Let's see... My main is 260 sq. ft. (yeah, I'm a big boy) So 260 * .03 = 7.8 sq. ft. pilot chute. Find the diameter of a 7.8 sq. ft. round: Area = pi * r² A / pi = r² 7.8 / 3.14 = 2.5 r² = 2.5 ft r = 1.6 ft radius diameter = 2r d = 3.2 feet A pilot chute that is 3 feet in diameter! Holy crap. Mine is probably half that. But it works just fine... Have I done my math wrong, or is there something wrong with this ratio?