In reply to Jed Rothwell's message of Fri, 16 Jan 2015 22:18:15 -0500: Hi, [snip] ><[email protected]> wrote: > >>That is the absolute upper limit to what a hydride can produce. 1430 J/g. >> >No chemical system can produce more than ~4 eV/atom which is close to what >> >the heat of formation of water is. >> >> Formation of 1 molecule of liquid water from Hydrogen and Oxygen gasses >> yields >> 2.96 eV. >> > >Right. Yes. Burning a diamond produces ~4 eV per carbon atom, I believe. >That is the maximum of any chemical reaction because diamonds have more >electron bonds per atom than any other common material. That is more energy >per atom but less per gram of fuel than hydrogen, because hydrogen is >lighter. H2 + O2 make the best fuel per unit of mass. > >Someone told me years ago there are a few exotic rocket fuels that might >reach 8 eV/atom, but nothing has actually been demonstrated. > >Rockets propelled by burning diamonds would be kind of neat! > >- Jed
One would think that it ought to be possible to significantly reduce the weight of the first stage of a rocket by using jet engines iso rocket engines. That way you save the weight of the Oxygen (by far the heaviest component), by using environmental air. I guess the Oxygen concentration in air isn't high enough to produce the required power level. Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
