AirLaunch used propane, and I think they got to hit fire. I don't think
they got to flight.
-R
On Thu, Feb 15, 2018 at 8:42 AM Ian Woollard <ian.woollard@xxxxxxxxx> wrote:
I don't know that anyone has ever flown propane as a fuel. Google suggests
you have to subcool propane to around 0F to get reasonable tankage
pressure. IRC someone (John Carmack?) suggested it becomes awkwardly
viscous at low temps, but it's possible they were thinking of
propane/butane mixes which wouldn't necessarily behave the same, but the
data on it seems to be behind a paywall and I don't have access, if you
really want to think about using it you should probably check that.
On 15 February 2018 at 01:15, William Claybaugh <wclaybaugh2@xxxxxxxxx>
wrote:
Evan:
Thanks, I had missed this.
I find myself wondering what an advisor would have said if Henry II (of
England) had asked for an iPhone: is SSTO a technology that is more
economic in future rather than today?
Because multiple analyses show SSTO at a limit price around $50 per Kg.,
it seems likely to be the preferred answer in a century or so when demand
has reached levels that justify that solution. The question I’m—in
part—trying to answer is whether a significant investment today can move
forward the time when SSTO flight rates are justified.
In the timeframe of SSTO viability it appears probable that “peak oil”
will be reached and thus that simpler hydrocarbons may be favored over
highly refined ones (because simple hydrocarbons can be relatively cheaply
derived from organic feedstock). Thus Propane over Kerosene.
Bill
On Wed, Feb 14, 2018 at 1:00 PM Evan Daniel <evanbd@xxxxxxxxx> wrote:
On Wed, Feb 14, 2018 at 1:55 PM, William Claybaugh
<wclaybaugh2@xxxxxxxxx> wrote:
If we are considering tripropellants, then the Hydrogen wouldpresumably be
used as the coolant (optimizing Isp by altitude is achieved by varyingthe
percentage of Hydrogen and Hydrocarbon being burnt). But that stillleaves a
potential coking problem at the hydrocarbon injectors and upstreamafter
shutdown; a hydrocarbon that evaporates w/o residuals seems likely tobe a
better choice than one that does not (like kerosene) if one is lookingto
avoid a post firing purge.
Part of XCOR's approach was to use a kerosene that evaporated without
residuals.
Doug's post on 3/29/17 to this list includes a photo and AIAA paper:
https://www.freelists.org/post/arocket/LPL-IPA-Effects-on-Copper,5
And a selected quote that the archives don't seem to display:
"...dry-residue-free fuels are strongly advisable, so that greasy
films cannot be created by fuel spills. We have had good results in
using 99% isopropyl alcohol as fuel; we even use the same supply for
the cleaning solvent to prepare the oxidizer plumbing. In the
transition to kerosene based fuels, we have settled on a grade of
kerosene equal or even superior to RP-1, a multiply-distilled product
with no non-volatile components. Conventional Jet-A or JP-4 has too
many high molecular weight species, aromatic compounds, and [too much]
sulfur content to be used in a long-life regeneratively cooled rocket
engine where low coking is mandatory. The jet fuels leave long lasting
residues, incompatible with oxygen, if spilled."
Evan Daniel
--
-Ian Woollard
Sent from my Turing machine