You will need the following.Rocket tube/motor;
An A3 piece of paper
PVA (white) glue
Black powder - https://www.instructables.com/id/Making-black-powder./
Bentonite clay (as above)
A 15mm dowel with 4mm bore (bore optional)
A spindle with 4mm bore extension (optional)
and tube, and ramming device could be used. or if you want you could remove 1/2 the fun and buy your own pre made motor?!?!?!?Car;''''
Of course you dont have to make some BP you could buy some, or already have some. but the Black powder on my other instructable is well suited to this project and will burn at a good rate.