General Advice (Rocket Motor)

My original topic contained the 9 motor designs listed in Figure 16-11. Unlike the new motors. I made them with steeply tapered cores, and I advised my readers to place their igniters no deeper than halfway to the front of the core. The original propellants burned quickly, and even the G100 had a burn time of less than one second. The tapered core and the partially inserted igniter provided a slower ignition time, and a few seconds of fire and smoke before lift-off. This was my attempt to provide a more realistic rocket flight: a feature considered important to people flying scale models, or rockets with fragile payloads. Unfortunately, the idea backfired, because people would often place the igniters too deep. When they did this, the motors would explode shortly after lift-off. generating another point of dissatisfaction with this motor building system.
To those of you planning to experiment with this method. 1 now advise you to start fresh. Forget the steeply tapered cores and the partially inserted igniters, and use the same tooling used to build the other motors in this topic. Slow the propellant’s burn rate by replacing the charcoal with 12 hour anthracite, and do your early experiments with core spindles shorter than what you think you will need to make a working motor. Then lengthen the cores a little at a time until you achieve the performance you want.