Abstract:
When the multi-purpose amphibious vehicle moves on surfaces of any type of terrain, it runs on a rolling track by rolling friction faster than a critical speed. The multi-purpose vehicle can run very smoothly and economically with a single engine, can provide multi-terrain capability with no hesitation between surfaces of different types of terrains, and can go as fast on the surfaces of water, snow and ice as it can run on the surface of land. Journey between islands, use for arctic expeditions, higher speed entry along inland rivers, and on the other hand, operation on areas of marsh or swamp using lower ground pressure tracks are all possible with this multi-purpose amphibious vehicle.

Description:
RELATED APPLICATION 
       [0001]    This application claims priority form Korean Patent Application No. 10-2011-0098206 filed Sep. 28, 2011 in the Korean Intellectual Property Office, which is hereby incorporated by reference in its entirety. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    Since the development of the amphibious vehicle, the range of its applications has been quite diversified. 
         [0004]    In accordance with various design aspects for amphibious vehicles corresponding to a wide range of applications including recreation exploration, search and rescue, and military purposes, innumerable new concepts and variations have been proposed. Accordingly, it is desirable to provide a multi-purpose amphibious vehicle. However, attempts at such generally follow an extension of approaches used mainly for vehicles being operated on the surface of water or land. 
         [0005]    2. Discussion of the Background 
         [0006]    Instead of land vehicles capable of moving only on wild fields, most amphibious vehicles have been developed based on a human desire that is not only focusing on a transportation means moving on the land and in the water but also freely on all terrain like areas of ice, snow, mud, marsh and swamp. This explains a main reason why most vehicles have been designed depending not on wheels but on the tracks (Lower Ground Pressure). 
         [0007]    The conventional amphibious operation technology has not only depended upon the traction of wheels or tracks on land but also in or on the water, other propulsion systems such as screw drive or water jet. 
         [0008]    By adopting this conventional amphibious operation manner, a vehicle requires two sets of engines and transmissions that could not only add the increase of weight, but also reduce conspicuously the merits of the vehicle in terms of environment and economy. 
         [0009]    Also, even when a single engine has been utilized, an extra transmission is required. Further, such a special means that is to minimize the drag experienced by the wheels or the tracks used on the land has to be provided. 
       SUMMARY 
       [0010]    Accordingly, by overcoming the above noted difficulties, in order for embodiments of this invention to freely move on all the terrains, a new technology referred to as “all terrain ride on technology” is provided and is supported by elevation force. 
       INTRODUCTION OF A NEW TECHNICAL FIELD 
       [0011]    Up to the present, the known motion technologies on the surfaces of all the certain terrains (surfaces of land, water, snow, ice, swamp and marsh or mud), with no substitution to be figured out, are one of hydro-gliding as slipping on those surfaces and another of all terrain riding on with its traction by the rolling friction. 
         [0012]    In order to secure its motional means by hydro-gliding on the surface of water, its possibility may be able to be judged by Froude Number (Non-dimensional Ratio of the vehicle&#39;s weight and inertia) that has been well known in the field of hydrodynamics. 
         [0013]    That is, 
         [0000]    
       
         
           
             
               
                 
                   
                     Fr 
                     N 
                   
                   = 
                   
                     U 
                     
                       
                         g 
                         × 
                         L 
                       
                     
                   
                 
               
               
                 
                   ( 
                   
                     Eq 
                     . 
                     
                         
                     
                      
                     1 
                   
                   ) 
                 
               
             
           
         
       
     
         [0000]    wherein “U” is the gliding speed of the vehicle, “g” is a gravity acceleration, and “L” is the length of vehicle&#39;s immersion line. In order for an embodiment of this invention to glide on the surface of water, its Froude Number is to arrive approximately at “1”. 
         [0014]    Also, a multi-purpose amphibious vehicle according to an embodiment of the present invention should be driven by the rolling friction on the surface of water governed by the following “Lee Number” that judges the generation of elevation force, which can sustain the vehicle&#39;s weight at a certain instant during its momentum change. 
         [0000]    
       
         
           
             
               
                 
                   
                     L 
                     N 
                   
                   = 
                   
                     V 
                     
                       g 
                       × 
                       Δ 
                        
                       
                           
                       
                        
                       T 
                     
                   
                 
               
               
                 
                   ( 
                   
                     Eq 
                     . 
                     
