System and method for oeprating air vehicle

A method for transitioning an air vehicle from a forward speed mode to a hover mode via a transition mode, the method comprising:

• (a) providing the air vehicle, wherein the air vehicle is a VTOL-type fixed wing air vehicle, comprising a first propulsion system, a second propulsion system and a fixed wing arrangement, wherein:
• said first propulsion system is configured for providing a first thrust to the air vehicle at a first thrust vector, the first thrust being sufficient for enabling powered aerodynamic flight to the air vehicle at least in said forward speed mode;
• said second propulsion system is configured for providing a second thrust to the air vehicle at a second thrust vector, the second thrust being at least sufficient for enabling vectored thrust flight to the air vehicle at least in said hover mode, wherein said second thrust vector is spatially fixed with respect to the air vehicle at a first fixed spatial position that is unchanged at least during said transitioning;
• and
• said fixed wing arrangement comprises high lift, mild stall wings;
• (b) causing the air vehicle to follow a transient path in said transition mode from said forward speed mode to said hover mode, wherein said transient path comprises manipulating a first magnitude of angle of attack of the air vehicle and a second magnitude of forward speed of the air vehicle during said transitioning to provide a corresponding aerodynamic lift component, and concurrently manipulating a third magnitude of said second thrust during said transitioning to provide a vertical vectored thrust component corresponding to said first magnitude of angle of attack, such that a summation of said aerodynamic lift component and said vertical vectored thrust component is sufficient for enabling the air vehicle to remain in controlled flight in said transition mode between conditions corresponding to said forward speed mode wherein said vertical vectored thrust component is zero, and conditions corresponding to said hover mode wherein said aerodynamic lift component is zero, and
• wherein a stall plateau of the high lift, mild stall wings enables said step of manipulating the first magnitude of angle of attack of the air vehicle and the second magnitude of forward speed of the air vehicle to provide said first magnitude of angle of attack corresponding to a high angle of attack, thereby enabling the spatially fixed second thrust vector to provide an aft braking force during said transition mode.

A method for transitioning an air vehicle between a forward speed mode and a hover mode via a transition mode, the method comprising:

• (a) providing the air vehicle, wherein the air vehicle is a VTOL-type fixed wing air vehicle, comprising a first propulsion system, a second propulsion system and a fixed wing arrangement, wherein:
• said first propulsion system is configured for providing a first thrust to the air vehicle at a first thrust vector, the first thrust being sufficient for enabling powered aerodynamic flight to the air vehicle at least in said forward speed mode;
• said second propulsion system is configured for providing a second thrust to the air vehicle at a second thrust vector, the second thrust being at least sufficient for enabling vectored thrust flight to the air vehicle at least in said hover mode, wherein said second thrust vector is spatially fixed with respect to the air vehicle at a first fixed spatial position that is unchanged at least during said transitioning;
• and
• said fixed wing arrangement comprises high lift, mild stall wings;
• (b) causing the air vehicle to follow a transient path in said transition mode between said forward speed mode and said hover mode, wherein said transient path comprises manipulating a first magnitude of angle of attack of the air vehicle and a second magnitude of forward speed of the air vehicle during said transitioning to provide a corresponding aerodynamic lift component, and concurrently manipulating a third magnitude of said second thrust during said transitioning to provide a vertical vectored thrust component corresponding to said first magnitude of angle of attack, such that a summation of said aerodynamic lift component and said vertical vectored thrust component is sufficient for enabling the air vehicle to remain in controlled flight in said transition mode between conditions corresponding to said forward speed mode wherein said vertical vectored thrust component is zero, and conditions corresponding to said hover mode wherein said aerodynamic lift component is zero.