Yes you are right here is a video of my 10lb EDF model just barely ROG with a motor and fan package that has been around for some years. 90mm
http://www.kcox.rchomepage.com/videos/Rhino.wmv
And here is one with an EDF airframe that is about 7 years old and it just barely got off this dirt field. Using off the self motor and fan unit. 90mm
http://www.kcox.rchomepage.com/videos/Plenum1.wmv