> ignitor,so he would add a little gunpowder to the engine to help it start > . One time, the news people showed up to cover the event. When he > launched his rocket, it started out fine, and the camera stayed on his face > as he watched his rocket climb. At one point, he busts out in hysterical > laughing,and the news people never explained to their audience why he did > that. AS it turned out, his rocket had exploded spectacularly at about 400 > feet! Not caused by the extra ignition.. E engines have a SERIOUS problem with cracked grains, resulting in explosion. > horizontal, accelerated to probably >600 knots, and slammed straight into > the telephone pole with a BANG that was loud even where we were 200 ft > away. That groundskeeper probably needed an underwear change! 600's a BIT optimistic. 300 I'd believe. My toys start with H engines, and I'm certed through J. I've broken mach, but it took a few more logs on the fire than an E engine will give. The mos hideous question we get is for a "schematic for a radio controlled launcher" or a "computer controlled launcher"... It always sounds like a cool idea, until you understand the penalties for one wrong ignition. I was at the meet here in muncie when AFAIK the first injury directly related to model rocketry occurred. A fellow was prepping his bird, and had his head over/inside the body, when the computer-controlled ejection malfed, blowing at least a gram of FFFF powder in his face. We had an optometrist on him in seconds (damn good luck!) and an ambulance rolling in a few more seconds. His sunglasses saved his eyes. This computer controlled recovery system is commonly used, but apparently his safety interlocks weren't functional, and it blew. They sense by barometric sensor, and it may be that a drop of sweat or conductive debris hit the controller board.