All But War is Simulation
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This document provides a history of flight simulation from its early origins through modern digital simulators. It discusses how simulation has evolved from simple mechanical devices to train pilots, to advanced digital systems that can simulate entire aircraft, crews, and complex scenarios like space missions and modern warfare. Key developments discussed include the Link Trainer in the 1920s-30s, increased use of simulation for military and commercial pilot training in World War 2, the transition to analog and then digital computers in the 1950s-60s which improved fidelity, and advances in visual systems, motion platforms, and computer processing power that have allowed simulators to become highly realistic training tools. The document concludes that while war itself cannot be simulated, modern simulators can effectively model many
All But War is Simulation
- 1. ALL BUT WAR IS SIMUATION Introduction to simulation Simulation today is a multi-million dollar industry and its application has spread to a vast number of training and analytical requirements. It is used in many contexts, such as simulation of technology for performance optimization, testing, training, education, business forecasting and video games. if we evaluate simulation over the course of history it can be written from many perspectives for example, uses of simulation in scientific modeling of natural systems or human systems to gain insight into their functioning; showing the eventual real effects of alternative conditions and courses of action; when the real system cannot be engaged, because it may not be accessible, or it may be dangerous or unacceptable to engage, or it is being designed but not yet built, or it may simply not exist. So, we can define simulation as:- ＾Simulation is the imitation of the operation of a real-world process or system over time.￣The act of simulating something first requires that a model be developed; this model represents the key characteristics or behaviors/ function of the selected physical or abstract system or process. The model represents the system itself, whereas the simulation represents the operation of the system over time. (Wikipedia) This work is based on a simulation industry that grew from commercial aviation and the space programs and while the use of simulation for military applications generated many developments, the role of the flight simulator has only really gained acceptance for military training in many countries during this last 60 decade. By comparison, the use of the Flight Simulator became an integral part of all commercial airline operations in the 1960¨s, and for both safety and training effectiveness, it became no longer practical and cost effective to train in the actual aircraft. With the space programs it is of course well recognized that it would not have been possible for man to have set foot on the moon without the training provided by simulation, and the use of simulation to assist the problems with the Apollo 13 Mission is now legendary. In recent times military all around the world are using simulation as weapon to train their pilots, technical staff and strategic / operational level planners to simulate flying,
- 2. maintenance practices and battle fields respectively, which is not possible in real world except but war. To go further and discussed the field of simulation we first briefly glance at the history of Flight Simulator. History for Flight Simulators The importance of training has been realized since the Wright Brothers first time escapes from gravitational forces of earth. From the early days of gliding it was usual for "pilots" to sit in the glider, which was exposed to a strong facing wind and "feel" the controls by keeping the wings in a horizontal position. Thus, even before the glider flew, the pilot had some experience of the lateral controls. In early 1910 before World War I land-borne aeroplanes were made by French to train there student pilots. The first known flight simulation device developed was Antoinette monoplane. A number of pilot training devices were developed during World War I include a 1915 UK trainer with a "rocking" cockpit described by H.G. Anderson, moving cockpit trainers by Lender and Heidelberg in France (patented in 1917), and the U.S."Ruggles Orientator" by W.G. Ruggles. Edwin Albert Link also known as father of flight simulation presented the electrical simulator in 1929, called the "Blue Box" or "Link Trainer". This was the most successful and well-known of this type of device.
