My 7.5" Big Motoreater on a Research N800 boost only. Ahoy! There is no smoke grain. This motor is a D grain for t' 98/15360 Aerotech case and burns for 17 seconds. Liftoff weight be 60 lb., shiver me timbers, o' which 27 lb. was t' motor. Avast, me proud beauty! Flown at Florida Winternationals 2008 t' 12500 feet (and 2 miles upwind due t' weathercocking).