System, a method and a computer program product for maneuvering of an air vehicle with tiltable propulsion unit

A system comprising:

• a control system configured to control a deceleration process of an air vehicle, which comprises at least one tiltable propulsion unit, each of the at least one tiltable propulsion units is tiltable to provide a thrust whose direction is variable at least between a general vertical thrust vector direction and a general longitudinal thrust vector direction with respect to the air vehicle;
• the air vehicle further comprises a wing configured to provide lift to the air vehicle;
• the wing being in a fixed position during flight of the air vehicle, the control system comprising:
• at least one input for receiving information indicative of monitored airspeed of the air vehicle and of monitored altitude of the air vehicle;
• and
• a control unit, configured to issue controlling commands to controllers of aerodynamic systems of the air vehicle, the aerodynamic systems comprising the at least one tiltable propulsion unit;
• wherein the control unit is configured issue the controlling commands for:
• controlling, during a descent of the air vehicle, a descending course of the air vehicle based on at least monitored airspeed and monitored altitude of the air vehicle, at least by controlling in a first part of the descent, an operation of the at least one tiltable propulsion unit to provide thrust in the general longitudinal thrust vector direction for propelling the air vehicle;
• and following a tilting of the at least one tiltable propulsion unit, controlling in a second part of the descent an operation of the at least one tiltable propulsion unit to provide thrust in the general vertical thrust vector direction for providing lift to the air vehicle;
• and
• controlling a reducing of a groundspeed of the air vehicle substantially to a hover, while the at least one tiltable propulsion unit provides thrust in the general vertical thrust vector direction, at least by controlling thrust power of the at least one tiltable propulsion unit for reducing a difference between measured groundspeed of the air vehicle and set groundspeed, while restricting reduction of the thrust power based on a lower threshold that is determined in response to a measured airspeed of the air vehicle;
• wherein the control unit is configured to issue the controlling commands while balancing between aerodynamic effects resulting from the wing and from the at least one tiltable propulsion unit.

A method for controlling a deceleration process of an air vehicle which comprises at least one tiltable propulsion unit, each of the at least one tiltable propulsion unit is tiltable to provide a thrust whose direction is variable at least between a general vertical thrust vector direction and a general longitudinal thrust vector direction with respect to the air vehicle;

• the air vehicle further comprises a wing configured to provide lift to the air vehicle;
• the wing being in a fixed position during flight of the air vehicle, the method comprising:
• during a descent of the air vehicle, controlling a descending course of the air vehicle based on at least monitored airspeed and monitored altitude of the air vehicle, said controlling comprising carrying out in the following order:
• in a first part of the descent, controlling an operation of the at least one tiltable propulsion unit to provide thrust in the general longitudinal thrust vector direction for propelling the air vehicle;
• and
• following a tilting of the at least one tiltable propulsion unit, controlling in a second part of the descent an operation of the at least one tiltable propulsion unit to provide thrust in the general vertical thrust vector direction for providing lift to the air vehicle;
• and
• controlling a reducing of a groundspeed of the air vehicle substantially to a hover, while the at least one tiltable propulsion unit provides thrust in the general vertical thrust vector direction, at least by:
• controlling thrust power of the at least one tiltable propulsion unit for reducing a difference between measured groundspeed of the air vehicle and set groundspeed, while restricting reduction of the thrust power based on a lower threshold that is determined in response to a measured airspeed of the air vehicle;
• and
• balancing, during the deceleration process, between aerodynamic effects resulting from the wing and from the at least one tiltable propulsion unit.

A program storage device readable by machine, tangibly embodying a computer readable code portion executable by the machine for controlling a deceleration process of an air vehicle which comprises at least one tiltable propulsion unit, each of the at least one tiltable propulsion units is tiltable to provide a thrust whose direction is variable at least between a general vertical thrust vector direction and a general longitudinal thrust vector direction with respect to the air vehicle;

• the air vehicle further comprises a wing configured to provide lift to the air vehicle;
• the wing being in a fixed position during flight of the air vehicle, the computer readable code portion comprising instructions for balancing, during the deceleration process, between aerodynamic effects resulting from the wing and from the at least one tiltable propulsion unit, the instruction comprising:
• during a descent of the air vehicle, controlling a descending course of the air vehicle based on at least monitored airspeed and monitored altitude of the air vehicle, said controlling comprising carrying out in the following order:
• in a first part of the descent, controlling an operation of the at least one tiltable propulsion unit to provide thrust in the general longitudinal thrust vector direction for propelling the air vehicle;
• and
• following a tilting of the at least one tiltable propulsion unit, controlling in a second part of the descent an operation of the at least one tiltable propulsion unit to provide thrust in the general vertical thrust vector direction for providing lift to the air vehicle;
• and
• controlling a reducing of a groundspeed of the air vehicle substantially to a hover, while the at least one tiltable propulsion unit provides thrust in the general vertical thrust vector direction, at least by:
• controlling thrust power of the at least one tiltable propulsion unit for reducing a difference between measured groundspeed of the air vehicle and set groundspeed, while restricting reduction of the thrust power based on a lower threshold that is determined in response to a measured airspeed of the air vehicle.