(under subclass 24) Propelled aeronautical machines sustained by their buoyancy relative to the air, having also provision for sustentation or vertical lift by the downward thrust developed by flapping or reciprocating blades attached to the machines. These blades may also provide a part or all of the forward propulsion.
(1) Note. For machines having fixed sustaining air foils as well as beating wings, see this class, subclass 11.
(2) Note. For machines sustained by beating wings alone, see this class, subclass 22.
(3) Note. For beating wing construction, per se, see this class, subclass 72.
