From: JamesL@Lugoj.com   
      
   "John"  wrote:   
   > When I was a kid in the early 70's I had a paperback book that was   
   > called "A guide to amateur rocketry" that had plans for rockets that   
   > used a "carmel candy" propellent based on sugar/Potassium Nitrate.  You   
   > would melt it in an oven and pour the mix into the rocket casing.  The   
   > rockets were about 4' long and describes as capable of reaching   
   > 15-20,000 ft.  I think the book was written by an army captain.  The   
   > other fuel it described was a zinc/sulfur mix.  I don't remember any   
   > ISP numbers after all this time.  I haven't seen the book in at least   
   > 20 years, saw it listed on bookfinder for $48   
      
   The book you are thinking of is probably "Rocket Manual for Amateurs" by   
   Capt. Bertrand R. Brinley; (C) 1960. (No ISBN number.) I read that book   
   back in the early 70's too. The copy I read went missing sometime in the   
   last few decades, so a year ago I managed to buy a used copy online via one   
   of the used book sellers who sell through Amazon.com.   
      
   Brinley did not give any ISP numbers for the "caramel candy" propellant but   
   did specify a theoretical ISP of 46 sec for zinc/sulfur at a chamber   
   pressure of 1000 PSI. However, that was after a correction factor of 50% -   
   the uncorrected ISP would have been 92 sec. (The stated reason for the   
   correction factor was because one of the exhaust products, zinc sulfide,   
   has a heat sublimation at the flame temperature, so that it would not   
   expand to produce thrust. But Brinley pointed out that at that time it   
   wasn't clear to what extent that happened, if at all.)   
      
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