Abstract:
A flight simulator rests on a plurality of air cushions as a hovercraft and assumes spatial attitudes depending upon the relative heights of the air cushions. Flight controls determine the volume of air supplied to each air cushion and thereby control the pitch and roll attitudes of the flight simulator. The simulator may be connected to an external support frame and may thereby be subjected to longitudinal, lateral, and rotational movements.

Description:
BACKGROUND 
     Spatial attitude simulators provide a working environment for the training of individuals whose jobs may require them to perform while in unusual spatial attitudes. Foremost amongst these are flight attitude simulators which are used to train pilots to fly aircraft that may be in any number of spatial attitudes during flight. Flight simulators have been known and used for many years, and generally require elaborate hydraulic, mechanical, and electrical actuation and control systems. The machinery and hardware used in traditional flight simulators requires extensive installation and setup, often including below-deck piping and wiring, and demand a high level of maintenance to keep them operating smoothly. For these reasons, flight simulators are expensive to acquire and maintain, and lack the portability that may be desirable for use in rural environments in which flight training facilities are few and far between. What is needed is a flight simulator that is inexpensive to acquire, easy to install and maintain, and that is portable with a minimum of activity required for setup and breakdown, and that may be stored for transport in small truck-sized bundles. 
     SUMMARY OF THE INVENTION 
     The pneumatically supported spatial attitude simulator of this invention is a flight simulator platform resting on a pneumatic air cushion that is constantly refreshed from a blower pump that supplies air to provide the cushion (“a hovercraft base”). In a manner similar to a hovercraft, air is pumped into an air cavities surrounded by a skirt. Hovercraft have existed since at least the 1950s, and are primarily used as transports that may travel laterally over a variety of diverse terrains. In this invention, however, the hovercraft base supporting the flight simulator does not traverse laterally, but simply raises or lowers as air pressure within any of a number of air cavities increases or decreases. A flight simulator cockpit supported by the hovercraft base will exhibit pitch upward or downward, and roll to the right or left, as air is directed to one or another of the supporting air cavities comprising the cushion. Direction, deflection, and diversion of the air supply can be accomplished using any number of control systems having different working components and media. Such systems include, but are not limited to, controllers using hydraulics, electrical, and mechanical air valve actuators. Such systems are in widespread use in actual aircraft, and their operation is well-known in the art of aircraft control systems. In the simulator of this invention, any of those controllers would be suitable to actuate air valves and diverters that would direct high pressure air into any one, or a plurality, of air chambers as desired to cause the responsive mechanical movement of the flight simulator cockpit. 
     In an embodiment of the invention, the simulator may be connected to stationary points (anchors) within its local environment, and may use those stationary points to induce lateral, longitudinal, and rotational movements to the simulator. The stationary points may be integral to the local environment, such as bulkhead or concrete floor anchors in a building, or may be a self-contained frame that is part of the simulator system. In the self-contained embodiment, the simulator may be harnessed to the anchor points with hydraulically or electrically actuated pistons and flexible straps that may also be expandable, such as bungee cords. Lateral or longitudinal movement of the simulator may be produced by elongating adjacent pistons and shortening opposing pistons. Rotational movement may be caused by elongating diametrically oppositely situated pistons while shortening adjacent pistons. The use of bungee cords to connect pistons to the simulator allows the simulator to experience pitch or roll attitudes caused by the hovercraft base while simultaneously undergoing rotational or lateral movement caused by external pistons and bungee cord connectors. 
