For the engine in question, the injector had a smaller diameter than the
throat. You're right; I neglected to consider that variable before I posted.
As far as is gas purge good enough to get all the fuel out of the LOX
system, sure, that's never been a probTHUMP. Huh. OK, I guess that is
sometimes a problem. Tempted to #facepalm, but it was a legitimate learning
experience. On the basis of which, I tell people, if you don't have to
switch from IPA to kerosene, don't. If you get IPA in the LOX manifold, it
will evaporate overnight. Kerosene, with its much lower vapor pressure,
will not. Then you get to see how your crew deals with an emergency.
(Joel Brinton won my eternal admiration for his aplomb in the after action:
"I teleported to the pickup truck - I wished to be there, and then I was -
grabbed the burn kit, and got ready to haul the pilot out the right side."
"Over the stick?" "If necessary." "That would have hurt." "Not as much as
being on fire.")
There's also fire fighting: water and IPA are infinitely inter-miscible.
You can dilute an IPA spill to non-flammability by throwing water on it in
almost any fashion. With kerosene, if you dump a lot of water on it as a
random deluge, you can float the burning kerosene away, to the great
displeasure of your lower-elevation neighbors.
-R
On Tue, Apr 26, 2016 at 12:00 AM Uwe Klein <uwe@xxxxxxxxxxxxxxxxxxx> wrote:
Am 26.04.2016 um 05:45 schrieb Henry Spencer:
On Mon, 25 Apr 2016, David Weinshenker wrote:
(That said, a lot of rockets have used aluminum tanks for ethanol,
without difficulties that I know of.)
Is ethanol even particularly corrosive to aluminum in the first place?
"Particularly", perhaps not, but slightly, yes. Enough to be a concern
on prolonged exposure, anyway -- I believe it's an issue in substitution
of bioethanol for gasoline as a vehicle fuel. I'd expect that much
depends on details like the exact alloy and the water content of (and
other impurities in) the ethanol.
Most issues i've heard of are related to incompatible elastomerics.
( seals and hoses )
As water is fully mixable with alcohol the biofuels can carry more
water? ( What previously gummed up the tank bottom.)
uwe
