Patents by Inventor William C. Fischer

William C. Fischer has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4385356
    Abstract: In a helicopter automatic flight control system having both automatic pitch attitude retention (70, 71) and automatic airspeed hold (84) and responsive both to pitch attitude error (206) and integrated (241) airspeed error (230), saturation of either the attitude error or integrated airspeed error circuitry is avoided by sensing (171) integrated airspeed error buildup to a threshold magnitude (which may be a significant fraction of the instantaneous authority of the automatic flight control system), and causing (169, 167) automatic slewing of the pitch attitude reference signal toward the current pitch attitude and reduction of the integrated airspeed error. In a disclosed embodiment, the correction of attitude reference and reduction of airspeed error is effected by utilizing an equal effective time constant (220, 221; 258, 259) for both actions over the same period of time (170, 168, 175).
    Type: Grant
    Filed: March 30, 1981
    Date of Patent: May 24, 1983
    Assignee: United Technologies Corporation
    Inventors: David J. Verzella, William C. Fischer, Don L. Adams, Stuart C. Wright
  • Patent number: 4383299
    Abstract: In an aircraft automatic flight control system (FIG. 1) beeping of the reference voltage in attitude synchronizing and beeping circuits (70, FIG. 4; 70R, FIG. 6) is inhibited (196, 201; 278, 282) in response to proportional commands (54, 55; 54R, 55R) in excess of a predetermined magnitude (183-186, 283-286). Beeping is inhibited only in the direction of the high proportional command, but not in the other direction. In a dual system (FIG. 1) pitch attitude beeping is inhibited only if both channels of the system have excessive proportional commands (195, 200, FIG. 3) whereas roll attitude beeping is inhibited if either channel has excessive proportional command (294, 295).
    Type: Grant
    Filed: March 30, 1981
    Date of Patent: May 10, 1983
    Assignee: United Technologies Corporation
    Inventors: William C. Fischer, Don L. Adams, David J. Verzella, Stuart C. Wright
  • Patent number: 4371936
    Abstract: In an aircraft automatic flight control system (FIG. 1) having pitch attitude synchronizing and beeping circuits 70-71 and airspeed control circuits 84, trimming of airspeed (233, 165) is achieved by beeping (104) or releasing trim (45) to adjust the pitch attitude synchronizer reference (208), causing the airspeed reference (232) to be synchronized (233, 165) for 25 seconds (156), unless the pilot applies force to the longitudinal axis (31, 32, 35) of the cyclic pitch stick (27), which causes (160, 156) termination of airspeed synchronizing.
    Type: Grant
    Filed: March 30, 1981
    Date of Patent: February 1, 1983
    Assignee: United Technologies Corporation
    Inventors: Don L. Adams, William C. Fischer, Stuart C. Wright, David J. Verzella
  • Patent number: 4371937
    Abstract: In an aircraft automatic flight control system (FIG. 1) having an airspeed controller (84), the engagement of the airspeed control function (244, FIG. 4 ) is initiated (123, FIG. 2 ) only in response to airspeed being greater than a 45 knot threshold (88). But once the speed threshold is attained, should the pilot override the airspeed control by applying force (35, 109) to the pitch attitude controller, airspeed engagement is retained (122) until a small airspeed error (126) indicates that the system has substantially regained the reference airspeed.
    Type: Grant
    Filed: March 30, 1981
    Date of Patent: February 1, 1983
    Assignee: United Technologies Corporation
    Inventors: Don L. Adams, William C. Fischer, Stuart C. Wright, David J. Verzella
  • Patent number: 4371939
    Abstract: The engagement (83) of a flight director (82) that provides automatic steering by roll angle of an aircraft which includes an automatic yaw trim system (FIG. 2) that will automatically coordinate turns induced by the flight director establishes (155, 157, 138) a heading hold disengagement mode which is maintained even if the flight director becomes disengaged (160) until the aircraft roll attitude is indicated as being nearly level (163). Exemplary roll channel (FIG. 1) and yaw channel (FIG. 2 ) of an automatic flight control system which may incorporate the invention are disclosed.
