Abstract: A flight control system of a turboprop airplane includes electronic controlled engines, which are governed by a manual operating device for setting the engine power in order to obtain a certain airspeed, a device for selecting a desired airspeed, and an engine control system for computing and controlling the required engine torque and speed as a function of ambient and engine conditions, the selected engine speed and the setting of said operating device. For automatically controlling the engine speed during the final approach to an airfield, the system includes an electronic approach speed control unit of which the adjustment signal influences the engine control device keeping the speed of the airplane during approach at a selected value whereby said manual operating device has a fixed setpoint. This electronic speed control unit may be carried out as an add-on device for retrofitting on a flight control system.

Abstract: Control system for synchrophasing the propellers of an aircraft, each propeller provided with a blade pitch controller for controlling the blade angle of the propeller, the systen containing for each propeller a control loop, comprising: a revolution rate controller, means for determining the blade passing frequency, an adjustable propeller revolution rate reference source supplying a revolution rate setpoint control signal, comparator means for comparing the blade passing frequency with said setpoint to generate an error signal for the revolution rate controller.

Abstract: A flight simulator includes a servo system connected with a control element, an electrical analog providing inputs to the servo system and receiving inputs from a digital computer and including a combining circuit, a divider and two integrators. Outputs from the two integrators to the computer are of digital form and the second integrator preferably is itself of digital form.

Abstract: A simulator of previously chosen mechanical properties of the steering system of a device such as an aircraft employs a controllable limiter for simulating the mechanical Coulomb friction of the control member and is arranged in a negative feedback loop and having two control signal inputs which determine the maximum and minimum outputs of the limiter in association with a further input signal corresponding to the friction concerning the control member. The limiter interrupts output until the level of the Coulomb friction to be simulated is exceeded.

Abstract: A flight simulating system is provided with a manually operated control member connected to a servomechanism which responds to manual input by the control member and reacts to provide realistic feedback to the control member in accord with simulated flight conditions. For this purpose, a combining circuit, a dividing circuit and two integrator circuits are provided in series. The combining circuit has an input which represents manual input force to the control member and another input from the flight-simulating computer which represents simulated internal forces acting on the controlled member and the dividing circuit divides the output of the combining circuit by a value representing the mass of the control member to produce a control member acceleration-related signal. This acceleration-related signal is integrated twice to produce, respectively, a control member velocity-related signal and a control member position-related signal.

Abstract: A method of measuring the rigidity, the damping coefficient and the inertia of a system consisting of a damped, spring-supported mass, particularly, the manually operable member of the control-system of an aircraft or a flight simulator, in which method the measurement of the rigidity takes place by determining the relationship between the force exerted on the mass and the deviation of the mass from the state of equilibrium at a speed and an acceleration of substantially zero value and storing the relationship. The method is characterized by the initial step of forming three electric signals--namely, a force signal having a value directly proportional to the force exerted on the mass, an acceleration signal having a value directly proportional to the acceleration of the mass, and a velocity signal having a value directly proportional to the speed of the mass.