Aircraft System Principles and Applications Research (Research Paper Sample)

Aircraft System Principles and Applications
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Aircraft System Principles and Applications
Introduction
Conventionally, aircraft use a blend of electrical, fluid and mechanical methods to generate power. Aircraft electrical power systems usually consist of a pair of engine-driven generators. These generators typically supply the entire aircraft’s AC power requirements. Electrical power transmission occurs through transformers and wires. Mechanical power is transmitted through gears, shafts, belts, chains, among other methods of conveyance. Fluid power is transmitted through liquids within a confined space. Gas can also be used for this transmission.
Fluid Power Generation
Fluid power entails the generation, control and transmission of the mechanical elements of the aircraft through the application of fluids in a confined system. Gases are also considered as fluids. Oil hydraulic uses pressurized synthetic oils and liquid petroleum oils. Pneumatic systems use compressed air that is subsequently released into the atmosphere after it has completed its task. Aircraft systems such as landing wheels, flight control surfaces, and flaps typically depend on fluid power for their operation. The complexity of the hydraulic system varies according to the type and size of the aircraft. Smaller aircraft only use hydraulic systems for operating the wheel brakes. Hydraulic systems in larger aircraft are huge and quite complicated.[Totten, George E., Steven R. Westbrook, and Rajesh J. Shah. 2003. Fuels and lubricants handbook: technology, properties, performance, and testing. West Conshohocken, PA: ASTM International.]
For a hydraulic system to be reliable, it has to be broken down into several sub-systems. Each and every subsystem has an accumulator, pump, filtering system and heat exchanger. Operating pressures can range from a few hundred pounds per square inch in light aircraft to thousands of pounds per square inch in larger aircraft. The use of hydraulic systems as a power source for the operation of aircraft units has several advantages. Hydraulics blend the use of lightweight materials together with the ease of installation and a simplification of inspection. These systems are very efficient with losses only occurring from fluid friction. Hydraulic systems are usually used to distribute force to different parts of the aircraft for actuation. Liquids are capable of this because they cannot be easily compressed. In addition to this, Pascal’s law stipulates that the transmittance of pressure applied to a confined liquid is done to every part with unaltered intensity. Manufacturers of fluid systems always indicate the most appropriate type of liquid to be used with their systems.
Mechanical Power Generation
Mechanical power systems in aircraft date way back to the pioneer aircraft. Mechanical systems operate through several mechanical parts such as pulleys, cables, and rods. In some instances, chains can be employed in transmitting forces from the flight deck controls to the various aircraft control surfaces. Although this technology is gradually being phased out, mechanical flight control systems are still used sport-category and small aircraft. Small aircraft do not experience significant aerodynamic forces. With the growth of the aviation industry, bigger and faster aircraft were constantly being churned out. Therefore, the aerodynamic forces meted on the control surfaces increased considerably. To moderate the force required to control the aircraft, complex mechanical systems were designed by aircraft engineers. Initially, hydro-mechanical designs that blended mechanical and hydraulic components were used. As the level of sophistication increased, the actuation of the control surfaces was done using electric motors. Complicated mechanisms that consist of gears have were developed to obtain the most mechanical advantage from a pilot’s inputs. They were also designed to minimize the forces needed from the pilots.[Taylor, 1990]
Electrical Power Generation
Electrical power generation methods use an electronic interface in the place of the traditional manual flight controls. The pilot’s movements of the flight control instruments are transformed into electrical signals and sent to the appropriate flight control system through wires. Computers involved in flight control determine the level of movement for each actuator to give the required response. The electrical system also permits automatic signals sent from the flight computers to carry out functions even without the pilot’s input. These systems automatically aid in stabilizing the aircraft. Mechanical and flight control systems are considerably heavy. They also need careful placement of flight control cables and hydraulic pipes in the aircraft. These systems are prone to failure, as such; they require redundant backups for instances of failure. In the electrical method, a computer is placed in between the pilot and the flight control surfaces. The computer modifies the pilot’s inputs while taking the control parameters into consideration. When the pilot moves a control instrument, an electrical signal is transmitted to a computer through several wires to ensure its reception. Once the signal arrives, the computer performs some calculations and includes another channel. The four signals are then sent to the appropriate surface actuators.[Crane, Dale: Dictionary of Aeronautical Terms, third edition, page 224. Aviation Supplies & Academics, 1997.] [Ibid]
Design of an Aircraft Power Distribution System
The Ultra Electric Power Distribution System aims to use a single power type for running the aircraft systems that are not involved in the aircraft propulsion. This system is bound to confer several advantages such as considerably reducing the aircraft maintenance and operation costs. It will also considerably optimize the performance of the aircraft. This system is environmentally friendly since it considerably reduces the emission of pollutant gases from aircraft. This system uses a 270 volts distribution topology. The main electrical subsystems are two-directional power converters which control, convert and condition the electrical power between the loads and the sources. A notable feature of this system is the capability of some of the flight control systems such as flight actuators to generate energy for the system. This technology is a shift from the present uni-directional systems because the system has to permit the bidirectional flow of power. This feature can greatly enhance the efficiency of the system; however, if the system is not properly desi...