     In a preferred embodiment of the invention, a simple mechanical controller attached to the “control stick” or “yoke” of the simulator operates a valve system that directs air into one or another of the segmented air chambers. In order to achieve the desired pitch and roll movements for a flight simulator, a minimum of three air chambers is recommended, although any number of air chambers greater than two can be used to achieve any desired spatial attitude. A preferred embodiment having a four-chambered system may be advantageous for simplicity of concept and installation, as each air chamber is situated beneath, and directly affects the positioning of the “nose,” the “tail,” or the “right” or “left” wing. As such, installation and setup can be completed by moderately skilled personnel, and control systems for a four-chambered system are straightforward in being coordinated to a simulator&#39;s control stick or yoke. For example, in a four-chambered system, movement fore and aft on the control stick or yoke will directly modify the airflow into air chambers in front of or behind the cockpit, while a right or left movement will direct airflow into the left or right air chambers. In addition, a four-chambered system embodiment may be particularly well suited to use a mechanical or hydraulic controller as the valves for diverting air into specific chambers may be in direct communication with the control stick or yoke. 
     Conversely, embodiments having an odd number of chambers will require greater complexity in a controller in order to translate stick or yoke movements into appropriate air valve openings. In such embodiments, electronic, or “fly-by-wire” systems may be incorporated, and can perform the coordinated valve movements required to achieve appropriate movement of the simulator cockpit by proportionately directing air into a plurality of chambers simultaneously. Thus, while the invention is primarily illustrated and discussed in terms of a four-chambered embodiment, it is not limited to that embodiment, and multi-chambered embodiments using hydraulic, electronic, or other control systems known in the art are included within the concept of the pneumatically actuated spatial attitude simulator of this invention. 
     In a four-chambered system, as air from the blower is directed into an air chamber, the valve system prevents or reduces air from being blown into the directly opposite chamber. Thus, if air is directed into a forward air chamber, and is shut off from flowing into the rear chamber, the simulator will experience a “nose-up” pitching movement. Similarly, if air is directed into a right-side chamber, and is reduced or eliminated from flowing into a left-side chamber, the simulator will experience a “left bank” rolling movement. 
     Attitude changes in the flight simulator of this invention are caused by differences in air pressure that develop as air escapes from beneath a skirt that surrounds the segmented air chambers that comprise the system. As air is constantly flowing from a blower, and is directed into all chambers as is dictated by the valve positioning, air pressure within a chamber into which less air is being directed will be reduced as air escapes, and that chamber will partially collapse until the air pressure is approximately equal to pressures elsewhere in the system. When a chamber collapses, the simulator will “tip” in that direction, producing the change in cabin attitude that results from movement of the controls. Conversely, when more air is directed into a chamber, the air pressure in that chamber will be increased, and a greater volume of air escaping beneath the skirt will cause that chamber to rise, relative to the surface upon which the simulator is resting, causing the cockpit attitude to “tip” away from that air chamber. When the control stick is centered, or neutralized, air will be directed equally into all air chambers, and the simulator will assume a neutral orientation with all air chambers being inflated to an equal height above the resting surface. 
     The flight simulator of this invention has few moving parts, and may be constructed from flexible and semi-flexible materials that are able to be folded and stored in a relatively small volume. The only external resource required to operate the flight simulator is electricity to power the blower that provides a constant supply of air for the system. The same characteristics of simplicity of installation and operation provide a portability that is not available in the large and complex simulators of the prior art. The relative simplicity of moving parts, and the use of inexpensive materials contribute to provide a flight simulator that is relatively inexpensive to acquire, simple to assemble, and that exhibits a range of motion and movement that is the equal of flight simulators found in the prior art. 
     While the flight simulator depicted and explained herein is shown with a simple, mechanical controller, other more elaborate controllers that may be electronic, hydraulic, or mechanical, are equally capable of controlling the air valves used to direct air to the proper air chambers, and may be suitable for permanent or semi-permanent installations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an overhead view of the invention showing the arrangement of the components. 
         FIG. 2  is an overhead view of the lower portion of the invention with the simulator cockpit removed. 
         FIG. 3  shows a four-chambered embodiment of the base in which one chamber is disconnected from the others. 
         FIG. 4  is a perspective view of an individual air chamber. 
         FIG. 5  is a front sectional view of the air chamber of  FIG. 3  taken along section line A-A. 
         FIG. 6  depicts a detailed view of an embodiment having a mechanical controller directing air to produce a pitch down movement of the simulator. 
