Newsgroups: sci.space.tech
From: henry@spsystems.net (Henry Spencer)
Subject: Re: Rocket engines-Basics expl ?
Date: Tue, 2 Jan 2001 03:13:20 GMT

In article <92qt5l$i6@dispatch.concentric.net>,
Hiram Berry <burningb@burningbridges.com> wrote:
>> >Temperatures exceeding 6000degC have been achieved with chemical fuels...
>
>...I suspect a bit of hyperbole is going on here
>concerning flame temperatures; the highest chemical flame temperature I've
>seen quoted (and promoted in Guiness as the hottest such ever achieved) is
>4988 C for the combination carbon subnitride/oxygen...

Grosse's paper on achieving solar-surface temperatures (6000degC+) with
chemical fuels was published in Science a number of years ago.  Alas, I
didn't save a copy and hence can't supply a precise reference.

By the way, beware of *calculated* flame temperatures, which don't always
account properly for dissociation etc.  Grosse's temperatures were
measured, not calculated.

>...The assertion that acetylene derivatives and
>similar fuels are only lab curiosities that don't deserve serious
>consideration as practical fuels seems flawed to me also.

I agree; note that I did *NOT* say that.  What I said was that the
6000degC+ combinations were lab curiosities; Grosse used ozone and
dicyanoacetylene, both of which are dangerous explosives.
--
When failure is not an option, success  |  Henry Spencer   henry@spsystems.net
can get expensive.   -- Peter Stibrany  |      (aka henry@zoo.toronto.edu)

Newsgroups: sci.space.tech
From: henry@spsystems.net (Henry Spencer)
Subject: Re: Rocket engines-Basics expl ?
Date: Tue, 2 Jan 2001 03:03:22 GMT

In article <92p35n$sr4$1@gw.retro.com>,
George William Herbert <gherbert@gw.retro.com> wrote:
>>(These are not, actually, the highest possible chemical flame temperatures.
>>Temperatures exceeding 6000degC have been achieved with chemical fuels...
>>but with combinations that are not particularly useful as rocket fuels...
>
>That's not true, acetylene mixtures (including acetylene-propane,
>MAPP, and various variants; possibly acetylene-CO for Mars) are
>reasonably attractive for some space launch applications and burn
>that hot.

Check the numbers, George -- last I saw, getting *that* hot (solar-surface
temperatures) required very careful choice of combinations and had only
been achieved with one or two of them.  (It was first done by Grosse,
burning ozone and dicyanoacetylene [NCCCCN], neither of which is usually
deemed acceptable as a propellant.)
--
When failure is not an option, success  |  Henry Spencer   henry@spsystems.net
can get expensive.   -- Peter Stibrany  |      (aka henry@zoo.toronto.edu)