The whizzwheel won me a heart for the night many many years back when I was a callow PPL youth. It was in my top pocket and while chatting up a young lady I convinced her I was an aerodynamicist because I showed her my "circular slide rule." I mumbled something about lift formulae of her boobs quoting Lift = CL half row something V squared alpha and showed her how to work the whiz wheel and Bob's yer Uncle...