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