The Boeing Company

Stephen L Wells

Seiya Sakurai

Clayton A Prow

Mithra M K V Sankrithi

Stephen John Fox

Monte R Evans

Douglas S Lacy

Kevin W Beyer

David Paul Eggold

Paul T Meredith

Wendi M DeWitt

Steven S Ogg

Neal Van Huynh

Paul M Vijgen

Jack S Noble

C Byram Bays-Muchmore

Edward W Gronenthal

Bernard P Paul, Jr

Michael F Fitzpatrick

Kenneth D Visser

Louis L LeGrand

Michael S Hoffman

Larry L Herrick

Paul L Johnson

Russell R Christianson

A method and apparatus for controlling airflow with a gapped trailing edge device having a flexible flow surface. The airfoil can include a first portion having a first leading edge, a first flow surface, and a second flow surface facing opposite from the first flow surface. The airfoil can further include a second portion having a second leading edge and a trailing edge, with at least part of the second portion being positioned aft of the first portion. The second portion is moveable relative to the first portion between a first position and a second position, with the second leading edge separated from at least part of the first portion by an airflow gap when the second portion is in the second position. The second portion includes a flexible flow surface that has a first shape when the second portion is in the first position, and has a second shape different than the first shape when the second portion is in the second position.

Method and apparatus for controlling airflow with a gapped trailing edge device having a flexible flow surface

Trailing edge devices configured to carry out multiple functions, and associated methods of use and manufacture are disclosed. An external fluid flow body (e.g., an airfoil) configured in accordance with an embodiment of the invention includes a first portion and a second portion, at least a part of the second portion being positioned aft of the first portion, with the second portion being movable relative to the first portion between a neutral position, a plurality of upward positions, and a plurality of downward positions. A guide structure can be coupled between the first and second portions, and an actuator can be operatively coupled between the first and second portions to move the second portion relative to the first portion. In one embodiment, a flexible surface can track the motion of the second portion and can expose a gap at some positions. In another embodiment, a controller can be coupled to the actuator and can be configured to direct the actuator to move the second portion to a high lift setting, a high drag setting, a roll setting, and a trim setting. In yet another embodiment, trailing edge devices on an airfoil can have scaled, mechanically similar guide structures.

Multi-function trailing edge devices and associated methods

An aircraft flight control system is provided for reducing the likelihood of an aircraft tailstrike. The flight control system includes a pitch command provided to a pitch control device for altering the aircraft's pitch attitude. The improvement is a system of altering the pitch command to avoid an aircraft tailstrike. The improvement includes determining a current tailskid closure rate and a current tail height; comparing the current tailskid closure rate with a threshold closure rate to determine an excess closure rate amount; and adding an incremental nose-down pitch command with the pitch command to avoid a potential aircraft tailstrike. The threshold closure rate is dependent upon the current tailskid height. The incremental nose-down pitch command is calculated as a function of the excess closure rate amount. An alternative embodiment is provided in which the current height is compared with a threshold height (that is a function of the current tailskid closure rate) to determine an excess height amount. The excess height is then used to form an incremental nose-down pitch command. Another embodiment is described using both height and rate thresholds to calculate the incremental nose-down pitch command. Alternative arrangements may be used in which other non-derivative and derivative values are used, e.g., pitch angle margin and pitch rate.

Aircraft tailstrike avoidance system

An airfoil assembly, such as a wing or horizontal stabilizer, has a gapped trailing-edge control surface and a door connected to the control surface by a linkage such that deflection of the control surface in one direction causes the door to pivot, thus opening an air flow slot for air to flow through. The air flow slot begins to open immediately with deflection of the control surface from its nominal position, thus establishing a desirable level of air flow to suppress separation on the control surface. The linkage connecting the control surface to the door is free of rolling or sliding elements, consisting exclusively of members pivotally connected to one another.

Gapped trailing-edge control surface for an airfoil

An improvement to an aircraft flight control system is provided for reducing the likelihood of an aircraft tailstrike. The flight control system includes a pitch command provided to a pitch control device for altering the aircraft's pitch attitude. The improvement is a system of altering the pitch command to avoid an aircraft tailstrike. The improvement includes determining a current tailskid closure rate and a current tail height; comparing the current tailskid closure rate with a threshold closure rate to determine an excess closure rate amount; and adding an incremental nose-down pitch command with the pitch command to avoid a potential aircraft tailstrike. The threshold closure rate is dependent upon the current tailskid height. The incremental nose-down pitch command is calculated as a function of the excess closure rate amount. An alternative embodiment is provided in which the current height is compared with a threshold height (that is a function of the current tailskid closure rate) to determine an excess height amount. The excess height is then used to form an incremental nose-down pitch command. Another embodiment is described using both height and rate thresholds to calculate the incremental nose-down pitch command. Alternative arrangements may be used in which other non-derivative and derivative values are used, e.g., pitch angle margin and pitch rate.

An airplane having a fuselage (11), opposed main wings (12), and blunt-leading-edge raked wingtips (8) is provided. Each main wing includes an outboard end (9) and a leading edge (14) having an outboard end leading-edge nose and nose radius. One blunt raked wingtip (8) is located at each main wing outboard end (9) and includes a leading edge (20) swept back from the main wing leading edge (14). Each blunt raked wingtip (8) further includes a plurality of local airfoils each having a leading-edge nose radius and a chord. The nose radius is greater than about 2% of the local chord for the majority of the airfoils. The relative bluntness of the raked wingtips minimizes boundary-layer separation, drag associated with boundary-layer separation, and premature buffeting of the aircraft during low speed flight.

Blunt-leading-edge raked wingtips

Growing community of inventors

Bothell, WA, United States of America

Stephen L Wells