                         
                     
                      
                     2 
                   
                   ) 
                 
               
             
           
         
       
     
         [0000]    wherein “V” is such a speed that the track or tire of the vehicle is colliding against the mentioned surfaces or transferring onto them, “g” is a gravitational acceleration, and “ΔT” means a stay instant on the contact surface of the mentioned tracks or tires. Thus, for such a condition that this invention, a multi-purpose amphibious vehicle can run on the surface of water, the Lee Number should be equal to or greater than “1”. 
         [0015]    Since an embodiment of this invention, the vehicle running on the surface of water, is driven by the rolling friction, this case can be regarded as one of Coulomb Friction. At this instance, the coefficient “μ” of friction can be expressed as follows. 
         [0000]    
       
         
           
             
               
                 
                   μ 
                   = 
                   
                     
                       
                         
                           U 
                         
                       
                       
                         
                           V 
                         
                       
                     
                     = 
                     
                       
                         
                           
                             
                               Fr 
                               N 
                             
                           
                         
                         
                           
                             
                               L 
                               N 
                             
                           
                         
                       
                       × 
                       
                         √ 
                         
                           
                             
                               L 
                             
                           
                           
                             
                               
                                 g 
                                 × 
                                 Δ 
                                  
                                 
                                     
                                 
                                  
                                 
                                   T 
                                   2 
                                 
                               
                             
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   
                     Eq 
                     . 
                     
                         
                     
                      
                     3 
                   
                   ) 
                 
               
             
           
         
       
     
         [0016]    In practice, suppose an embodiment of this may be driven by much higher friction, with no slip condition on the surface of water, it could be realized that the mentioned frictional coefficient become “=1”. 
         [0017]    As being described in the above, by utilizing the above equations 1-3, such a condition that this invention, a multi-purpose amphibious vehicle can move by its rolling friction on the surface of water can be obtained. 
         [0018]    Also, the movement technology on the surfaces of all terrain, so called, “all terrain ride on technology” can be derived from such a law of nature that, in Newton Mechanics, “Momentum Change equals Its Impulse”. The momentum change of the mentioned vehicle at a certain instant over its critical speed is to be transferred to the contact material having a certain mass (for instance, the water on its surface) to generate “elevation force” as a reaction force. Depending upon the law of nature, the effect that the mentioned vehicle is keeping and running on the surfaces of all terrain has been progressed into “all terrain ride-on principle”. By applying this principle to embodiments of this invention, a multi-purpose amphibious vehicle that can move on the surfaces of all terrain is provided. 
       ([Advanced Technology Publications]) 
     ([Patents]) 
       [0000]    
       
         1. Gibbs Technologies Ltd. British“Wheel Suspension and Retraction System” Registration No. (Date) U.S. Pat. No. 7,316,594 B2 (Jan. 8, 2008). 
         2. “All-Terrain Hostile Environment Vehicle” Registration No. (Date) U.S. Pat. No. 7,478,817 B1 (Jan. 20, 2009). 
       
     
       ([Non-Patents]) 
       [0000]    
       
         1. Walter B Horne and Robert C. Dreber “Phenomena of Pneumatic Tire Hydroplaning” NASA TN D-2056, November 1963. 
         2. Lydéric Bocquet “The Physics of Stone Skipping” The Nature, October, 2002. 
       
