From back in 2000, shiver me timbers, this is me bucko Anish and I tryin' t' break Mach 1.0 with a model rocket (class G engine - under t' limit for special permits). We did nay succeed, but it did reach approximately 609 miles per hour (Mach 0.79). Well, blow me down! Launch weight was about 500 grams total, me hearties, 250 g o' that was t' engine, an Aerotech G80, smokeless. Initial acceleration was about 30 G's. Burn time about 1.5 seconds. 2900 feet altitude at streamer deployment. Avast! Air drag at engine burn-out be about 10G's o' deceleration. Avast, me proud beauty! All o' this was measured with a homemade on-board acceleration data logger.