A method of producing a pulsatile jet flow from a substantially constant flow primary jet in a way that is mechanically efficient, easy to implement, and allows direct control over pulse duration and pulsing frequency is disclosed herein. The invention includes at least two components: (a) a constant flow fluid jet produced by any normal method (e.g., propeller) that can be directionally vectored fluidically, mechanically, or electromagnetically and (b) a nozzle with multiple outlets (orifices) through which the vectored jet may be directed. By alternately vectoring the jet through different outlets, a transient (pulsatile) flow at an outlet is obtained even with a substantially constant primary jet flow. Additionally, the nozzle outlets may be oriented in different directions to provide thrust vectoring, making the invention useful for maneuvering, directional control, etc.

A thrust reverser drive arrangement is described for use in driving a thrust reverser cowl for movement relative to first and second guide tracks, the drive arrangement comprising a first actuator located, in use, close to the first guide track, and a second actuator located, in use, close to the second guide track, the actuators being arranged to be driven in synchronism and at the same speed by a drive motor to drive the cowl for movement, wherein at least one of the first and second actuators is provided with a load limiter to limit the transmission of loads through that actuator in the event that that actuator is subject to a compressive loading greater than a predetermined level.

Provided are flight control mechanisms, such as omnidirectional thrust mechanisms (OTMs), and methods of using such mechanisms. These mechanisms may be positioned in wings, tails, or other components of aircraft. A mechanism may comprise a center member and top and bottom panels. The center member may comprise two curved segments joint at a center edge. The top and bottom panels may be independently pivotable relative to the center member. At high speeds, the top panel and/or the bottom panel may be pivoted outward to change the lift, drag, roll, and/or other flight conditions. The mechanism may also include a gas nozzle to direct compressed gas to the center member. The center member and/or the top and bottom panels redirect this gas resulting in forces in one of four directions, which are used for controlling the aircraft at low speeds, down to hover.

Provided are flight control mechanisms, such as omnidirectional thrust mechanisms (OTMs), and methods of using such mechanisms. These mechanisms may be positioned in wings, tails, or other components of aircraft. A mechanism may comprise a center member and top and bottom panels. The center member may comprise two curved segments joint at a center edge. The top and bottom panels may be independently pivotable relative to the center member. At high speeds, the top panel and/or the bottom panel may be pivoted outward to change the lift, drag, roll, and/or other flight conditions. The mechanism may also include a gas nozzle to direct compressed gas to the center member. The center member and/or the top and bottom panels redirect this gas resulting in forces in one of four directions, which are used for controlling the aircraft at low speeds, down to hover.

A method of producing a pulsatile jet flow from a substantially constant flow primary jet in a way that is mechanically efficient, easy to implement, and allows direct control over pulse duration and pulsing frequency is disclosed herein. The invention includes at least two components: (a) a constant flow fluid jet produced by any normal method (e.g., propeller) that can be directionally vectored fluidically, mechanically, or electromagnetically and (b) a nozzle with multiple outlets (orifices) through which the vectored jet may be directed. By alternately vectoring the jet through different outlets, a transient (pulsatile) flow at an outlet is obtained even with a substantially constant primary jet flow. Additionally, the nozzle outlets may be oriented in different directions to provide thrust vectoring, making the invention useful for maneuvering, directional control, etc.

A gas turbine engine for an aircraft includes an engine core including a turbine, a compressor, a core shaft, and a core exhaust nozzle, the core exhaust nozzle having a core exhaust nozzle pressure ratio calculated using total pressure at the core nozzle exit; a fan including a plurality of fan blades; and a nacelle surrounding the fan and the engine core and defining a bypass duct, the bypass duct including a bypass exhaust nozzle, the bypass exhaust nozzle having a bypass exhaust nozzle pressure ratio calculated using total pressure at the bypass nozzle exit;

wherein a bypass to core ratio of:

[00001]$\frac{\mathrm{bypass}.Math..Math.\mathrm{exhaust}.Math..Math.\mathrm{nozzle}.Math..Math.\mathrm{pressure}.Math..Math.\mathrm{ratio}}{\mathrm{core}.Math..Math.\mathrm{exhaust}.Math..Math.\mathrm{nozzle}.Math..Math.\mathrm{pressure}.Math..Math.\mathrm{ratio}}$

is configured to be in the range from 1.1 to 2.0 under aircraft cruise conditions.

A thrust vectoring exhaust nozzle is disclosed. The nozzle includes an inner nozzle for changing a first degree-of-freedom of exhaust gas, an outer nozzle for changing a second degree-of-freedom of exhaust gas, a mounting bracket, a first linear actuator, a second linear actuator, a first double universal joint, and a second double universal joint. The inner nozzle is coupled to the outer nozzle. The inner nozzle is coupled to the mounting bracket. The outer nozzle is coupled to the first and second joint. When the nozzle is mounted, the inner nozzle, the outer nozzle, and the exhaust are coaxially aligned in neutral position. Actuation of the first and second linear actuators drives the first and second double universal joints independently to each other. The independent motion of the first and second double universal joints rotates the inner and outer nozzles simultaneously about the exhaust in a horizontal direction and vertical direction enabling thrust vectoring.

The present disclosure relates to optimisation of a cold nozzle, or bypass exit area, for a gas turbine engine, in particular for a geared turbofan gas turbine engine. Example embodiments include a method of optimising a geared turbofan gas turbine engine for an aircraft, the method comprising: determining expected service parameters for the aircraft, the expected service parameters including an expected range of travel for the aircraft; selecting components for the geared turbofan gas turbine engine to define a first smaller cold nozzle area if the range of travel is within a first smaller range and to define a second larger cold nozzle area if the range of travel is within a second larger range.

Provided are flight control mechanisms, such as omnidirectional thrust mechanisms (OTMs), and methods of using such mechanisms. These mechanisms may be positioned in wings, tails, or other components of aircraft. A mechanism may comprise a center member and top and bottom panels. The center member may comprise two curved segments joint at a center edge. The top and bottom panels may be independently pivotable relative to the center member. At high speeds, the top panel and/or the bottom panel may be pivoted outward to change the lift, drag, roll, and/or other flight conditions. The mechanism may also include a gas nozzle to direct compressed gas to the center member. The center member and/or the top and bottom panels redirect this gas resulting in forces in one of four directions, which are used for controlling the aircraft at low speeds, down to hover.

Provided are flight control mechanisms, such as omnidirectional thrust mechanisms (OTMs), and methods of using such mechanisms. These mechanisms may be positioned in wings, tails, or other components of aircraft. A mechanism may comprise a center member and top and bottom panels. The center member may comprise two curved segments joint at a center edge. The top and bottom panels may be independently pivotable relative to the center member. At high speeds, the top panel and/or the bottom panel may be pivoted outward to change the lift, drag, roll, and/or other flight conditions. The mechanism may also include a gas nozzle to direct compressed gas to the center member. The center member and/or the top and bottom panels redirect this gas resulting in forces in one of four directions, which are used for controlling the aircraft at low speeds, down to hover.