Flight path angle

Claim 1

APPARATUS FOR COMPUTING THE FLIGHT PATH ANGLE OF AN AIRCRAFT COMPRISING MEANS FOR SUPPLYING A FIRST SIGNAL RESPONSIVE TO THE RATE OF CHANGE IN ALTITUDE OF THE AIRCRAFT, MEANS FOR SUPPLYING A SECOND SIGNAL RESPONSIVE TO THE AIRSPEED OF THE AIRCRAFT, MEANS FOR DIFFERENTIALLY COUPLING THE FIRST AND SECOND SIGNALS TO EFFECT A FIRST RESULTANT ERROR SIGNAL, A MAIN SERVO MOTOR MEANS CONTROLLED BY SAID FIRST RESULTANT ERROR SIGNAL, MEANS FOR SUPPLYING A THIRD SIGNAL PROPORTIONAL TO THE ABSOLUTE MAGNITUDE OF THE SPEED OF TRAVEL OF THE AIRCRAFT RELATIVE TO GROUND, MEANS FOR DIFFERENTIALLY COUPLING THE SECOND AND THIRD SIGNALS TO EFFECT A SECOND RESULTANT ERROR SIGNAL, AN AUXILIARY SERVO MOTOR MEANS CONTROLLED BY SAID SECOND RESULTANT ERROR SIGNAL, MEANS FOR SUPPLYING A VARIABLE AIRSPEED CORRECTION SIGNAL, MEANS FOR APPLYING SAID AIRSPEED CORRECTION SIGNAL TO SAID SECOND SIGNAL, MEANS TO OPERATIVELY CONNECT SAID AUXILIARY SERVO MOTOR MEANS TO SAID VARIABLE AIRSPEED CORRECTION SIGNAL SUPPLY MEANS IN SUCH A MANNER THAT SAID AUXILIARY SERVO MOTOR MEANS MAY VARY SAID AIRSPEED CORRECTION SIGNAL IN A SENSE TENDING TO DIMINISH SAID SECOND RESULTANT ERROR SIGNAL, MEANS TO OPERATIVELY CONNECT SAID MAIN SERVO MOTOR MEANS TO SAID FIRST AND SECOND MENTIONED COUPLING MEANS SO AS TO ADJUST IN OPPOSITE SENSE THE DIFFERENTIAL COUPLING OF THE FIRST AND SECOND SIGNALS AND THE DIFFERENTIAL COUPLING OF THE SECOND AND THIRD SIGNALS IN A SENSE TENDING TO DIMINISH THE FIRST AND SECOND RESULTANT ERROR SIGNALS TO ZERO, AND OTHER CONTROL MEANS SIMULTANEOUSLY DRIVEN BY SAID MAIN SERVO MOTOR MEANS TO A POSITION CORRESPONDING TO THE COMPUTED FLIGHT PATH ANGLE OF THE AIRCRAFT.