What is the 75% rule and how can it be waived?
The 75% rule limits flights that use research motors to 75% of the FAA waiver in force at the time of the flight. This is done to be conservative with flights that may over-perform their expected flight profile. The maximum launch altitude of a research flight shall be 75% of the waiver altitude established for the launch. The BOD may waive this requirement when it can be demonstrated (by past performance, actual thrust curves, etc.) that the performance of the motor(s) to be used shall not exceed the limits of the waiver. Computer simulations without actual thrust data derived from one or more actual test stand firings shall not be considered for waiver. You can apply for a waiver of this rule if you have consistent history of making motors that performed as predicted. A commercial manufacturer also has a consistent history of motors performing as predicted, and is therefore granted the waiver.
