[BProckets] sugar formulae stability

[Dan Durachko]

Sleeter's book (I don't have it with me here at work) indicates that
KN-sucrose formulae undergo some sort of reaction (crystallization?) that
alters the propellant grain in such a way that the burn rate increases with
time.  Probably reaches some maximum - I don't have any idea of what a plot
of the change in burn rate might resemble.  Anyway, following his method,
you use a burn rate modifier (baking soda) to temper the burn rate such that
you don't blow the casing and/or the nozzle you are using.  Since you're
pushing the envelope of the materials you're using you would not want any
significant increase in burn rate with storage of engines or you risk a
cato.  So, I guess my question really should have been more like "Do all
sugar formulae increase in burn rate during storage?"  I don't recall
Sleeter indicating the reaction was due to the hygroscopic nature of the
sugar propellant but I don't believe that was the case.

I may very well (no . . . I DID) have gone down this road armed with less
knowledge than I should have had.  I don't even recall whether his sugar
formula used a binder like his other propellants do or if it was dry rammed.
I sort of brushed off that section of the book because of the mention of
limited shelf life.  I do remember he suggests using his sugar rockets
within 48 hours of production.  Just wouldn't work for me at this time.

Thanks for the input,

Dan

-----Original Message-----
From: bprockets-bounces at amateurrocketry.com
[mailto:bprockets-bounces at amateurrocketry.com] On Behalf Of donnie long
Sent: Friday, November 05, 2004 11:52 AM
To: Black Powder rockets discussion list
Subject: RE: [BProckets] homemade rocket body material sources and
techniques- "sugar" question

I have shot mine after a year and no problem, I am at
work now so won't be able to give isp or either, check
rick nakka site to get that info and your book should
tell you the other, assuming.  donnie
--- Dan Durachko <DanDurachko at psu.edu> wrote:

> I'll determine this on my own eventually but am I
> correct in my current
> understanding that *all* so-called "sugar"
> formulations have quite limited
> post-production shelf life?
> 
> Also, what are the theoretical and/or practical
> Isp's for BP vs sugar?
> 
> -----Original Message-----
> From: bprockets-bounces at amateurrocketry.com
> [mailto:bprockets-bounces at amateurrocketry.com] On
> Behalf Of donnie long
> Sent: Friday, November 05, 2004 10:39 AM
> To: Black Powder rockets discussion list
> Subject: Re: [BProckets] homemade rocket body
> material sources and
> techniques
> 
> Rocketryonline.com, rocketreviews.com, good place to
> start, riknakka.net or put in sugar rocket engines. 
> I
> started out over 10 years ago with bp but switched
> to
> sugar engine's, easier, cheaper, more power.  donnie
> --- Dan Durachko <DanDurachko at psu.edu> wrote:
> 
> > All:
> > 
> >  
> > 
> > I haven't actually built a rocket in over twenty
> > years and have just
> > recently zeroed in on my first BP engine a la
> > Sleeter's book.  In
> > anticipation of getting the book I'd been savings
> > all sorts of tubes and
> > have a box of balsa sheeting scraps for fins from
> my
> > other hobby pursuits.
> > Also, I've only built Estes kits as a youth.
> > 
> >  
> > 
> > Questions:
> > 
> >  
> > 
> > 1)       What are good web or book resources for
> > constructing rocket bodies?
> > 
> > 2)       At what point need I be concerned about
> > high g forces on launch
> > shredding my rockets and is this ultimately an
> > empirical determination?
> > 
> > 3)       What techniques are used to prep
> > paper/cardboard tubes for final
> > painting?  (Some of my salvaged tubes have rather
> > unattractive grooves in
> > them due to their spiral wound nature.  I may wish
> > to fill them in and paint
> > over them sometime.)
> > 
> > 4)       What are the currently favored types of
> > wadding to protect the
> > chute, etc.?
> > 
> > 5)       What are some sources of nosecones? 
> (I'll
> > ultimately make some on
> > my own from balsa and fiberglass and things like
> > those eggs pantyhose come
> > in but assume there are lots of sources I haven't
> > yet thought of.)
> > 
> > 6)       Is there a quick and dirty way to
> calculate
> > how much delay I should
> > build into my engines for a particular design so
> > that I don't pop the chute
> > WAY too early or WAY too late?
> > 
> > 7)       Feel free to chime in with any other
> > guidelines you may think I
> > should be made aware of.  (Shock cord info, fin
> > geometry, etc.)
> > 
> > 8)       Oh yeah, I remember seeing some stuff
> > awhile back about guys
> > stripping down and hacking into digital disposable
> > cameras for high altitude
> > stills.  Any cutting edge references to that sort
> of
> > aerial photography
> > would be much appreciated as well.
> > 
> >  
> > 
> > Whew . . . that should do for a start!
> > 
> >  
> > 
> > Later,
> > 
> >  
> > 
> > Dan
> > 
> > > _______________________________________________
> > BProckets mailing list
> > BProckets at amateurrocketry.com
> > http://exrocketry.net/mailman/listinfo/bprockets
> > 
> 
> 
> 
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