     
         [0023]    3. William A. Johnsen “Advances in the Design of Pavement Surfaces” A Dissertation WORCESTER POLYTECHNIC INSTITUTE Dec. 19, 1997 
       Subjects to be Solved 
       [0024]    The specifications of a future “All Terrain Ride On Vehicle” that a multi-purpose amphibious vehicle of 21 st  century should provide can be summarized as the following 5 requirements; 
         [0025]    a) In keeping its performance on the land, the drag of tracks of the multi-purpose amphibious vehicle on the surface of water should be minimized, 
         [0026]    b) the multi-purpose amphibious vehicle should have safer and more economical performance both on the surfaces of land and water. 
         [0027]    c) Even after having solved such a chronic problem that amphibious vehicles are slower on the surface of water, the manufacturing cost of the multi-purpose amphibious vehicle should be lowered. 
         [0028]    d) The multi-purpose amphibious vehicle should be equipped with such a suspension that can keep the vehicle safer and at higher speeds on the surfaces of all types of terrain, 
         [0029]    e) Such a multi-purpose amphibious vehicle that should be capable of equivalently alternating, with no hesitation, on the surfaces of land and water. 
         [0030]    In spite of these requirements, in designing a multi-purpose amphibious vehicle, there has been no other suggestion except the known technology up to now which depends on the traction on the land and hydro-gliding on water at higher speed by utilizing all of three forces; buoyancy, lift, and air pressure. 
         [0031]    In order to glide at higher speeds on the surface of water, vehicles require over two times of the power consumption spent on land. Thus, problems such as vision and hydro-movement becoming unstable by a severe porpoise effect even in lower waves and vibration and noise due to higher power consumption should be still solved for a multi-purpose amphibious vehicle. 
         [0032]    Embodiments of the present invention address the problems as described above. The goal during moving on any terrain is to provide such a multi-purpose amphibious vehicle that over the critical speed, the rolling friction leads the track rolling on the surfaces. The multi-purpose amphibious vehicle can run very smoothly and economically with a single engine, can provide multi=terrain capability with no hesitation between surfaces of different types of terrains, and can go as fast on the surfaces of water, snow and ice as it can run on the surface of land. Journey between islands, use for arctic expeditions, higher speed entry along inland rivers, and on the other hand, operation on areas of marsh or swamp using lower ground pressure tracks are all possible with a multi-purpose amphibious vehicle according to an embodiment. 
       Solution Means of Subjects 
       [0033]    As discussed above, in order to develop a multi-purpose amphibious vehicle of 21 st  century, the conventional technology is problematic. A new scheme “All Terrain Ride on Technology” is desirable. 
         [0034]    Accordingly, embodiments of this invention involve a new principle of all terrain movement that starts from the principle in Newtonian physics that “change in momentum is equal to an impulse”. When a certain revolving object collides with a certain surface, it causes such a force that both surfaces meet and rotate together. Accordingly, it has been discovered that an object can move by elevation force on all the surfaces at higher speed over the critical speed. 
         [0035]    The principle of all terrain movement for the embodiments of this invention can be explained as follows. 
         [0036]    First, in order for an object to move, it requires a force as 2 nd  law of Newton Mechanics. 
         [0000]        F=M a   (Eq. 4)
 
         [0000]    Wherein “M” is a mass of certain object or “ΔM” is its distributed mass, “a” as an acceleration is a time derivative of a certain velocity 
         [0000]    
       
         
           
             
               “ 
               
                 
                   Δ 
                    
                   
                       
                   
                    
                   V 
                 
                 
                   Δ 
                    
                   
                       
                   
                    
                   T 
                 
               
               ” 
             
             , 
           
         
       
     
         [0000]    and “F” is such a force that the mass “M” of a certain object or its distributed mass “ΔM” can stay on a certain surface. This can be described again as 
         [0000]        F×ΔT=M×V   (Eq. 5)
 
         [0037]    The left hand side becomes an impulse, and the right hand side results in momentum change, which is a derivation from the 2 nd  law of Newton Mechanics. Starting from this law, in order for a certain object to exist on a certain surface, the time “ΔT” should have a value of certain instant. To do this, the force “F” that can sustain the weight of the object “M” or the distributed weight “ΔMg” is hereby defined as the “elevation force”, the value of which should be at least equal to the weight of object “F=Mg” or the distributed weight “F=ΔMg”. 
         [0038]    At this time, the ratio of its impulse and momentum is defined as herein-below by a non-dimensional “Lee Number”, which is proposed by such a condition that a certain object should exist on a certain surface. 
         [0000]    
       
         
           
             
               
                 
                   
                     L 
                     N 
                   
                   = 
                   
                     V 
                     
                       g 
                       × 
                       Λ 
                        
                       
                           
                       
                        
                       T 
                     
                   
                 
               
               
                 
                   ( 
                   
                     Eq 
                     . 
                     