         FIG. 7  shows the position of the controller of  FIG. 3  when the simulator is being placed in a nose-up and bank left attitude. 
         FIG. 8  diagrammatically illustrates the position of the pilot&#39;s seat, control stick, and air diversion chamber that is responsive to movements of the control stick. 
         FIG. 9  provides detail of the mechanical controller that diverts air among the air chambers in response to stick movements. 
         FIGS. 10   a - 10   c  show side views of attitude movements of the simulator in response to movements of the control stick. 
         FIGS. 11   a - 11   c  show front views of attitude movements of the simulator in response to movements of the control stick. 
         FIG. 12  is a plan view of an embodiment having an integral support frame. 
         FIG. 13  is a front elevation view of the simulator of  FIG. 12  showing the integral support frame. 
         FIG. 14  is a side view of the simulator of  FIG. 13 . 
         FIG. 15  is a plan view of the embodiment shown in  FIG. 12  with the simulator being rotated clockwise by the action of external pistons and flexible connectors. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An overhead view of the simulator  10  of this invention is depicted in  FIG. 1 . An air inlet  18  from a blower (not shown) provides a constant stream of air to be distributed among a plurality of air chambers to support the simulator. A plurality of chambers are combined to form a base component  12 . The simulator body  14  rests upon the base component and includes a cockpit  16 . The cockpit has a control stick  48  extending vertically between an operator&#39;s knees, and a seat  50  that may be adjusted as necessary for an operator (pilot) to be comfortably seated while reaching the rudder pedals  52  and the control stick  48 . In some embodiments, a control yoke, such as is commonly found on commercial airliners and other civil aircraft, may be substituted for the control stick. In embodiments in which the physical movement of the control stick is mechanically translated into valve positions for directing air into the air chambers, the basic fore and aft movements of a yoke are identical to those of a control stick in controlling aircraft attitude, and the right-left movement of a control stick can be replicated with a simple mechanical interface in the simulator. In other embodiments that use electrical or hydraulic systems to detect control stick movements and translate them into valve positioning, appropriate movement sensors and actuators are well-known in the art. 
       FIG. 2  shows the base component  12  with the simulator body  14  removed. Air chamber  20  is directly under the “nose” of the simulator body  14 , while air chamber  22  is directly below the “tail” of the simulator body  14 . Air chamber  26  is beneath the right “wing” of simulator body  14 , while air chamber  24  is beneath the left “wing.” Air from blower  38  comes through air inlet  18  and enters controller box  28  where, depending upon the internal positioning of valves within controller box  28 , air is directed in varying amounts into air chambers  20 ,  22 ,  24  and  26  through internal pipes  30 ,  32 ,  34  and  36 , respectively. 
       FIG. 3  depicts an embodiment of the base of the simulator having four air chambers. In an embodiment, each chamber is pneumatically separate from the other chambers other than the air inlet that connects each chamber to the controller box. When the simulator is disassembled, each air cushion may be separately packed, stored, or transported independently. 
       FIG. 4  is a perspective view of a single air chamber  64 . The air chamber is a plenum that is open at the bottom, to allow air under pressure to escape. The exterior surface is divided into an upper surface  66 , that supports the simulator cockpit, and a lower skirt,  68 , that provides lift as it retains air within the plenum. As shown in  FIG. 5 , air enters the air chamber through an inlet  70  and circulates through the chamber, eventually exiting beneath the skirt  68 . When the simulator is in operation, equal volumes of air enter each chamber, and generate equal air pressures that will hold the simulator at equal heights for all chambers as air currents  72  pass through the chamber  66  and exits beneath the skirt  68 . As airflow through one chamber increases as a result of manipulation of the control stick, increased air volume will increase the air pressure within that chamber, causing the upper surface of the chamber to raise to a greater height and increasing the air exit passageway (the distance between the skirt and the floor), as air  72  exits through the passageway beneath the skirt. At the opposite chamber, the airflow will be decreased, causing a drop in air pressure that translates into a lowering of the height of the upper surface of the chamber. 
