Flight control and actuation systems
Liebherr develops, supplies and supports flight control and actuation systems and takes care of the product management over the complete life cycle.
Liebherr offers primary and secondary flight control systems, other actuation systems and hydraulic systems. The core parts of these systems - i.e. mechanical, hydraulic parts and electronics hardware with embedded software - are developed and manufactured in-house.
As a system supplier, Liebherr is capable to design and qualify complete flight control and actuation systems, from side stick in the cockpit to the movable surface actuators on the wings. The scope covers primary and secondary flight control systems that can be hydraulically or electrically driven. Latest fly-by-wire systems are part of the product program in this area.
High lift control systems are required to limit take-off and landing speeds by increasing wing high lift. This is achieved by wing leading and trailing edges extension devices.
High lift control systems can be driven hydraulically, electrically or with hybrid technology. For electrically driven systems that require high power electronic drives, Liebherr develops and produces special motor control units.
Flap and slat actuation
Liebherr develops and produces flap and slat actuation systems to extend the movable trailing edges and leading edge surfaces. These systems consist of a set of components that are installed along the wing trailing edge such as power control unit, geared rotary actuators, ball screw actuators, transmission shafts or position sensors. Liebherr’s capability does not only include the development and production of these components but also the system controller including hardware and software.
The primary flight control system is part of the complete function needed to pilot an aircraft. It is actuating three sets of movable surfaces of the airframe - aileron, rudder and elevator. Liebherr supplies such control systems including actuators and electronic controllers.
Fly-by-wire technology is part of the systems that Liebherr offers for new applications. Actuators can be hydraulically or electrically driven depending on the aircraft architecture. Latest technology electro hydraulic actuators (EHA), electric back-up hydraulic actuators (EBHA), or electro-mechanical actuators (EMA) have been successfully integrated into the Liebherr product portfolio.
Main rotor and tail rotor actuation
Helicopters are controlled in their flight by acting on the rotor blades whether from the main rotor or from their tail rotor. This is achieved with dedicated actuators mostly hydraulically driven.
Liebherr develops and produces actuators for main and tail rotor as well as complete systems including actuators and actuator controllers.
Having developed one of the first fly-by-wire flight control systems for helicopters, Liebherr also has extensive experience in this area.
During certain aircraft flight phases, particularly during landing, it is necessary to quickly and strongly reduce the wing lift. This is achieved by rising dedicated wing control surfaces against the air flow going along the wing profile.
This is achieved with dedicated spoiler actuators that are currently most of the time hydraulically powered.
The rear horizontal stabilizer of an aircraft is used to stabilize the airframe during the flight. To adjust this stabilizer at an appropriate position, an actuator is used that drives it to required setting. On most recent aircraft, this actuator, mostly of ball screw type, is hydraulically or electrically driven.
Liebherr supplies folding wing tip actuation systems that include wing fold actuation, latch actuation and locking systems for commercial aircraft.
Liebherr develops and manufactures actuators to open and close doors for applications like cargo doors or landing gears doors. These actuators are used on commercial airplanes and military transport aircraft.
Liebherr also is able to supply complete customized door actuation systems featuring actuators, control manifolds and system electronic controllers with embedded software.
Liebherr develops and manufactures hydraulic pumps and motors ranging from 1,500 psi over 3,000 psi up to 5,000 psi. These piston pumps and motors are used in high reliability applications like electro-hydraulic actuators or high lift systems on commercial airplanes and military transport aircraft.
Electrically driven pumps are also part of the Liebherr product portfolio. They are used on board different aircraft like fighters and helicopters.
Aircraft and helicopters use hydraulic circuits to power different systems like flight control actuation, landing gear extension and retraction or landing gear door actuation. These utility functions require system control in order to fulfil the various tasks in the right sequence, for example to open doors, deploy mechanism and lock the doors in the open position.
This is achieved with customized manifolds featuring complex hydraulic circuits and carrying various components like sensors or valves. Selected materials are aluminum, steel and titanium.
Liebherr is a specialist in designing, developing and manufacturing of such system control components.
Liebherr has complete flight control actuation system testing capabilities.
In a dedicated test center in Lindenberg, Germany, the various subsystems can be installed and tested together. Liebherr designs and manufactures the test rigs for complete primary and secondary flight control systems integration including the test rig control load and failure simulation.