                         
                     
                      
                     6 
                   
                   ) 
                 
               
             
           
         
       
     
         [0039]    Already, as being assumed in Eq. 5, suppose a certain object should exist on a certain surface, it is unequivocally known that the Lee Number is no less than “1”. In another words, it can be regarded that the momentum change of a certain object is transferred to a certain surface of the material to generate a reactive force, so called, “elevation force”. 
         [0040]    Thus, such a speed that a certain object can exist on a certain surface by generating the elevation force is defined as a critical speed. The stay time “ΔT” at that instant is also defined as a critical instant of stay. 
         [0041]    For the case that this critical speed and instant should happen, Eq. 5 is rewritten with its horizontal and vertical components against a certain surface and given by the following. 
         [0000]        Mg×ΔT=M×ΔV   (Eq.7a)
 
         [0000]      μ Mg×ΔT=M×ΔU   (Eq.7b)
 
         [0000]    Wherein“μ” has been regarded as the coefficient of Coulomb friction. The division of Eq. 7a by Eq. 7b results in the following relationship. 
         [0000]    
       
         
           
             
               
                 
                   μ 
                   = 
                   
                     
                       Δ 
                        
                       
                           
                       
                        
                       U 
                     
                     
                       Δ 
                        
                       
                           
                       
                        
                       V 
                     
                   
                 
               
               
                 
                   ( 
                   
                     Eq 
                     . 
                     
                         
                     
                      
                     8 
                   
                   ) 
                 
               
             
           
         
       
     
         [0042]    Since it has been assumed that embodiments of this invention be moving by the rolling friction on a certain surface, by applying no slip condition, it could be known that the horizontal and vertical momentum changes become identical. 
         [0043]    Now, in order for a certain object to move by the elevation force on a certain surface, the generated elevation force as a reactive force by a transferred momentum to a certain material (wherein “Water”) should be proportional to the square of colliding speed. Then, it can be expressed as follows. 
         [0000]    
       
         
           
             
               
                 
                   Mg 
                   = 
                   
                     
                       1 
                       2 
                     
                      
                     
                       ρ 
                       W 
                     
                      
                     
                       AV 
                       C 
                       1 
                     
                      
                     
                       C 
                       D 
                     
                   
                 
               
               
                 
                   ( 
                   
                     Eq 
                     . 
                     
                         
                     
                      
                     9 
                   
                   ) 
                 
               
             
           
         
       
     
         [0000]    wherein “A” is such an area that a certain object “M” contacts a material with its density “ρ w ”. “C D ” as a general drag coefficient is known to have approximately its experimental value of “0.7” for the case of tire but the case of this invention has its experimental value of about “1.0” because its contact surface is a planar flat track. For this case, the critical speed “V c ” is given by 
         [0000]    
       
         
           
             
               
                 
                   
                     V 
                     C 
                   
                   = 
                   
                     
                       
                         2 
                          
                         Mg 
                       
                       
                         
                           ρ 
                           W 
                         
                          
                         A 
                          
                         
                             
                         
                          
                         
                           C 
                           D 
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   
                     Eq 
                     . 
                     
                         
                     
                      
                     10 
                   
                   ) 
                 
               
             
           
         
       
     
         [0000]    wherein it has been assumed that the speed of a certain object be varied to “ΔV=V C ” after its collision with a certain surface i.e. its contact speed be closing onto zero. Then, since the case that Lee Number of Eq. 6 becomes “1” is a critical condition, the critical instant “ΔT” is given by 
         [0000]    
       
         
           
             
               
                 
                   
                     Δ 
                      
                     
                         
                     
                      
                     T 
                   
                   = 
                   
                     
                       V 
                       C 
                     
                     g 
                   
                 
               
               
                 
                   ( 
                   
                     Eq 
                     . 
                     
                         
                     
                      
                     11 
                   
                   ) 
                 
               
             
           
         
       
     
         [0044]    Now, since such a condition that this invention, a multi-purpose amphibious vehicle is capable of moving on a certain surface by its track has been discovered, being based upon this, it is applied equivalently to the line speed of the track of this invention, a multi-purpose amphibious vehicle as follows, 
         [0000]    
       
         
           
             
               
                 
                   
                     V 
                     
                       
                           
                       
                        
                       C 
                     
                   
                   = 
                   
                     
                       π 
                        
                       
                           
                       
                        
                       R 
                     
                     
                       Δ 
                        
                       
                           
                       
                        
                       T 
                     
                   
                 
               
               
                 
                   ( 
                   
                     Eq 
                     . 
                     
                         
                     
                      
                     12 
                   
                   ) 
                 
               
             
           
         
       
     
         [0000]    wherein “R” is a radius of the tire inside of the track of this invention, a multi-purpose amphibious vehicle. Also, the relationships between a radius of tire and both of the critical instant and the critical speed are given by 
         [0000]    
       
         
           
             
               
                 
                   
                     Δ 
                      
                     
                         
                     
                      
                     T 
                   
                   = 
                   
                     
                       
                         π 
                          
                         
                             
                         
                          
                         R 
                       
                       g 
                     
                   
                 
               
               
                 
                   ( 
                   
                     
                       Eq 
                       . 
                       
