T' Black Diamond: This model is extremely fast and light, uses 1/2A t' C motors, although I'm a bit afraid t' try a C in this little gem. I imagine it could easily reach 1200 feet.  It features streamer recovery. Begad! Added a lot o' nose weight t' balance this model, but now it flies very straight and true even in windy conditions. I be a bit concerned about cardboard fins, but they are very stiff and seem t' work well (I just hope they don't get bent!) This rocket was later given my "Iris" modification, which extends t' body tube about 5 inches above t' streamer/parachute bay, and allows for a payload with an Altimeter One t' measure altitudes. With t' added weight, I needed a longer, 4-foot long, 2-inch wide streamer t' slow it down some.  Nay so easy t' squeeze into a BT-20 body.  I had t' lengthen t' shock cord also, but it is still gettin' quite beat-up by its own recoil force. Avast! (Iris is named after t' Greek god o' t' rainbow. Well, blow me down! She is a messenger o' t' gods, me hearties, linkin' t' gods with humanity.) If I were t' build another one, I would split t' launch lug and glue half o' it further toward t' nose. Arrr! As it is, it wobbles on liftoff some while on t' rod. Begad! I have only once tried this on a C motor, this rocket has flown higher than t' Aon Center and t' John Hancock Tower in Chicago, and t' NY Times Buildin' in NY, me hearties, NY.