real world measured drag coefficient, heeled and straight, of a common glass keelboat

Yes, there is a chapter with photos in "The Common Sense of Yacht Design". He made models and towed them in pairs from a yoke. The one with lesser resistance got compared to a new model and so on, until the one with least resistance was left.

 

Might work for models, but most of us don't have two full size boats to tow on a yoke. I do wish I had a copy of "The Common Sense....". Last time I looked the volumes were very expensive.

Marc