NAR recommend "Safe practices" "Launching Safely in the 21st Century" from NAR report 10-29-2005
"Safe Liftoff
Current text:
4.12.1 A high power rocket shall be launched from a stable device that provides rigid
guidance until the rocket has attained a speed that ensures a predictable flight path.
Proposed text: Add 4.12.1.1 When the wind at launch exceeds 5 miles per hour, the launch
guidance device shall be of a length to ensure that the rocket reaches a speed of at least four
times the wind speed before its departure from the device.
Rationale:
The NAR Special Committee's analysis shows that the center of pressure of a rocket
moves forward (toward a potentially unstable condition) and the flight trajectory of a rocket rotates
significantly off of the vertical direction when the rocket is exposed to a crosswind while traveling at
low velocities. If the crosswind is greater than 1/4 of the velocity at which the rocket departs the
launch device, the rocket's trajectory will depart from vertical by as much as 15 degrees, and the
rocket's center of pressure will move forward approximately one caliber (body diameter) compared
to the position calculated by most commercial rocket design software. This non-vertical flight and
reduction in stability could lead to an otherwise-safe rocket becoming a flight safety hazard. It is
important to establish a requirement for safe launcher separation speed , in order to prevent the
hazards of unstable flight or of flight outside the range of 20 degrees of vertical that is the limit
established in paragraph 4.12.3 of this Code that could lead to impact outside the launch site."