Aircraft rudder authority control system
A system that acts on a rudder (L) having its stop parts commanded or moved by an actuator (A) is described. The rudder system comprises a reversible mechanical system with movable stop parts working based on control/command signals, having stop parts (M, M′) inside of the field of movement of the actuator (A), interfering in the movement of said actuator; the mentioned control signals are based on informations of the aircraft such as traction of the engines or other signal from each engine (pressure, temperature or axis rotation speed); flight speed (“airspeed”); altitude; skidding angle; aircraft on the ground. The system limits the deflection of the rudder in flight with symmetrical traction, enough for normal maneuvers, and it allows total authority of the rudder (L), allowing a larger movement (larger deflection angle) just when necessary, in other words, when there is a traction asymmetry between the engines and, for aircrafts having wheels mechanically connected to the pedals and rudder, when they are maneuvering on the ground during taxi operations.
1. An aircraft rudder authority control system comprising a reversible mechanical system which includes:
an actuator operatively connected to the rudder which causes the rudder to pivotally deflect in rightward and leftward directions in response to receiving a rudder command input;
right and left stop parts operatively interacting with the rudder to define maximum rightward and leftward rudder deflections, respectively, wherein the right and left stop parts are independently moveable relative to one another between an open position which allows for a greater maximum rightward and leftward rudder deflection and a closed position which allows for a lesser maximum rightward and leftward rudder deflection, respectively; and
a controller operatively connected to the right and left stop parts, the controller issuing a control signal to at least one of the right and left stop parts in response to receiving at least one input signal selected from an aircraft engine asymmetry signal indicative of asymmetrical engine traction, an aircraft airspeed signal, an aircraft altitude signal, an aircraft skidding angle signal or an aircraft weight on wheels signal indicative of the aircraft being on ground to thereby cause the at least one right and left stop parts to move between the closed and opened positions thereof which in turn permit greater and lesser maximum rightward and/or leftward rudder deflections, respectively.
2. The aircraft rudder authority control system of claim 1 , wherein the control system (a) moves each of the right and left stop parts to the closed position thereof in response to an absence of the aircraft engine asymmetry signal to thereby permit lesser maximum rightward and leftward rudder deflection during flight and to thereby allow for normal aircraft maneuvers, and (b) moves at least one of the right and left stop parts to the open position thereof to permit for greater maximum rightward and leftward rudder deflection in response to the controller receiving the aircraft engine asymmetry signal and/or the aircraft weight on wheels signal.
3. The aircraft rudder authority control system of claim 1 , wherein the controller quantifies the input signal to determine an amount of movement to the open position that is required of the right and/or left stop parts in order to achieve balanced rudder deflections.
4. The aircraft rudder authority control system of claim 1 , wherein the right and left stop parts are symmetrically positioned relative to one another.
5. The aircraft rudder authority control system of claim 1 , wherein when one or both of the right and left stop parts are open, the controller issues a control signal to move one of both of the stop parts to a closed position thereof in dependence upon the at least one input signal received thereby.
6. The aircraft rudder authority control system of claim 1 , wherein the right and left stop parts include one or more restoring devices for reducing apparent fluttering of the rudder during certain flight conditions and thereby assist to correct any undesirable flight characteristics.
7. The aircraft rudder authority control system of claim 6 , wherein the restoring devices comprise a spring.
8. The aircraft rudder authority control system of claim 1 , wherein the control signal issued by the controller is either a binary control signal which moves the right and left stop parts between predetermined open and closed positions thereof, or is a proportional control signal which moves the right and left stop parts to variable opened and closed positions that are a function of the at least one input signal received thereby.
9. The aircraft rudder authority control system of claim 1 , wherein the system is a passive protection system.
10. The aircraft rudder authority control system of claim 1 , wherein the right and left stop parts are symmetrically positioned relative to one another.
11. The aircraft rudder authority control system of claim 1 , wherein the right and left stop parts are asymmetrically positioned relative to one another.