Reverse mechanism for a jet system

Abstract

A jet propulsion system includes an inlet receiving a fluid, and a housing defining a discharge nozzle through which fluid is discharged to provide propulsion of a vehicle in a first direction. The jet propulsion system also includes a reverse mechanism movable between a deployed position redirecting fluid from the discharge nozzle toward the first direction and providing propulsion of the vehicle in a second direction substantially opposite the first direction and a non-deployed position allowing fluid to exit the discharge nozzle and provide propulsion of the vehicle in the first direction. The reverse mechanism produces a flow entrainment that enhances forward thrust while the reverse mechanism is in the non-deployed position which results in a net thrust gain over the thrust attributed to the discharge nozzle alone.

1 . A jet propulsion system comprised of:
 a housing having a discharge nozzle through which fluid exits and provides propulsion of a vehicle along a first direction; and   a reverse mechanism having a diverting assembly pivotally coupled to the housing for movement between a non-deployed position allowing fluid to exit the discharge nozzle and provide propulsion of the vehicle in a first direction and a deployed position forming a substantially hemispherical inner surface for redirecting fluid from the discharge nozzle and providing propulsion of the vehicle in a second direction substantially opposite the first direction.   
   
   
       2 . The jet propulsion system as set forth in  claim 1 , wherein the reverse mechanism includes a ring attached to the housing, the ring having an inner surface spaced apart from an outer surface of the housing forming an annulus through which flow will pass. 
   
   
       3 . The jet propulsion system as set forth in  claim 2 , wherein the reverse mechanism includes a substantially hemispherically shaped diverting assembly coupled to the ring for movement between the deployed and non-deployed positions. 
   
   
       4 . The jet propulsion system as set forth in  claim 3 , wherein the diverting assembly is formed of a fabric material. 
   
   
       5 . The jet propulsion system as set forth in  claim 4 , wherein the fabric material includes a opening formed between two parts of the diverting assembly, the two parts being movable between the deployed position, in which the opening is closed to prevent fluid from passing therethrough, and non-deployed position, in which the opening is open to allow fluid to pass therethrough. 
   
   
       6 . The jet propulsion system as set forth in  claim 5 , wherein the diverting assembly includes a pair of movable support frames supporting the two parts of the diverting assembly along the opening, 
   
   
       7 . The jet propulsion system as set forth in  claim 6 , wherein each support frame is pivotally coupled to the ring and provides movement of the two parts of the diverting assembly between the deployed and non-deployed positions. 
   
   
       8 . The jet propulsion system as set forth in  claim 6 , wherein each support frame has opposite ends pivotally coupled to opposite sides of the housing, each support frame extending generally arcuately between the opposite ends. 
   
   
       9 . The jet propulsion system as set forth in  claim 5 , wherein the two parts of the diverting assembly are movable to a neutral position between the deployed position and the non-deployed position, in which the amount of thrust in the first direction is substantially the same as the amount of thrust in the second direction. 
   
   
       10 . The jet propulsion system as set forth in  claim 2 , wherein the housing includes a fixed portion interconnected to the vehicle and a movable portion movably coupled to the fixed portion, the discharge nozzle being disposed on the movable portion of the housing. 
   
   
       11 . The jet propulsion system as set forth in  claim 10 , wherein movable portion is pivotally coupled to the fixed portion for movement along at least one pivot axis. 
   
   
       12 . The jet propulsion system as set forth in  claim 10  including a support frame pivotally coupled to the housing for movement along a generally horizontal first axis. 
   
   
       13 . The jet propulsion system as set forth in  claim 12 , wherein the movable portion is coupled to the support frame for movement therewith about the first axis. 
   
   
       14 . The jet propulsion system as set forth in  claim 13 , wherein the movable portion is pivotally coupled to the support frame for movement about a second axis. 
   
   
       15 . The jet propulsion system as set forth in  claim 14 , wherein the first axis and second axis are substantially orthogonal relative to each other. 
   
   
       16 . The jet propulsion system as set forth in  claim 3 , wherein the diverting assembly includes a plurality of dimensionally stable shells movable between the deployed and non-deployed positions. 
   
   
       17 . The jet propulsion system as set forth in  claim 16 , wherein the shells are movable about a common pivot axis relative to each other. 
   
   
       18 . A jet propulsion system comprising:
 a housing defining a discharge nozzle through which fluid exits and provides propulsion of a vehicle along a first direction; and   a reverse mechanism movable between a deployed position redirecting fluid from the discharge nozzle toward the first direction and providing propulsion of the vehicle in a second direction substantially opposite the first direction and a non-deployed position allowing fluid to exit the discharge nozzle and provide propulsion of the vehicle in the first direction, the reverse mechanism enhancing forward thrust while the reverse mechanism is in the non-deployed position by increasing the mass flux and momentum of the flow at the exit of the discharge nozzle through flow entrainment.   
   
   
       19 . The jet propulsion system as set forth in  claim 18 , wherein the reverse mechanism includes a ring securely fixed to the housing, the ring having an inner surface spaced apart from an outer surface of the housing to define an annular channel through which fluid diverted by the reverse mechanism can flow, the annular channel narrowing to accelerate fluid passing therethrough. 
   
   
       20 . The jet propulsion system as set forth in  claim 18 , wherein the reverse mechanism includes a pair of movable support frames pivotally coupled to the housing moveable between the deployed and non-deployed positions an inner surface of the support members spaced apart from an outer surface of the housing in the non-deployed position to define an annular channel through which fluid diverted by the reverse mechanism can flow, the annular channel narrowing to accelerate fluid passing therethrough. 
   
   
       21 . The jet propulsion system as set forth in  claim 18 , wherein the reverse mechanism includes a diverting assembly with a curved inner surface for reversing fluid exiting the discharge nozzle producing reverse thrust. 
   
   
       22 . The jet propulsion system as set forth in  claim 18 , wherein the reverse mechanism is offset relative to a center line of the discharge nozzle. 
   
   
       23 . A jet propulsion system comprising:
 a housing defining a discharge nozzle through which fluid exits and provides propulsion of a vehicle along a first direction; and   a reverse mechanism pivotally coupled to the housing, the housing moveable relative to the discharge nozzle in a pitch and steer axis wherein a thrust vector of fluid exiting the discharge nozzle may be manipulated to control damping of an attitude and motion of the vehicle in any of the pitch, roll and yaw axes.   
   
   
       24 . The jet propulsion system as set forth in  claim 23  wherein the reverse mechanism is movable between a deployed position redirecting fluid from the discharge nozzle toward the first direction and providing propulsion of the vehicle in a second direction substantially opposite the first direction and a non-deployed position allowing fluid to exit the discharge nozzle and provide propulsion of the vehicle in the first direction, the reverse mechanism enhancing forward thrust while the reverse mechanism is in the non-deployed position by increasing the mass flux and momentum of the flow at the exit of the discharge nozzle through flow entrainment. 
   
   
       25 . A jet propulsion system attached to a watercraft comprising:
 a housing defining a discharge nozzle through which fluid exits and provides propulsion of a vehicle along a first direction; and   a ring securely fixed to the housing, the ring having an inner surface spaced apart from an outer surface of the housing to define an annular channel through which fluid diverted by the reverse mechanism can flow, the annular channel narrowing to accelerate fluid passing therethrough.