Fluid motor with moveable members workable independently of its drive means

An air-borne craft which includes at least one propeller which is driven by a hydrostatic fluid motor and wherein said fluid motor receives a hydrostatic pressure fluid supplied by a hydraulic fluid flow supply means through respective fluid lines to said fluid motor, and which further includes in said hydrostatic fluid motor a housing, revolvably mounting a rotor, containing working chambers for the reception of pressurized fluid and displacement means for the transfer of force of fluid to a portion of the rotor and to revolve the rotor and a control body associated to the rotor and to the housing to control the flow of fluid into and out of the working chambers,

• wherein a passage body extends from a portion of said housing into a centric bore of said rotor independently of said control body;
• wherein said passage body includes two ports, two control fluid passages and two control ports;
• wherein said passage body is substantially stationary relatively to said rotor, and has a fitting portion interrupted by said control ports;
• wherein an axially moveable piston is provided on said rotor and said rotor includes a seal portion of a configuration complementary to said fitting portion and able to seal therealong;
• wherein said piston includes passages periodically aligning by an alternation with one of said control ports at one time of said alternation and with the other of said control ports at an other time of said alternation;
• wherein said rotor carries a fluid pressure housing which includes a pair of pressure chambers with springs and said piston therein while said passages alternatingly communicate one of said pressure chambers with one of said control ports;
• and,
• wherein said piston seals between said pressure chambers, is axially moveable in said pressure chambers and is having a connection member which extends through one of said pressure chambers and out of said one of said pressure chambers through one end of said one of said pressure chambers whereby it is sealingly fitted in said one end of said one of said pressure chambers.