There's definitely a drag loss vs gravity loss trade off. I forget, were you gimbaling or steering with fins, or what? Ben On Saturday, November 16, 2013, wrote: > The reason I asked was that the software we first used with the Condor > Project spit out a solution to our problem of not building a tank to get to > 16+ km, which was the goal, was to throttleable back the motor. As a bonus, > it actually gave us a little bit more altitude than going full bore. in the > sim, We ran full throttle at 450 lbf for 9 seconds and then went down to > 110lbf for the next 60 seconds or so. The sim shows us hitting mach .92 at > throttle back and then slowing down to about mach .83 before gaining speed > again and going through mach a about 11Km. The rocket using this flight > profile was 26% lighter and got 10 to 15% higher than a sim of the same > design but full throttle until burn out. > > I understand the problem with solids but there has got to be a way to keep > it under mach in the initial boost stage so that going through mach and > heating is just not an issue anymore. > > Robert > > At 06:22 PM 11/15/2013, you wrote: > >> On Fri, Nov 15, 2013 at 4:19 PM, <qbert@xxxxxxxxxxxxxxx> wrote: >> > After going through several space blog updates I ran into a Sugar Shot >> to >> > Space blog which then led me to Bens Brokets assessment of heat vs >> speed and >> > altitude. The question I have, would it not be better to go slower >> though >> > the lower atmosphere, say up to 40,000, or even 60,000 feet until >> > approaching mach lessening both the dynamic forces and heating. >> > >> > Robert >> >> >> If the thought "would it not be better to go slower though the lower >> atmosphere" is run as far as possible, the usual conclusion is "let's >> build a rockoon" or "let's build a space elevator". But going >> hypersonic at 13km isn't impossible, it just takes some attention to >> materials and design. >> >> Ben >> > > >