- 3. However, despite twenty years of development, simulation was not seen as a substitute for actual flight. The acceptance of simulated flight as a useful training aid had to wait for further developments in the science of flying. In 1937, Links presented the approach of blind flying training with moving instruments, known as Instrument flying training. Over years of the Link Trainer and these device was produced in many versions and sold to many countries such as England, Japan, France, Germany and the USSR. In 1937 American Airlines became the first world airline to purchase a Link Trainer for their Pilot Training. Simulation During World War II At the start of the Second World War the need arose for the training of very large numbers of pilots and other skills involved in the operation of various military aircraft with basic pilot instruction being performed in part on Link Trainers both in the USA an Britain. Developments in aircraft design such as variable pitch propellers, retractable undercarriages and higher speeds made sound training in cockpit drill essential, and the fuselage mock-up was introduced to assist with these procedures. One such device was the Hawarden Trainer made from the centre section of a Spitfire fuselage which enabled training in the procedures of a complete operational flight. Ed Link together with aerial navigation expert P. Weems designed a massive trainer suitable for use by an entire bomber crew and which needed to be housed in a 15 metre high silo-shaped building. The pilot flew the trainer, while the bomb aimer¨s station provided the appropriate sight and targets over which the trainer was flying. The navigator was provided with all the radio aids as well as a very elaborate celestial view from which he could take his required Astor-sightings. The stars, of which an adequate number were collimated, were fixed to a dome which was given movement to correspond to the apparent motion of the stars with time and changes in bomber longitude and latitude. The first Celestial trainer was delivered in 1941 and while only a few of these devices ended up in England hundreds of these devices were installed and operated in the USA for war time training. One of the great technological successes of the war was the part played by the trainer group at the Telecommunications Research Establishment (TRE) in the design of synthetic radar trainers for all the new radars developed during the war years. Many trainers were designed and built for specific training during the war years usually by adding extra features to the basic link trainer and indeed the need for training and the use of simulation had now been well established and the benefits proven beyond any doubt. Analog Computers Based Simulators The major advances in electronics during World War II and the development of analogue computers now made the technology available to solve the flight equations of motion of the aircraft thereby allowing simulation of the response to aerodynamic forces rather than empirical duplication of their effects. Many of the early generation analogue devices actually contained both forms of simulation; however certain devices were indeed
- 4. true analogues and these were certainly the direct ancestors of the modern flight simulator. With the now proven ability of the flight simulator to provide meaningful training and the technology flowing from the developments of electronics in World War II, many simulation devices were constructed and three major manufacturers emerged during this period:- ? Bell Laboratorie and Curtiss-Wright Corporation manufactured full simulator for Boeing 377 aircraft for Pan American Airways, which became the first full aircraft simulator to be owned by an airline. ? In the mid 1950¨s, Pan American and QANTAS became the first airlines to place into service simulators for the B707 aircraft which at that time would have then been the world¨s most sophisticated simulators ever produced. Even with improved hardware and design, the reliability of the large analogue simulators of the day began to fall and despite continuous efforts by large maintenance teams, reliable utilisation of 10-12 hours a day appeared the maximum achieveable. It became obvious that the demands for increased fidelity and reliability could no longer be achieved with the analogue computer.
- 5. Digital Simulators The general purpose digital computers of the day could not be used for real time flight simulation due to their poor arithmetic and input /output capabilities and it was indeed fortunate that a second generation of digital computers was then being developed which appeared able to satisfy the speed and cost requirements of flight simulation. A research program was initiated by the University of Pennsylvania in 1950 which resulted in a special purpose device being designed at the University which was named UDOFT (Universal Digital Operational Flight Trainer) which was actually manufactured by the Sylvania Corporation in 1960. In the early 1960¨s Link developed their own design for real time simulation - the Mark 1 - which used three parallel processors for arithmetic, function generation and radio station selection. This device also used a drum memory for the programmed instructions to augment the storage capacity (10K) and speed limitations of the core memory available at that time. It was without doubt the most successful breakthrough and these simulators were purchased by most of the world¨s major airlines and the U.S. Military. There was now a total swing to digital computation by all the manufacturers of the day, however many hybrid devices were also produced which in some cases proved as unreliable as the analogue devices they were replacing. By the 1970¨s the general purpose computers had improved to the extent that some of these could be considered for flight simulation and from this time onwards the selection of the computer has been a major issue for each and every simulator manufacturer. It is interesting to note that not all these decisions have resulted in good simulation and many lessons have been learned along the way in terms of resolution and speed and capacity requirements. Motion Systems Early simulators produced up to the mid 1950¨s had no fuselage motion systems. This was often justified by the statement that pilots no longer flew ＾by the seat of their pants￣;
