Thanks for the info. I have to ask though... what do you mean by "building up" an Estes engine with masking tape? I got a couple of great rocket glider plans from the "Scale Models" magazine I subscribe to from the U.K. I tried using an Estes "A" engine plugged with epoxy (didnt want the ejection charge) but the energy burst was to sudden and the heat burn't the tail off the glider. That explains my quest for Rapier engines.
Jim