Chris, I'm sure, when I did the "chalk-and-talk" conversion course on to the "Queen of the Skies" back in 1971, or so, it was referred to as "Wiffle Tree". However, I see from the magic of search engines now that it can be found under both spellings, with and without the "h", so I bow to accepting "Whiffle" as well.
Either way, the WT is an ingenious device. With such an equine history, maybe the "Iron Duck" should really have been the "Iron Horse" ...
JD
