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