- 6. however, the fact remained that the simulators did not completely feel like the aircraft they simulated. It was found that handling improvements could be introduced by empirical adjustment of the simulator control loading and aircraft dynamics which in part gave some compensation for the lack of motion. In 1958 Redifon produces pitch motion system for BOAC as apart of Comet IV simulator. The need for extended motion cues has always been recognised and many innovative designs have appeared which often required massive structures and hydraulic systems which became a maintenance nightmare and in many cases actually produced incorrect cues. A great deal of research on motion systems has been carried out by NASA and of course the landing of the Lunar Landing Module presented an unusual challenge and one which had to be trained for with simulation. From their research, NASA produced a set of motion equations which have been used by most of the simulator manufacturers. The need for the use of motion systems for flight simulation has over the years generated quite some controversy; however, many of the experiments used to argue the case against motion systems have used very early motion systems, which without doubt, provided many false cues and certainly may have even provided some negative training. While it is well understood that motion systems may be ineffective in the simulation of highly maneuverable military fighters, there is little doubt in the view of the training captains from the world airlines and the world regulatory authorities that motion systems are essential for commercial aircraft flight simulation. Visual Systems Systems for providing the out of window visual scene have been proposed and constructed since the inception of the flight simulator with some of the early Link Trainers being mounted inside a panoramic display to give the illusion of flying high. It is well beyond the scope of this paper to even attempt to address the many concepts for visual systems that have been tried over the history of the flight simulator and therefore only some of the more successful ones have been discussed. The point-light source projection or shadow graph method enjoyed some popularity in the 1950¨s, especially for helicopter simulators. However, the shortcomings of the shadow graph seem to have limited the success of this system. During this period another method of visual presentation was developed by Link using film and an anamorphic optical system
- 7. known as VAMP which, while producing a good quality picture, was very limited due to the inability to fly outside the area of interest contained on the film strip. Development of closed circuit television systems commenced also in the 1950¨s where the scene was contained on a moving belt and viewed by the camera through an optical probe which allowed for pitch roll and rotation, and which was then projected on a flat screen mounted in front of the flight simulator cockpit. Initially these were monochrome systems and were produced by Curtiss-Wright and Link at the Link Division of General Precision in England (formerly Air The first color Trainers Link Ltd). The first color system was produced by Redifon in 1962. The belt model was then replaced with a Rigid Model and the camera moved over the terrain which was now capable of containing models of town and country with even lighting for realistic night time simulation. These systems usually operated with a scale factor of 2000:1 and remained in service well into the 1970¨s. The first computer image generation (CGI) systems for simulation were produced by the General Electric Company (USA) for the space program. Early versions of these systems produced a patterned ＾ground plane￣ image while later systems were able to generate images of three dimensional objects. Progress in this field was rapid and closely linked to developments in digital computer hardware with a parallel development taking place in night- only computer image generation systems using calligraphic or stroke writing rather than a raster scan, which enabled a superior reproduction of light points. These systems were initially developed and marketed by McDonnel-Douglas Electronics Corporation with VITAL and Evans & Sutherland / Redifon with NOVOVIEW. Link soon followed with a system developed by its English operation Link Miles known as the IMAGE Visual Systems. All of these CGI systems were displayed on a picture tube and viewed through a beam splitter from a mirror mounted in front of the display. While the quality of the displays were quite acceptable, there were limits to the size of the scene able to be produced and displays were mounted in juxtaposed locations in an attempt to improve the pilot¨s field of view (QANTAS, for example, installed a six window, six channel system). The final development, which is still in operation to-day, then moved to a projected picture (though now produced on a curved screen) allowing for continuous viewing in excess of 180 degrees thereby enabling training for a circling approach. In addition, the quality and content of the displayed picture improved to such an extent that route familiarization was now possible using the flight simulator.
- 8. But now todays visual system are the heart of any flight simulators. Generating high quality visual cues, generating weather conditions and in case of military simulation generation of enemy threats and simulating war scenarios is no more any challenge. Simulators todays are not only limited to the skill enhancement of pilots. But they are reached to a place from where we can simulate war and estimate the result even not firing a single bullet. Hence, it is rightly to say ＾All But War Is Simulation￣. By Muhammad Adil Khan