I've been reading through the copy of "High Power Rocketry 2" that I bought at NARAM-51 and last night was particularly looking at the required field sizes for various motors and something stuck out that has been bothering me.
How do many of our launches comply with this regulation (since its basis is in the NFPA code it *is* a regulation and not an organizational guideline)? According to the charts, a half mile square field would just be large enough to fly H and maybe I motors while I know of many launches on fields that size that have allowed much larger motors. The field for NARAM-51 by size alone would barely have been big enough for B and C motors based on its width but H's and I's were flown. Even the well known sod farm used at Southern Thunder at one mile square would only allow an L or maybe a small M. The code seems to indicate an area free of trees but are we basing our usage on fields beyond the launch field?
If we go purely "by the book," it would seem that many of our launches are significantly over-powered for the field size.
What am I missing?
How do many of our launches comply with this regulation (since its basis is in the NFPA code it *is* a regulation and not an organizational guideline)? According to the charts, a half mile square field would just be large enough to fly H and maybe I motors while I know of many launches on fields that size that have allowed much larger motors. The field for NARAM-51 by size alone would barely have been big enough for B and C motors based on its width but H's and I's were flown. Even the well known sod farm used at Southern Thunder at one mile square would only allow an L or maybe a small M. The code seems to indicate an area free of trees but are we basing our usage on fields beyond the launch field?
If we go purely "by the book," it would seem that many of our launches are significantly over-powered for the field size.
What am I missing?