(under subclass 4) Aeronautical machines having provision for sustentation in part or entirely by aerodynamic action on airfoils in fixed relation to the machines, and having also sustaining elements having radially extending airfoil blades, the sustaining elements being rotatable about substantially vertical axes by the reaction of the relative wind on the airfoil blades.
(1) Note. For machines having only auto-rotating wings for sustentation, see this class, subclasses 17.11+.
(2) Note. For the rotating sustaining wings, per se, see this class, subclass 39.
