James Yawn describes a method of preparing KNO3-sugar propellant that
does not require melting either component, but just heating an aqueous
syrup of mixed sugars, separately warming the dry KNO3, and then
mixing them off the heat -- a lot like BP blender rockets
conceptually. In fact it's JUST like blender rockets except that both
the fuel & oxidizer dissolve in hot water instead of just the
oxidizer. Mixed sugars such as corn syrup and sucrose are used to
inhibit formation of large xtals. The product is said to burn almost
as fast as propellant made by cooking the complete mixture.
However, the resulting mixture is not so plastic as to be rammable
into a case, or cast as a slurry as with blender rockets. Rather, he
rolls it into a cylinder with a core, then primes it inside and out to
form a constant-rate grain that he slides into the case. It's not
clear from his instructions (or what I've read of them so far) how
long after mixing the material remains plastic enough to do this
without reheating -- and it's heating the complete mixture that I
wanted to avoid -- and then how long it takes to dry and harden in
place.
Has anyone used this for firework sky rockets? If I wanted to turn it
into a progressive burner with a nozzle (apparently eliminating
caseless from consideration), is there another way to inhibit the
outside surface while allowing a fit loose enough to get it into the
case to begin with, but tight enough to resist the pressure during
firing? Or, with a catalyst, might caseless with no nozzle be fast
enough to allow it to lift go-getter style?
Robert
- posted 11 years ago