Flight Controls

YYaaww Cyclic stick cilcyC Cyclic YYaaww Cyclic Cyclic CCoolllleeccttiivvee Anti-torque pedals Collective lever 6-2 CC oo eellll cc vviitt ee of this project is to develop an adaptive neural network-based Control stick flight control system. Applied directly to flight control system feedback errors, IFCS provides adjustments to improve Elevator aircraft performance in normal flight, as well as with system failures. With IFCS, a pilot is able to maintain control and Pulleys safely land an aircraft that has suffered a failure to a control surface or damage to the airframe. It also improves mission capability, increases the reliability and safety of flight, and eases the pilot workload. Today’s aircraft employ a variety of flight control systems. Cable Push rod For example, some aircraft in the sport pilot category rely on weight-shift control to fly while balloons use a standard burn Figure 6-1. Mechanical flight control system. technique. Helicopters utilize a cyclic to tilt the rotor in the desired direction along with a collective to manipulate rotor As aviation matured and aircraft designers learned more about pitch and anti-torque pedals to control yaw. [Figure 6-3] aerodynamics, the industry produced larger and faster aircraft. Therefore, the aerodynamic forces acting upon the control For additional information on flight control systems, refer surfaces increased exponentially. To make the control force to the appropriate handbook for information related to the required by pilots manageable, aircraft engineers designed flight control systems and characteristics of specific types more complex systems. At first, hydromechanical designs, of aircraft. consisting of a mechanical circuit and a hydraulic circuit, were used to reduce the complexity, weight, and limitations Flight Control Systems of mechanical flight controls systems. [Figure 6-2] Flight Controls Aircraft flight control systems consist of primary and As aircraft became more sophisticated, the control surfaces secondary systems. The ailerons, elevator (or stabilator), were actuated by electric motors, digital computers, or fiber and rudder constitute the primary control system and are optic cables. Called “fly-by-wire,” this flight control system required to control an aircraft safely during flight. Wing flaps, replaces the physical connection between pilot controls and leading edge devices, spoilers, and trim systems constitute the flight control surfaces with an electrical interface. In the secondary control system and improve the performance addition, in some large and fast aircraft, controls are boosted characteristics of the airplane or relieve the pilot of excessive by hydraulically or electrically actuated systems. In both control forces. the fly-by-wire and boosted controls, the feel of the control reaction is fed back to the pilot by simulated means. Primary Flight Controls Aircraft control systems are carefully designed to provide Current research at the National Aeronautics and Space adequate responsiveness to control inputs while allowing a Administration (NASA) Dryden Flight Research Center involves Intelligent Flight Control Systems (IFCS). The goal Neutral Control stick (AFT—nose up) LEGEND Hydraulic pressure Hydraulic return Pivot point Elevator (UP) Control valves Control cables Neutral Power disconnect linkage Neutral Power cylinder Figure 6-2. Hydromechanical flight control system. Figure 6-3. Helicopter flight control system.