[SS-Propellant] Launch of the Propellant Development phase ofSS2S

[Rich Nakka]

dormans wrote:

>  
>
> Richards, Paul Kelly's and Near's  motors that are cited as exhibiting 
> the triangular thrust curve  when using Sorbitol all used bates grains 
> that were presumably prepared in the same way.  A casting tube filled 
> from the top with molten propellant and allowed to cool.  Is it 
> possible that the KN, being heavier, is settling a bit from the top 
> and leaving a thin layer of fuel rich propellant at the top?  So that 
> it's not the space between the grains causing the ignition delay, but 
> that half of the grain ends have this layer of fuel rich propellant 
> that is delaying ignition.  The use of an ignition primer or pyrogen 
> ignition would not necessarily help if this is the case.  Has this 
> already been considered?  It's an easy theory to test, just trim a 
> thin layer off the tops of all the grains after curing or maybe it 
> would be easier to top off the grains during casting with a thin layer 
> of KN rich propellant or KN/SU as Tony has suggested.
>
> Randy
>
Very interesting theory, Randy. KNSB is the only sugar propellant that 
cures (hardens) slowly enough for this to be a possiblity. It is 
certainly worthwhile doing a test. Simply cast a slug of KNSB and allow 
it to cure, cut out some strands from the top & bottom (maybe middle, 
too) and measure burn rate....

Richard


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