Simple Rocket Propellent
Potassium Nitrate (KNO3)
The first thing to do is to prepare doses: 75% of Potassium Nitrate, 15% of Carbon and 10% of Sulphur, then pour into a peste the potassium nitrate and reduce it in a fine powder. Now pour the sulphur and the carbon into the peste and mix to obtain a homogeneus grey powder.
This mixture burns very fast and produces extremely high temperatures, so it can be used to make cheap rockets or as thermite.