How Do Actuators Assist an Aircraft?
Actuators are essential for all aircraft, serving to control doors, retractable landing gear, position engine vanes and thrust reversers, and adjust parts like the elevator, rudder, ailerons, slats, spoilers, flaps, and all other flight control surfaces. Critical for helping an aircraft remain in flight, it is essential for parts like an actuator to continuously provide reliability and integrity for improved aircraft efficiency. To better understand the importance of actuators and their role within aircraft, we will navigate through their history and how they are capable of making aircraft faster, easier to maneuver, and more cost-effective.
Converting electrical signals to mechanical movement, actuators play an active role in many aircraft control systems. Originating from the use of cables and rods to more sophisticated pieces of equipment, actuators can now be found in either hydraulic, pneumatic, or electric variations. Stemming from the birth of pneumatic actuation systems during World War II, shortly followed by the implementation of hydraulic actuation systems as the need for such items grew, actuators were meant to be a durable solution for car braking systems. Widely implemented in the 1960s for aircraft, electric actuators streamlined the path for further innovation and the creation of electrohydraulic, electrohydrostatic, and electromechanical actuators.
Primarily found in commercial and passenger-centric aircraft, electromechanical actuators have become the primary actuation type for nearly all aircraft systems. Putting aside the need for hydromechanical systems utilizing hydraulic circuits and shifting towards a more electric-based approach, actuators powered by electricity generated from the engines are capable of performing with improved functionality. Replacing mechanical linkages with electrical cables with control fly-by-wire systems, such improvements increase the ability for an aircraft to interpret actions performed by a pilot's control column movements. Either using hydraulic control valves to initiate hydraulic actuators or electric motors to set electromechanical actuators in motion, fly-by-wire assemblies allow engineers to integrate more electrically-powered actuators to improve system functions.
Integrated into an aircraft's electrical network based on calculating an actuator's specifications, these items are often chosen depending on their sustained force and velocity requirements. Alongside such factors, the weight of an actuator is critical as heavier versions of such items are known to increase fuel consumption. That being said, smaller and lighter options are available to mitigate such issues. However, to continually incorporate additional electrical actuation technologies into aircraft, every bit of weight and power consumed by an actuator has to be considerably reduced and highly measured. As actuators have grown to incorporate electromechanical functions and have improved their reliability while sustaining prolonged abuse with no backlash, they still require general maintenance as per manufacturer recommendation. In case of part malfunction, actuator systems oftentimes come equipped with two or more motors, or drives, for redundancy.