       FIGS. 6 and 7  depict a sectional plan view taken along line C-C of  FIG. 9 , showing an embodiment of a controller box  28  in which the mechanical motion of the control stick is translated into opposite valve openings and closings to cause airflow into opposite air chambers to increase or decrease. Other embodiments using hydraulic controllers or electromechanical sensors and actuators, for example, are equally suitable for the invention, and are well-known in the art. In the mechanical embodiment depicted in  FIG. 6 , the controller box  28  is located beneath the cockpit floor. In the embodiment depicted in  FIGS. 6-9 , movements of the control stick  48  within the cockpit pivot about a fulcrum located at the point where the control stick passes through the cockpit floor, causing control stick movements in the controller box to be the reverse of the movement imparted by the pilot. In  FIG. 6 , the control stick  46  has been moved forward in the cockpit, reflecting the pilot&#39;s decision to lower the nose of the simulator. As the control stick pivots about its fulcrum located at the floor of the cockpit, its movement is translated to a backwards motion within the controller box  28 . An embodiment of a pushrod interconnect  74  between the control stick  48  and the air valves for opposing chambers is depicted in  FIG. 6   a . Valves  40  (nose) and  42  (tail) are located at opposite ends of pushrod  76 , and simultaneously open and close air valves in opposing chambers as key ring  78  is moved forward or backward by the control stick  48  which extends through key slot  80 . As can be seen, sideways right-left movement of control stick  48  will not cause fore and aft movement of the interface, while forward and backward movement of the control stick will cause valves  40  and  42  to move in a fore or aft direction, thereby simultaneously opening and closing air valves in opposing chambers. A second pushrod interconnect (not shown in  FIG. 6   a ) situated at right angles to the first, will simultaneously open and close air valves in the other two chambers in response to right-left movements of the control stick. In this manner, movement of the control stick in any direction will produce a coordinated combination of valve openings and closings to cause incoming air to be directed into some air chambers and to restrict airflow into opposing air chambers, thus causing the simulator to be moved to various attitudes. 
     In  FIG. 6 , it can be seen that the control stick has been moved forward, but has not been moved to the right or left, thus indicating a nose-down, wings level aircraft attitude. In response to this movement, valve  40  has moved against its corresponding valve seat, closing off airflow from air inlet  18  into air pipe  30 . The same movement causes valve  42  to open to a maximum, thereby permitting an increased airflow into air pipe  32 . Valves  44  and  46  have not moved, as the control stick is midway between full right and full left, and air flows equally into air pipes  34  and  36 . The result of this movement is to decrease airflow into chamber  20  and increase airflow into chamber  22 , thus causing the nose of the simulator to pitch down while the wings are held level. 
     By contrast,  FIG. 7  depicts a controller box configuration in which the pilot has moved control stick  48  backward and to the left, seeking a nose up and left bank aircraft attitude. In controller box  28 , this movement causes the fore and aft pushrod interconnect to move forward, opening valve  40  and closing valve  42 , and causes the left-right pushrod interconnect to move to the right, opening valve  46  and closing valve  44 . The result is to increase airflow into chambers  20  and  26 , and to reduce airflow into chambers  22  and  24 , thereby giving the simulator a nose up and left bank attitude. 
       FIGS. 8 and 9  show a sectional view of the cockpit and controller box taken along lines B-B in  FIG. 1 . In  FIG. 8 , the cockpit seat  50  and rudder pedals  52  are adjustable, and the control stick  48  extends through the floor  54  of the cockpit and into controller box  28 .  FIG. 9  shows controller box  28  and its components in greater detail. Valves  40  and  42  control the amount of air entering air pipes  32  and  30 . Pitch pushrod interconnect  60  controls the movement of valves  40  and  42 . Roll pushrod interconnect  58  is seen end on, and controls valves  44  and  46 . Air pipes  30 ,  32 ,  34  and  36  have enlarged areas to house the valves, and to permit the operation of valves  40 ,  42 ,  44  and  46 , respectively, as they control the flow of air into the air pipes. 
