The Solid fuel for rocket I made with KNO3 + Charcole + Sulpher + Suger. (Namely Black Powder).
By weight, the ratio is 8:2:1:1.
Mix with very small amount at a time.
You can test with rice dust insted of suger, for storing.
Make the motor body with thick paper ( I Prefer brown paper with glazed magazine paper) multi layer.
Don't use adhesive in every fold, but use at last fold only. The small air gap will insulate and save the motor body from burning.
Make Nozzle using paper curve with two hollow pipe/dowel and rope, or Hard sand ramming.
Make fuse with cotton thread dipping in thin gum solution and rolling with black powder. Dry it.
I Do motor dia 1cm only and nozzle dia 3mm (Appx). Fill the motor with 5-7cm only with black powder, tightly.
Cover/seal the top of the motor (With or without burst charge / stars)
You can use some flash powder with a few copper sulphet crystal for the easiest star.
It flies just like charm.
More in the book of wfvisser's "Practical pyrotechnic" free e-book,
here and
"Fireworks: The Art, Science, and Technique" by Shimizu, Takeo. You can find the book over net.