This link describes the difficulties of burning boron (forms molten layer that shields the remaining boron from oxygen) and says that by adding some percentage of magnesium the burning issues are better. http://www.afsbirsttr.com/Library/Documents/Innovation-050610-MACHI-OSD05-T001.pdf
Also the same link lists the kJ/g for solid boron, 59 kJ/g. Solid Boron is 2.35 g/cm^3 and this works out to about 138 MJ/liter which is the same value found on wikipedia But I can't find the kJ/g or MJ/liter for powdered Boron. Note that powdered Aluminum is 3.8 times less dense than solid aluminum. So is Boron 3 to 4 times less dense than solid Boron? If so, Alan's number of 53 hours of run time should be reduced by a factor of 3 down to 17.6 hours. There is no way to ignite solid Boron - it has to be powder. On Fri, Mar 11, 2011 at 9:46 PM, Alan J Fletcher <a...@well.com> wrote: > At 05:54 PM 3/11/2011, Jones Beene wrote: > > Well, yes. Borates may be non-toxic, but how cleanly do you think a boron > fill in this kind of configuration could burn in air? > Think about it! It’s completely out of the question ! > > > http://www.islandone.org/Launch/boron-sharp-article.htm > > Boron combustion (including air) is a very rich research field, > particularly in rocketry. > They don't seem to think it's a problem leaving boron combustion products > in the atmosphere. >
