Solid fuel rocket motor manufacturers usually provide a variety of propellant types. Some fuel mixtures burn quickly for high thrust for a short period of time. Others burn slower for a lower thrust for a longer period of time. Some produce little smoke. Some make a dense black smoke. And some burn with a red, blue or other color flame.
Most commercial solid fuel used with high power rockets is a composite material made of ammonium perchlorate with a rubber binder. The rubber also serves as the fuel. Different additives can be used to create effects like sparks or colored flames.
Another type of motor is a hyrbid. It uses a gas, like N2O (nitrous oxide) as the oxidizer (source of oxygen), and a solid material, like cellulose, as the fuel.
Submitted by: Dean A. Roth