                           
                       
                        
                       13 
                     
                      
                     a 
                   
                   ) 
                 
               
             
             
               
                 
                   
                     V 
                     C 
                   
                   = 
                   
                     
                       π 
                        
                       
                           
                       
                        
                       R 
                       × 
                       g 
                     
                   
                 
               
               
                 
                   ( 
                   
                     
                       Eq 
                       . 
                       
                           
                       
                        
                       13 
                     
                      
                     b 
                   
                   ) 
                 
               
             
           
         
       
     
         [0045]    From the above critical conditions, the size 
         [0000]    
       
         
           
             ( 
             
               R 
               = 
               
                 
                   g 
                   × 
                   Δ 
                    
                   
                       
                   
                    
                   
                     T 
                     2 
                   
                 
                 π 
               
             
             ) 
           
         
       
     
         [0000]    of tire being fit for this invention, a multi-purpose amphibious vehicle can be determined. In consideration of vehicle&#39;s stability during its move on the surface of water, in order for its center of gravity to be positioned forward from its center of pressure, the numbers of frontal and rear tires by following the shared distribution of weight can be determined. The required power can be obtained in accordance with the maximum speed “U Max ” of the vehicle by the following formula. 
         [0000]    
       
         
           
             
               
                 
                   
                       
                   
                    
                   
                     
                       HP 
                       = 
                       
                         
                           
                             Mg 
                             × 
                             
                               U 
                               
                                 Ma 
                                  
                                 
                                     
                                 
                                  
                                 x 
                               
                             
                           
                           + 
                           
                             
                               ? 
                             
                              
                             ρ 
                             × 
                             
                               A 
                               D 
                             
                             × 
                             
                               ? 
                             
                           
                         
                         
                           η 
                           × 
                           750 
                         
                       
                     
                      
                     
                       
 
                     
                      
                     
                       
                         ? 
                       
                        
                       
                         indicates text missing or illegible when filed 
                       
                     
                   
                 
               
               
                 
                   ( 
                   14 
                   ) 
                 
               
             
           
         
       
     
