E9 motors are CATO*-prone but have very long burn times; three seconds or so. One would take a light weight rocket (say 1.35" x 20") to 1000’ or more.
I would have started out with MUCH smaller motors, and for CRIPES sake do it in a parking lot far away from anything flammable. A concrete dumpster housing niche would be perfect.
*“Catostrophic failure”
