So far no one has mentioned the sound of the old RR Conways blowing off the compressed air used to spin them up...I could tell if the old Empress 60 (DC 8 50 series) was on time just about every night as it fired up all four and taxied off...my parents house was close enough to YVR that on a cold fall night it was easy to hear the start, then breakaway thrust...the sound of those four noisemakers shook the night air and crackled long into the climb toward Toronto...I used to try to listen until I couldn't hear her...and imagined it was over the prairies when that sound finally died off. It still stays with me...it was (and still is) aviation history!