Heli+:
Aside from Gordy's notes (I haven't got the time to read through it yet, sorry) I think you are talking about an article by our fellow PPRuNer Shawn Coyle in the "Vertical" February Edition "Torque Talk - Keeping up with the Joneses" (Page 112):
http://verticalmagonline.com/(S(h1rr...)/Default.aspx