Using Jet Vanes on four engines can still make things more complicated. You still have to take into consideration the different percentages in engine times. Each engine comes to power at a different time and the exact thrust produced by each engine will most likely change with catalyst useage. The parameters for vane control would sould be ever changing and then you still have to deal with balancing the craft on the four engines with different thrust outputs. There is of course extra plumping and all the actuators and electronics to go with four engines. The single engine simplifies things. This I how I see it but I am not an authority on anything.
--- [EMAIL PROTECTED] wrote: > I don't know about gimballing, but I do think it > makes sense to put their > already-developed 4-engine system and their > already-developed jet vane system > together and just be done with major development > work. > > Cheers, > > Roger > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf > Of Russell McMahon > Sent: Tuesday, June 08, 2004 2:02 PM > To: ERPS list > Cc: John Carmack > Subject: Re: Multiple engines (was RE: [ERPS] > Liquox) > > Not that I claim to know anything, but: > I'm wondering if John is walking (or flying) the > inevitable path to > gimballing? > Starting with multiple engines seemed really > marvellous (and it was) but he > found that jet vanes were immensely more > satisfactory in practice. > The first successful mass produced liquid fuelled > rocket used jet vanes, but > they have pretty much vanished from the medium to > large sector and been > replaced either by vectoring using fluid injection > or by gimballing. What > are the advantages of jet vanes over gimballing? > > Perhaps: > - Less actuator force? > - Quicker response? > - Includes roll control? > - Engine rigidly fixed to frame. > - ??? > > Once you have gimballing implemented, the actual > control aspects look like > theyd be a dream compared to multiple engines or jet > vanes. > Longevity (measured in burn time) is preseumably > less of a problem than jet > vanes. Engineering deals in providing adequate force > rather than > thermomechanical considerations (vane > ablation/survival, bearing/shaft life. > ...). Reliability and safety would seem to be > superuor - it does or doesn't > work and as long as it can survive the (horrendous) > vibration environment it > keeps working. > > Thoughts? (may be from John?) > > > Russell McMahon > > > _______________________________________________ > ERPS-list mailing list > [EMAIL PROTECTED] > http://lists.erps.org/mailman/listinfo/erps-list > _______________________________________________ > ERPS-list mailing list > [EMAIL PROTECTED] > http://lists.erps.org/mailman/listinfo/erps-list __________________________________ Do you Yahoo!? Friends. Fun. Try the all-new Yahoo! Messenger. http://messenger.yahoo.com/ _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