    Type: Grant
    Filed: March 30, 1981
    Date of Patent: February 1, 1983
    Assignee: United Technologies Corporation
    Inventors: Don L. Adams, William C. Fischer, Stuart C. Wright, David J. Verzella
  • Patent number: 4371938
    Abstract: In an automatic flight control system (FIG. 1) an airspeed control engage function (84) is automatically engaged (136, FIG. 2; 244, FIG. 4) in response to airspeed above a threshold magnitude, such as 45 knots (88, FIG. 2) and will remain engaged (subject to a fault condition, 135) until the airspeed command (75) reaches a predetermined, insignificant magnitude (132). An airspeed error integrator 241 which accommodates the difference between a reference attitude and an attitude required for a reference airspeed, does not react to large airspeed errors as a consequence of pilot maneuvering due to pilot force on the control stick (35, 109) opening the input (252, FIG. 4) to the airspeed error integrator.
    Type: Grant
    Filed: March 30, 1981
    Date of Patent: February 1, 1983
    Assignee: United Technologies Corporation
    Inventors: Stuart C. Wright, Don L. Adams, William C. Fischer, David J. Verzella
  • Patent number: 4330829
    Abstract: Oscillations in helicopter attitude sustained by the aerodynamic response of the helicopter to an automatic flight control system which is responsive to an attitude sensor, are eliminated by band reject (notch) filtering of a control system stability command to the aircraft, derived from rate of changes of such attitude at a frequency related to the aircraft attitude oscillations induced by the rate-controlled stability compensation.
    Type: Grant
    Filed: July 7, 1980
    Date of Patent: May 18, 1982
    Assignee: United Technologies Corporation
    Inventors: William C. Fischer, Don L. Adams
  • Patent number: 4314307
    Abstract: An electrical circuit for allowing electrical power to be applied to the ctro-mechanical sensors of an automatic flight control system of an aircraft only when either the Engine Start switch or AFCS Engage switch is closed separately or simultaneously. Upon the closing of either one or both of the switches, a pair of latching relays are energized which in turn provide electric power to the electro-mechanical sensors.
    Type: Grant
    Filed: May 5, 1980
    Date of Patent: February 2, 1982
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Albert Sivahop, Don L. Adams, Sr., William C. Fischer
  • Patent number: 4313201
    Abstract: The main roll and yaw axes of a helicopter having a main rotor operative in response to cyclic and collective pitch commands and a tail rotor operative in response to pitch commands, include stability inputs to actuators which are selectively provided by an analog channel, a digital channel, or one half by each, the digital channels being manifested in a digital computer system which includes programs of self-test, in-flight comparison between the inputs and outputs of corresponding analog and digital channels, and ground tests of testable rate gyro inputs to the various digital and analog channels and the outputs thereof.
    Type: Grant
    Filed: March 5, 1980
    Date of Patent: January 26, 1982
    Assignee: United Technologies Corporation
    Inventors: William C. Fischer, Albert Sivahop
  • Patent number: 4279391
    Abstract: A helicopter having an automatic flight control system including an inner, stability loop is rendered less sensitive to short-term, inadvertent pilot inputs by applying a washed-out derivative of a stick position signal to the inner stability loop in a sense to countermand the pilot action. Using a washed-out signal countermands only short-term rapid stick motions, which may be induced by the pilot actively, but inadvertently, or inactively due to coupling between the pilot or the stick and motion of the fuselage, while permitting purposeful, long-term stick positions to have the full, intended effect.
    Type: Grant
    Filed: January 24, 1979
    Date of Patent: July 21, 1981
    Assignee: United Technologies Corporation
    Inventors: Don L. Adams, Richard D. Murphy, William C. Fischer