Textron Innovations Inc.

Bell Helicopter Textron Inc.

Ronald Lorenz Kisor

Albert Gerard Brand

Robert L Fortenbaugh

Robert Blyth

Jose Manuel Rodriguez

A system and method for protecting a rotorcraft from entering a vortex ring state, the method including monitoring a vertical speed of a rotorcraft, comparing the vertical speed to a vertical speed safety threshold, and performing vortex ring state (VRS) avoidance in response to the vertical speed exceeding the vertical speed safety threshold. The performing the VRS avoidance includes determining a power margin available from one or more engines of the rotorcraft, limiting the vertical speed of the rotorcraft in response to the power margin exceeding a threshold, and increasing a forward airspeed of the rotorcraft in response to the power margin not exceeding the threshold.

System and method for protection against vortex ring state

A control system having a first loop configured to provide a longitudinal blowback value of a rotor blade during flight and a second loop associated with the first loop, the second loop being configured to provide a design maximum total flapping value and a lateral flapping value. A method includes calculating a flight control limit from the design maximum total flapping value and the lateral flapping value. An upper longitudinal cyclic control limit is calculated by adding the flight control limit to the longitudinal blowback value. A lower longitudinal cyclic control limit is calculated by subtracting the flight control limit from the longitudinal blowback value.

System and method for limiting cyclic control inputs

A flight control system for a rotorcraft to prevent the adverse effects of the vortex ring state is disclosed. In the flight control system of the present invention, selected control inputs are sent the rotorcraft prior to the onset of the vortex ring state. In the preferred embodiment, the control inputs are transient, do not require input from the pilot, and do not affect the flight path of the rotorcraft.

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Coppell, TX, United States of America

Ronald Lorenz Kisor