I have a few questions about sugar rocket motors.
Its my understanding they are very hygroscopic, ie they absorb mositure very readily.... would it be posible to perhaps prevent this by vaccuum degasing and squishing the sugar propellant together to also prevent voids and get any extra moisture out plus then apply a thin vaccum bagged coating or carrier film?
Also has anybody ever done any end burning sugar rocket motors successfuly?
tia
terry dean nar 16158
The big moisture problem, for KNSU, comes from humidity in the air affecting the grain surface after the grain is cast. With high humidity, the surface of an exposed grain will literally dissolve into a syrupy goo in just a few hours. Storage in vacuum bags or desiccant jars is standard.
Jimmy Yawn has some nitrocellulose lacquer coating tests on his website. It seemed to keep the humidity out, but I don't know if he has working motors with such a coating.
Sure, my first sugar motors were 4" long end burners modeled after Estes motors (very short core to start with). But it depends upon what you mean by "successful". Low thrust and very inefficient; but they flew, every once in a while. ;)
They were nothing compared to the "great discovery" of core burners, though. If you measure "success" against a modern BP or APCP motor, the end burning KNSU PVC motor is just a big Jetex. But I imagine that a catalyzed sugar propellant grain in a properly designed (higher Kn) aluminum motor case would make a usable, if not efficient, motor.
What, exactly, are you looking for in an end burning candy motor?
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