How to calculate the Gust Envelope?
The gust envelope is four lines overlaid on the flight envelope, usually the plus/minus of maximum gust at design cruising speed (Vc) and half maximum gust at maximum speed (Vd) as required by the certifying authority. This is usually +-50ft/sec (15.2m/sec) and +-25ft/sec (7.6m/sec).




n is the normal acceleration in a sharp edged gust
K is the tailplane gust alleviation factor. In a canard this is an aggravation factor.
u is the airplane mass ratio


The source contains examples of how the lines are calculated. The following information (defined) is required: