Control method and system for aircraft powerplants comprising a gas turbine driving avariable pitch propelling device

Claim 1

A CONTROL SYSTEM FOR THE POWERPLANT OF AN AERODYNE HAVING A GAS TURBINE AND AN AERODYNAMIC PROPELLING DEVICE DRIVEN THEREBY AND EQUIPPED WITH BLADES THE PITCH OF WHICH MAY BE VARIED, COMPRISING MEANS FOR ADJUSTING THE QUANTITY OF FUEL DELIVERED TO THE TURBINE IN ORDER TO MAINTAIN CONSTANT THE WORKING ROTATION SPEED THEREOF, MEANS FOR INDEPENDENTLY CONTROLLING MANUALLY THE BLADE PITCH OF THE PROPELLING DEVICE BETWEEN THE MAXIMUM AND MINIMUM PERMISSIBLE PITCHES, MEANS FOR CONTINUOUSLY COMPARING THE ACTUAL TURBINE TEMPERATURE WITH AN UPPER LIMIT CORRESPONDING TO THE MAXIMUM PERMISSIBLE TEMPERATURE FOR SAID TURBINE, MEANS FOR CONTINUOUSLY COMPARING THE ACTUAL RATE OF FLOW FOR THE FUEL DELIVERED TO SAID TURBINE WITH UPPER AND LOWER LIMITS RESPECTIVELY CORRESPONDING TO THE THEORETICAL MAXIMUM AND MINIMUM RATES OF FUEL FLOW FOR SAID TURBINE AND, INDEPENDENTLY FROM ANY MANUAL CONTROLLING ACTION, MEANS FOR AUTOMATICALLY REDUCING THE BLADE PITCH AS SOON AND AS LONG AS THE FIRST ONE OF THE ACTUAL TURBINE TEMPERATURE AND OF THE ACTUAL RATE OF FUEL FLOW TENDS TO EXCEED ITS UPPER LIMIT, MEANS FOR AUTOMATICALLY INCREASING THE BLADE PITCH AS SOON AS THE FIRST ONE OF THE DIFFERENCE BETWEEN THE ACTUAL RATE OF FUEL FLOW AND ITS LOWER LIMIT AND OF THE FUEL FEEDING IN FLIGHT FOR THE TURBINE TENDS TO A ZERO VALUE, AND MEANS FOR RENDERING SUCH BLADE PITCH INCREASING MEANS, WHEN THE FUEL FEEDING IN FLIGHT TENDS TO A ZERO VALUE, INOPERATIVE IN THE CASE OF A MANUALLY CONTROLLED PITCH DECREASING.