On Sat, 2002-09-28 at 13:33, David Weinshenker wrote: > Randall Clague wrote: > > > > On Sat, 28 Sep 2002 11:07:40 -0700, David Weinshenker > > <[EMAIL PROTECTED]> wrote: > > > > >By "emergency scram" I meant the rapid simultaneous shutdown of both > > >propellants, without "sequencing down" through monoprop mode - i.e., > > >a shutdown during which the catpack could not be kept operating while > > >purging the fuel side of the plumbing. > > > > Ah. "ABORT ABORT, ALL STOP! Crap. What happened?" > > > > Yes? > > Yeah, that sort of thing... those "yank the prevalves shut and > ask questions later" type of moments. (Not planning to have them, > but we had better plan _for_ them...)
I'm reading this and thinking about emergency shutdown and wondering - is the immediate cure worse than the cold? i.e. what abnormal conditions are you putting on the engine by doing a full stop - and does this actually help the situation or do you cause greater risk to the system? At any rate such a shutdown would probably guarantee that you do not have to worry about starting that engine again. The other thought is - in such a situation, would an orderly shutdown actually be quick enough and less dangerous? Given a HTP/kero engine, with HTP regen cooling a normal stop operation might be: 0.00s Three way valve on fuel line switched from fuel to purge gas. 0.10s close fuel/purge valve 0.20s switch HTP valve to purge gas 0.30s close HTP/purge valve (Times are wild guesses with little relation to reality but shows the general idea.) Perhaps the "emergency" shutdown would do the same thing with 50ms intervals rather than 100ms intervals. Dave _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