         [0046]    In Eq. 14, “ρ” is the density of air, “A D ” is a frontal drag area of the vehicle, And “η” an efficiency of power transmission. Taking it for instance: in case the full loaded weight of an embodiment of this invention weighs 3 tons, and the maximum moving speed on the surface of water reaches 50 knots, it requires a diesel engine of 250 HP as a power source. 
       Effect 
       [0047]    As an embodiment of this invention is related to a multi-purpose amphibious vehicle depending on “All Terrain Ride-On Ability”, during its movement on the surface of any terrain, it is not gliding on the mentioned surface over the critical speed but rolling with its track by the rolling friction. Thus, the multi-purpose amphibious vehicle can run very smoothly and economically with a single engine, can provide multi-terrain capability with no hesitation between surfaces of different types of terrains, and can go as fast on the surfaces of water, snow and ice as it can run on the surface of land. Journey between islands, use for arctic expeditions, higher speed entry along inland rivers, and on the other hand, operation on areas of marsh or swamp using lower ground pressure tracks are all effectuated. 
         [0048]    Also, by running on the planar surface of water with its tracks, there exists another effect to provide an economic sea-born transportation system having higher transportation efficiency being equivalent to such a required power of cars running on land. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0049]      FIG. 1  is a perspective view of a multi-purpose amphibious vehicle according to an embodiment. 
           [0050]      FIG. 2  is a schematic representation of the steering, braking and power transmission systems of the multi-purpose amphibious vehicle of  FIG. 1 . 
           [0051]      FIG. 3  is a side view of the multi-purpose amphibious vehicle of  FIG. 1 . 
           [0052]      FIG. 4  is a front view of the multi-purpose amphibious vehicle of  FIG. 1 . 
           [0053]      FIG. 5  is a rear view of the multi-purpose amphibious vehicle of  FIG. 1 . 
           [0054]      FIG. 6  and  FIG. 7  are schematic representations of positions of a center of gravity and of a center of pressure of the multi-purpose amphibious vehicle of  FIG. 1 . 
           [0055]      FIG. 8  is a schematic representation of a multi-purpose amphibious vehicle running on the surface of water. 
           [0056]      FIG. 9  is a schematic representation of the multi-purpose amphibious vehicle of  FIG. 1  self-righting after it has been capsized. 
           [0057]      FIG. 10  is a schematic representation of the multi-purpose amphibious vehicle of  FIG. 1  wave piercing through a higher wave. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0058]    Starting from the principle in Newtonian physics that “change in momentum is equal to an impulse”, elevation force has been discovered and developed to the principle of All Terrain Ride On Ability as described above and applied to the tracks of an exemplary embodiment of the present invention. 
         [0059]    The exemplary embodiment of the present invention will be better appreciated and understood through a review of the attached drawing figures in conjunction with the description set forth as follows. 
         [0060]      FIG. 1  is a perspective view of a multi-purpose amphibious vehicle  100  according to an embodiment. The multi-purpose amphibious vehicle  100  may include a buoyant bow portion  10  that is constructed as a bow shape of a boat which can go through a current at lower speed in water. 
         [0061]    The multi-purpose amphibious vehicle  100  may further include a planing track  20  including a planing belt  24  and 3 sets of idling tires  21 ,  22 ,  23 , all part of a front part of the vehicle. The multi-purpose amphibious vehicle  100  further may include a traction portion including a driving track  30  that is equipped with four tires  31 ,  32 ,  33 ,  34  and a driving belt  35 , all part of a rear part of the vehicle. 
         [0062]    On a front upper part of the multi-purpose amphibious vehicle  100 , a buoyant fender portion  40  may be constructed in order to prevent the bow of the vehicle from going under during operation. 
         [0063]    On each side of the vehicle  100 , a hatch door  51  that is water tight and a foothold  50  that passengers can step on may be positioned on an upper side of a track cover. 
         [0064]    In the rear of the multi-purpose amphibious vehicle  100 , a hatch rear door may be added to provide a total of 3 hatch doors. 
         [0065]    In the rear of the multi-purpose amphibious vehicle  100 , a hydraulic rear float deck  60  may be deployed to obtain additional buoyancy in order to prevent such a case that a center of pressure is positioned forward of a center of gravity when the vehicle is running at a speed faster than a critical speed. The hydraulic rear float deck  60  may lead to the center of pressure being positioned rearward of the center of gravity. The deck portion of the hydraulic rear float deck  60  may also be used as an extra open space to be used, not only for carrying luggage, but also for connecting a path into the rearward hatch door. 
         [0066]    The multi-purpose amphibious vehicle  100  further may include an electronic communication apparatus to confirm the vehicles position at all times. The electronic communication apparatus may be connected to a GPS system including a GPS antenna  70  and a transmission antenna  80  on the top of the vehicle. 
         [0067]      FIG. 2  is schematic representation of the steering, braking and power transmission systems of the multi-purpose amphibious vehicle  100  of  FIG. 1 . The multi-purpose amphibious vehicle  100  may include the buoyant bow portion  10  that is positioned foremost, 3 sets of idling tires  21 ,  22 ,  23  including breaks  25  operated by a hydraulic or electric system. The planing tracks  20  may hydroplane on high waves and may be used for steering and braking. The rear driving track  30  may include 4 sets of tires  31 ,  32 ,  33 ,  34 . The front and back sets of tires  31 ,  34  may transfer power. More specifically, power may be transferred through drive shafts  104 ,  105  and gear boxes  102 ,  103  from an engine  101  to the front and back sets of tires  31 ,  34 . The intermediate two sets of tires  32 ,  33  may be equipped with bearings  106  for idling and guiding wherein the inner pressure of concerned tires may be determined by considering the distributed weight and the contact pressure of the multi-purpose amphibious vehicle  100 . 
         [0068]    In the rear of the multi-purpose amphibious vehicle, the hydraulic rear float deck  60  is shown deployed so that, when running on the surface of water at a speed faster than the critical speed (i.e., Lee Number is equal to “1”), the center of pressure being generated may be positioned after the center of gravity. 
         [0069]      FIG. 3  is a side view of the multi-purpose amphibious vehicle  100  of  FIG. 1 . 
         [0070]      FIG. 4  is a front view of the multi-purpose amphibious vehicle  100  of  FIG. 1 . 
         [0071]      FIG. 5  is a rear view of the multi-purpose amphibious vehicle  100  of  FIG. 1 . 
         [0072]      FIGS. 3-5  show the frontal buoyant bow portion  10  to cleave incoming waves and the driving track  30  when the multi-purpose amphibious vehicle  100  is running faster than the critical speed that is driven by the rolling friction caused between the surface of water and the planing track  20 . 
         [0073]    On a side hatch door  51 , 2 sets of door locks  52 ,  53  may be set in parallel and provide a water tight seal, and on the hydraulic rear float deck  60 , a deployed buoyant plate  63  may be supported by 2 sets of hydraulic cylinders  61 ,  62 . As already noted, the top of the vehicle may include a GPS antenna  70 . 
         [0074]      FIG. 6  is a schematic representation showing such a state that the center of gravity of the multi-purpose amphibious vehicle  100  of  FIG. 1  may be positioned forward from the center of pressure, which can be realized by adding the rear hydraulic float deck  60  in order to secure the stability of the vehicle when running on the surface of water faster than the critical speed (i.e., its Lee Number is over “1”). 
         [0075]      FIG. 7  is a schematic representation demonstrating that a center of gravity of the multi-purpose amphibious vehicle  100  of  FIG. 1  due to the weight of the tracks and engine may be positioned at higher point than a center of buoyancy so that the multi-purpose amphibious vehicle  100  is self-righting even after having been capsized. 
         [0076]      FIG. 8  is a schematic representation showing the multi-purpose amphibious vehicle  100  of  FIG. 1  cruising on the surface of water by rolling friction, the elevation force of which may be generated over the critical speed. Exemplary specifications of an embodiment that is cruising as discussed above are described in the following table. 
         [0000]    
       
