Some numbers stick in your head for no apparent reason. The main rotor diameter of the 206B-1 Kiowa was 35'4.0". Tail rotor diameter 5'2.0". I remember the low RRPM warning light came on at 330 RPM, forget what speed 100% NR was. The Kiowa also had an engine fire warning system which I've never seen in a civilian B206. Plenty of other differences.