Yaw control device for a nozzle having a rectangular outlet section
The invention relates to a yaw control device for an aircraft fitted with a supersonic nozzle having a rectangular or flat section comprising a supersonic throat extended by a diverging portion in which supersonic flow occurs. In order to enable the aircraft to be controlled in yaw in the absence of a vertical fin, the device of the invention makes use of jet control surfaces in the form of airfoils disposed in the diverging portion of the nozzle. The control surfaces are movable about respective pivot axes in order to generate a lateral force when in a deflected position, so as to enable the aircraft to turn about its yaw axis.
1. A yaw control device for an aircraft fitted with a supersonic nozzle of rectangular cross section, said nozzle having a stationary supersonic throat extended by a diverging portion, the supersonic throat having an outlet downstream of which supersonic flow occurs, said device comprising at least one jet control surface in the form of an airfoil disposed fully within the diverging portion of the nozzle to be completely in said supersonic flow, said at least one jet control surface being disposed vertically so as to be movable about a vertical axis of rotation, to generate a lateral force when in a deflected position, thereby enabling the aircraft to turn about its yaw axis,
the device further comprising a stationary element disposed upstream from at least one jet control surface in the nozzle, said stationary element presenting an aerodynamic leading edge in order to protect the control surface from the supersonic flow in the nozzle.
2. A device according to claim 1 , wherein the stationary element is disposed upstream of the at least one jet control surface, wherein some portion of said stationary element is disposed in the supersonic throat and in a region of sonic or subsonic flow.
3. A device according to claim 1 , wherein the at least one jet control surface comprises a plurality of jet control surfaces, each of said control surfaces being connected to a single control lever enabling said jet control surfaces to be deflected simultaneously.
4. A supersonic nozzle of rectangular or flat section, including at least one yaw control device according to claim 1 .
5. An aircraft without a vertical fin, including a nozzle according to claim 4 .
6. A method of providing yaw control for an aircraft fitted with a supersonic nozzle of rectangular cross section, said nozzle having a stationary supersonic throat extended by a diverging portion in which supersonic flow occurs, the supersonic throat having an outlet, said method comprising:
disposing at least one jet control surface in the form of an airfoil fully in the diverging portion of the nozzle vertically completely within said supersonic flow, so as to be movable, about a vertical axis of rotation;
generating lateral force by moving at least one jet surface into a deflected position, thereby enabling the aircraft to turn about its yaw axis; and
disposing a stationary element having an aerodynamic leading edge upstream from jet control surface in the nozzle, said at least one leading edge being structured and arranged to protect the control surface from the supersonic flow in the nozzle.
7. A method according to claim 6 , further comprising:
disposing the stationary element upstream of the at least one jet control surface, wherein some portion of said stationary element is disposed in the supersonic throat and in a region of sonic or subsonic flow.
8. A method according to claim 6 , wherein disposing the at least one jet control surface comprises disposing a plurality of jet control surfaces inside the diverging portion, and wherein the control surfaces are connected to a single control lever for causing them to be deflected simultaneously.
9. A method according to claim 6 , wherein disposing the at least one jet control surface comprises disposing a predetermined the number of jet control surfaces inside the diverging portion.