Mia Maximus Culpa 
Whirlygig,
A couple of years ago Lu Zuckerman wrote in PPRuNe;
"Swishplate will have a totally different meaning in San Francisco."
It is all now very clear. Messrs. Errol Flynn and Stuart Granger published their voluminous half-page dissertation on 'Blade Control' in San Francisco. I just assumed .....
Dave