Abstract: A blade root for propeller and rotor blades made of fiber-reinforced composite material, for arrangement in propeller or rotor hubs of aircraft, ground effect vehicles, wind power generators or blowers with adjustable or variable pitch. The blade root comprises a parted blade ferrule and a basic body, so that the blade body is arranged between the basic body and the blade ferrule. The inner surface of the blade ferrule has a first, upper cylindrical segment, a second segment with a smaller diameter adjoining the first segment and being curved inwardly toward the longitudinal axis of the blade root, and a third segment with a larger diameter adjoining the second segment and extending outwardly. The blade ferrule is joined with the blade body by gluing. The parted blade ferrule is held together with two high strength rings, press-fit onto the ferrule. A pitch change pin is press-fit through the metal and composite part of the blade root.

Abstract: A hydraulically reversible, adjustable propeller unit for aircraft, land vehicles and watercraft, with a propeller with at least two blades, the pitch of which is controllable by means of a control unit (controller), whereby a hydraulic connection exists between the rotating propeller and the stationary control unit for controlling the blade pitch, with a spring-preloaded piston actuated by means of a hydraulic fluid, and with adjustable mechanical stop means for the start position, the brake position and the cruising or sailing position, whereby the piston is designed as a spring-preloaded double piston consisting of an inner piston and a ring piston arranged around the inner piston, said two pistons being lockable with each other by means of a centrifugal-force locking mechanism; the stop means for the start position is designed for limiting the setting range of the locked double piston in order to prevent unintentional reversing at speeds above about 1500 rpm; and the brake position can be reached only whe