Abstract: System for reducing vibrations in the cabin of an aircraft driven by two or more propellers each having n blades (n being an integer equal or larger than 2) of which the relative phase angle can be adjusted, said system comprising synchrophase means for adjusting said relative phase angle such that a predetermined relative phase angle is maintained. The system furthermore comprises means supplying information about the vibration level at one or more positions within the cabin or thereto related information and for generating a thereto corresponding level signal, and a control unit which in response to said level signal supplies an error signal to the synchrophase means causing the synchrophase means to adjust the blades of the various propellers such that a new relative phase angle is maintained which differs m.(2.pi./n) radians (m being an integer) from the previous relative phase angle.

Abstract: The invention provides an assembly of accelerometers for use in a system for measuring the three dimensional movements of a rigid body comprising nine linear accelerometers which are connected to said rigid body in a spacial configuration with reference to an imaginary orthogonal coordinate system. At a first position on the X-axis at a predetermined distance from the origin two accelerometers are installed, the sensitive directions thereof being parallel to the Y-axis and to the Z-axis respectively. At a second position on the Y-axis of the coordinate system at a predetermined distance from the origin two accelerometers are installed, the sensitive directions being parallel to the X-axis and to the Z-axis respectively. At a third position on the Z-axis at a predetermined distance from the origin two accelerometers are installed, the sensitive directions being parallel to the X-axis and to the Y-axis respectively.

Abstract: The present invention relates to a movement simulator having a support frame and a subframe movable relative to the support frame and connected by a variable element. A simple control assembly is electrically connected to the variable element for controlling its length. The transducer assembly having at least one acceleration transducer attached to the variable element supplies an acceleration signal of a subframe relative to the support frame to the control assembly. The invention includes circuitry to avoid non-defined senarios in determining the acceleration signal.

Abstract: A method of an apparatus for ultrasonic inspection of multi-layered structures having acoustic transmission (I, III, V and VII) and reflection (II, IV, VI and VIII) frequency bands. Variations in one or more parameters of specific layers are largely restricted to specific frequency bands of said layers. By analyzing transmitted or reflected signals with respect to the frequency bands of the structure, interpretation of signals due to parameter variations as caused by voids, inclusions or delaminations can be effectively eliminated. The method is preferably used for the inspection of laminated structures consisting of metal layers bonded by fibre reinforced resin layers.

Abstract: System for reducing vibrations in the cabin of an aircraft driven by two or more propellers each having n blades (n being an integer equal or larger than 2) of which the relative phase angle can be adjusted, said system comprising synchrophase means for adjusting said relative phase angle such that a predetermined relative phase angle is maintained. The system furthermore comprises means supplying information about the vibration level at one or more positions within the cabin or thereto related information and for generating a thereto corresponding level signal, and a control unit which in response to said level signal supplies an error signal to the synchrophase means causing the synchrophase means to adjust the blades of the various propellers such that a new relative phase angle is maintained which differs m.(2.pi./n) radians (m being an integer) from the previous relative phase angle.

Abstract: A display for presenting symbolically to an aircraft flight crew the resolution advisory information developed by a Traffic Collision Avoidance System (TCAS) computer aboard an aircraft. The flight display shows a a line symbol representing the artificial horizon, a pitch scale extending perpendicular to said line symbol and indicating pitch angles with reference to said line symbol, and an aircraft reference symbol indicating by its position along said pitch scale the momentaneous aircraft pitch attitude. Furthermore a pitch cue symbol is displayed consisting of a first line segment extending parallel to the artificial horizon and across said pitch scale, said first line segment indicating a limit pitch value processed from the TCAS vertical speed limit ouput, and an area indicator extending below or above said line segment indicating a range of pitch values bounded by said limit pitch value, which range of pitch values has to be avoided by the aircraft flight crew.

Abstract: To improve forming properties of laminated structures comprising two sheets of a non-ferrous metal alloy connected by an adhesive, which hardens at heating and between which an adhesive layer is bonded to the metal sheets, a new sequence of heat treatments is proposed. The alloy of the sheets is in soft condition before the sheets are bonded to each other. The bonding temperature and time are selected such that it remains substantially in soft condition and only after forming further heating is applied to obtain hardening of the alloy sheets.

Abstract: The invention relates to a movement simulator having a support frame and a subframe movable relative to the support frame and connected by a variable element. A simple control assembly is electrically connected to the variable element for controlling its length. The transducer assembly having at least one acceleration transducer attached to the variable element supplies and an acceleration signal of a subframe relative to the support frame to the control assembly.

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.