A hydraulically adjustable propeller assembly for an aircraft, a land vehicle or a water craft, includes an engine, a propeller unit having a propeller which comprises at least two propeller blades whose pitch is hydraulically settable, a pressure control unit which predetermines a fluid pressure for setting the pitch of the propeller blades and which is hydraulically connected to a pressure chamber of the propeller via a control line, and a pump unit which supplies a hydraulic fluid which is under a base pressure to the pressure control unit. The pump unit is a unit driven independently of the engine and the pressure control unit and includes at least one electrically operated main pump which supplies the hydraulic fluid which is under the base pressure for the pressure control unit.

The present invention relates to a controllable pitch propeller capable of changing a blade pitch according to the sailing conditions of a ship and, specifically, to a controllable pitch propeller having an optimal hub-to-tip diameter ratio, the propeller being capable of reducing the size of a hub so as to have a high efficiency that is close to the propulsion efficiency of a fixed pitch propeller (FPP). In order to accomplish the aforementioned objective, the present invention relates a controllable pitch propeller which comprises a hub mounted at the propelling shaft of a ship, and a blade that is mounted at the circumference of the hub and that has a variable pitch, and which is technically characterized by a H/D ratio, of diameter (H) of the propeller and diameter (D) of the hub, of 0.170-0.2.

The invention relates to a control apparatus for a hydraulic variable-pitch propeller (12) of an aircraft, land vehicle or water vehicle, comprising: a hydraulic oil feed line (24); a control line (16) which can be connected to the variable-pitch propeller (12); a pressure generating device (73) which is connected to the hydraulic oil feed line (24) and provides hydraulic oil with a basic pressure; a servo valve (78) which is arranged downstream of the pressure generating device (73), the input pressure to which servo valve is the basic pressure and the output pressure from which servo valve during normal operation defines a control pressure in the control line (16) and which servo valve is connected to a controller (28) which delivers a control signal for changing the control pressure; and pressure reducing means which are arranged downstream of the servo valve (78) and upstream of the control line (16), which are mechanically actuated and which, in the event of a failure of the servo valve (78), change the control pressure in the control line (16).

A method to fill hydraulic oil in hydraulic steering systems for boats. The method uses a closed system to reduce mess and waste, but does not require power and can be performed by a single operator. A bleed lock is secured to a ram's bleeders and hydraulic oil fed to a helm. By rotating a boat's steering wheel and moving the motor, air will flow out of the system into the bottle and hydraulic oil will flow into the system.

A method to fill hydraulic oil in hydraulic steering systems for boats. The method uses a closed system to reduce mess and waste, but does not require power and can be performed by a single operator. A bleed lock is secured to a ram's bleeders and hydraulic oil fed to a helm. By rotating a boat's steering wheel and moving the motor, air will flow out of the system into the bottle and hydraulic oil will flow into the system.

The invention relates to a control apparatus for a hydraulic variable-pitch propeller (12) of an aircraft, land vehicle or water vehicle, comprising: a hydraulic oil feed line (24); a control line (16) which can be connected to the variable-pitch propeller (12); a pressure generating device (73) which is connected to the hydraulic oil feed line (24) and provides hydraulic oil with a basic pressure; a servo valve (78) which is arranged downstream of the pressure generating device (73), the input pressure to which servo valve is the basic pressure and the output pressure from which servo valve during normal operation defines a control pressure in the control line (16) and which servo valve is connected to a controller (28) which delivers a control signal for changing the control pressure; and pressure reducing means which are arranged downstream of the servo valve (78) and upstream of the control line (16), which are mechanically actuated and which, in the event of a failure of the servo valve (78), change the control pressure in the control line (16).

A propulsion system includes at least one permanent magnet motor, the magnet motor including an outer housing structure. In the housing structure, a stator and a rotor are arranged in such a way that a gap is formed between the stator and rotor, the stator being fixedly connected to the housing structure, while the rotor is connected to a motor shaft extending through the housing structure. A plurality of coils/windings are arranged around an inner circumference of the stator, while a plurality of permanent magnets are arranged around an outer circumference of the rotor. Through a coupling, the motor shaft is connected to a propeller shaft including a propeller. A thrust bearing and a propeller pitch control system are integrated into the permanent magnet motor.