Aircraft engine nacelle cowling mechanism

1. An aircraft propulsion system comprising:

an engine assembly including a fan that rotates to move air;

a cowl that surrounds at least a portion of the engine assembly when the cowl is in a closed position, the cowl including an outer surface arranged away from the engine assembly that provides an aerodynamic surface; and

a cowl mechanism connected to the cowl and configured to guide the cowl along a movement path from the closed position to an open position, wherein

in the open position, an entirety of the cowl is arranged farther away from a horizontal plane passing through a rotating axis of the fan than in the closed position,

the cowl mechanism guides the cowl along the movement path between the open position and the closed position so that no portion of the cowl extends beyond a clearance plane at any position along the movement path,

the cowl mechanism is configured to be mounted to a pylon extending away from a fuselage of the aircraft in a horizontal direction, and

the clearance plane extends in a vertical direction through an intersection point that is a point on an outer surface of the cowl in the closed position that is closest to the fuselage.

2. The aircraft propulsion system according to claim 1 , wherein

the movement path is defined by a motion of a point on the outer surface of the cowl,

the movement path includes a straight line during a first portion of the movement path from the closed position to the open position, and

the movement path includes a curved line during a second portion of the movement path from the closed position to the open position, the second portion being further from the closed position than the first portion.

3. The aircraft propulsion system according to claim 1 , wherein

in the open position, the entirety of the cowl is moved away from the horizontal plane by a distance equal to at least an outer radius of an engine core of the engine assembly.

4. The aircraft propulsion system according to claim 1 , wherein

the cowl includes an upper cowl that surrounds an upper portion of the engine assembly, and a lower cowl that surrounds a lower portion of the engine assembly,

in the closed position, the upper cowl and the lower cowl are configured to be latched to each other by at least one latch along the horizontal plane,

the cowl mechanism further includes

an upper cowl mechanism attached to the upper cowl,

a lower cowl mechanism attached to the lower cowl, and

a mid-link connecting the upper cowl to the lower cowl,

the cowl mechanism being further configured to simultaneously move a second one of the upper cowl and the lower cowl along the movement path when a first one of the upper cowl and the lower cowl is caused to move along the movement path by an external force.

5. The aircraft propulsion system according to claim 4 , wherein

the cowl mechanism is configured to counterbalance a weight of the upper cowl and the lower cowl so that the external force required to move the upper cowl and the lower cowl along the movement path is less than a maximum force that can be manually and safely applied by a single individual.

6. The aircraft propulsion system according to claim 1 , wherein

the engine assembly further comprises a v-groove, and the cowl includes a v-blade configured to engage with the v-groove in the closed position, and

the cowl mechanism is configured to guide the cowl along a vertical direction in the movement path from the closed position towards the open position at least until the v-blade is completely clear of the v-groove.

7. The aircraft propulsion system according to claim 1 , wherein

the open position is a position of the cowl in which the portion of the engine assembly is made accessible for performing a maintenance function.

8. The aircraft propulsion system according to claim 7 , wherein

making the engine assembly accessible for performing the maintenance function includes moving the cowl enough to perform at least one of the following without removing the cowl from the aircraft that includes the aircraft propulsion system:

a direct visual inspection of the portion of the engine assembly,

an inspection of the portion of the engine assembly using a non-flexible, straight borescope,

an inspection of the portion of the engine assembly using a flexible borescope,

removal of the portion of the engine assembly from the aircraft, and

removal of an entirety of the engine assembly from the aircraft.

9. The aircraft propulsion system according to claim 8 , wherein

the cowl mechanism is configured to guide the cowl along the movement path so that in the open position, the cowl is rotated by less than 45 degrees away from the closed horizontal position.

10. The aircraft propulsion system according to claim 1 , wherein

the cowl mechanism further includes at least two links that are configured to change their positions with respect to each other while the cowl is moved between the closed position and the open position, and

the cowl mechanism further includes a locking device that when installed is configured to be attached to the at least two links to prevent the at least two links from changing their positions with respect to each other, and when installed, the locking device prevents the cowl from being moved away from the open position.

11. The aircraft propulsion system according to claim 1 , wherein the cowl includes a duct configured to change a movement direction of the air moved by the engine assembly fan.

12. The aircraft propulsion system according to claim 1 , wherein the cowl mechanism is further attached to a pylon of an aircraft.

13. A cowl movement mechanism that connects to at least one cowl configured to surround at least a portion of an engine assembly in a closed position of an aircraft propulsion system, the engine assembly including a fan that rotates to move air, and the at least one cowl including an outer surface arranged away from the engine assembly that provides an aerodynamic surface, the cowl movement mechanism comprising:

a plurality of links configured to guide the at least one cowl along a movement path from the closed position to an open position;

the plurality of links are configured to guide the at least one cowl along the movement path so that an entirety of each cowl in the at least one cowl is moved farther away from a horizontal plane passing through a rotating axis of the fan than in the closed position, wherein

the plurality of links are configured to guide the cowl along the movement path between the open position and the closed position so that no portion of the cowl extends beyond a clearance plane at any position along the movement path,

the cowl movement mechanism is configured to be mounted to a pylon extending away from a fuselage of an aircraft in a horizontal direction, and

the clearance plane extends in a vertical direction through an intersection point that is a point on an outer surface of the cowl in the closed position that is closest to the fuselage.

14. The cowl movement mechanism according to claim 13 , wherein

the movement path is defined by a motion of a point on the outer surface of the cowl,

the movement path includes a straight line during a first portion of the movement path from the closed position to the open position, and

the movement path includes a curved line during a second portion of the movement path from the closed position to the open position, the second portion being further from the closed position than the first portion.

15. The cowl movement mechanism according to claim 13 , wherein

in the open position, the entirety of the cowl is moved away from the horizontal plane by a distance equal to at least an outer radius of an engine core of the engine assembly.

16. The cowl movement mechanism according to claim 13 , wherein

the cowl includes an upper cowl that surrounds an upper portion of the engine assembly, and a lower cowl that surrounds a lower portion of the engine assembly,

in the closed position, the upper cowl and the lower cowl are configured to be latched to each other by at least one latch along the horizontal plane,

the cowl mechanism further includes

an upper cowl mechanism attached to the upper cowl,

a lower cowl mechanism attached to the lower cowl, and

a mid-link connecting the upper cowl to the lower cowl,

the cowl mechanism being further configured to simultaneously move a second one of the upper cowl and the lower cowl along the movement path when a first one of the upper cowl and the lower cowl is caused to move along the movement path by an external force.

17. The cowl movement mechanism according to claim 16 , wherein

the cowl mechanism is configured to counterbalance a weight of the upper cowl and the lower cowl so that the external force required to move the upper cowl and the lower cowl along the movement path is less than a maximum force that can be manually and safely applied by a single individual.

18. The cowl movement mechanism according to claim 13 , wherein

the open position is a position of the cowl in which the portion of the engine assembly is made accessible for performing a maintenance function that includes moving the cowl enough to perform at least one of the following without removing the cowl from an aircraft that includes the cowl movement mechanism:

a direct visual inspection of the portion of the engine assembly,

an inspection of the portion of the engine assembly using a non-flexible, straight borescope,

an inspection of the portion of the engine assembly using a flexible borescope,

removal of the portion of the engine assembly from the aircraft, and

removal of an entirety of the engine assembly from the aircraft.