He says that HTP and Propane/Ethane don't go boom if they accidentally mix they're immiscible. Um. That's good, don't think I'll try it though ;-)
Anyway, cool idea. He wasn't positioning it as SSTO, it was more an upper stage thing.
-Ian
Sean Patrick Daly wrote:
This once again makes me weary about pressurized/gravity feed tanks. From the earliest stages of my designs, I have always wanted to implement a solution that would ensure my engines would never be starved under a negative G environment.I have thought of a few different ways that one might counter this issue. 1. Design a cylindrical tank with a piston/plunger. Pump the Nitrogen in through one side, pressurizing the tank, causing the plunger to move down the length of the tank pushing the HTP/Hydrocarbon out the other end. 2. Design a tank with a bladder bag system. Nitrogen is pumped into the tank, squeezing the bag, expelling the HTP/Hydrocarbon out the other end. This is a proven method in Fighter jets, but I'm still unsure if this will work at 600PSI+ tank pressures. It's an added expense, added weight, and added R&D, but at some point, (depending on your design/flight profile, it may need to be addressed. In the case of an SSTO, or any craft coming out of orbit/when coming off apogee and traveling back though the atmosphere, the craft can/probably will be in a negative G state. If you are coming out of "orbit", I would assume that most of the trip down, the liquid in the tank could quite possibly not be exactly where you "want it to be". My first thought was that this would only be an issue if you needed to restart your engine and fly back under power. I now wonder how this would affect ACS engines near/at/coming off apogee (not much atmosphere up there, so normal flight controls are useless until you get a little lower). I have been concentrating on the piston tank design so far, as it suits my needs, and I am WAY behind most of you in the development cycle. The bladder design looks to be much lighter and more efficient, but looks to be more cumbersome to implement, so I'll stick to the piston for now. Sean -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of David J. McCue Sent: Wednesday, November 13, 2002 6:40 PM To: [EMAIL PROTECTED] Subject: Re: [ERPS] Armadillo flight checklist At the risk of stating the obvious, I want to mention that atmospheric drag can put you into a negative G situation just by throttling back far enough while still climbing. A draggy vehicle like the one JC is going to fly will decelerate very quickly in air. I suspect that he will have to throttle down very slowly to avoid starving the engines. -Dave Mc On Wed, 13 Nov 2002 [EMAIL PROTECTED] wrote:Make sure you approach apogee slow enough that you don't get near zero or negative G's, causing the peroxide to move away from the feed plumbing. Or, realize that the engines may temporarily shut down, with major peroxide slosh, and deal accordingly. Dan In a message dated 11/13/02 12:23:26 PM, [EMAIL PROTECTED] writes: << The takeoff weight will be 350 pounds, and the acceleration will be under 1G, so this will look very different than an HPR launch >> _______________________________________________ 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 _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
