Thridle Op Des
I am surprised that you remember that far back... Are you sure that wasn't a pterodactyl flapping across the Horley skyline!
It is odd that an unbearably loud, unsociable noise to some, is the stuff of wet dreams to the rest of us! I'm sure there are more than a couple of old 212 hands, who have strived to attain just the right AOB/ROD/Pitch ATT/Speed combination, in order to create the ultimate blade slap. Especially returning from that late night medivac - it's only fair; if you're up at that ungodly time... Everyone else should be too!
Doc