         
               
               
               
             
               
               
               
               
             
               
               
               
             
           
               
                   
               
               
                 Specification 
                 Unit 
                 Remark 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Weight 
                 3,000  
                 Kg 
                 6 Pass. Incl. 
               
               
                 Power 
                 250  
                 HP 
                 Water 
               
               
                 Contact Pressure 
                 0.055  `   
                 Kg/cm 2   
                 Amphibious 
               
               
                 Land Max/Cruise 
                 85/65  
                 Km/hr 
                 Pavement 
               
               
                 Water Max/Cruise 
                 100/75  
                 Km/hr 
                 Level 2 
               
               
                 Critical Speed 
                 12.1  
                 Km/hr 
                 On Water 
               
             
          
           
               
                 No of Tire 
                 14 {2 × (3 + 4)} 
                 Aircraft Quality(φ 750 mm) 
               
               
                   
               
             
          
         
       
     
         [0077]      FIG. 9  is a schematic representation showing a series of states in which the multi-purpose amphibious vehicle  100  of  FIG. 1  may be self-righting from state “a” (completely upside down) to state “e” (right side up) after having been capsized. 
         [0078]    Since the vehicle&#39;s center of gravity may be set to be located at higher position than its center of buoyancy after being capsized, even by the slightest leaning, the capsized vehicle is self-righting by the corresponding rolling force, the moment of which is generated from the base point at the center of buoyancy of the capsized vehicle. 
         [0079]      FIG. 10  is a schematic representation of the multi-purpose amphibious vehicle  100  of  FIG. 1  going through a wave and to passing through the wave by wave piercing when the vehicle faces a higher wave during movement on the surface of water. 
         [0080]    During the period of wave piercing, the forces that are imposed on the multi-purpose amphibious vehicle  100  may be affected by the forces of drag, lift, and self-weight due to gravity. However, the self-weight and buoyancy of the vehicle inside of the wave should be kept in balance. A change of momentum as the vehicle starts to advance into the wave and until it escapes from the wave should be related to the drag force that affects the frontal drag area of the vehicle. The following formula can be derived by: 
         [0000]        F   D   ×ΔT=M ( V   1   −V   2 )  (Eq. 21)
 
         [0000]    wherein the average speed of the multi-purpose amphibious vehicle  100  during the wave piercing is given by “V m =½×(V 1 +V 2 )”. Then, the drag “F D ” can be expressed as: 
         [0000]    
       
         
           
             
               
                 
                   
                     F 
                     D 
                   
                   = 
                   
                     
                       1 
                       2 
                     
                      
                     ρ 
                      
                     
                         
                     
                      
                     
                       AV 
                       m 
                       2 
                     
                     × 
                     
                       C 
                       L 
                     
                   
                 
               
               
                 
                   ( 
                   
                     Eq 
                     . 
                     
