Test Pilot

New Aircraft design must be tested thoroughly before a plane leaves the ground, or is even manufactured, to avoid costly - and sometimes fatal mistakes. Computer - aided design has now become standard practice in the aviation industry.
Computers and simulators are greatly assisting the old method of building model aircraft and examining their behaviour in a wind tunnel. The American manufacturer Lockheed now uses a powerful Cray X-MP/24 dualprocessor supercomputer to help with aircraft design. Using a technique called computational aerodynamics, the computer can quickly calculate the airflows around the aircraft.
The computer calculates the pressures and forces on various parts of the structure so that the aircraft's structural and flight characteristics can be predicted. Lockheed engineers have checked the results from the computers by wind tunnel testing of traditional models. But a sigle engineer's computer workstation can require a huge amount of memory. Sikorsky engineersuse the 2400 Turbo desktopworkstation, supplied by Silicon Graphics. High-capacity disks are used to store all the data.

Engineering simulators
Another modern piece of equipment used by aircraft designers is the engineering simulator. Flight simulators were once used solely for training pilots. Now they are a valuable tool for aircraft designers as well. Almost the entire process of designing an aircraft can now be handled by the computer-driven engineering simulator.
    With conventional aircraft design, the last component to be added was often the pilot. Engineers had to build a full-sized prototype air-craft before a test pilot could find out how easy, or difficult, the machine was to fly. This could lead to expensive mistakes. But simulators use the pilot's comments vey early in the design process.
    The characteristic of a proposed new aircraft can be fed into a computer that is used to drive a flight simulator. A pilot then has the chance to 'fly' the new aircraft in the simulator before the aircraft is ever built. Important design changes can, therefore, be made at an early stage.
    A good example of this is the development of the Sikorsky/Boeing Vertol LHX light helicopter. Designers were not sure whether one or two pilots would be needed to fly the helicopter in certain attack modes. The simulator enabled a single pilot to attempt such attack profiles before a final design decision was made.

Cockpit control
A simulator is an expensive piece of equipment. The visual system alone can cost $2 million for a civil aircraft simulator, and $10 million for a military system. The main flight simulator used in the LHX development programme cost $25 million.
A flight simulator duplicates all aspects of a real aircraft cockpit. All of the instruments and displays are driven by a computer, but they behave in exactly the same manner as the real thing. Often, the only way to tell hat you are in a simulator is to look out of the window. Although the hardware is accurate, the view from the cockpit is usually nothing more than a cartoon-like representation of the real world.
Producing an artificial landscape and making it change in response to the movements of the simulated aircraft takes a phenomenal amount of computer power. Some of the technology used in flight simulators has much in common with arcade video games.

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