John: In moving to jet vanes, you traded a (relatively) easy engine problem and a hard control problem for a hard engine problem and a (relatively) easy control problem. Better still would be to keep both of the easy problems and get rid of the hard problems. I can see at least two ways of doing this.
1) Use a central engine with jet vanes as you have currently, and add any number of additional engines in a symmetrical pattern around it in order to gain the total thrust required. So long as you have enough control authority to compensate for any unevenness in these engines, it will work. 2) Go back to your original four-engine configuration, with each engine having one jet vane, oriented radially. You can put all the servos in the centre facing outward. This should give you greater control, especially for roll. In either of these options, you have already done all the engine development you need to do, and can get on with flying rockets. Roger -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of John Carmack Sent: Friday, June 04, 2004 9:12 PM To: [EMAIL PROTECTED] Subject: Re: [ERPS] Liquox At 06:59 PM 6/4/2004 +0200, you wrote: > John Carmack wrote: > > > We are considering mixed-monoprop + liquid catalyst for building huge > > engines (20,000 lb thrust) where solid catalyst would cost fifteen >thousand > > dollars or so. > > Changing from heterogenous to homogenous HP decomposition is not a small >step. > > Could you give an idea of the mixed monoprop composition intended? Are we >still talking 50 % H2O2? > > In which case you'd probably equally use glowplugs to ignite the alcohol >in the approx. only 200�F decomposition products. > Of which a large part initially 'll consist of oxygen and the rest of >*wet* steam. Have you been able to ignite such so far? > > JD All of our engines and vehicles for the last year have been 50% peroxide + methanol mixed monoprop, running slightly lean of stoichemetric. We have done several hundred firings, with up to 120 second burns, 145 s measured Isp, and 3700 lbf motors. It does actually work. It is superior to 90% peroxide monoprop in every way (cost, availability, performance, handling) except for startup characteristics and motor size. We used glow plugs for a while, but spark plugs work better. Once the bottom catalyst pack is up to temperature, the extra ignition source is no longer required. John Carmack _______________________________________________ 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
