1. Flight Control Systems and Actuators
Group 3

2. Types of Flight Control Systems
Mechanical
Hydraulic-Mechanical
Fly-by-wire
Other

3. Mechanical Flight Controls
Common on General Aviation Aircraft
Gives pilot a lot of “feel” as he is directly connected to the control surfaces on the aircraft
Generally is made up of cables, pulleys, rods, and sometimes even chains
Routing these kind of systems throughout the aircraft requires a lot of thought and creativity at times
Generally not very good when there are large stick forces. The pilots strength becomes the limiting factor.

4. Hydraulic Mechanical Flight Controls
Analogous to power steering on a car, easier physically to make control inputs but loss of “feel” can be a problem
Sometimes referred to as “boosted”
Adds complexity to an already complex system
Added weight
Has to include hydraulic lines, actuators, pumps, and a linkage between the hydraulic system and the mechanical cockpit controls
Makes flying the aircraft less demanding and allows for high loads on control surfaces and much physically larger control surfaces
Sometimes makes use of “Artificial Feel Devices”

5. Fly By Wire Really more of a subset of Hydraulic Controls
Commonly uses a hydraulic control circuit to physically move the control surfaces and a computer controlled (digital) circuit that takes pilot input and actuates the hydraulic system
Common on newer commercial and military aircraft
Computer “interpretation” of pilot input allows for better stability of the aircraft allowing much more “on the edge” designs to be capable of flying
Has to be redundant because the computer is the only path between the pilot and the controls

6. Other Flight Controls
Electrically actuated flight controls which uses electric motors to move control surfaces, still an emerging technology
Warping uses piezoelectric materials to warp the wings of an aircraft
Closed circuit hydraulic controls, each individual control surface has its own full hydraulic system, eliminates a central system
Intelligent flight controls, uses neural networks to determine changes in flight dynamics and adjust control laws accordingly