Usin' E-25-7 Aerotech ammonium perchlorate core burnin' motors, single-use. Ahoy! In a light weight rocket, with plastic wings (ali metal was too heavy) and epoxy joints, t' impulse o' an E-25 can just break t' speed o' sound at sea level = 760mph. Well, blow me down! T' rocket makes a slight 'crack' sound, unlike t' sound it makes in a heavier machine but it is a subtle difference. We couldn't measure t' speed for sure - Estimates were usin' software (speeds were from 1000 - 1500mph). Well, blow me down! These were built for speed rather than altitude but they still go high. Ya scallywag! Details in t' video. I also made even smaller rocket usin' these motors usin' 18mm diameter tubes. These are 24mm. Ahoy! If you do this play safe. Mind you I'm nay sure these motors are made in this spec anymore. Ya scallywag! This video was made a while ago.