       FIGS. 10   a ,  10   b , and  10   c  are side views of the simulator  14  showing attitude changes in pitch as the control stick  48  is moved backward ( FIG. 10   b ), forward ( FIG. 10   c ), or placed in a neutral position ( FIG. 10   a ). These attitudes are produced when the control stick&#39;s movement causes valves in the forward and rearward air chambers to open or close, causing more or less air to be deflected into those chambers. The valves may be actuated mechanically, as depicted in  FIGS. 6-9 , or may be hydraulically or electrically actuated valves, as are well known in the art. 
     Similarly,  FIGS. 11   a ,  11   b , and  11   c  show front views of the simulator  14  undergoing attitude changes in roll as the control stick  48  is moved from side to side. In  FIG. 11   a , the control stick is centered between the pilot&#39;s knees, and the simulator&#39;s “wings” are horizontal. In  FIG. 11   b , the control stick has been moved to the pilot&#39;s right, and the simulator&#39;s attitude is in a right bank.  FIG. 11   c  shows the control stick to the pilot&#39;s left, and the simulator is in a left bank. Under balanced flight conditions, such turns will produce right and left turns, respectively, and a fully instrumented simulator would indicate such turns with a compass needle moving right or left, a turn-and-bank indicator moving right of left of center, and an attitude director or artificial horizon indicating a right of left wing down attitude. 
       FIG. 12  depicts a support frame  74  surrounding the simulator base and cockpit. In  FIG. 12 , the support frame  74  is shown as being roughly square or rectangular, but the specific shape is not important and the support frame can be circular, oval, or any other convenient shape. In the embodiment depicted in  FIGS. 12-14 , the frame rests on the ground, and four support pillars  84 , roughly positioned near the corners of the simulator, extend upward to secure the bungee cord connectors  78  and pistons  80  to a stationary anchor external to the movable parts of the simulator system. Support struts  76  are provided to prevent the support frame  74  from becoming distorted when forces are applied to the frame through support pillars  84 . The pistons  80  may be hydraulic, electric, or of any other suitable activation type, and are connected to a control and actuation system through lines which may be hydraulic or electric  82 . Lines  82  are shown as extending from pistons  80  into support pillars  84 , from whence they may be routed internally within the frame  74  to the controller box  28  (not shown in  FIGS. 12-14 ) where rudder pedal movements may be sensed and acted upon, and to an external control panel being operated by a “flight instructor.” 
       FIG. 13  is a rear view of an embodiment of the simulator and support frame in which pistons  80  and flexible connectors  78  hold the simulator between support pillars  84 . A hydraulic or electric line  86  extends from the rear of the simulator down to a lower portion of the support frame and is threaded through the frame to the support pillars  84 , where it exits the frame and provides power to actuate the pistons  80 .  FIG. 14  is a side view of the simulator of  FIG. 13  being stabilized by the support frame  74 . 
       FIG. 15  shows how the pistons  80  and flexible connectors  78  can be actuated to cause the simulator to experience a clockwise rotation. Pistons at the upper right and lower left of  FIG. 15  are compressed, while pistons at the upper left and lower right are extended to impart a rotational movement to the simulator in response to input from rudder pedals or external flight conditions. Because the simulator is support on a cushion of air, it can move rotationally without having to overcome friction, and can therefore simulate actual flight conditions. In a similar fashion, simultaneous compression of the upper left and upper right pistons, and extension of the lower left and lower right pistons, would impart a slight “forward” movement of the simulator. Simultaneous compression of the pistons at the upper and lower right sides and extension of the pistons on the left side would cause the simulator to move slightly to the right. Reversing the movements of all piston sequences described above would cause the opposite movement of the simulator. 
     It is to be understood that the embodiments described herein are exemplary of the simulator of this invention, and that other and further controls and movements for the simulator will occur to persons of ordinary skill in the art. Such other controls and movements are contemplated to be within the scope of the invention as described, and the scope is limited only by the appended claims and legal equivalents thereof.