Abstract: A rotary wing aircraft is disclosed and includes a fuselage, a gas turbine engine operated air compressor within the fuselage, and a jet nozzle driven rotor assembly situated over the fuselage and having a rotor axis about which the assembly rotates. The rotor assembly includes a generally hollow rotor hub and a plurality of generally hollow jet nozzle driven rotor blades extending radially outwardly of the rotor hub. The rotor hub defines air conduit means to the rotor blades. A section of at least one rotor blade comprises a foldable flexible air conduit for folding the rotor blade in a radial plane relative to the rotor hub. Releasable stabilizing means, including a droop stop, is disposed between the rotor hub and an outboard portion of the rotor blade beyond the flexible air conduit section, whereby the stabilizing means may be released and the blade folded in its radial plane with the flexible air conduit section acting as a hinge.