Fin Area on a Rocket


The size of the fins controls a rocket’s stability and the amount of weather cocking (turning into the wind). The best way to determine final fin size is to do a center of gravity measurement and calculate the center of pressure. The center of pressure should be aft of the center of gravity by a distance of one body tube diameter or more. However, the center of pressure calculation assumes you know the fin size, but what do you use for a starting point? For a three fin rocket the related formula is shown here.

Related formulas


fAfin area in inches (dimensionless)
dbody tube diameter in inches (dimensionless)
Lbody tube length in inches (dimensionless)