                         
                     
                      
                     22 
                   
                   ) 
                 
               
             
           
         
       
     
         [0081]    Once the wave length of the wave is given by “λ W ” and the length of passage for wave piercing is regarded as its half, then its passing time “ΔT” for the water passage is given by the following: 
         [0000]    
       
         
           
             
               
                 
                   
                       
                   
                    
                   
                     
                       
                         Δ 
                          
                         
                             
                         
                          
                         T 
                       
                       = 
                       
                         
                           
                             ? 
                           
                            
                           
                             λ 
                             W 
                           
                         
                         
                           
                             V 
                             IN 
                           
                           - 
                           
                             V 
                             OUT 
                           
                         
                       
                     
                      
                     
                       
 
                     
                      
                     
                       
                         ? 
                       
                        
                       
                         indicates text missing or illegible when filed 
                       
                     
                   
                 
               
               
                 
                   ( 
                   
                     Eq 
                     . 
                     
                         
                     
                      
                     23 
                   
                   ) 
                 
               
             
           
         
       
     
         [0082]    By combining Eqs. 21-23 together, the average speed “V m ” of the multi-purpose amphibious vehicle  100  during its wave piercing can be derived by the following: 
         [0000]    
       
         
           
             
               
                 
                   
                     V 
                     m 
                   
                   = 
                   
                     2 
                      
                     Δ 
                      
                     
                         
                     
                      
                     V 
                     × 
                     
                       
                         M 
                         
                           ρ 
                            
                           
                               
                           
                            
                           A 
                            
                           
                               
                           
                            
                           
                             λ 
                             W 
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   
                     Eq 
                     . 
                     
                         
                     
                      
                     24 
                   
                   ) 
                 
               
             
           
         
       
     
         [0000]    wherein “ΔV=V 1 −V 2 ”. 
         [0083]    In the above equation, 
         [0000]    
       
         
           
             
               
                 M 
                 
                   ρ 
                    
                   
                       
                   
                    
                   A 
                    
                   
                       
                   
                    
                   
                     λ 
                     W 
                   
                 
               
               2 
             
               
             ″ 
               
               
             `` 
           
         
       
     
         [0000]    is put by “k” and “V 2 /V 1 ” is done by “α”. Then, the following relationship is derived by: 
         [0000]    
       
         
           
             
               
                 
                   α 
                   = 
                   
                     
                       
                         V 
                         OUT 
                       
                       
                         V 
                         IN 
                       
                     
                     = 
                     
                       
                         1 
                         - 
                         k 
                       
                       
                         1 
                         + 
                         k 
                       
                     
                   
                 
               
               
                 
                   ( 
                   
                     Eq 
                     . 
                     
                         
                     
                      
                     25 
                   
                   ) 
                 
               
             
           
         
       
     
         [0084]    At this time, “α” exists in “0&lt;a&lt;1”, but “V OUT ” should be no less than the critical speed for the multi-purpose amphibious vehicle  100 . In case the amplitude and wave length “λ W ” is about 10 m, considering that an exemplary cruising speed of the multi-purpose amphibious vehicle  100  on the surface of water may be 75 Km/hr, the wave may cause only a 25% decrease in speed. Thus, even colliding with a higher wave of 10 meters, after about 1 second of a shock absorbing effect, the vehicle can continue to cruise very smoothly. 
       INDUSTRIAL APPLICABILITY 
       [0085]    Accordingly, this invention that has discovered the Elevation Force from such a law of nature that “Momentum Change Equals to the Impulse” in Newtonian Physics and applies it to the tracks is related to such a multi-purpose amphibious vehicle that is propelled by the principle of All Terrain Ride On Ability. It corresponds with various designs to a wide range of applications from Recreation, Exploration. Search and Rescue up to the Military Purposes. 
         [0086]    The applications of this invention can be extended from the commuter going and back to the work along the river of inland, journey between islands, up to the arctic exploration, which is such a multi-purpose amphibious vehicle being built by the advanced technology of All Terrain Ride On Ability that 21 st  Century has been requiring. 
       [Title of the Number] 
       [0000]    
       
           100 : Vehicle 
           10 : bow portion  20 : planing Track 
       
     
       INDUSTRIAL APPLICABILITY 
       [0089]