grades:  commercial high-concentration
peroxide invariably has stabilizers added.)  This makes it a logical
choice for amateur efforts and small-scale development projects.

I have heard serious proposals for using N2O for bigger things, too.
Quite apart from handling issues, it can be self-pressurizing, and its
performance -- while not great -- is respectable.

Also, handling concerns are non-trivial even for professional rocketry,
especially for reusable vehicles.  (NASA has repeatedly studied replacing
the shuttle OMS/RCS hypergolics with something a bit less obnoxious,
because it would cut orbiter maintenance costs and hassles quite
substantially.)
--
Being the last man on the Moon                  |     Henry Spencer
is a very dubious honor. -- Gene Cernan         | henry@zoo.toronto.edu