Potassium nitrate/sugar propellant improvement

We know that hexamine can not be oxidized with KNO3 but with the additive phenolphthalein. My simple assumption was now that phenolphthalein could improve the combustion behavior of potassium nitrate/sugar  (sucrose, sorbitol etc.) as well, so I made a quick comparison test of 2g KNO3/sucrose and 2g KNO3/sucrose (65:35 ratio) with some phenlphthalein added:

The mixture with the added phenolphthalein was easier to ignite and burned much quicker. The melting points of sucrose (185–186 °C) and sorbitol (110–112 °C) are far lower than the melting point of phenolphthalein  (260 °C), so phenolphthalein and KNO3 could be both dissolved in dry heated sugar.

Update August 29, 2011 

I just found a first source (The chemistry of fireworks by Michael S. Russell) where it is mentioned that phenolphthalein was used to enhance the burn rate of gun powder. Page 42: "...together with an organic fuel, known as phenolphthalein, which is said to enhance the burn rate."
I was not aware of this. I found the effect of phenolphthalein by myself without this knowledge.
Another source (Black Powder Manufacturing, Testing & Optimizing by Ian von Maltitz) says on page 27: "Phenolphthalein has been used as a charcoal substitute [for black powder]. Its use hasn't gone much beyond the experimental stage. This is possible because phenolphthalein is very expensive when compared to charcoal..."

Neither phenolphthalein and KNO3 nor phenolphthalein and KClO3 are combustible without a second fuel. 

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